eChapters

16.1 INTRODUCTION

Mulch, a technical term, means ‘covering of soil’. A mulch is a layer of material applied to the surface of soil. It may be applied to bare soil or around existing plants. Mulches of manure or compost will be incorporated naturally into the soil by the activity of worms and other organisms. Mulching is the process or practice of covering the soil/ground to make more favourable conditions for plant growth, development and efficient crop production. While natural mulches such as leaf, straw, dead leaves and compost have been used for centuries, during the last 60 years the advent of synthetic materials has altered the methods and benefits of mulching. The research as well as field data available on effect of synthetic mulches make a vast volume of useful literature. In this manner it plays a positive role in water conservation. The suppression of evaporation also has a supplementary effect; it prevents the rise of water containing salt, which is important in countries with high salt content water resources.

17.1 INTRODUCTION

Bearing habit indicates position of f lower bud with respect to vegetative growth of the plant after cessation of juvenility. Different fruit trees have different bearing habits. The knowledge of bearing habits will be of much importance for regulating the bearing of any plant by means of pruning. Terminal bearers are not normally pruned, whereas in case of lateral bearers pruning certainly increase the bearing, as it encourages the sprouting of lateral buds. Fruit trees may bear the fruits either terminally on a long or short growth, laterally on present or past season growth or adventitiously from any point on the trunk or root. The relative position of a fruit with reference to its potential bud giving rise to f lower or inf lorescence in the shoot is known as bearing habit. Knowledge on the bearing habit is a pre-requirement before performing pruning in any fruit crop (particularly in ber, guava, grape etc.). Proper understanding of bearing habits helps a lot in manipulating time and period of f lowering and fruiting which consequently inf luence harvesting and yield of better-quality fruits.

18.1 INTRODUCTION

The decline in productivity of old and senile orchards existing in abundance has become a matter of serious concern for the orchardists, traders as well as scientists. In India 30-35% area under fruit crops is occupied by old, senile, and pest-and-disease- affected orchards. For overcoming the problem of unproductive and uneconomic orchards existing in abundance, large scale uprooting and replacement with new plantations will be a long term and expensive strategy. Thus, rejuvenation of old and senile orchards is a good alternative.

19.1 DEFINITION OF ORGANIC FARMING

1.According to IFOAM (International Federation of Organic Agriculture Movement), Organic Farming definition includes all agricultural system that promote the environmentally, socially and ecologically sound production system of food and fibres. IFOAM stresses and supports the development of self- supporting system on local and regional level.

2.As per the definition of the USDA study team on organic farming “organic farming is a system which avoids or largely excludes the use of synthetic inputs (such as fertilizers, pesticides, hormones, feed additives etc) and to the maximum extent feasible rely upon crop rotations, crop residues, animal manures, off-farm organic waste, mineral grade rock additives and biological system of nutrient mobilization and plant protection”.

3.In another definition FAO suggested that “Organic agriculture is a unique production management system which promotes and enhances agro-ecosystem health, including biodiversity, biological cycles and soil biological activity, and this is accomplished by using on-farm agronomic, biological and mechanical methods in exclusion of all synthetic off-farm inputs”.

1.1 General

Renewable technologies are considered to be clean sources of energy. The optimal use of these resources minimize environmental impacts, produce minimum secondary wastes, and are sustainable based on current and future economic and social needs. Sustainable development requires methods and tools to measure and compare human activities’ and its environmental impacts for various products. Renewable energy sources (RES), which include biomass, hydropower, geothermal, solar, wind, and marine energies, supply 14% of the world’s total energy demand. Renewable resources refer to primary, domestic, and clean or inexhaustible energy resources. Large-scale hydropower energy supplies 20 % of the global electricity need. Wind power in coastal and other windy regions is a promising source of energy.

Renewable energy resources can make a decisive contribution to the economic, social and sustainable development of rural regions in developing countries, yet the consumption of fossil fuels is dramatically increasing along with improvements in the quality of life, the industrialization of developing nations, and the increase of the world’s population. It has long been recognized that excessive consumption of fossil fuel leads not only to a diminishing fossil fuel reserves more quickly, but also has a significant adverse impact on the environment. Such impacts result in increased health risks and the threat of global climate change. Changes to improve environmental conditions are becoming more politically acceptable globally, especially in developed countries. Society is slowly moving towards seeking more sustainable production methods, minimizing waste, reducing air pollution from vehicles, generating distributed energy, conserving of native forests, and reducing greenhouse gas emissions. Increasing consumption of fossil fuel to meet out current energy demands, however, has sounded alarms over regarding potential energy crisis. This has generated a resurgence of interest in promoting renewable alternatives to meet the developing world’s growing energy needs. Excessive use of fossil fuels has caused global warming from carbon dioxide emissions, therefore, promoting renewable forms of clean energy is eagerly required. To monitor the level of these greenhouse gas emissions, an agreement that has fulfills the objectives of the Kyoto Protocol was create with overall pollution prevention targets.

2.1 Introduction

The name thermodynamics stems from the Greek words therme (heat) and dynamis (power), which is most descriptive of the early efforts to convert heat into power. It may be defined as the science that deals with the relations among heat, work and properties of a system. Today, thermodynamics is broadly interpreted to include all aspects of energy and energy transformations, including power generation, refrigeration, and relationships among the properties of matter. It is viewed as the science of energy, and thermal engineering is concerned with making the best use of available energy resources.

Thermodynamics basically entails four laws or axioms known as Zeroth, First, Second and Third law of thermodynamics.

The zeroth law deals with thermal equilibrium and establishes a concept of temperature.

The first law pertains to the conservation of energy and introduces the concept of internal energy.

The second law indicates the limit of converting heat into work and introduces the concept of entropy.

The third law defines the absolute zero of entropy.

The concept of energy was introduced by Newton in the field of mechanics during generalizing the hypothesis of kinetic and potential energies. Energy may be defined as the capacity to do work and it is a scalar quantity. It cannot be seen or observed. Its presence can, however, be felt by the properties of the system. There occurs a change in one or more properties of the system in case of energy transfer. The absolute value of energy of a system is difficult to measure, whereas the energy change is rather easy to calculate. Energy follows the conservation law, one of the most fundamental laws of nature, which simply states that during an interaction, energy can change its form from one form to another but the total amount of energy remains constant, that is, energy cannot be created or destroyed only form can be changed.

3.1 The Sun

The Sun is a star. It is a huge, spinning, glowing sphere of hot gas. It appears so much larger and brighter than the other stars because we are so close to it. The Sun is the center of our Solar System and contains most of the mass in the Solar System. All of the planets in our Solar System, including Earth, orbit around the Sun. In sun the energy generation is a multi-step process of thermo-nuclear fusion reactions. In the thermo nuclear fusion hydrogen (four protons) combines to form helium (one helium nucleus). The mass of the helium nucleus is less than that of four hydrogen protons and mass having been lost in the reaction is converted to energy. The reaction is represented as

4.1 Introduction

Heat is energy which flows due to difference in temperature. Whereas energy is stored heat. Therefore, when the heat energy transfer is completed. It is stored in the form of potential or kinetic energy, in general as internal energy. Heat as energy is measured in terms of observed changes in other forms of energy & other physical properties. A heat transfer analysis is required for estimating the size, the efficiency and cost of the equipment necessary to transfer a specified amount of heat in a given time. It is well known fact that the size of a solar collector or a heat exchanger depends not so much on the amount of heat to be transmitted but rather on the rate at which heat is to be transferred under given conditions.

4.2 Modes of Heat Transfer

Heat is transferred from one body to another in three possible ways, conduction, convection, and radiation.

5.1 Introduction

Energy in the form of heat is one of the main energy requirements in domestic, agricultural, industrial and commercial sector of our economy. From an enduse point of view, solar thermal energy finds its application in these areas. Solar thermal energy devices convert radiant energy of the sun into thermal energy for different productive works. In fact, solar energy consists of infrared radiation, it is characteristics of infrared radiation that whenever it falls on any object, it converts into thermal heat energy.

