eChapters

14.1 Introduction

The observation of phytosociology deals with the germination of growth on tree species in the industrial effluents. It shall be calculated germination potential based on germination capablility of the seeds. The growth parameters are measured then calculated leaf weight ratio, stem weight ratio, root weight ratio, top dry weight, sturdiness quatient, volume index and quality index. The following sub chapters dealing with formulae used to calculate the above parameters. The data so collected is then analyzed. The usual methods, which are employed in analysing the data, are averages, dispersion, skew ness, correlation, etc. The leaf weight ratio, stem weight ratio and root weight ratio are calculated by using the following formulae made by Kumaran (1991).

13.1 Introduction

The World Bank Standards for water quality parameters show important because the acute and chronic impact on aquatic ecosystem causes very dangerous to the animals and human beings. It describes about the level of toxic concentration would be allowed to the aquatic ecosystem to survive living beings. The Indian standards also describes about the limit of toxic constituent, which are harmful to the aquatic living beings.

12.1 Introduction

Volatile Organic Compounds (VOCs) are chemicals that evaporate easily at room temperature. The term “organic” indicates that the compounds contain carbon. VOC exposures are often associated with an odor while other times there is no odor. Both can be harmful. There are thousands of different VOCs produced and used in our daily lives.

11.1 Introduction

Generally, except particular cases, the typical civil wastewater do not present substantial differences according to the town where they are produced, therefore the type and the sequence of water treatment are nearly the same.

Conversely, the industrial wastewater characteristics are extremely varying according to the type of activity. For example, the oil industry wastewater will contain high concentrations of oily substances and hydrocarbons, the galvanic industry will produce heavy metal polluted wastewater, a food industry will produce wastewater containing biodegradable substances and so on. Consequently also the whole cycle of treatment, being aimed at the removal of particular pollutants, will be different according to kind of industry. The individual treatments of a wastewater treatment plant can be classified in different ways. According to the functioning principle it is possible to distinguish biological, physical and chemical treatments.

Biological plants are more commonly used to treat domestic or combined domestic and industrial wastewater from a municipality. They use basically the same processes that would occur naturally in the receiving water, but give them a place to happen under controlled conditions, so that the cleansing reactions are completed before the water is discharged into the environment.

Physico-chemical plants are more often used to treat industrial wastewaters directly, because they often contain pollutants which cannot be removed efficiently by microorganisms— although industries that deal with biodegradable materials, such as food processing, dairies, breweries, and even paper, plastics and petrochemicals, may use biological treatment. And biological plants generally use some physical and chemical processes, too.

10.1 Introduction

Industrial effluents, which are deteriorate their quality, and push them to the brink of extinction in the process of unplanned discharge, giving rise to the need for suitable conservation strategies for the receiving water body. Unfortunately, over the years, less attention has been given to industrial effluents world over. The degradation of the industrial effluents has altered their functions, affecting the ecological balance. The objectives of carrying out the physico-chemical and biological analyses of water bodies are as follows:

1. Generally, industrial effluent functions directly relate to their physical, chemical and biological integrity. Water quality evaluation for industrial effluent leads to information about their misuse by indicating the pollution status. 1st define water quality objectives as the overall direction and purpose of the industrial effluent and furthermore define goals as milestones to be met during the course of a book. Since the quality of aquatic life depends on the water quality, a thorough assessment of the water quality is an integral part of industrial effluent toxicity evaluation. The assessment of the chemical criteria of the industrial effluent helps in

9.1 Introduction

The sources and types of chemical pollution to which freshwater systems can be exposed are many and varied. The origins of pollutants entering these systems range from those that are predominantly point sources (i.e., industrial effluents) to those that are mainly diffuse, such as agricultural run-off and acid deposition. Some of these are effectively continuous, whereas others are intermittent or episodic.

Pollutants can also be characterized by their quality: general organic loading, specific organic toxicants, inorganic toxicants, and acids. While most of the sources listed above produce mixtures of these characteristics, particular components are enhanced. Industrial effluents generally are the source of specific toxicants, but might also lead to general organic loading.

Some consideration should also be given to the types of system exposed to these pollutants. Most freshwater systems flow, but some more rapidly than others; that is, lakes and ponds have a slow throughput, the so called lentic systems whereas that for rivers and streams is rapid. Because they flow rapidly, the so-called lotic systems have been used for the transport of materials, such as removing industrial pollutants from factories and organic effluents from sewage works.

A view exists that lotic systems that depend substantially on organic inputs from terrestrial ecosystems as a basis for their economy should have the capacity for self-cleansing of at least organic pollutants. However, this perception has been challenged recently (Royal Commission on Environmental Pollution, 1992). Of course, “still” or so-called lentic waters may also be important repositories of pollutants, and are certainly exposed to diffuse inputs from agricultural land leading to eutrophication.

Thus, the challenge for aquatic ecotoxicology is to develop methods that can not only assess but also estimate the ecological impact of chemicals on a variety of complex ecosystems under diverse and complicated circumstances (e.g., periodic perturbations or steady trickles, and mixtures of varying complexity). The predictive approach is important in risk assessment used in the regulation of chemical pollutants. Assessment, at times referred to as a “retrospective approach,” is used to determine whether particular contaminants have an impact on specified natural ecosystems. This chapter reviews current methods, first predictive and then retrospective approaches, to address such problems. Initially, one must define what is to be measured, for it has relevance to both approaches.

8.1 Introduction

Contamination of drinking water supplies from industrial waste is a result of various types of industrial processes and disposal practices. Industries that use large amounts of fresh water for processing have the potential to pollute waterways through the discharge of their waste into streams and rivers, or by run-off and seepage of stored wastes into nearby water sources. Other disposal practices, which cause water contamination, include deep well injection and improper disposal of wastes in surface impoundments.

Industrial wastes consists of both organic and inorganic substances. Organic wastes include pesticide residues, solvents and cleaning fluids, dissolved residues from fruits and vegetables, and lignin from pulp and paper to name a few. Effluents can also contain inorganic wastes such as brine salts and metals. This is an incentive for industry to pre-treat their water by neutralizing the chemically active components, recycling, dilution or extraction and collection for proper disposal.

The waste disposal practices, which presently pose a threat to drinking water supplies, include deep well injection of wastes and wastes that are dumped and retained in surface impoundments or evaporation ponds. (Ministry of Industries, 1994).

In keeping with the functions delegated to the Central Pollution Control Board under the Water (Prevention & Control of Pollution) Act, 1974, they covered a number of industries, their production and location with details of receiving water besides details on the raw material they used, the process they adopted to process them, inplant control systems, pollution control system provided and the future requirement with cost implications, monitoring system etc.

These documents are also aimed at developing standards for effluents and emissions as Minimal National Standards that can be adopted uniformly throughout the country. The State Pollution Control Boards (SPCBs) can tighten the standards, wherever the local situation demands.

While implementing these standards, the status of technologies adopted by the industries and further requirements to meet the overall objective of pollution control have been assessed. The technology requirement for pollution control industry wise has been presented in the following groups of industry categories.

