eChapters

The purpose of a sub-surface drainage system is to lower the ground water table and removal of salts beyond the crop root zone. The ground water table may rise due to commonly practiced flood irrigation method, seepage from unlined channels, percolation of rain and runoff water and sub-surface flow from higher areas. Sub-surface drainage consists of drains laid at a specified depth, spacing and grade below the ground surface. The size, spacing and depth of drains depend largely on the soil-water properties viz. , infiltration, saturated hydraulic conductivity, drainable porosity; and the requirement of removal of water through drains in certain time period fixed on the basis of rainfall and crop cultivated. The drains are usually placed in a pervious stratum. Suitable filter of coarse sand and gravel may be used when it is placed in a low permeable stratum. Sub-surface drainage serves the important job of removal of concentrated salt solution from the crop root zone particularly in arid and semi-arid region.

11. 1 Introduction

Agricultural drainage is the removal of excess water from the farmland for the purpose of providing favorable soil air environment for plant growth. Removal of water may take place form the surface or below the surface of the land. The practice of lowering ground water table below the root zone depth to improve the plant growth or to reduce the accumulation of salts in soil is also called as drainage.

Drainage system is broadly classified as surface and subsurface drainage. Removal of excess water over the land surface is known as surface drainage and that of removing water below the surface is known as subsurface drainage. The flow of water in the form of evaporation or evapotranspiration also play important role in improving drainage situation. It gives the idea of the time required to get the wetland workable though it is not called a type of drainage as because this is very slow process and cannot be controlled by the human activities. However, using of certain tree plants e. g. , Eucalytus, Poplar, Casurina or similar species in wet fields, which transpires at high rate and improves the drainage problem by lowering the shallow water table is the new idea known as bio-drainage.

10. 1 Land and Water Resource

India has got the world’s 2. 45% area and 16. 87% of population with only the 4% of available fresh water (Table 10. 1). This indicates the necessity of development of water resources and optimal use of it. India at macro level does not have short of water. But the shortage of water is due if not properly managed by conservation and sector wise utilization.

Poor quality of water is one of the important factors causes gradual accumulation of salts on the ground or in the root zone of crops leads to saline and alkaline condition. This results in loss of permeability, toxicity and anaerobic conditions. In salt affected soils plants face constraint to derive their nutrients at the required rate due to high soil moisture tension, which affects adversely the crop growth and productivity.

8. 1 Introduction

Water is a precious commodity. Necessity of conservation of water supply is increasingly felt all over the world as the demand of it continues to increase when the sources of supply are increasingly scarce. The conveyance and proportional distribution of water is one of the most important part of any irrigation project. Water available in the stream, reservoirs or wells is carried to the field of use through canals. The economy of any irrigation project largely depends on how efficiently the water is being transported and distributed in respect to water losses and cost.

Water losses in irrigation channels are mainly due to evaporation from the water surface and seepage from the bed and side of the channels. Seepage losses some time become the single important factor which causes unavailability of water particularly in downstream of the channel in canal irrigation system and excess pumping of water in tube wells and river lift irrigation system.

Lining irrigation channels means to cover the channel earthen surface by any substance, which can considerably reduce the seepage loss. The concrete, brick, stone, natural clay of low permeability, bituminous material, plastic compounds, etc. , are used for channel lining.

7. 1 General

The major portion of water in a crop field gets lost through evaporation and transpiration. Evaporation is the process by which water is changed from the liquid state to vapor state. It takes place from the adjacent soil, water surface or from the surfaces of leaves of the plants. Transpiration is the removal of water vapour through plant body. Evapotranspiration (ET) is the sum of evaporation and transpiration. The process of evaporation and transpiration goes on simultaneously and difficult to separate them in a crop field.

The term consumptive use is used to refer evapotranspiration together with the water used in the metabolic activities of the crop plants. The actual amount of water used in metabolic activities is insignificant (less then 1% to ET). Therefore, the consumptive use and evapotranspiration are often used as synonymous term. It includes the water consumed by the plants for metabolic activities or transpiration plus the water evaporated from the land and water surfaces of the cropped area.