The conversion of sun light into thermal energy is easily or conveniently achieved by means of a metallic or plastic cover, painted black with ordinary black board paint or having selected coating over it and covered with one- or double-glazing cover for transmitting solar radiation inside it. This metallic cover is known as absorber, below it either channels or pipes or passages for allowing entry of water or air are provided, through which heat energy is transferred to working medium either air or water. The absorber plate is covered with suitable thickness of insulating material on its back or sides for preventing loss of heat from the absorber plate. This complete system is enclosed in an airtight box. When exposed to solar radiations, the blackened metallic surface absorbs solar energy and converts into heat. This heat could be used for cooking of food, heating of water and air, evaporation of moisture form the grains etc. In fact, absorber works on the principle of black body, which absorbs maximum and a good absorber, is a good emitter. Hence generated heat could be utilized for different applications.

6.1. Introduction

Solar crop drying has been demonstrated to be cost effective and an effective alternative to traditional and mechanical drying systems, especially in location with god sunshine during the harvest season. Considerable energy savings can be made with open sun drying since the source of energy is free and sustainable. However, this method of drying is extremely weather dependent and has the problems of contamination, infestation, microbial attacks, etc., thus affecting the product quality. Additionally, the drying time required for a given commodity can be quite long and results in post-harvest losses. Solar drying of agricultural products in enclosed structures by natural convection is an attractive way of reducing post harvest losses and low quality of dried products associated with traditional sun-drying methods. The crop is vulnerable to damage due to hostile weather conditions. The crop is also susceptible to re-absorption of moisture, if it is kept on the ground during periods of no sun, which reduces its quality. This type of problem can be solved by solar dryer. Many dryers have been developed and used to dry agricultural product in order to improve shelf life .Most of these either use expensive sources of energy such as electricity or combination of solar energy and some other form of energy which is not cost effective and dependent on regular supply of fuel.

Principally, drying requires temperature for removing moisture from product, air flow rate to remove moisture from drying chamber and optimum relative humidity within the drying chamber to allow fast drying. These all three requirements for drying can easily be achieved from solar energy. Solar drying is one of the direct applications of solar heat, which involves removal of moisture from the products through the application of solar energy. The removal of moisture requires only low temperature heating, which can be met easily by absorbing solar energy by the surface. This increases the temperature of the air inside the dryer. The moisture produced from the drying product is usually carried out along with the exhaust air. The characteristic of solar energy is good for the drying at low temperature i.e. high flow rates with low temperature rise. The intermittent nature of solar radiation can not affect the drying performance at low temperature. Further, solar energy is available at the site of use and saves transportation cost.

7.1 Introduction

A greenhouse is quasi-permanent structure, covered with a transparent or translucent material, ranging from simple homemade designs to sophisticated pre-g\fabricated structures, wherein the environment could be modified suitable for propagation or growing of plants. Materials used to construct a greenhouse frame may be wood, bamboo and steel or even aluminum. Covering can be glass or various rigid or flexible plastic materials. Depending on the covering material, different terminology have been used in the context of greenhouse structures as mentioned below:

Glasshouse: A greenhouse with glass as the covering material is called glasshouse

Polyhouse: It is a greenhouse with polyethylene as the covering material.

8.1 Introduction

Solar energy can be directly converted into electrical energy. Energy conversion devices which are used to convert sun light into electricity by use of the photovoltaic effect are called solar cells. The advantages of solar cells are:

1.They are reliable, convenient and durable.

2.It is green, sustainable and pollution free technology.

3.Directly solar radiation can be converted into electricity (conversion of global solar light by flat plate photovoltaic).

4.Maintenance cost is quite low therefore suitable even in isolated and remote area, since no moving parts are involved.

5.Solar cells are quite compatible with almost all environments, respond instantaneously with solar radiation.

6.Considerable expected lifetime i.e. 20 years or even more.

9.1 Introduction

Basically, for heating or cooling the space using solar energy, the solar energy is to be collected, stored and distributed properly in the space to be heated or removed from the space to be cooled. There are two basic approaches for solar houses, there are:

(a)Active solar house technology

(b)Passive solar house technology

In active approach, the solar energy is collected and stored in some separate solar energy collector and then energy is distributed in the space where heating is to be done using electrically operated pumps and fans coupled with radiator etc. The storage of solar energy in active solar house may be in the form of storage as sensible heat or storage as latent heat or chemical heat storage. As per requirement of heating the size of solar collector and storage system be decided. Generally, the active concepts of solar houses are used for heating purpose. Active concept can also be used for space cooling applications. Solar vapor compression and absorption system can be used for this purpose, essentially, this includes incorporation of solar heat collectors, thermal storage system, auxiliary heat supply system (to compensate intermittent nature of sun energy) and control systems. Further, there are three ways of solar space heating i.e. solar air systems, solar liquid systems and solar heat pump systems.

10.1 Introduction

Winds are the motion of air around the Earth. This movement in air is caused by the uneven heating of the planet’s surface by the sun. The idea of using wind as a form of power is not new. The traditional applications of wind were primarily as sources of kinetic energy for rural, agricultural and a limited number of industrial uses such as pumping water and grinding grain.

Presently wind energy can be used for two major applications, such as wind mills for pumping water for drinking as well as for irrigation purposes and second application is as aero-generator for electricity generation for domestic and industrial uses. In addition to this, presently wind energy battery charger are also available, which can store energy for lights, radio communication, hospital equipment and to power various emergencyrelated equipment.

The wind energy has an enormous resource, but the problems of utilizing the winds are many and varied. Wind energy is very diffuse in nature and local topographical features significantly alter the prevailing winds, thus leading to the extremely site specific nature of wind energy.

Scientists have estimated that as much as 10% of the world’s electricity could be prepared by wind generators by the middle of 21 century. India has estimated wind power potential of 40,000 MW. India now, ranks fourth in the world in wind power generation.

The world’s largest wind farms are in California (USA), where wind turbines can generate power up to about 1120 MW. The first wind mill used as source of electric power was built in Denmark in 1890.

11.1 General

Biogas is generated through a process of anaerobic digestion of organic materials. The materials normally used are human and animal waste, crop residues, agro-industrial waste and other biomass in a combination with water. Biogas production technology contributes in following ways:

(a)It provides a better and cheaper fuel for cooking, lighting and for power generation.

(b)It produces good quality, enriched manure to improve soil fertility.

(c)It provides and effective and convenient ways for sanitary disposal of human excreta, improving the hygienic conditions.

(d)It generates social benefits such as reducing burden on forest for meeting cooking fuel by cutting of tree for fuelwood, reduction in the drudgery of women and children etc.

(e)As a smokeless domestic fuel, it reduces the incidence of eye and lung disease.

(f)It also helps in generation of productive employment.

The biogas technology is primarily based on fermentation of cellulosic rich organic matter under anaerobic conditions. The methane producing bacteria become more active after the creation of anaerobic conditions, thus, the gas produced become rich in methane & carbon dioxide, beside traces of hydrogen sulphide, ammonia, oxygen, water vapour etc. depending on the feed material and other conditions. For burning of gas, it is necessary that methane contents should be more than 50 per cent. The complete knowledge of process of methane production including its chemistry, physiology, bio-chemistry, micro-biology and bacteriology has been studied over years in many parts of the world. The culture and isolation of microbes under various environmental conditions have been successfully experimented to improve rate of reaction. The conditions, under which cattle dung, organic wastes, bushes, weeds etc. will produce methane, can be understood through chemistry of fermentation.