7.1 Introduction

The rapid population and industrial growth experienced beginning in the middle part of this century has led to spiraling increases in the demand for forest wood. Historical data reveal that there was a 159.6% increase in overall wood production between 1970 and 1993. Wood is defined simply as wood in the rough, and includes trees felled for any purpose. The majority of total wood production has been for use as fuel wood and charcoal, much of which is harvested by villagers, and to some degree urban squatters.

Since 1970, there has been a 160% increase in fuel wood and charcoal production. The largest portion (104%) occurred between 1970 and 1980, which may be attributed to the introduction of fuel wood species earlier, during the Second Five Year Plan period. Looking at the decades to come, the demand for fuel wood is likely to continue growing in pace with future increases in population, which is growing at the rate of 24 % per decade. It is estimated that by the year 2010, demand for fuel wood and charcoal will exceed 33 million cubic meters (FAO, 1993). Since there is expected to be little further change in the area under potential productive forests, there will be an increasing probability of a shortage of wood production in India (Planning Commission, 1992).

6.1 Introduction

The state of India’s forests is important in many ways, whether it be as a source of fuel and fodder for rural citizens, of industrial inputs for a growing economy, as a habitat for thousands of plant and animal species, a sink for carbon dioxide emissions, or as a protective cover for its soils.

The forest resources forms an ecological system consisting of tree dominated vegetative associations. Forests not only provide timber, fuel wood, pulpwood fodder and fiber grasses, and non wood forest produce and support industrial and commercial activities but also maintain the ecological balance and life support systems essential for food production, health, and all round human development. The innate complexity and inherent diversity of forest ecosystems make it difficult to establish clear cause-and effect relationship or to predict the outcomes of a given intervention accurately. Figure 6.1 shows that the percentage of land mass with forest covered and non forest area in India

5.1 Introduction

The source of pollution are many and varied. The most critical are domestic sewage and industrial effluent discharging into rivers, lakes, ponds etc. Treatment facilities for domestic sewage in class 1 cities having population of more than 1,00,0000 and class 2 cities having population between 50,000 and 99,999 can process hardly 10% of the wastewater generated. Wastewater treatment facilities are difficult to quantify due to lack of continuous data. On an average, the treatment capacity in class 1 cities can handle only 60% of the wastewater collected and less than 15% of the total volume of wastewater generated.

The Indian industry has grown annually at an average rate of 5.5% during the last 50 years. Among different industrial sectors, water pollution is concentrated with in a few industrial sub-sectors mainly in the form of toxic wastes and organic pollutants. Out of the total pollution contributed by the industrial sub-sectors, 40% to 45% of the total pollutants can be traced to the processing of industrial chemicals and nearly 40% of the total organic pollution to the food products industry alone. Food products and agro-based industries together contribute 65% to 70% of the total industrial wastewater in terms of organic load. Blair T Bower, consultant, the Urban Institute, USA, remarks: "… If substantial further growth of Asia’s cities cannot be avoided and if the environmental disasters that could be associated with that growth are to be prevented, there is only one alternative: urban environmental quality management must be substantially improved throughout the region".

The total quantity of water used by the domestic and industrial sectors is much less than that consumed for irrigation. However, the wastewater released from the above sectors has a great concentration of pollutants, and is discharged at specific disposal points. Thus, the wastewater generated from domestic and industrial projects causes much more water pollution as compared to any other source.

4.1 Introduction

India is a land of many rivers, lakes, ponds, coastal, marines and mountains. Its geographical area of about 329 million hectare is crises crossed by a large number of small and medium, large rivers, some of them figuring amongst the mighty rivers of the world. The rivers and mountains have a greater significance in the history of Indian civilizations, development, religious and spiritual life. It may not be an exaggeration to say that the rivers are the heart and soul of the Indian civilizations

India is a union of States with a federal set up. Politically, the country is divided into 26 States and 7 Union Territories. A major part of India’s population of 869 millions (1991 census) is rural and agriculturally oriented for whom the rivers are the source of their life. India is a land of many religions, diversity of cultures and languages. The different regions of the country have different cultural, linguistic and other ethnic groups. The land and people present a vast panorama of diversity in unity. Physiographically, India may be divided into seven well-defined regions.

3.1 Introduction

India, when gained independence in 1947, was predominantly an agrarian economy, with a stagnant national income. The country inherited a weak industrial base, restricted to only a few industries. Agricultural growth was virtually negligible, the country had a stagnant cropped area where by only a very small proportion of agricultural land was irrigated. On the eve of the country’s independence, on 15^th August 1947, Jawaharlal Nehru, India’s Prime Minister, reminded the country that the task ahead included ending poverty, ignorance, and disease and inequality of opportunity. India began the process of planning with the launching of the 1^st five-year plan in April 1951. The central purpose of planning was to ‘initiate a process of development which would raise living standards and open out to the people new opportunities for a richer and more varied life’. Afterwards, the five-year plans were formulated seeking development in a sustainable manner.

The country, over the past has travelled a long way indeed in its drive towards economic growth, modernization of the economy, feudal economy at the time of independence has been transformed into one based on a fairly developed and diversified industrial structure and a sound agricultural base with a large potential for further industrialization and development. The income and consumption levels of people, on an average, have increased and the consumption basket has diversified. A noteworthy achievement indeed has been the elimination of famines with which the country continued to be afflicted right until independence. That achievement is far from negligible since many other countries in Asia and Africa are yet to free themselves of this malady. There is also other achievement, varying from the successful functioning of a democratic system to the emergence of a strong and large scientific community (Dreze Sen, 1995). The figure 3.1 shows the per capita income during 1997-1998. It shows that the maximum income from Northern India compared to Southern India. However, having adapted the pattern of economic development that brought prosperity to the Western, India has also seen widespread environmental damage and degradation in the pursuit of economic growth. The concern for preserving the environment against the onslaught of industrial expansion, intensification of agricultural, and adoption of a resource-intensive lifestyle has not been given the attention it deserved, and the costs of environmental degradation have not been internalized in the development process. While the Indian economy study made by two World Bank staffers shows that the country is paying an enormous price for this onward march, which has brought in its wake ecological devastation and numerous health problems.

The science is a process of refining our understanding of nature by continual questioning and active investigation on questions. Students can approach science in this manner, rather than as a collection of facts to be memorized. The Environment is to provide up-to-date information to the important concepts in the study of environment. Information is presented from an analytical, observation and multidisciplinary perspective from which we must view environmental issues in order to deal successfully with them. The environment may be defined as response of a human being influenced by various factors such as abiotic and biotic, which are present in the ecosystems.

2.1 Multidisciplinary Approach

The approach of environment science is multidisciplinary in nature like botany, zoology, physics, hydrology, hydraulics, chemistry, biophysics, biochemistry and biology. It integrates various subjects and includes few of the most important topics of modern civilization as well as oldest philosophical concerns. Applied and basic aspects of environment requires a solid function in the nature of our relationship with nature, in addition to fields like economics, anthropology, history, sociology and philosophy of the environment.

Water is an important element for life on the earth. It is an essential recurrent natural resource for environmental sustenance, agricultural productivity, industrial growth, power production, enrichment and renewal of land and air. For easy assess to the water, the first human settlements occurred along the banks of rivers and ensuing civilizations flourished in river valleys. For example, the Indian civilization of Mohanjodaro and Harappa developed in the Indus valley, the Egyptian civilization in the Nile valley, the Chinese civilization in the Yangtze valley, the Babylonian civilization between the Tigris and the Euphrates rivers, Aztec, Maya and Incas civilization in the basin of Amazon river.