The factors affecting the rate of evaporation are the vapour pressure at the water surface and air above, air and water temperatures, wind speed, atmosphere pressure and size of the water body. Other factors remaining same, the rate of evaporation increases with an increase in the water temperature. Higher wind velocity causes greater scope for evaporation. Decrease in atmospheric pressure increases evaporation. The solute dissolved in water causes reduction in the rate of evaporation than that of pure water. The evaporation from soil surface occurs in same way to free water surface when the soil particles are surrounded by thin film of water and pore spaces are partially filled. However, in such situation greater resistance has to overcome for evaporation from the soil particles than while evaporating from a free water surface. The evaporation process practically stops when the moisture content in soil goes below a threshold value.

The plants collect water by its root system available in the soil medium. A soil rich in nutrients cannot ensure success of crops unless the presence of satisfactory state of water and air, mechanical attributes and thermal regime. The physical properties of soil and plants greatly influence the movement, retention and use of water. The soil should provide sufficient pore spaces and size distribution and decomposition of rocks and for the movement and retention of water for plant needs. Rainwater, irrigation, groundwater, seepage, etc. , contribute in replenishing the water in dried up soils. In all the cases thorough understanding of behavior of water is required to ensure the need of water to plants and optimize the use of irrigation water.

5. 1 Irrigation Channels

Canal or channel is an artificially made conduit through which water is supplied to the field from river, tank, reservoir or wells. The open channel is the most common type of water conveyance system. If the pipes and drains are partially full behave like open channel. The irrigation channel may be lined or unlined and the flow is either uniform or varied.

The canal may be classified in following ways.

(a) Classification based on the source of supply

(i) Permanent or perennial canal

(ii) Inundation canal

Scheduling irrigation is the process of determining when to irrigate and how much to irrigate. Selecting the appropriate time span in between two irrigation and applying the required volume of water in each irrigation, ensures saving of water, minimize energy use, higher crop yield and lower production costs. Irrigation applied earlier than due date causes loss of water through evaporation or deep percolation and later causes water stress to plants and thereby affects the growth and yield of the plants. Scheduling of irrigation may be required in two field conditions: (i) when availability of water is adequate, (ii) when availability of water is limited.

In the places where water is adequate scheduling of irrigation follows full irrigation with time sequence of minimum number of irrigation to ensure maximum yield and high water use efficiency. When water is limited its use is rationalized by using at the sensitive stages of the plants and withholding irrigation at other stages. The sensitive stages so selected that by using the available water provides possible maximum yield.

3. 1 Introduction

Irrigation efficiency evaluates how effectively the water has been distributed for the purpose of crop production. Water is conveyed to crop field through canal water courses and channels. During this process considerable amounts of water get lost through run off, deep percolation, evaporation, etc. The losses of water greatly depend on the skill of the irrigator, degree of land preparation, and design and planning of the system. The extent of water losses starting to diversion of water from its source to crop field though conveyance and ultimate application and distribution of water in crop field which can be estimated separately. The estimation of these efficiencies enables one to identify the step(s) where improvement is required. The method of measurement and evaluation for its efficiency is prerequisite for proper use of water. Irrigation efficiency in developing countries in general is poor particularly in gravity irrigation methods. However, water is become more and more scarce. Due to pressing need of it judicious and efficient management is one of the vital issues to be solved on priority basis.

Measurement of water used in irrigation ensures the application of required amount of water in crops. Knowing the rate of flow the adjustment to period of control at gates, etc. can be done to regulate the water at different branches of canals. To get the total control over the supply of water there should have the provision of water measurement at the critical points in irrigation systems.

Units of Measurement

Water is measured at rest or in motion. The water of reservoir, ponds, tanks, etc. at rest is measured in volumetric unit as liter, cubic meter, hectare-meter and hectare-centimeter. Water flowing in rivers, canals, channel, etc. is measured in liter/s, liter per hour, meter per second and hectare-meter per hour or day.

1. 1 Introduction

Irrigation is the artificial application of water needed to the crop field. It is the process of uniformly wetting the root zone depth. The wetting may be done over the land surface or below of it. The application of water in excess to the requirement or accumulation of water in crop field due to rain or unplanned seepage is not considered as irrigation. However, irrigation is supplemental to rainfall. Irrigation water is considered as single most important inputs for crop production.