12.1 General

The term “biomass” generally refers to renewable organic matter generated by plants through photosynthesis. Materials having organic combustible matter is also referred under biomass. Biomass is an important fuel source in our overall energy scenario. Biomass is produced through chemical storage of solar energy in plants and other organic matter as a result of photosynthesis. During this process conversion of solar energy in sugar and starch, which are energy rich compounds takes place. The chemical reaction of photosynthesis can be written as:

6CO₂ + 6H₂ O + sun light → C₆ H₁₂ O₆ + 6O₂ + 636_kcal

It indicates that the storage of 636 kcal is associated with the transfer of 72 gm carbon into organic matter. Biomass can be directly utilized as fuel or can be converted through different routes into useful forms of fuel. In fact, biomass is a source of five useful agents, which start with `F’ like Food, Fodder, Fuel, Fiber and Fertilizer. Further, biomass has many advantages like.

13.1 Introduction

Geothermal energy is the nature-based heat generated from within the earth. Underneath the earth’s relatively thin crust, temperature range from 1000 to 4000°C & in some areas, pressures exceed 138 MPa is available. Geothermal energy is most likely generated from radioactive thorium, potassium and uranium dispersed evenly throughout the earth’s interior which produce heat as part of the decaying process. This process generates enough heating, keep the core of the earth at temperature approaching 400°C. Composed primarily of molten nickel & iron, the core is thought to be surrounded by a layer of molten rock, the mantle at approximately 100°C. Nine major crustal plates float on the mantle & currents in the mantle cause the plates to drift, colliding in some areas and diverting in others. When two continental plates converge a complex series of chemicals in the form of molten magna rises in the earth’s crust and depending upon its magnitude, it may break the crust and reach at the earth surface. Volcano, hot spring, geysers & fumaroles are natural geothermal resources near the surface and perhaps where economic drilling operations can tap their heat and pressure.

14.1 Introduction

Hydro-electric power is electricity produced by the movement of fresh water from rivers and lakes. Gravity causes water to flow downwards and this downward motion of water contains kinetic energy, that can be converted into mechanical energy, and then from mechanical energy into electrical energy in hydro-electric power stations. (“Hydro” comes from the Greek word hydra, meaning water). At a good site hydro-electricity can generate very cost-effective electricity.

15.1 Introduction

The oceans cover 71% of the earth’s surface and it acts a natural collector and store of solar energy. On an average day, 60 million sq. km. of tropical seas absorb an amount of solar radiation equivalent in heat content to about 245 billion barrels of oil, if this energy could be trapped, large scale renewable source becomes available especially for tropical countries. The energy available in the ocean is clean, continuous throughout the year and renewable.

Renewable energy contribution to the available energy resources is very important to the country as it is presently facing an energy resources crunch. Out of the total installed capacity of approximately 370.106 GW as on March 2020, Renewable Power Plants including hydro-electric plant contribute 35.86 % of total installed capacity. However, with the present increase in demand, more attention is required to extract the renewable sources so that at least 50 to 60 % share for the total energy requirement by the renewable energy sources.

There are various forms of ocean energy such as Ocean Thermal Energy Conversion (OTEC), Wave Energy, Tidal Energy, Salinity Gradient Energy, Offshore Wind Energy, Marine Currents, Marine Biomass Conversion. Among these, the first three forms are likely to be technically viable for the future.

More recently Ministry of New and Renewable Energy (MNRE), Government of India hasdeclared Ocean Energy as renewable energy, and clarified to all the stakeholders that energy produced using various forms of ocean energy such as tidal, wave, ocean thermal energy conversion among others shall be considered as renewable energy.

MNRE reported that, the total identified potential of tidal energy is about 8000 - 9000 MW, with about 7000 MW in the Gulf of Cambay in Gujarat, about 1200 MW in Gulf of Kutch and less than 100 MW in Sundarbans. Primary estimates of wave energy potential along Indian coast are about 5 – 15 MW/m, so that theoretical estimates are around 40 – 60 GW. Ocean Thermal Energy Conversion (OTEC) has a theoretical potential of 180,000 MW in India subject to suitable technological evolution. As of date, there is not any installed Ocean Energy capacity in India.

16.1 Fuel Cell

Fuel cell is an electrochemical device that convert chemical energy of a reaction directly into electrical energy. The basic physical structure of a fuel cell consists of an electrolyte layer in contact with a porous anode and cathode on either side. A schematic representation of a fuel cell with the reactant or product gases and the ion conduction flow directions through the cell is shown in Fig. 16.1

17.1 Introduction

It is well known fact that planners as well as end users have to consider any resources as technology from economic point of view. Therefore, it is important to have techno – economic analysis of each energy source option. In the feasibility study of particular energy option, three tier judgment approaches is required, which include technical feasibility, economical viability and social acceptability. Hence in the rural energy planning programme one has to considered techno socio economic analysis of an individual energy option. Since in integrated rural energy planning, locally available energy resources are used, presuming that it is socially recognized. Hence in the IREP project, the need and scope of techno economic analysis in terms of economic analysis of different technical feasible options, before between “economic” and “finical” analysis should be kept in mind. An economic analysis is needed to verify that a particular energy source will provide “net benefit” to society as a whole, before its final integration in the energy context, while a financial analysis integrated in the energy practices. In simple words, a financial analysis is concerned with goods and services, money inflow and outflows and the transfer of payments. An economic analysis also considers the social benefits and costs of goods and services which are not traded in a market.

1.1. Soil Resource Evaluation

Soil is the essence of life on the planet Earth. It has sustained humanity and human civilizations through five functions (Karlen et al. 1997) viz., i) sustaining biological activity, diversity and productivity; ii) regulating and partitioning water and solute flow; iii) filtering, buffering, degrading, immobilizing and detoxifying organic and inorganic materials, including industrial and municipal byproducts and atmospheric decomposition; iv) storing and cycling nutrients and other elements within the earth’s biosphere; and v) providing support to socioeconomic structures and protection for archaeological treasures associated with human habitation. Reeling under the pressure of increasing food, fodder, feed, fibre and fuel production, soil has been used as a medium of plant growth with considerable reliance on external supply of major nutrients, irrigation water, plant protection chemicals, etc. Although soil, a product of millions of years of weathering, has supported various forms of terrestrial life, its sustainable management holds the key for meeting the basic requirements of burgeoning population and development commitments. So intense has been the pressure of increasing food, fodder, feed, fibre and fuel production that the soil has been exploited often exceeding its carrying capacity. The soils are increasingly used for agricultural and non-agricultural uses, such as disposal of farm, urban and industrial wastes, ensuring environmental safety etc. This is possible by the judicious use of this resource.

A clear and intimate knowledge of the kinds of soils and their extent of distribution are essential prerequisites in developing rational land use plans for agriculture, forestry, irrigation, drainage, etc. soil resource inventory or mapping provides an insight about their potentials and limitations. It is therefore imperative to prepare an inventory of this resource for developing optimum land use plan and conservation plans.

Soil survey is essentially a study and mapping of soils in their natural environment. It is the systematic examination, description, classification and mapping of soils of an area.

2.1. History of Soil Survey in India

The original investigations on Indian soils were carried out by Voelcker dates back to 1893 and by Leather to 1898.They classified the soils of the country into four major groups, namely the Indo-Gangetic alluvium, the black cotton soil or regur, red soil and laterite soil. Schokalskaya (1932) has published a soil map of India based on the Russian concept which describes 16 soil groups such as climate,vegetation, soil-forming materials, salinity, alkalinity, swamps and peats (Bhattacharyya et al. 2013). In 1935,Wadia and his co-workers collected a soil map of India with significance on geological formations and classified the soils as red, black (regur), laterite and lateritic soils of Peninsular India and also Indo-Gangetic Plains (IGP) which includes delta, desert, bhabar, terai and alkali soils. Vishwanath and Ukil (1943) published a soil map of India by placing the soils in different climatic zones for the first time. This was prepared by Imperial Agricultural Research Institute, New Delhi, and published in the year 1943. There were 17 kinds of soils identified, viz., deep black soils, black clay soils, black loamy soils, black sandy soils, red sandy soils, brown sandy soils, red and yellow soils, dark reddish brown soils, mixed soils (white and yellow), alluvium (Indus, Gangetic, Brahmaputra), coarse alluvium, soils of swamp lands, calcareous soils, usar soils, kallar soils, coastal alluvium soils and soils of Great Himalayan Ranges.