The industrial revolution, which, began in the early 18th century in some European and Asian countries, set in the motion for new forces in the society and greatly changed the pattern of social life on the earth. Rapid industrialization and urbanization subsequently brought many changes in the environment and ecosystems in the world. India also witnessed a phenomenon of industrial development in the post independent era. The last four to five decades have witnessed population explosion and increase in the per capita consumption of food, consumer goods and utilization of natural resources. These have lead to the proportionate increase in the domestic and industrial effluent generation in India. The water pollution is continuously increasing at an alarming rate in Europe and Asia. By the end of this century. India's Population is projected to double itself from its present level. Similarly the per capita consumption of food has been estimated to increase by 40% resulting in 50 % production of industrial and domestic effluents in near future.

Apart from the quantity, there will be qualitative changes in the effluent generation which are likely to contain greater amount of oil, toxic chemicals, detergents and dyes. A large number of these compounds are non-biodegradable and are cumulative, thus rendering toxic product. Certain group of animals and plants are selective in their functions and can executive certain toxic chemicals and heavy metals. These biomes are helping more effectively on recycling of industrial effluent as well as domestic effluent management system.

In nature, there exists a balance between abiotic and biotic communities like animals and plants population, raw materials and total biomass present at any time. This balance ensures natural recycling and optimum production in naturally balanced ecosystems. The plant growth is slow, but it ensures optimum utilization of waste products and a healthy environment. The increased population and its human desire to possess all comforts and pleasures had lead to over exploitation of natural resources. The high demand of natural resources lead to the beginning of waste accumulation due to the creation of man made imbalances in the environment. The environment is to provide up to date information about important concepts in surrounding. Information is presented from an analytical, observational and multidisciplinary perspective from which we must view environmental issues in order to the study successfully.

Greenhouse technology development has made good progress in India during the last two decades, and steps necessary for promoting greenhouse cultivation of flower and vegetable crops have been started. Energy-efficient greenhouse cultivation continues to be an area of active research and development, and this is sought to be achieved through precision equipment and protocols. While the gap between the demand and supply of most horticultural crops remains wide and the country plans to double the production of horticultural crops by 2012, the protected cultivation technology holds the key to meet the targets. It clearly emerges that greenhouse technology has multipurpose application for sustainable development of a hilly zone. During harsh winter which otherwise threatens the survival of human beings in these remote hilly areas, popularization and further improvements in greenhouse management could provide a sign of relief in solitude of white snow cover.

The popularity of greenhouse-grown produce continues to rise as it provides a variety of produce during the “off” season. Greenhouses are good for healthy plant nursery production and other a number of crops for profit. Though the greenhouse farming in India like in other countries is progressing but there are certain problems and constraints as stated below.

1.Greenhouse production generally is highly technical and requires constant and continuous attention during cropping period. Relevant information about the crop environmental requirement such as right temperature, humidity etc is essential.

2.Knowledge about the right type of inputs for greenhouse production is a must which is not easily available.

3.Greenhouses cultivation increases the land, water and fertilizer productivity along with reduction in pesticide use. But such interventions are associated with very high initial cost. Although, it is linked with several Government Schemes in India and have 50-90% of subsidies depending on intervention, status / socio-economic condition and policy of State and Central Government.

4.Uninterrupted and regular power supply is required for operating cooling and heating system of the controlled environment greenhouses which necessitate a back-up power pack which is also expensive and underutilized.

Nutrient film technique popularly known as NFT is one of the methods of soilless farming or hydroponics where in plants have their roots in a shallow stream of recirculating water containing all the nutrients required for plant growth dissolved without any solid growing medium. The lower portion of roots remain submerged in flowing nutrient medium in a water tight gully having enough air for the roots. The nutrient film technique was developed during the late 1960s by Dr Allan Cooper at the Glasshouse Crop Research Institute, England. The method is already used in commercial horticulture in many countries including India. NFT is potential for other crops such as animal fodder and even energy-source plants for fuel production.

NFT related technologies

Hydroponics : Cultivation of plants in nutrient solutions is known as hydroponic cutlivation. This ia gerally done under protected structures and in containers arranged horizontally or vrtically (vertical garden). Use of nutrient film or fertilizers is made to feed the plants. Hydroponics can be practiced following nutrient film technique method, trough method, deep water floating method and coco peat bag culture.

Soilless media or culture

Gravel culture is a general term which applies to the growing of plants without soil in an inert medium into which nutrient solutions are usually pumped automatically at regular intervals. Haydite (shale and clay fused at high temperatures), soft- or hard-coal cinders, limestone chips, calcareous gravel, silica gravel, crushed granite and other inert and slowly decomposing materials are included in the term “gravel”. The more important greenhouse flowering crops include roses, carnations, chrysanthemums, gardenias, snapdragons, lilies, asters, pansies, annual chrysanthemums, dahlias, bachelor buttons and others.

Media ingredients and Mix

Commercially available materials like peat, sphagnum moss, vermiculite, perlite and locally available materials like sand, red soil, common manure/ compost and rice husk can be used in different proportions to grow greenhouse crops. These ingredients should be of high quality to prepare a good mix. They should be free from undesirable toxic elements like nickel, chromium, cadmium, lead etc. Most common medium other than soil used in India in greenhouses is coco peat. In other countries these are Rockwool and Peat-vermiculite.

Pasteurization: The heat treatment given to soil to free it of harmful microorganisms or pathogens and pests is called pasteurization. It kills weed seeds also.

Pasteurization of greenhouse plant growing media

Greenhouse growing medium may contain harmful pests such as disease causing organisms, nematodes, insects and weed seeds. It is advisable to decontaminate it by heat treatment or by treating with volatile permissible chemicals.

Flooding

Flooding affects both above and below ground ecosystem processes in greenhouses. Below-ground changes may be less obvious, they are as important as the above-ground changes. Soil microorganisms are sensitive to disturbance, and shifts in soil microbial community structure are expected when anaerobic conditions develop from flooding. The useful aerobic microbes are destroyed by flooding. It takes time to built-up their population in the soil to benefit plants. Due to anaerobic condition created by flooding in greenhouse plant roots in soil are not able to breath, function and hence wilting of plants occurs. Flood irrigation in excess create flood like condition in greenhouses at time. Excess water in soils is a major factor affecting plant survival and functioning. In saturated soils, the supply of atmospheric oxygen into the soil is curtailed and various facultative and obligate anaerobic microorganisms use oxidized compounds as electron acceptors for respiration, thus converting them to reduced forms. The reduction and the associated processes influence plant survival, growth and functioning in wetlands. Flood irrigation should always be just wet the soil not flood inviting stagnation of water.