Introduction

Social disinterestedness could be an anticipation that applies issues of amends and candor to policy. Aback the Sixties, the anticipation of amusing disinterestedness have been activated in an advance of institutional contexts, calm with apprenticeship and accessible administration. The anticipation of amusing disinterestedness is about afflicted aback to the works of philosopher and Plato. Definitions of amusing disinterestedness will vary, about all focus aloft the ethics of amends and fairness. Disinterestedness in fashionable societies involves the role of accessible directors, United Nations bureau breadth assemblage accountable for authoritative assertive that amusing casework breadth assemblage delivered equitably. This bureau demography into application actual and accepted inequalities a part of groups; candor relies on this amusing and actual context. Amusing and bread-and-butter bigotry has abiding furnishings on societies and as well the bloom of populations. The acceptance from an ample alter of disciplines breadth assemblage acclamation disinterestedness in avant-garde agency that. Solutions alter from acclamation cyber banking accretion aberration to apprenticeship quality, cyber banking action to bent amends reform and affluence of accession disinterestedness problems that anon and alongside accept an aftereffect on animal bloom and well-being. The aggregation seeks to acknowledgment such queries as, will a bigger pay advance superior of action measures, calm with health, nutrition, and ancestor’s circadian life? As added cities ahead hikes in their pay, this assay can acquaint approaching choices apropos the after-effects on staff, their families, employers, and as well the community. An administration of assets, resources, and liabilities a part of the individuals during a nation or association that’s advised accurate and simply. Whereas some accept that bread-and-butter disinterestedness needs that anybody voters pay an agnate quantity, others accept that the abundance paid care to wait aloft the abundance that every accountable will allow to pay while not disproportionate hardship. Put simply, disinterestedness is possession. Aural the affairs world, disinterestedness refers to stock. Aural the accounting and aggregation disposition world, disinterestedness (or added normally, shareholders’ equity) refers to the abundance of basic contributed by the abode owners or the acumen amid a company’s absolute assets and its absolute liabilities. The fashionable era is casual through an alluringly and annealed aggressive laissez-faire abridgement that’s about there’s no acknowledgment to actualize some individuals at an advantage while not creating others worse off. This cessation refutes the claims of ambitious bread-and-butter planners, United Nations bureau assert that markets breadth assemblage disorganized free-for-alls which centralized chief would be added economical. During a class disconnected association the advantages of amusing appear can’t be aggregate appropriately by the all categories of individuals. It’s simple to appetite agitated with the abstraction that markets appreciate appropriate and to again draw inappropriate abstracts apropos policy. It’s basic to arouse that authority is apropos a way to achieve goals; it doesn’t say something apropos what your goals care to be. Locution that the bazaar aftereffect is economical doesn’t beggarly that that aftereffect is about alluring for all the individuals. In fact, in some affairs analive action could advisedly baldest accessory bulk aftereffect that’s not economical.

Introduction

Agricultural productivity during past three decades resulted in depletion of natural resource base besides creating several environmental and ecological problems. In contrast the demand scenario features a growth rate in food requirements to meet the ever-increasing demand of the growing population. The total food grain demand of India by 2020 is estimated at 294 million tones as against the present 224 million tonnes (2010-11), which has to come from the almost static net cultivated area of about 142 million ha. This improvement in food grain production has to be achieved while dealing with the factors affecting the ecological balance and sustainability of Agricultural resources. Soil and water conservation is an important aspect, which needs very careful dealing with proper attention of the researchers and planners particularly in the context of agriculture of rainfed areas. As the water without soils is useless for crop cultivation, the soils without water nothing but desert. At least 20 % of total land is deserted and very difficult to use with another 20 % is sandy and poor in nutrient content subjected to severe soil erosion and excessive land degradation which causes fragile nature of eco-system and threatens food security of such areas. Soil erosion reduces productivity and cuts crop yield and causes at least 10 metric tons of topsoil loss per hectare per year. Now days, soil and water conservation is gaining paramount importance globally due to its obvious reasons. The main objective of the subject to protect soils against damage due to excessive runoff by natural, mechanical, cultural and agronomic measures to be adopted to bring a state of equilibrium between climate, soil, rainfall, slope and vegetation.

Introduction

India is the seventh largest having 329.73 million ha of geographical area and second most populous country having more than a billion population in the world. There is no other substitute other than to use every square inch of land and every drop of water effectively and efficiently. Though there was markedly increase in annual food grain production from 51 (195051) million tones t0 206 million tones (200001), still the death on hunger is visualized.