Soil survey works were started in 1954, in most of the states as a part of their agricultural development programme, and Bihar (Soil Survey and Land use Planning Scheme, Sabour) was pioneer. In 1954, the soil survey work was started under the leadership of Dr. P. P. Jha following the conventional procedures in Bihar (including Jharkhand) to delineate the soil associations based on geology, relief, physical and chemical characteristics of soils for the first time in India by the then Soil Survey Scheme at Sabour (Mishra et al. 2001; Mishra 2015, 2016). Meanwhile, the National Atlas Organization, Kolkata, prepared a soil map of India in 1957 classifying Indian soils into six major groups and 11 broad types. Murthy and Pandey (1983) applied the working principles of the USDA 7^th Approximation in classifying the Indian soils with available data on soil classes and thus used the US system for the first time at great soil group level, which was transformed into a soil map of India on 1:6.3 million scale. Mishra et al. (1994) attempted to propose “Fluvisols” as the 13th Order in USDA Soil Taxonomy for active floodplain soils frequently occurring in different parts of India and elsewhere. Mishra (2015, 2016) proposed a framework of Indian system of soil classification mainly based on land use options.

Soil Classification

Soil classification deals with the systematic categorization of soils based on distinguishing characteristics as well as criteria that dictate choices in use.

Soil classification is grouping of objects in orderly and logical manner into classes based on the properties of soils (differentiating characters) for the purpose of studying and identifying them. The soil individuals are grouped into classes of the lower category (soil series) which are grouped into classes of higher categories (soil orders). The lower categories are defined by large number of differentiating characters and higher category by a few differentiating characteristics.

For soil resources, experience has shown that a natural system approach to classification, i.e. grouping soils by their intrinsic property (soil morphology), behaviour, or genesis, results in classes that can be interpreted for many diverse uses. Differing concepts of pedogenesis and differences in the significance of morphological features to various land uses can affect the classification approach. Despite these differences, in a well-constructed system, classification criteria group similar concepts so that interpretations do not vary widely. This is in contrast to a technical system approach to soil classification, where soils are grouped according to their fitness for a specific use and their edaphic characteristics.

In recent times, the interpretations cover a wide spectrum of soil uses, both for agricultural and non agricultural (sewage and human waste disposal, high way construction, water and gas supply, recreation, wild life, urban and industrial structures) and many specialized uses. Soil survey if correctly carried out according to scientific principles, can provide the data base for various interpretations. This is because the same soil properties determine the behaviour of a soil for a variety of different uses. For instance, the content of clay, silt and sand, the shrink and swell behaviour, the permeability of soil to water and air, content of calcium carbonate, salts, organic matter, gypsum, soil depth, depth of ground water, hard pan formation, co-efficient of linear extensibility, water holding capacity etc. are examples of such properties that are important to plant growth and these properties also strongly influence non farm uses. Some examples in support are

A hard or petrocalcic horizon or other slowly permeable layer (clay-pan) in a soil restricts the movement of air and water, thus adversely affecting the plant root growth. Such a layer limits the soils suitability for septic tanks and other onsite waste disposal. It also makes a poor sub grade for high way construction.

A soil high in soluble salts is a poor medium for plant growth; it is also corrosive to iron and steel structures, such as pipelines and fences, causing high maintenance and repair costs.

High organic matter content is generally favourable to plant growth, but it is a limitation for road construction.

The strongly gypsiferous soils (gypsum content >10%) are considered unsuitable for arable crop cultivation because of its dissolution under irrigated or even moderate rainfall and making the surfaces uneven through the developments of sink holes. Such soils are unsuitable for irrigation and drainage canal networks and also for construction of roads, bridges etc.

The shrink- swell soils of India (vertisols) because of summer monsoon rains are suitable for growing a “kharif” crop but are very dangerous for construction of roads, air strips, buildings, laying gas, water pipelines which get distorted, develop cracks and lead to sunken floors etc.

Land is merely an area of the earth’s surface comprising all physical, chemical and biological environments that influence the land use (FAO ,1976). Land refers not only to soil but also to climate, landforms, hydrology, geology, natural vegetation including fauna and flora. The land use simply means management of a land for specific uses to meet the human needs in all rural, urban and industrial context, whereas the land use plan refers to a coherent set of decisions about the ways to achieve the desired level preferably on economic background. Thus, the land use planning is the systematic evaluation and assessment of a land and associated attributes for the purpose of identifying the best land use options beneficial to landowners or users without degrading the land resources or environment. It includes not only the landowner or users, but also the policy or decision makers as well as economic experts for financial measures from planning stage or logistic planning to execution.

Land cover

Relates to the type of feature present on the surface of the earth e.g., Fields, trees, concrete high ways.

Land use

Relates to the human activity associated with a specific piece of land. The same land would have a land cover consisting of roofs, pavements, grass and trees. The land use in an area is really an intervention by the people over the existing natural eco-environment for satisfying their needs.

Land cover is distinct from land use despite the two terms often being used interchangeably. Land use is a description of how people utilize the land and socio-economic activity - urban and agricultural land uses are two of the most commonly recognised high-level classes of use. At any one point or place, there may be multiple and alternate land uses, the specification of which may have a political dimension.

Maize is an important crop of Uttarakhand and is cultivated in about 22 thousand ha in both hills and plains. The crop is grown for food, feed and fodder and forms an integral constituent of all major cropping systems prevalent in the state. Kharif (June-September) is the main grown season in the hills, whereas in the foothills and tarai plains, the crop is grown during zaid (Feb-May) as well. The crop is grown broadly for two different end products – grain and green ears. In areas where maize forms staple diet, the crop is grown for grain, whereas in areas adjoining/en route popular tourist destinations and towns, the crop is grown mainly for green ears. The crop is also gaining importance as an industrial crops following establishment of maize processing industry in the state.

The major maize growing districts of the state are Dehradun, Nainital, Pithoragarh, Pauri, Tehri and Almora (Fig. 1), which together comprise about 90% of total

Maize (Zea mays L.) is one of the most versatile crops having the highest genetic yield potential among cereals and wider adaptability under varied agro-climatic conditions rightly earning it the name of ‘the queen of cereals’. Maize is cultivated in all agricultural areas around the world and is an economically significant crop for all human population. It is grown from 58⁰ L north to 40⁰ L south and extends from the sea level up to an altitude of above 3,800 m; covering regions with rainfall varying from 250 to 10,000 mm (Hallauer and Miranda, 1988). Globally, maize occupies an area of about 184.0 million ha with production of 1065 million tons and productivity of 55.2 q/ha (FAOSTAT, 2014). It is the third most important cereal crop and a major source of energy, protein and other nutrients for human and livestock in the world (Jompuk et al., 2011). India is the second most important maize growing country in Asia, and now ranks as the world’s fifth largest consumer of maize. It is an important cereal crop in India covering an area of 9.42 million ha with a production of 24.35 million tonnes and productivity 25.83 q/ha (Anonymous, 2015). Maize is cultivated in the country throughout the year mostly during rainy or Kharif season (June to September, 80%) followed by winter or Rabi (November to April,18%) and spring (February to May, 2%) for various purposes including grain, fodder, green cobs, sweet corn, baby corn and popcorn.