A chain of reactions is initiated upon soil flooding leading to reduced soil redox potential conditions. These reactions include physical, chemical and biological processes that have significant implications on plants growth. Physical processes include restriction of atmospheric gas diffusion in the soil leading to depletion of soil oxygen and accumulation of carbon dioxide. Shortly after flooding, the limited supply of oxygen in soil pore spaces is depleted rapidly by roots, microorganisms, and soil reductants. This process leads to oxygen depletion and reduction in soil oxidation reduction potential followed by a chain of soil chemical changes. The processes that follow include denitrification, reduction of iron, manganese and sulphate, and changing soil pH

Drainage is the natural or artificial removal of excess water from a surface or sub-surface from an area or field or soil or greenhouse. The internal drainage of most agricultural soils in greenhouse is good enough to prevent severe waterlogging. Water logging creates anaerobic conditions that harm root growth in absence of oxygen. Soils need artificial drainage to improve production or to manage water supplies in certain conditions. Though the roots need moisture but they need oxygen too and poor drainage is g result in roots rotting and death of plants.

The irrigation water inside the greenhouse may accumulate and cause anaerobic condition. Similarly plants in pots should not accumulate water. Water should not stand in pots and beds for longer period. If it stays longer drainage is poor and needs to be corrected. It is better to have good drainage system in greenhouses or protected structures.

Besides irrigation rains water seeps in the greenhouse. The drainage system prevents running or its accumulation in low lying portion of the greenhouse. Drainage system in greenhouses is a must for avoiding damage to the crops.

The following various types of irrigation methods and their systems are used in crop production in greenhouses and plant nurseries.

1.Hand Watering

2.Perimeter Watering System

3.Tube Watering System

4.Drip Irrigation System

5.Overhead Spray System

6.Ebb and Flow System.

About 80% of the world population live in developing countries and are dependent on agriculture. Agricultural products, just after harvesting, are dried to the safe moisture level. Open solar drying for drying agricultural products is being practiced since ages throughout the world. Due to its several drawbacks as danger of (dust, rain, ultra-violet rays, birds, animals etc.), advance technique, i.e. greenhouse drying, is being adopted for drying crops to reduce the drying time and increase the quality of the food products.

Drying involves a heat and mass transfer phenomenon in which heat energy supplied to the product surface is utilized in two ways: (i) to increase the product surface temperature in the form of sensible heat and (ii) to vaporize the moisture present in product through the provision of the latent heat of vaporization. The removal of moisture from the interior of the product takes place due to induced vapour pressure difference between the product and surrounding medium. The moisture from the interior diffuses to the product surface to replenish the evaporated surrounding moisture.

The working principle of greenhouse drying is in which the product is placed in trays receiving the solar radiations through the plastic cover and moisture is removed by natural convection or forced convection.

Greenhouse drying are being adopted to reduce the losses and to increase the quality of the dried products. Solar energy is the most promising power source of energy for drying of agricultural products. Most of the farmers adopt open sun drying because it is abundant and inexpensive. But the open sun dried products are also subjected to remarkable losses due to environment. Losses of fruits and vegetables are estimated to be 30%-40% during drying under open sunlight. The post-harvest losses can be reduced by adopting advanced means of drying, i.e. greenhouse drying. The greenhouse dryer can be operated in natural and forced mode as required. Studies reveal that the greenhouse dried products are of superior quality and better colour retention as compared to open sun drying.

There are several systems for greenhouse heating based on heat source and purpose or crops to be produced in greenhouse.

Electric heaters

Unit space heaters, either floor mounted or supported, are normally dependent on electricity supply supported by stand-by generators. Abroad they are fuelled with natural or bottled gas or fuel oil and use fans for heat distribution. This system requires a relatively moderate capital investment, is easy to install, and provides for easy expansion of facilities. If unit air heaters are used, they should be spaced and directed to blanket the entire area with heated air.

Hot Water Systems

Hot water systems utilize metal pipes that can be perimeter, under benches, or overhead fan forced unit heaters can be used. This system requires a boiler, valves, and other necessary controls. Hot water system is simpler to install and normally requires less maintenance than a steam system. Hot water systems are mainly used in smaller greenhouse.

The modern or climate controlled greenhouse requires massive inputs of energy and cost of claddings to grow crops out of season making them high cost structures. However, growing of certain horticulture crops and their nurseries out of season is happening in a sustainable way, using the heat from the sun and soil too. These are called passive solar greenhouses designed to retain as much warmth as possible. This concept has revolutionized vegetable production in Ladakh, high altitudes and other parts of the country in winter months.

The solar greenhouse is especially successful in China and are contributing mainly in vegetable production. Solar passive greenhouses are designed in different shape size using different local and other materials keeping in view the local climate and terrain. The poly houses mentioned earlier such as, low cost polyhoses, Ladakhi poly house, solar trench, polyench are passive solar green houses. Being the opposite of the climate controlled greenhouse, the passive solar greenhouse is heated all-year round with solar energy alone, even when the outdoor temperature drops below freezing point. The indoor temperature of the structure can be higher than the outdoor temperature. The temperature can be around 25°C (45°F).

Such greenhouses have been experimented by Defence Research and Development Organization through its establishment FRL (Field Research Laboratory) now DIHAR (Defence Institute of High Altitude Research), Leh/ Ladakh since 1962 during November to the end of March, the period during which the outside temperature drops there below freezing. The average temperature in the coldest month is between -15°C and -18°C. Over the several decades of research different and effective designs of such greenhouses have been standardized which are suitable to produce fresh vegetables like most of the leafy vegetables, tomato, cole crops and potato at sub zero temperature.

There are different types of greenhouses, the low cost and high cost or low technology or high technology greenhouses. The cost of greenhouse and expenditure on crop production under these greenhouses would vary according to technology to be used and the crop is to be produced. The cost would vary from place to place with location of greenhouse. For each type of greenhouse its cost would vary according to geo-climate, the production practices and input expenditure/availability. The cost of construction of greenhouse in 2019 hence varies from Rupees 500 to 6000 per square meter.

The variety of greenhouses and greenhouse material, equipment and accessories are so many. However, there are certain basic materials that essential in almost all types of green houses. These are

Structural framing materials

Such materialsinclude low maintenance non-heat conducting timber; strong and durable galvanized steel; or light, low-maintenance and sturdy aluminium alloys. Though plastic pipe frames are usable, they are not very strong to withstand snow load or strong wind sheering forces. What one should choose as the framing material would be determined by the material one wishes to use as glazing, his budget and the permanence of the structure one desires. Aluminium is a popular material for greenhouse framework because it is relatively lightweight, rustproof, affordable and easy to assemble. The downside is that it is not a good insulating material and in very cold weather, heat loss from the metal frame could inflate your heating bill. Also, you would need to look for sturdy frames if your greenhouse is located in an area that experiences high winds. Condensation could also occur on an aluminium frame. Wooden structural frameworks for garden greenhouses are also a popular choice for its aesthetic value, natural feel and the ’warmth’ it exudes. It is an easy material to work with especially if you are not using a greenhouse kit for building. Some greenhouse owners would settle for nothing else as they believe it is the only material that complements the natural beauty of plants inside the greenhouse! Wood is a good insulating material so it will not allow heat loss in cold weather. Reinforced wood has superior strength and has an excellent load bearing capacity. Being a natural material, it has the potential to develop mildew or disease and offer a haven to tiny pests. So, when you choose wood to build the framework of your greenhouse, be sure that you pick a high quality hardy wood such as redwood, cypress or cedar. Also, treat wood with non-hazardous chemicals so that your plants are not adversely affected. The preservatives used for wooden greenhouse frames should be pressure treated, salt type or copper naphthenate. Copper naphthenate is a general use preservative used for pressure treating utility poles and timber. It is known to be very effective in preventing mould, mildew and dry rot. It works very well against wood-damaging fungi and insect pests. Pentachlorophenol is a restricted use wood preservative and is toxic to plants and humans. It is not available to the general public and poles or timber treated with it are not suitable for use in a greenhouse. PVC pipe can also be used as support for small greenhouses that are to be covered with polyethylene, but PVC requires additional support to withstand strong winds. Being flexible, PVC can be used particularly well in hoop houses. Though it has the advantage of offering insulation and, if UV treated, are long-lasting, they are not good at bearing the load of hanging baskets and shelving to any appreciable degree. PVC that is treated to be resistant to ultraviolet radiation is also known as UPVC.