The demand for food is increasing with everincreasing population growth rate. So there is no option other than to increase food production. There is very little or no scope of horizontal expansion due to land limitation, the question of vertical expansion is the only way to fit with the situation. Genetically improved crop variety, hybrids, mechanized agriculture, higher rate of fertilizers and chemicals application may give one or two more green revolution, but the question lies how far it can sustain greenness?

Adoption of improved crop cultivars, cropping system, increasing cropping intensities, precision farming can hold good to get out of this situation where whole system is to be considered.

The cropping intensities in the states like Assam, Bihar, MP, Orissa, UP and West Bengal are 137.7, 137.8, 125.6, 154.6, 148.6 and 159.6 percent, respectively (FAI, 199495). This indicated that a vast majority of lands remain fallow during dry season due to lack of proper technologies, which are under rainfed conditions, neglected. Except West Bengal, more than half of the arable land remains fallow during rainless period. Increasing cropping intensities in rainfed uplands is not easily achievable but there is great potential of intensification of cropping in rainfed lowland by utilizing natural resources and conserved residual moisture. Pulses like black gram, green gram, lentil, lathyrus, chick pea and oilseeds like linseed, groundnut, rapeseed could not only increase the cropping intensities but also come forward to increase national productivity.

Introduction

Organic agriculture implies growing of agricultural crops and animal husbandry components while not chemical plant food, weed killer and pesticides used. An agricultural practice followed in organic farming squarely measure ruled by the principles of ecology and squarely measure amongst the ecological means that.

Organic agriculture could be a production system that avoids or mostly excludes the employment of synthetically combined fertilizers, pesticides, growth regulators, placental feed habit-forming and genetically changed organisms. Organic farmers admit crop rotation, inexperienced manures, compost, biological blighter management, and mechanical cultivation to keep up soil productivity and management pests as way as doable and practicable. Organic agriculture could be a distinctive production management system and key issue of maintenance of agricultural property that promotes and enhances agro-ecosystem health, together with multifariousness, biological cycles and soil biological activity, and this is often accomplished by victimization on-farm science, biological and mechanical ways in exclusion of all artificial off-farm inputs during this context, a serious thrust towards organic cultivation, however, would require variety of alternative initiatives and infrastructural support. Active involvement in learning crops and their diseases, development of organic manure, natural pesticides, coaching of farmers, and provision of storage and property square measure all vital areas to appear into.

Organic farming has become progressively vital in agriculture given the rising variety of issues that use of chemical fertilizers and pesticides squarely measure throwing up GM (genetically modified) crops could give a wonderful yield however their long-run effects square measure hitherto untested and other people aren’t quite able to trust these foods excepting for this, there has been a big rise within the demand for organic food across the globe. Promoting these organic-farming techniques solely leaves India best poised to take advantage on the export potential of those foods.

Introduction

Rainfed agriculture plays and will continue to play a dominant role in providing food and livestock for an increasing world population. Rainfed agriculture practiced on 80% of the world’ agriculture land area and generates about 70% of the world’s staple food including most of the food in poor communities in developing and least favoured areas. The most recent estimates have put global rainfed croplands at 1.75 billion ha (Bha) at the end of the last millennium, or about 5.5 times the irrigated area in the world. India ranks 1^st amongst the countries that practice rainfed agriculture both in terms of extent 86 (mha) and value production. Agriculture water management deals with the administration of a key input to agricultural production and offers to hope that land and water use will be intensified. Scarcity of water resources and growing of competition for water many sectors reduces its availability for irrigation. Effective management of water for crop production in water scarce area requires efficient approaches for increasing crop productivity and drought tolerance by genetic improvement and physiological regulation may be the means to achieve efficient and effective use of water. A single approaches would not be able to tackle the forthcoming challenge of producing more food and measures with engineering solutions (water saving technologies, irrigation methods, deficit irrigations, proper deficit sequencing, modernization of irrigation system) and agronomic and soil manipulation (seed priming, seedling age manipulation, direct or wet seeded rice. proper crop choice, integrating agriculture and aquaculture, increasing soil fertility and addition of organic matter, tillage and soil mulching). The term enhancing water productivity implies how we can most efficiently improve the outcome or yield of a crop with water currently in use, the answer lies in three main pathways of increasing water productivity with multiple use of water. Transpire most of the supplied water (minimization of unwanted loss), exchanged water for carbon dioxide more effectively inproducing biomass, and convert most of the biomass into grin or other farm of harvestable product. Many technologies to improve water productivity and the management of scarce water resource are available, amongst the most promising and efficient proven technique are limited supplemental application of irrigation for optimize the use of limited water and water harvesting for improved farm income in drier environment.Improving (water productivity, however requires exploiting not only water management but also other input such as improved cultivars, fertility management and cultural practice which influence crop productivity and yield.