Agriculture is the predominant sector in the economy of Jammu and Kashmir. Directly and indirectly, it supports about 80 per cent of the population besides contributing nearly 60 per cent of the state revenue. The total geographical area of the state is nearly 22.2 million hectare and population of 12.5 million, which is approximately 1.04% of the national total. The J&K is divided into three agro-climatic zones: Cold arid desert areas of Ladakh, temperate Kashmir Valley and the humid sub-tropical region of Jammu. Each has its own specific geo-climatic condition which determines the cropping pattern and productivity profile.

In Jammu province, a small portion of the land lies in the plains along the borders of Punjab while the rest of the area is hilly, dominates both in maize and wheat production. About 67 per cent of the area is under maize and wheat production with the production of 21.25q/ha maize and 15.36 q/ha wheat. This region contributes 79.56 per cent and 95.69 per cent of total production of these two cereals respectively. Even though the yield is not high, the region makes appreciable contribution to the cereals production.

The second agro-climatic zone Kashmir is also known as ‘cultivator’s paradise’. The region practically depends on irrigation, which is easily available. A large area of level land has alluvial soil. Extensive elevated plateaus of the alluvial or lacustrine material (locally called Karewas) also exist in the Kashmir valley. These Karewas are productive only in the face of sufficient rainfall or adequate irrigation facilities. Rice is the chief crop of this zone, followed by maize, oat, barley and wheat.

Ladakh zone is endowed with bare rocky mountains and bare gravel slopes. Villages are located near pockets of land with level ground and irrigation facilities, where cultivation is viable. In this region, barley is the major cereal crop followed by summer wheat. Millets and wheat rank second in importance and are grown in the warmer belt of the region.

Maize is one of the most important cereal crops of the world. Being a C₄ plant, it is physiologically more efficient than rice, wheat and other important cereal crops which belong to C₃ category. In Punjab, traditionally, maize is grown during Kharif season but from last few years the area under spring maize is increasing because its cultivation is highly profitable and commercially viable after harvesting of potato crop. No doubt, Punjab has been the leading state in contributing to the national food security but simultaneously paddy-wheat rotation resulted in depletion of underground water, deterioration in soil health and environmental pollution. These problems need to be addressed for the sustainability of these natural resources and at the same time meeting the food grain production for the ever-increasing human population. Under such circumstances, maize crop is a viable alternative to replace some area occupied by rice and can help in breaking rice–wheat dominant cropping pattern in the state. Promising maize hybrids possessing high grain yield potential and offering comparable economic returns to the farmers are available with Punjab Agricultural University as well as with the private sector.

In Punjab, maize is commonly used in the form of chapatis, boiled or roasted green cob, breakfast food like cornflakes, popped grains etc. Maize chapatis are used as a delicacy with saag. The high carotene content of yellow grained maize is considered very useful in imparting yellow colour to egg yolk. Therefore, a substantial quantity of maize grain is utilized as an important ingredient of animal/ poultry feed industry. The use of maize grains for such purposes is going to increase as poultry and dairy industries are expanding. Maize plant is extensively used as green as well as dry fodder. The digestibility of maize fodder is better than sorghum, bajra and other non- legume forage crops. Maize plant does not have any anti quality factor hence can be fed to cattle at any stage. Maize can be utilized as an industrial raw material for number of industries viz., starch, ethanol, rubber, paper, cosmetics and pharmaceuticals etc. Quality Protein Maize (QPM) can be promoted for nutritional security of poor masses whereas pop corn, baby corn and sweet corn can help in increasing the farm income due to high market value. In Punjab, major industries which are utilizing maize are The Sukhjit Starch & Chemical Limited, Kapurthala, and M/s Field Fresh Food Pvt. Ltd, Ladhowal, Ludhiana.

Maize is one of the most important food, feed, fodder and industrial crop in Haryana and is cultivated in all the three seasons (Kharif, Rabi and spring). It was cultivated on 6 thousand hectares in Kharif season with average productivity of 2.83t/ha during 2015-16. The maize is also increasing in spring season which was grown on ~ 7 thousands hectare with productivity of 4.5t/ ha. The specialty corn (baby corn and sweet corn) is also grown in >2 thousand hectare area of Haryana in national capital region. The demand of maize is increasing every year due to growth in poultry industry and expansion of maize based industries. There is a good scope of cultivation of specialty types of corn (baby corn, quality protein maize and sweet corn) in Haryana as it is very near to national capital, Delhi. The cultivation of specialty corn and its value addition by establishing

Uttar Pradesh, a fourth largest state of India geographically, where agriculture is a prime occupation and this is the traditional maize growing state, accounts 7.7% of area and 5.4 percent of total maize production of the country with an average yield of 1791 kg/ha (IIMR Annual Progress Report, Kharif Maize 2015). Maize is mainly taken as a Kharif crop but, gradually Rabi maize is gaining popularity with the availability of high yielding varieties and advanced production technologies. The rice, wheat, potato, sugarcane based cropping is more popular, and maize is given a moderate priority. The current level of growth in productivity definitely fall short to meet the demand of rapidly growing population even it may increase the poverty, unless vigorous measures are taken to accelerate yield, growth, employment generation, increasing the income of farming family and ultimately targeting for the sustainable climate resilient maize production.

Maize is mainly used as a staple food and quality feed for animals. In addition to that it also serves as a basic raw material for several industries like, starch, oil, protein, alcoholic beverages, food sweeteners, pharmaceuticals, cosmetic, textile, gum, package, paper etc. A major portion of the maize produce is directly consumed as a food in the form of boiled or roasted green ears, chapattis, porridges of various forms, popcorn, cornflakes etc. and as livestock feed viz., cattle, poultry and piggery both in

the form of grain and fodder The central rachis of maize cob, to which the grains are attached remains as an agricultural waste after threshing, has many important agricultural and industrial uses. It is approximately 15 to 18% of the total ear weight and contains 35% cellulose, 40% pentose and 15% lignin (used as a raw material in cardboards). Its uses in agriculture includes as a litter for poultry and as a soil conditioner.

Chhattisgarh, the 26^th state of the Indian Union came into existence on November 1^st, 2000. The state is geographically situated in the central part of India, between the latitudes of 17° 46' N - 24° 5' N and the longitudes of 80° 15' E - 84° 20' E. Its proximate position with the Tropic of Cancer has a major influence on its climate. The total geographical area is around 137.90 lakh ha of which cultivable land area is 46.77 lakh ha and forest land area is 63.53 lakh ha with more than 2.55 crore population. In Chhattisgarh region about 22% of net cropped area was under irrigation. About 80 percent of the population in the state is engaged in agriculture and 43 percent of the entire arable land is under cultivation. Paddy is the principal crop and the central plains of Chhattisgarh are known as rice bowl of central India. Other major crops are coarse grains, wheat, maize, groundnut, pulses and oilseeds.

Importance of Maize in Chhattisgarh

Earlier maize was mainly cultivated in Surguja and Bastar division of Chhattisgarh but now it is emerging as main cash crop in entire Chhattisgarh state. There had been an increase of 20 per cent in maize crop acreage in Chhattisgarh during the past 10 years. Now the farmers of the area are cultivating maize in lines, applying atrazin weedicide, full dose of chemical fertilizers, etc. They are willing to buy the hybrid seed for cultivation from the market and taking maize as green cob and also utilizing as green fodder. Maize threshers have been purchased by some farmers in the region which is an indicative of large maize production.

For industrial utilization of the maize Chhattisgarh state has “Raja Ram Maize Factory” in Rajnandgaon district. They are producing and supplying Maize starches, liquid glucose, dextrose mono hydrate, dextrin, maltose liquid, malto dextrin, maize oil, maize gluten, maize grit, maize husk etc. But most of the maize production is used as poultry feeds in the state. Traders purchase it directly from the farmers’ fields in the villages. It is also exported to the neighboring states either as grain or green cob. Around 10-15% is retained by the farmers for own consumption and seed purpose.