Greenhouses should provide a controlled environment for plant production with sufficient sunlight, temperature and humidity. Greenhouses need exposure to maximum light, particularly in the morning hours. Consider the location of existing trees and buildings when choosing your greenhouse site. Water, fuel and electricity make environmental controls possible that are essential for favourable results. For this reason, use reliable heating, cooling and ventilation.

The greenhouse temperature requirements depend upon which plants are to be grown. Most plants require day temperatures of 70 to 80 degrees F, with night temperatures somewhat lower. Relative humidity may also require some control, depending on the plants cultured. Some plants grow best in cool greenhouses with night temperatures of 50 degrees F after they are transplanted from the seeding tray. These plants include azalea, daisy, carnation, aster, beet, calendula, camellia, carrot, cineraria, cyclamen, cymbidium orchid, lettuce, pansy, parsley, primrose, radish, snapdragon, sweet pea and many bedding plants. Some plants grow best in warm greenhouses with night temperatures of 65 degrees F. These plants include rose, tomato, poinsettia, lily, hyacinth, cattleya orchid, gloxinia, geranium, gardenia, daffodil, chrysanthemum, coleus, Christmas cactus, calla, caladium, begonia, African violet, amaryllis and tulip. Tropical plants usually grow best in high humidity with night temperatures of 70 degrees F.

Planning

A greenhouse, is basically the purpose of providing and maintaining a growing environment that will result in optimum production at maximum yield. The agriculture in the controlled environment is possible in all the regions irrespective of climate and weather. It is an enclosing structure for growing plants, greenhouse must admit the visible light portion of solar radiation for the plant photosynthesis and, therefore, must be transparent. At the same time, to protect the plants, a greenhouse must be ventilated or cooled during the day because of the heat load from the radiation. The structure must also be heated or insulated during cold nights. A greenhouse acts as a barrier between the plant production areas and the external or the general environment.

Site selection and orientation

A greenhouse is designed to withstand local wind, snow and crop loads for a specific cropping activity. In this way, the structure becomes location and crop specific. The building site should be as level as possible to reduce the cost of grading, and the site should be well aerated and should receive good solar radiation. Provision of a drainage system is always possible. It is also advisable to select a site with a natural windbreak. In regions where snow is expected, trees should be 30.5 m away in order to keep drifts back from the greenhouses. To prevent shadows on the crop, trees located on the east, south, or west sides should be at a distance of 2.5 times their height.

Soil is the main growing medium. Natural as well as synthetic substitutes to soils are cropping up. Under greenhouse cultivation growing medium is generally top soil as used in open field/traditional farming. The practices of soil preparation for planting crops are more or less same as under open field. Generally, crops are planted on raise beds. As under open conventional farming soil preparation are made as per the crops or their varieties/hybrids to be grown. To enrich the soil with nutrients soil is tested for its physical and chemical properties and amended accordingly keeping in view the crop requirement. The soil composition is checked with each crop cycle and amended as per requirement of next crop. To avoid the harmful microbes and insects build up in the soil it is advisable to solarize or fumigate the greenhouse soil each year during hottest month of the year. Soil solarisation is an environment friendly soil pathogen management method and practiced widely in north India.

Soil Solarisation

Soil solarisation is an environment friendly method of using solar thermal power for controlling pests such as soil borne plant pathogens including fungi, bacteria, nematodes, and insect and mite pests along with weed seeds and seedlings in the moist soil by mulching the soil usually with a transparent polyethylene cover, to trap solar energy in greenhouses. It may also be described as a method of decontaminating soil or soil disinfestation using sunlight or solar thermal power. This energy/temperature causes desirable physical, chemical, and biological changes in the soil.

The productivity of a crop is result of genetic make-up (heredity) and environment (climate) and their interaction. The components of crop environment or climate or microclimate are light, temperature, air compositions and the nature growing medium or soil. In open fields, only manipulation of nature of the soil or root medium by tillage, irrigation and fertilizer application is possible. Under greenhouse structure control of any one or more of the components of the micro climate is manipulated.

Light

The visible light of the solar radiation is a source of energy for plants. Light energy, carbon dioxide (Co2) and water all enter in to the process of photosynthesis through which carbohydrates are formed. The production of carbohydrates from carbon dioxide and water in the presence of chlorophyll, using light energy is responsible for plant growth and reproduction. The rate of photosynthesis is governed by available fertilizer elements, water, carbon dioxide, light and temperature. The photosynthesis reaction can be represented as follows

Many crops can be grown in greenhouse but the choice depends on number of factors.

1.Requirement of the farmer, what for she/he wants to grow the crop.

2.For personal use number of vegetable crops and herbs and fruits like strawberry and papaya can be grown.

3.In case of commercial crops, the market must be ascertained before the choice of the crop.

4.Greenhouse must be equipped to create micro-climate for the crop of choice.

5.The choice of crop is a crucial factor for the economic feasibility and success of a commercial greenhouse operation. The revenue of cultivated crop makes the venture to progress.

6.Crop varieties, suitable for greenhouse cultivation should differentiate themselves from open-field varieties to fetch better price on quality.

Application of greenhouses in agriculture is mainly to modify microclimate for the production of crops with multiple objectives of raising crops in season offseason, round the year, early crops, late crops, breed crops, raise genetically engineered plants, seed production so and so forth. With hi-tech agriculture and modern techniques greenhouses are used for growing crops anywhere and everywhere, on soil under soil, water, under water and space. Greenhouses are mainly used for crop nursery production, crop production largely in vegetables, flowers and herbs. Among fruits mainly strawberry is grown under greehouses commercially. Other fruits can also be grown.

Besides crop production greenhouses are used for dehydration or drying of produce, seed production, for crop improvement using biotechnology and other sciences. Use of greenhouses in uncongenial environments for crop production is common in places like high altitudes, deserts, arctic climate and alike. One of the largest greenhouse complexes in the world is in Almería, Andalucía, Spain, where greenhouses cover almost 200 km2 (49,000 acres). One of the important use of greenhouses world over is raising tissue culture plants through a popularly known process hardening. For hardening of tissue culture plants different types of low and high technology greenhouses are must. Greenhouses in hot, dry climates used specifically to provide shade are sometimes called shade houses. Hydroponic crop production is generally done in greenhouses. Greenhouses are also used as retail market centres mainly for ornamental plants and seedlings and grafts of horticultural crops. Greenhouses are used for maintaining bee (honey bees and bumble bees) colonies as crop pollinators.