Introduction

Despite fact that more than two-third of the earth’s surface is covered with water, currently, near about 450 million people in 29 countries are facing severe water shortage and at least 20 percent more water would be required to feed additional 3 billion populations by 2025. About 97.5 percent of ocean-sea water is not available due to its salinity and 2.49 percent is locked up in ice and only 0.01 percent is technologically available and economically accessible water either from surface or ground water sources for human uses. So water saving technologies developed so far is very pertinent to propagate amongst the users. Water is an essential natural resource for sustaining the environment and supporting life where the agriculture is the major user of water resource. Water is an indispensable for sustainable agricultural growth and development. Previously, rainfed agriculturewas associated primarily with conservational land treatments to check soil erosion and land degradation.But in the areas of medium to heavy rainfall, there is ample scope of tapping excess rain water through suitable water harvesting structures constructed for this purpose for its subsequent uses as irrigation or to apply lifesaving irrigation to the crops which should also come under the purview of water management for crop production. Although there is a difference in the objectives of water management where there is abundant availability of water from continuous flow connected with perennial sources or lakes and rivers and that of from restricted or limited supply from collection of excess rain through water harvesting structures.The former is associated with to obtain as much as yield of crop per unit area under water application and later is associated with increasing productivityof crop per unit of water application even under rainwater recycling and its effective management for the purpose of irrigation. Hence, both the rainwater and irrigation water are considered to be equally important to context of agricultural development of the country to get higher water use efficiency and proper utilization of water resources (Zaman,et.al., 2017).

Introduction

On the basis of inputs based ecological principles, the all possible and available resources are allocated to achieve maximum outputs. One of the most promising paradigms of external inputs based agriculture that have emerged for the benefit of small scale resource-poor farmers and that is termed as low external input and sustainable agriculture (LEISA), which can enable such farmers to achieve higher income and attain sustainability by: (i) Optimizing the use of locally available resources, thereby achieving a synergetic effect amongst the various components of the farming system (soil, water, animals, plants, etc.) so that they complement each other in the production of output; and (ii) Minimizing the use of external inputs, except where there is a serious deficiency and where the effect on the system will be to increase recycling of nutrients.

Low External Inputs and Sustainable Agriculture (LEISA): Low external input sustainable agriculture (LEISA) is a way of thinking about farming. It incorporates some ideas found in what people have labelled eco-logical, organic, regenerative, biological, or simply alternative agriculture. Amongst the goals that now drive the interest in low-input sustainable agriculture, two stand out: profitable and productive farming, and protection of resources and environmental quality. Companion objectives include ensuring safe and nutritious food supplies and reducing health risks to farm workers. LEISA involves farmers substituting management, scientific information, and on-farm resources for some of the purchased inputs they currently depend on maintain production sustainability. Sustainability has been defined, for the purpose of including resource-poor as well as resource-rich farmers, as managing agricultural productivity while maintaining or improving the resource base. This means that agriculture must be environmentally solid, economically feasible, socially scrupulous, and flexible (for future needs).

Introduction

The sustainable agriculture begins with ideal soil health with minerals and organic matters. The sustainable farming practices enhance and protect soil health, water quality and water quantity, biodiversity, manage insect pests, disease and weeds. The Indian council of Agricultural Research (ICAR) set up an All India Soil Survey Committee in 1953 which divided the Indian soils into eight major groups. (i) Alluvial soils (ii) Black (or Regur soil) (iii) Red and Yellow soils (iv) Laterite soils (v) Arid and desert soils (vi) Saline and alkaline soils (vii) Peaty and marshy soils and (viii) Forest and mountain soils.