Bihar is an important maize growing state in India after Karnataka, Andhra Pradesh, Telangana, Rajasthan and Maharashtra, where it is cultivated during all season. However, the yield of maize is much higher during Rabi and summer seasons than the Kharif. Due to climate change and other factors, the yield of maize is likely to further decline during the Kharif season. However, the cultivation of maize in Bihar during the Rabi season will be much more profitable as compared to wheat due to rise in temperature. There is need to develop maize varieties which can with stand biotic and abiotic due to changing climate factors.

Decadal trends of maize area, production and stresses yield in the Bihar from 1950–2015.

Maize or corn (Zea mays L.) is second most important crop after rice in Jharkhand. Though considered as a Kharif season crop, it can be successfully grown in other two crop seasons viz., Rabi and zaid also as the climatic condition in Jharkhand is conducive for growth of the plants. Rabi maize has comparative advantage over Kharif maize due to low incidence of diseases and insect pests slow growth of weeds and crop does not have to suffer on account of heavy rainfall hence, higher yield potentiality could be realized from Rabi maize. In Jharkhand, the Kharif crops including the maize are grown as rainfed as the 80 to 85% of the annual rainfall takes place during June to September. The share of maize under irrigated condition is restricted to only 15 to 18% of the total cropped area. Maize is not only an important source of nutrient to the human beings but also constitutes a basic component of animal and poultry feed. Here, farmers grow maize mainly for green cobs as cash crop whereas the grains are to be used for human consumption as well as for animals and poultry feed. The cultivation of the specialty corns like baby corn, sweet corn and popcorn is still in its infancy in Jharkhand and hence, large scale cultivation of specialty corn in the state will take some more time. Establishment of food processing unit in the state is at the nascent stage. However, the Government of India is implementing a Mega Food Park in Getalsud Industrial Area of Ranchi district in Jharkhand. The establishment of this mega food park is expected to give a significant boost to the food processing sector in Jharkhand.

West Bengal is the fifth largest state in terms of (GSDP) Gross State Domestic Product after Maharastra, UP, TN and AP and is the third largest contributor in agriculture sector of real GDP. West Bengal has 3% of India land mass and 8% population with population density of 1029 per km².

Agriculture accounts for about 17% (2013-14) GSDP and provides employment to over 55% of workers. About 64% of the geographical area of West Bengal is under cultivation. There is little scope for further increase the current cultivable area. Because it is difficult to maintain the growth rate in the absence of adequate infrastructure support, crop diversification and market access.

Food production remained stagnant as the green revolution by-passed the state. However, there has been a significant increase in food production since 1980’s and the state is now one of the few Indian states with a surplus in food production, producing nearly 20% of the rice and 33% of potato. Agriculture accounts the largest share of the labour force. Rice, potato, jute, sugarcane and wheat are the top five crops of the state, while other major food crops include maize, pulses, oilseeds, wheat, barley and vegetables. In recent years, significant changes have occurred in maize production and utilization due to increasing commercial orientation of maize crop and rising demand for diversified end users, specially for feed and industrial uses. A sizable number of districts in West Bengal have potential for growing winter maize. Though maize favourably responds to better crop management both in Kharif and Rabi season, the erratic rainfall pattern of the south-west monsoon comes in the way of timely field operations of Kharif season. In absence of any major environmental impediments in Rabi, the desired field operations can be planned and executed at the most desired time. Moreover, the various environmental factors including absence of any major disease and insect pests in this season, helps in realizing the better profits from every additional unit of monetary inputs. Hence, future of Rabi maize in West Bengal is bright.

Maize is the only cereal crop which is being used as human food, animal feed and as a source of large number of industrial products. In Odisha traditionally maize is a Kharif season crop and second most important crop next to paddy during Kharif season in terms of both area and production. The Rabi maize is cultivated under irrigated condition, and accounts only 7% of total area and production of the State. While only 24% of the Kharif maize area have irrigation facilities. Irrespective of the season, it is that is the fourth most important food grain crop with respect to area in the state which is next to rice, mungbean and urdbean. Even though maize is grown as a sole crop in the state but, some farmers are also adopting maize based inter-cropping and the major recommended/adopted inter-crops are arhar, cowpea, yam, runner bean, greengram and blackgram. The comparative analysis of compound annual growth rate (CAGR) of area, production and yield of the major crops is the state was done for the years 2004-05 to 2013-14. The CAGR study of major crops revealed that no other major crop including rice has the impressive growth rate a like maize in the state (Fig. 1).

Maize is presently the crop with growing importance in the state. Earlier it was primarily grown for human consumption only. In view of rapidly increasing demand of poultry feeds and fodder in Assam presently it has more use in some small industries. It is the raw material for most of the feed industries. Presently the crop has state acreage of 27953 hectare and production of 93179 tonnes with a productivity of 3333 kg/ha (2014-15).

While most other states in India are gradually moving away from their traditional agriculture based economy toward industry or service oriented economy, Assam is still predominantely dependent on the agricultural sector. While the sociopolitical problems afflicting the state since the last few decades are partly to blame for a lack of conducive environment for economic development of the state, particularly in industry or service oriented areas, there are various economic reasons (e.g. fragmented land) responsible for the lagging agricultural sector in the state. Economy of Assam is fundamentally based on agriculture. Over 70% of the state’s population relies on agriculture as farmers, agricultural laborers, or both for their livelihood.

Assam produces both food and cash crops. The principal food crops produced in the state are rice (paddy), maize (corn), pulses, potato, wheat, etc., while the principal cash crops are tea, jute, oilseeds, sugarcane, cotton, and tobacco. Although rice is the most important and staple crop of Assam, its productivity over the years has not increased while other crops have seen a slight rise in both productivity and acreage.

Maharashtra is the third largest state in terms of area in the country located in the north-centre of peninsular India. It links the southern part of the northern plains to the southern peninsula. Maharashtra occupies the western and central part of the country with total 3.08 lakh sq. km geographical area and has a long coastline stretching nearly 720 kilometers along the ARabian Sea. The prominent physical trait of the state is its Plateau character, which has up to 1350 meters high altitude. Physiographically this state may be divided into three natural divisions-the coastal strip (the Konkan), the Sahyadri or the Western Ghats and the Plateau. The Sahyadri mountain ranges provide a physical backbone to the state on the west, while the Satpuda hills along the north and Bhamragad-Chiroli-Gaikhuri ranges on the east serve as its natural borders. It has a geographical area of 307713 sq. km and is bounded by north latitude 15°40’ and 22°00’ and east longitudes 72°30’ and 80°30’.

NBSS & LUP has divided the state into 356 soil mapping units and published a map of the soils of Maharashtra. It has broadly categorized as soils of Konkan coast, soils of Western Ghats, soils of upper Maharashtra, soils of lower Maharashtra. The soil status of Maharashtra is residual, derived from the underlying basalts. In the semi-dry Plateau, the regur (black-cotton soil) is clayey, rich in iron and moisture-retentive, though poor in nitrogen and organic matter. The rainy Konkan and the Sahyadri Range, the same basalts give rise to the brick-red laterites, which are productive under a forest cover, but readily stripped into a sterile varkas when devoid of vegetative cover. The soil in the Deccan Plateau is made up of black basalt soil. This type of soil is rich in humus. The soil is commonly known as the black cotton soil because it is best suited for the cultivation of cotton. The volcanic action which had taken place in the Deccan region has given rise to the soil texture and composition. These igneous rocks break down into the black soil which is very fertile. The Wardha-Waliganga river valley has old crystalline rocks and saline soils which make the soil infertile. This type of soil has a natural resistance to wind and water erosion because it is rich in iron and granular in structure. A very important advantage of this type of soil is that it can retain moisture. This makes the soil very reactive to irrigation.