Different types of greenhouses or protected structures are designed to meet the specific needs. They can be classified based on shape, utility, construction, cladding material, net houses and technology adopted.

A. Classification based on shape of greenhouse: Greenhouses can be classified based on their shape or style. For the purpose of classification, the uniqueness of the cross section of the greenhouses can be considered as a factor. As the longitudinal section tend to be approximately the same for all types, the longitudinal section of the greenhouse cannot be used for classification. The cross sections depict the width and height of the structure and the length is perpendicular to the plane of cross section. Also, the cross section provides information on the overall shape of the structural members, such as truss or hoop, which will be repeated on every day. The commonly followed types of greenhouse based on shape are lean-to, even span, uneven span, ridge and furrow, saw tooth and quonset.

Lean-to type greenhouse: A lean-to design is used when a greenhouse is placed against the side of an existing building. It is built against a building, using the existing structure for one or more of its sides. It is usually attached to a house, but may be attached to other buildings. The roof of the building is extended with appropriate greenhouse covering material and the area is properly enclosed. It is typically facing south side. The lean-to type greenhouse is limited to single or double-row plant benches with a total width of 7 to 12 feet. It can be as long as the building it is attached to. It should face the best direction for adequate sun exposure. The advantage of the lean-to type greenhouse is that, it usually is close to available electricity, water, and heat. It is a least expensive structure. This design makes the best use of sunlight and minimizes the requirement of roof supports. It has the following disadvantages:

Plants require proper environment for its growth and development. If environment is not suitable crop would not do well. To ensure proper environment to commercial crops for their better growth and development covered structures are used which provide microclimate appropriate for their growth and development. Growing of crops under such protective structures, also known as greenhouses, is termed as greenhouse technology. The structures harness solar radiation for photosynthesis in plants or can be provided with artificial lights (LEDs) for the purpose. The technology embraces many aspects of farming such as modelling of structures, agronomic practices for the production of the crop and the commercial viability of the venture. The technology ensures crop production in a cover more or less independent of natural prevailing environment. The covering or cladding permits desirable aspect of sun and air and help in modifying crop production environment inside. The modification of environment is aimed of creating micro-climate inside the structure/greenhouse most appropriate for the growth and development of the crop.

Hence greenhouse can be defined as a framed or inflated structure with claddings like glass polyethylene sheets, poly carbonates, fibre reinforced plastics and others in which plants are grown by creating microclimate conducive to crop for its growth and development with or without automation and mechanization. The purpose of growing crops under greenhouse conditions is to extend their cropping season and to protect them from adverse environmental conditions, such as extreme temperatures, precipitation and pests. A large number of greenhouses/poly houses have come up in almost all states of India. Though in infancy but greenhouse cultivation particularly in horticulture crops and nursery production is visible.

Precision agriculture is yet to be popularized for taking its enormous advantages. In laser land levelling and micro irrigation/ fertigation it must have made its prominence but others it is with research institutes where research is focussed on the spatial variability of production environments, development of efficient and suitable data management systems, efficiency of various types of image analyses and optical sensing, efficiency of sensors and related technologies, designs of precision agriculture equipment, optimal inputs and service uses, and their spatial allocations, potentials of unmanned aerial vehicles (UAVs), nanotechnologies and several others.The adoptions of precision-agriculture technologies have, so far, mostly been limited to parts of developed countries. Major contributions to the profitability of precision agriculture is reduced costs of plant protection inputs and higher output revenues.

Site-specific weed control technologies practiced in precision farming are defined as machinery or equipment embedded with technologies that detect weeds growing in a crop and take action to maximise the chances of successfully controlling them taking into account predefined factors such as economics.Some of the commercial hardware and software developed for precision agriculture practices comprise tools for weed mapping and control software that adapts spraying to local weed occurrence. However, few farmers have adopted sitespecific weed management, although several studies have shown that weed occurrence and density varies significantly within a farm or a field. Site-specific weed control techniques have gained interest in the precision farming community over the years. Managing weeds on a subfield level requires measuring the varying density of weeds within a field. Decision models aid in the selection and adjustment of the treatments, depending on the weed infestation. The weed control can be done either with herbicides or mechanically. A site-specific herbicide application technology can save large amounts of herbicides. Mechanical weed control techniques adapting to the weed situation in the field are applicable to a wide spectrum of crops.

A system for the discrimination of different weed species and crops from images is done which generates weed maps automatically. Models for the yield effect of weeds are developed and applied in on-farm-research experimental setups. Economic weed thresholds are derived and used for an herbicide application with a patch sprayer.Herbicide use has not eliminated weed problems in agriculture and the need for manual weed removal is still an issue within specialty crop systems, particularly during the first several weeks of crop emergence when competition for resources is greatest.

Precision agriculture is a powerful technology with potentially important applications to weed management. However, growers should remember good agronomic practices, including preventing weed infestations, managing herbicides wisely to prevent resistance, and minimizing environmental impact associated with weed management. Weeds, and methods used to control weeds, can have negative economic and environmental impacts. With precision agriculture, growers can take advantage of the patchy nature of weeds by targeting management efforts only where they are needed instead of wasting expensive and potentially hazardous inputs where weeds are not present. Weeds are patchy because weed spread, survival, and reproduction are variable within a field and over time. Weed patches stay in about the same place from year to year, even though weed density within a patch may vary

Precision farming involves the collection of data by observation and measurement, and the subsequent response. Sensing is key to the collection of data; whether this is remote from space by satellites, by aircraft or drones, or by proximal sensors used on the ground, mounted on vehicles or otherwise. Responses are increasingly automated and data are often integrated into wholefarm management systems. Early commercial applications were directed towards improving crop nutrition, however, utilising precision technologies to control weeds, pests and diseases is now a reality.

Precision crop protection requires detailed data on the occurrence and distribution of problems at the earliest possible stage of detection. An early detection is the key for successful management of pests in precision farming. Some of the key aspects are:

Identification: Identifications of crops, targets and beneficial; temporal and spatial distribution: presence of the target before, during and after the crop growth period;

Sampling techniques: statistically valid sampling regimes must be used to permit an accurate view of any problem

Thresholds: under particular circumstances, the point at which action to ensure levels of infestation or damage are kept to those deemed to be acceptable;

Prediction: the speed and pattern of development of a problem must be capable of being modelled, e.g. spread and severity of insect pests and fungal diseases; weed emergence according to species, dormancy and environmental conditions.

Yield mapping or yield monitoring is a technique in agriculture of using GPS data to analyse variables such as crop yield and moisture content in a given field. This data produces a yield map that can be used to compare yield distribution within the field from year to year. This allows farmers to determine areas of the field that, for example, may need to be more heavily irrigated or are not yielding any crop at all. It also allows farmers to show the effects of a change in field-management techniques, to develop nutrient strategies for their fields, and as a record of crop yield.