Karnataka is India’s eighth largest state in geographical area covering 1.92 lakh sq km and accounting for 6.3% of the geographical area of the country. As per the population Census 2011, agriculture supports 13.74 million workers, of which 23.61 per cent are cultivators and 25.67% agricultural workers. A total of 123,100 km² of land is cultivated in Karnataka constituting 64.6% of the total geographical area of the state (Table 1). Of the total cultivated area in the state, about 33.0% is covered by cereals, 42% by pulses and 19% by oilseeds and 6.0% by commercial crops (Savitha and Kunnal, 2015). Agriculture employs more than 60% of Karnataka’s workforce. The large portion of agricultural land in the state is exposed to the vagaries of monsoon with severe agro-climatic and resource constraints.

Maize production in India has been dominated by erstwhile Andhra Pradesh and Karnataka which together contribute around 38 per cent of the total maize production of the country. Erstwhile Andhra Pradesh has achieved the highest mean yield of 4441 kg/ha in the country during the last decade (2001-02 to 2010-11) by surpassing Karnataka which had the highest productivity in the country, earlier. The main reason for achieving the highest productivity in the country was due to adoption of improved production technology along with 100% area grown under hybrids. In Telangana, maize is the third most important crop after rice and cotton. It is cultivated in 5.74 lakh hectares, predominantly in Kharif season (4.54 lakh ha), with a productivity of 3.69 t/ha (2015-16).

Trends in maize area, production and productivity in the state (1950 to 2016)

The erstwhile Andhra Pradesh (including Telangana) is the non-traditional maize growing state. But, the climate of the state is very favorable for the crop and hence maize can be grown in any season in the state. However, it is mainly grown as a rainfed crop during monsoon season, concentrated in Telangana. The trends in area, production and productivity of maize in erstwhile Andhra Pradesh have shown a remarkable increase during the past six decades. During 1955-56, the maize acreage in the state was very less (1.89 lakh ha), which has been up by 5.3 times to the present (2014-15) level of 9.95 lakh hectares. The production has also increased dramatically from merely 1.14 lakh tonnes during 1955-56 to 42.36 lakh tones during 2014-15, which is nearly 37 times higher. Similarly, the productivity of maize in the state was merely 601 kg/ha during 1955-56, which has been increased to 4257 kg/ha during 2014-15 (Fig. 1).

Maize (Zea mays L.) is the third most important grain crop in India after rice and wheat with respect to area and production. It has wide ecological adaptability and is grown in almost all parts of the country extending from extreme semi-arid to sub-humid and humid regions. The crop is also popular in low and mid-hill areas of Western and North Eastern regions. It has the highest yield potential and used as human food, animal feed and as a source of large number of industrial by-products. Hence, it is called as “Queen of cereals”. In India, about 59% of the total production is used as feed, while the remaining is used as industrial raw material (17%), food (10%), exports (10%), and other purposes (4%).

Tamil Nadu has a total geographical area of 13 million hectares with a coastal line of 922 km and is endowed with 3 per cent of water resources of the country. Out of 13 million hectares of geographical area, the cultivable area in Tamil Nadu is around 7 million hectares and 55 per cent of which is dryland. The State has gross irrigated area of 33.94 lakh ha out of which 79% is under food crops and 21% is under non-food crops. In Tamil Nadu, maize was grown in an area of 0.14 lakh ha during 1970-71 with the annual production of 0.16 lakh tonnes, mainly concentrated in Tanjore, Pudukkottai and Trichy districts. Due to rapid increase in the demand of maize for poultry and animal feed, industrial uses and introduction of high yielding varieties and hybrids, the area under maize has gone up to 3.8 lakh ha with the production of 22.45 lakh tonnes during 2013-14. The major maize growing districts are Perambalur, Tuticorin, Dindigul, Erode, Karur, Ariyalur, Salem and Southern districts of Tamil Nadu. The demand and production of maize is increasing more rapidly as compared to other major commodities. It is estimated that the demand for maize will continue to increase in coming days (Yadav et al., 2016). Thus, in the next 10 years there is a necessity and opportunity for doubling India’s maize production from the current level of approximately 26 million MT.

The state of Madhya Pradesh is one of the high profile maize growing state of the country cultivating maize in about 11.32 lakh hectare area which is ~12% of the total maize area of the country having 90-95% of total maize area having rainfed. Madhya Pradesh is situated in heart of India between 17°-26° N latitudes and 74°-84° E Longitude. The rainfall in maize growing belt varies from 800 to 1600 mm. Due to erratic and uneven rainfall in the state, the production and productivity of maize fluctuates every year. Maize cultivation in the area is associated with resource poor tribal farmers. As the demand for maize is growing globally due to its multiple uses for food, feed and industrial uses, we need to produce more from same or even less resources, which can be achieved through targeting technologies in potential regions.

Besides, monsoon crop due to mild winter conditions the climate allows the cultivation of maize during winter successfully under assured irrigation conditions. At present about 50 thousand ha area is under Rabi cultivation with high productivity levels as compared to monsoon crop. However, the major area increase was achieved during past few years mainly due to adoption of hybrids and shift in acreage under non-traditional areas, replacing soybean crop on farmers field. Uncertain climatic conditions and more disease and pest problem lead farmers to adopt maize in place of soybean.

The trends in area production and productivity of maize in Madhya Pradesh has shown a remarkable increase during four decades. During 1966-67 the maize acreage in the state was very less (5.59 lakh ha) that has grown up by 11.32 lakh ha in 2014-15. Moreover, the productivity also increased dramatically from mere 811 kg/ha during 1966-67 to 1513kg/ha in 2014-15.

Maize ranks fourth after rice, wheat and bajara with respect to area and production, and grown on 4.23 lakh ha average with 6.72 lakh tones production and yield 1589 kg/ha in the Gujarat (2014-15). The state has 38.0% lower than national yield. It mainly grown in Panchmahal, Dahod, Mahisagar, Vadodara, Chhota Udepur, Kheda, Sabarkantha, Banaskantha and Aravali districts as rainfed Kharif and irrigated winter/Rabi crop for food, feed and industrial raw materials.

It is staple food and feed of tribal and grown as sole and intercrops with pigeon pea, black gram and soybean in Kharif season. The white and yellow flints to semi-flint maize are preferred to prepare bread and other food preparations

Maize (Zea mays L.), the “Queen of Cereals” is one of the most important highly evolved coarse cereal crop originated at Mexico. This is most widely distributed crop of the world cultivated predominantly in tropics and sub-tropics right from sea level to 4000 m altitude as irrigated or rainfed crop. The demand for maize as an animal feed will continue to grow faster than the demand for its use as a human food, particularly in Asia, where, doubling of production is expected from the present level of 165 m t to almost 400 mt.

Maize (Zea mays L.) is the third most important crop of country after rice and wheat and is cultivated round the year. Its grain is used as feed, food and industrial raw material. Enormous progress has been made during last six decades to enhance yield potential through genetic improvement and alleviate effects due to various biotic and abiotic-stresses. In India, it is an important crop not only in terms of acreage but also in context to its versatility for adoption under wide range of agro-climatic conditions. Of the different forms used for human consumption, 45% is consumed as staple food in various forms viz., bread, biscuits, cookies or transformed into corn flakes, soups, fresh-roasted sweets, boiled cobs and vegetables etc. Maize grain is main ration for poultry birds while forage maize is used as fresh or dry fodder for dairy industries. In Rajasthan maize occupies 0.89 m ha area with an annual production of 1.55 mt and productivity of 1.74 t/ha (Govt of Rajasthan, 2015). Being major Kharif crop in Rajasthan, the productivity levels of maize are still below the national average and farmers are not getting better economic returns. However, profitability can be accelerated further by growing recently popular speciality corns.