Yield is ultimate indicator of variation of different agronomic parameters in different parts within the field. So mapping of yield and interpretation and correlation of that map with the spatial and temporal variability of different agronomic parameters helps in development of next season’s crop management strategy. Yield monitors measure the volume or mass flow rate to generate time periodic record of quantity of harvested crop for that period. Time periodic yield data is then synchronized with location address obtained from on-board GPS system to create most common colour coded thematic map. Yield mapping can be carried out easily in mechanized crops. By using either loading cells that weighed the crop passing on a conveying belt or an array of sonic beam mounted over the grape discharge chute to estimate the volume, and the tonnage, of fruit harvested. Tree crops seem to have more stable yields. In handpicked fruits yield mapping is more difficult. Yield maps are one of the most valuable sources of spatial data for precision agriculture. In developing these maps, it is essential to remove the data points that do not accurately represent the yield at a corresponding location. Map averaging or smoothing is usually done to aid data interpretation. A long yield history is essential to avoid drawing conclusions that are affected by the weather or other unpredictable factors during a particular year. Processed yield maps can be used to investigate factors affecting the yield or to prescribe variable rate applications of agricultural inputs according to spatially variable yield goals (yield potential).

Sensing of heterogeneities in the field is the prerequisite for timely and spatially adjusted insect pests and disease management. Recent developments in sensor technologies have led to a broadening of their capacity to detect pests and thereby improve application in crop protection practice. These sensors can be space-borne (satellite), air-borne (airplane, unmanned aerial vehicle) or groundbased (handheld, vehicle-mounted) and provide spatial information that has added value management. Insects are usually unevenly distributed throughout an area in nature. Despite this knowledge, analytical methods and technology have limited insect pest management to uniform management decisions in the field. The methods and technology to map and analyse insect spatial distribution have been developed to a level where the uneven nature of insect populations can be considered for application of insect-pest management practices. Site-specific pest management utilizes spatial information about pest distribution to apply control method only where pest density is economically high within a field. This results saving in pesticide and labour cost. In conventional farming pesticides are applied uniformly to the field resulting in heavy use of pesticide and labour beside polluting the environment. Site-specific application of pesticides in precision farming helps to overcome this problem

Near-range and remote sensing techniques have demonstrated a high potential in detecting diseases and in monitoring crop stands for sub-areas with infected plants. The occurrence of plant diseases depends on specific environmental and epidemiological factors; diseases, therefore, often have a patchy distribution in the field. The use of non-invasive optical sensors for the detection, identification and quantification of plant diseases on different scales is made of in precision farming. Most promising sensor types are thermography, chlorophyll fluorescence and hyperspectral sensors. For the detection and monitoring of plant disease, imaging systems are preferable to non-imaging systems. To utilise the full potential of these highly sophisticated, innovative technologies and high dimensional, complex data for precision crop protection, a multi-disciplinary approach—including plant pathology, engineering, and informatics—is required.

A. Precision irrigation

The prevalent flood irrigation in crops would be the thing of past because of limited water resources, waste of water in leaching and evaporation and cumbersome management resulting in considerable loss of water. The micro irrigation (sprinkler and drip- irrigation) are preferred depending on the field topography. Undulated fields are better irrigated by sprinkler and laser levelled field by drip irrigation. There are precise tools to deliver only required amount of water at different stages of growth of crops with the help of sensors. Irrigation water volume release is mechanised and automated. Efforts of using microirrigation methods such as sprinkler and drip irrigation have been made in last three decades in many parts of the world. There is no ideal irrigation method available which may be suitable for all weather conditions, soil structure and variety of crops cultures.

Precision irrigation is worldwide accepted concept in irrigation. Precision irrigation involves the accurate and precise application of water to meet the specific requirements of individual plants or management units and minimize adverse environmental impact. Commonly accepted definition of precision irrigation is sustainable management of water resources which involves application of water to the crop at the right time, right amount, right place and right manner thereby helping to manage the field variability of water in turn increasing the crop productivity and water use efficiency along with reduction in energy cost on irrigation. It utilizes a systems approach to achieve ’differential irrigation’ treatment of field variation (spatial and temporal) as opposed to the ’uniform irrigation’ treatment that underlies traditional management systems. Precise and regulated application of irrigation water and plant nutrients at low pressure and frequent intervals through drippers/emitters directly into the root zone of plant with the help of close network of pipes is known as drip irrigation system.

In crop production mostly basic inputs are seeds or seedlings/planting material, irrigation water, fertilizers, weedicides and pesticides. Site specific input application means providing plant input requirement at right time, in right amount and at right place. Site specific is a term that refers to treating the smallest possible area as a single unit. A site is simply the smallest unit the farmer can manage with the tools available. The treatment of each site is specific to the needs of each site as determined by soil test data and crop scouting reports. There are technology tools for using site-specific management more effectively. In precision agriculture site specific application tools and technologies are as under:

In crop production mostly basic inputs are seeds or seedlings/planting material, irrigation water, fertilizers, weedicides and pesticides. Site specific input application means providing plant input requirement at right time, in right amount and at right place. Site specific is a term that refers to treating the smallest possible area as a single unit. A site is simply the smallest unit the farmer can manage with the tools available. The treatment of each site is specific to the needs of each site as determined by soil test data and crop scouting reports. There are technology tools for using site-specific management more effectively. In precision agriculture site specific application tools and technologies are as under

Soil map is a map showing diversity of soil types and its properties such as pH, texture, organic matter and depth of horizons in the area of interest obtained as the end of soil survey. Generally, soil maps are used to simply identify soils and their properties, but are sometimes required for more specific purposes, such as the suitability of soils for a particular crop, suitability for irrigation, erosion risk and many other specific needs or environmental threats.

Soils fulfil many functions important for agriculture, forestry and the management of soil resources and natural hazards. The functionality of soils depends on their properties; hence, accurate and spatially highly resolved maps of basic soil properties such as texture, organic carbon content and pH for specific soil depth are needed for the sustainable management of soils. The surface soil organic carbon (SOC) concentration is a useful soil property to map soils, interpret soil properties, and guide fertilizer and agricultural chemical applications.

Traditionally farmers apply fertilizers, chemicals and other crop production inputs to optimize the production of the field as a whole. This results in application of over application of inputs and low inputs in certain locations of the field because of variation in field characteristics including soil organic carbon, soil texture, soil nutrients, field topography, and other properties. In addition, uniform applications may increase the chances of pollution of the environment due to excess application in some field area. Precision farming technology has been shown to optimize application rates if the variation of field characteristics can be used to guide the application rate of crop-production inputs. The organic carbon concentrations of surface soil have been used to spatially vary the application rate of some crop-production inputs. The surface soil organic carbon concentration affects the activity of many herbicides, influences plant-available nitrogen and also affects the soil’s ability to adsorb plant nutrients. Knowing its concentration may therefore be useful, especially if its spatial distribution could be determined accurately and for low cost.

Crops are grown in soil. There are different types of soil. The soil type helps farmers decide what crops will grow best because some crops do better with particular types of soil. Testing the soil helps determine what nutrients are available or unavailable for growing certain crops. Farmers usually have local agricultural experts test the soil on their land for information on how to proceed in growing crops. The best soil has a balance of nutrients, such as potassium, magnesium, and others. Certain crops may need more of one nutrient, so farmers put back those ingredients into the soil for better crops.

Six different types of soil are listed below along with the crops which do well in these soils.

1.Loam: This type of soil helps grow the best possible crops because it provides the necessary elements for plant growth and development. Loamy sand contains mostly sand plus clay and silt. Such soils are good for root vegetables, such as carrots, radish, turnip, beets, leafy vegetables, potatoes and tomatoes.

2.Clay: Cabbage and broccoli grow well in clay soil, but it is not good for root vegetables because of its dense texture which does not allow free flow of water.

3.Sand: Root vegetables, such as turnips, parsnips, and carrots, grow well in sandy soil.

4.Silt: Silty soil is fertile and offers nutrients for plant development. Lettuce, cabbage, carrots, turnips, and many other vegetables flourish in silt. Strawberries, raspberries, blackberries do well.

5.Peat: Peaty soil provides plant growth when mixed with rich organic matter, lime, and compost that reduces its acidity. Legumes, root crops, cabbage, and spinach are easily grown in soil that’s well-drained.

6.Chalk: Sweet corn, beets, spinach, and cabbage are among the vegetables that benefit from chalkier soil. It is recommended that farmers use fertilizers and balance the pH levels to deal with the alkaline that can sometimes stunt growth.

In soil culture, also known as in-ground culture, crops are raised on level ground as well as in raised beds. Soil culture is more often used in growing vegetables (e.g., tomatoes, lettuce, cucumbers, and peppers) rather than ornamental crops such as herbs, roses, freesia, and foliage plants as well as popular with smaller commercial and organic growers. The soil should be well drained, fertile, have a medium to light texture and be high in organic matter. The soil in a greenhouse should be worked as deeply as possible to break any existing hardpans or those that may have developed because of repeated traffic over the area. Fumigation or pasteurization of the soil is a must before each crop or at least once a year. This will help to destroy disease, nematodes and weeds. If soil is steamed, hold it at 180 degrees F (82°C) for 4 hours. Production techniques used in soil culture are similar to intensive crop production methods used in the field. Although soil is readily available at most places where a greenhouse is located most commercial growers, no longer rely on soil culture in the greenhouse as they did ealier. Some of the reasons include insect and disease pressures and costly fumigation.

Seedling:A seedling is a very young plant that grows from a seed. When the moisture, light, and temperature conditions are correct, the seedling’s development begins with seed germination and the formation of three main parts:

1.Radicle - Embryonic root

2.Hypocotyl - Embryonic shoot

3.Cotyledons - Seed leaves.

In vegetables and annual ornamental crops where generally seed size is small they are germinated in nursery beds or in plug trays indoor (greenhouse) or outdoor(field), hardened before transplanting.

Sapling: A sapling is a young tree, say more than 1 year and less than 3 years’ old. In the life cycle of trees, a seedling converts into a sapling as the next stage of development. It is nearly one-meter tall and generally remains to be known as a sampling until its stem reaches 7 centimetre in diameter. The time period of this stage depends upon the particular species of a tree. In vegetable and annual ornamental crops seedlings generally are one month to 40 days old. Older than this, seedlings do not give better yields on transplanting. Very young seedlings exhibit larger mortality on transplanting.

Transplanting: Transplanting or replanting is the technique of moving a plant by uplifting from one location to another. From nursery beds seedlings or saplings are shifted and planted either in the field or greenhouses for commercial growing. Seedlings are uprooted if grown in soil medium. They are transplanted with growing medium. Uprooted seedlings take time to establish at a new place and face transplanting shock- time taken by roots to establish contact with the soil or growing medium.

Sowing of Seed: It is a process of planting seeds of crops in well prepared or no till field or nursery beds/pots for raising crops in following methods:

Methods of Sowing: The sowing method is determined by the crop to be sown and resources on the disposal of farmer. There are 6 sowing methods which differ in their merits, demerits and adoption. Those are:

1.Broad casting

2.Broad or Line sowing

3.Dibbling

4.Transplanting

5.Planting

6.Putting seeds behind the plough.

It is a common knowledge that most of the farmers apply irrigation water until all the points in the field are fully wetted and covered with a thin sheet of water. Studies have indicated that a significant (20-25%) amount of irrigation water is lost during its application at the farm due to poor farm designing and unevenness of the fields. This problem is more pronounced in the case of rice fields. Unevenness of fields leads to inefficient use of irrigation water and also delays tillage and crop establishment options. Fields that are not levelled have uneven crop stands, increased weed burdens and uneven maturing of crops. All these factors tend to contribute to reduced yield and produce quality which reduce the potential farm income. Effective land levelling is meant to optimize wateruse efficiency, improve crop establishment, reduce the irrigation time and effort required to manage crop.

Reasonably levelled agriculture fields has advantage over uneven and undulating crop fields as unevenness of the soil surface has a significant impact on the seed germination, crop stand and its yield. Traditionally land levelling was being done throughout India by bullock drawn plough or tractors and applying different devices for levelling the field by visual assessment e.g. on small plots with hoes, or with draft animals and equipment such as ploughs and bars or scrapers or grading. Equipment such as grading blades and hydraulically operated levellers mounted on wheels are used with tractors. More advanced and sophisticated levelling equipment is operated with a laser emitter, a laser sensor or receiver, and a scraper pulled by a tractor. After the desired level or slope of the field and/or the difference of the high and low spots have been surveyed, the emitter is set to send a rotating laser beam creating a plane of laser light above the field surface. The laser light is used as the levelling reference. It directs the hydraulic system of the moving tractor and scraper, and thereby controls the levelling. Hence, laser levelling or laser land levelling is levelling the crop field within certain degree of desired slope using a guided laser beam throughout the field.

Precision farming is also known as precision agriculture. A farmer is not only expected to produce more for the increasing population and his family but save and protect the fragile environment while practicing it. Advanced technologies with appropriate and exact inputs such as precision farming can take care better of environment. Precision farming is right farming operations at right time leading to maximize profit. Every farming activity performed with precision by doing the right thing, in the right place, in the right way, at the right time and with right technology leading to maximize profit is known as precision farming. It is an efficient, eco-friendly and accurate management of agriculture inputs such as water, seed, fertilizers, pesticides and harvesting tools and machinery to maximize profit and reduce waste. The basic concept of precision farming is to match agricultural inputs and operations as per crop (variety/hybrid/cultivar) and agroclimatic conditions with accuracy to their better use efficiency. Perfection (nothing requisite is wanting) in farming is the key to precision farming.

Precision farming is based on global positioning system (GPS). The unique character of GPS is precision in time and space. Its use is spreading to all farm operations. Precision farming is an integrated information and production based farming system that is designed to increase long term, site specific and whole farm production efficiency, productivity and profitability while minimizing, waste and unintended impacts on the environment. This concept of precision agriculture is based on observing, measuring and responding to inter and intra field variability in crops.

Farm management strategy is the key to precision agriculture that uses integrated smart technologies such as sensors, GIS, GPS, satellite radars, drones, IoT (Internet of things) and data analytics to develop informed crop production and management decisions. The field variations are precisely measured with the help of technologies to optimize applications of inputs such as manures, fertilizers, pesticides, bio-agents and water use to increase crop yield at minimum cost. The aim of precision farming is to increase productivity, decrease production costs and minimize the environmental impact of farming.