Maize (Zea mays L., 2n=20) is a cereal crop that is grown widely in more than 165 countries in a range of agro-ecological environments. Even in Asia, the rapid increase in maize acreage in the last decade is an indication that it is winning the battle as compared with rice. The Asian region will see itself as a major global player in the near term. In the past it was mainly confined to food in India and many other countries however, now it has become the industrial crop. Maize has several industrial applications and more than 1000 products are being developed from maize in India and around 3500 products in USA and other countries. It is a raw material for many of the important industries viz. pharma, textile, paper, film, tyre food, processing, packing and biofuel, etc. The growth rate of poultry, livestock, fish, wet and dry milling industries are very high therefore, maize demand will continue to increase in year to come.

Global Maize Scenario

Globally, maize is primarily used as feed livestock and has many industrial uses; however in many developing countries it is still used as a food crop. Small-scale farmers in both sub-Saharan Africa and Mesoamerica generally grow maize as a food crop for household consumption and for saline urban markets. Maize is particularly important in the diets of the rural and urban poor in sub-Saharan Africa and Latin America. Globally, maize is grown in 165 countries in a total of 185.1 million hectares area with 1018.1 million tones of production and 5.52 tonnes/ha productivity (Anonymous 2015-16). Almost 70% of the total maize production in the developing world is coming from low and lower middle income countries. In Asia, maize has recorded the fastest annual growth (around 4%), as compared to other cereals. Maximum maize production was in USA (353.7 million tonnes) followed by China (218.6 million tonnes) and Brazil (80.3 million tonnes) (Fig. 1), while the area under maize cultivation was in China (36.3 million hectare) followed by USA (35.5 million hectare) and Brazil (15.3 million hectare) (Fig. 2). The average world maize productivity is 5500 kg/ha, but the highest productivity of maize was achieved in USA (9970 kg/ha) followed by Canada (9591 kg/ha) and France (8137 kg/ha) (Fig. 3).

Maize (Zea mays L.) occupies an important place in world agriculture due to its high yield potential and greater demand. Because of its divergent character, maize is grown over a wide range of climatic conditions, ranging from near sea-level to several thousand meters above sea-level (2,700 msl). It can also be grown in all types of soils ranging from sandy to heavy clay. Among the factors adversely affecting productivity, incidence of diseases is prominent. In India Maize is prone to a number of biotic stresses like foliar diseases, downy mildews, banded leaf and sheath blight, stalk rots and ear rot caused by fungi and bacteria, incidence of which are variable in time, space, and genotype. Disease may be minimized by the reduction of the pathogen’s inoculum, inhibition of its virulence mechanisms, and promotion of genetic diversity in the crop (Richard et al., 2005). Conventional plant breeding for resistance has an important role to play that can now be facilitated by marker-assisted selection.

Chemical control measures for some of the diseases are helpful in reducing losses, however for stabilizing production it is necessary to build level of genetic resistance. Germplasm improvement programme undertaken in sixties and early seventies by All India Co-ordinated Maize Improvement Project provided an opportunity for combining resistance against important diseases with other desirable agronomic traits. Thus, breeding for resistance had been an important objective of the overall crop improvement programme and it had been a cooperative venture of the plant breeders and plant pathologists. Consequently, it was recognized that there should be an efficient technique for the mass multiplication of inoculums, artificial inoculation technique and scoring/rating of plant disease as a pre-requisite for the successful identification of resistant sources in such improvement programme. With these objectives in to consideration, a six days seminar on the “Techniques of scoring for resistance to diseases of maize in India” was held at Andhra Pradesh Agriculture University, Hyderabad during 15-20 March, 1982 (Payak and Sharma, 1983).

The ability to fast-track development and delivery of improved maize cultivars with capacity to provide climate-resilience (high and stable yields in stress-prone environments), coupled with improved nutritional quality, will be critical for sustainable intensification and diversification of maize-based cropping systems, and for providing enhanced income opportunities to the smallholders. This warrants coordinated multi-institutional efforts and implementation of innovative strategies to further increase genetic gains through breeding, and to translate these gains in the farmers’ fields. This article will focus only on the novel tools/ technologies/strategies that are being employed by CIMMYT for increasing genetic gains, especially for grain yield under stress-prone environments in the tropical/sub-tropical regions of sub-Saharan Africa, Latin America and Asia.

Novel tools/techniques/strategies for increasing genetic gains in the tropics

“Genetic gain” (also called as selection response) refers to the difference in the mean value of the selection criterion between original generation and next generation (formed from only the selected individuals), when they were compared in the same environment. The selection criterion is the trait(s) on which selection is based. While conventional breeding has been successful in improving maize yields over the decades, and especially in the last one decade in India through single-cross hybrids, the significantly rising demand for maize in the tropical regions of sub-Saharan Africa and Asia warrants sharp increases in genetic gains. Thus, the major challenge for the present generation of product development teams is to double the genetic gains for grain yield under stressed environments, i.e., from the present <1% to at least 1.5% within the next 5-6 years.

Maize occupies an important position in the world economy, and serves as an important source of food and feed (Gupta et al., 2015a). Together with rice and wheat, it provides at least 30% of the food calories to more than 4.5 billion people in 94 developing countries (Shiferaw et al., 2011). In India, maize is an important cereal too, and is grown on an area of 9.2 million hectares with production of 24.2 million tonnes (www.indiastat.com). The demand for cereals will continue to increase as a consequence of the expanding human population. The world will have around 7.7 billion people by 2020, and it will reach up to 9.3 billion by 2050, and the demand for maize between now and 2050 will double in the developing world (Rosegrant et al., 2009). By 2025, India too would require to double the production (50 million tonnes) of maize grain to meet the domestic demand (Yadav et al., 2016).

Malnutrition caused by inadequate consumption of balanced diet has emerged as one of the alarming problems especially in the under-developed and developing world. Mostly the resource-poor suffer from ‘hidden hunger’, a term often used to describe malnutrition caused due to micronutrient deficiencies in staple food diet (Bouis and Welch, 2010).

An estimated two billion people suffer from micronutrient deficiency, while 795 million people are undernourished (IFPRI, 2016a). Of the 667 million children under the age of five worldwide, 159 million are stunted, while 50 million do not weigh enough for their height (IFPRI, 2016b). An estimated 45% of deaths of children under age five are linked to malnutrition (Black et al., 2013). Malnutrition contributes to global burden of disease, and loss in annual gross domestic product (GDP) in Asia and Africa to extent of 11%. South Asia is home to more than 35% of the world’s poor, and 21.9% of the population of India lives in poverty, and thus vulnerable to various health problems (IFPRI, 2016a). 15.2% of the people in India are undernourished, and more than one third of the world’s underweight malnourished children live in India, posing severe socio-economic loss to the country.

The ever mounting population in 21^st century is a great challenge for the researchers to provide ample food and that has to be achieved within the context of existing challenges such as deteriorated arable land along with increasing adverse affects of changing climate. There is demand to increase food production to the tune of 70% by 2050 (Wani and Sah, 2014). Although major crops have achieved good progress, vulneRability to climatic variability emerged as a serious concern in crop improvement which could be attributed to higher sowing densities that in turn lead to more competition for water and nutrients. Abiotic stresses can be considered as major yield restraining factors among different crops. The projected estimations for changes in abiotic stresses such as drought, water logging and heat reveals far serious concerns for crop productivity (Qin et al., 2011; Bailey-Serres et al., 2012). Therefore, the concern of global food security in the era of climate change has compelled plant scientists in different crops to shift to breeding for climate resilient genotypes. Maize, being a hardy crop has an inherent potential to perform well under sub-optimal environments with minimum crop management (Kole et al., 2015). Abiotic stresses such as drought, heat and water logging affects maize yield adversely.

Although, conventional breeding approaches have exploited its fullest potential for production of elite maize hybrids but still little success attained for breeding climate resilient genotypes or varieties owing to the fact that stress tolerance is multi-genic or quantitative in nature. Therefore, the best option is to utilize the molecular breeding along with the conventional approaches for development of climate smart varieties.