eChapters

Abstract

Out of 1.37 billion populationof India 67 % lives in rural areas whose major source of income is agriculture and allied activities (World Population Review, 2019). In simple words, the livelihood of this vast majority is closely related to rural enterprises. Fostering rural entrepreneurship may be affected by several issues, infrastructure being one of them. This paper attempts to examine the relationship between infrastructure investment by the state and rural entrepreneurship in India, with ‘Gross Fixed Capital Formation’ and ‘Agriculture, Forestry, and Fishing, Value Added’ considered as proxy variables. Time series econometrics is compiled with the data collected from World Bank Database for the period of 1961-2017. The study has established evidence in support of greater investment in infrastructure enhancing rural entrepreneurial opportunities in India.

Abstract

Agriculture is the backbone of India’s economic development and has experienced immense growth in the past few decades. Agriculture not only involves the participation of male workers but also experiences active participation of all family members, as well. Women, as part of the family, take up agricultural activities as an extension to their household chores. The Government and voluntary agencies have also recognised the need for women in the farming community to become self-reliant and active participants in the agricultural sector. Increasing awareness and educating themselves with the passage of time, farmers have made themselves aware of new techniques of farming and growing and established themselves as agricultural entrepreneurs in the long run. Many initiatives supporting women entrepreneurs and creating a supportive ecosystem for women to become agricultural entrepreneurs have been initiated by the state. The case of Anita Devi popularly known as the Mushroom Lady of Bihar has been taken up in this paper to substantiate with evidence how government initiatives have helped her gain success and grow as an agricultural entrepreneur. This study aims at disseminating how such initiatives help in creating an ecosystem that motivates agricultural entrepreneurs in general and women in particular.

Abstract

This paper is rooted in the issue of the failure of Green Revolution which was intended to achieve self-sufficiency in the agriculturally dominant country of India, following its independence. However five decades later, the current focus of the country is on engaging in a sustainable and economically feasible agricultural practice using principles of agro ecology. This paper tries to explore the potential of application of organic farming in a vast country like India. The author posits that organic farming can help India reverse the damage caused by Green Revolution by allowing for natural methods of agriculture rather than a severely mechanical form. This paper focuses on the modern concept of organic farming combining tradition, science and innovation, and the debatable issues surrounding organic farming particularly dealing with its economic feasibility and sustainability prospects. It is acknowledged that for the successful implementation of organic farming there has to be appropriate matching of the supply and demands the organic products. However, there is a need to address the challenge of adoption of organic farming in a diverse country like India because of its huge variance in education, income, living standards and health of the existing and potential consumers. The prospect of organic farming is discussed from the perspective of consumer awareness and state initiatives, in this paper.

Abstract

The agriculture and allied sector provide livelihood for 58% of India’s population. A large population and rising disposable incomes are key growth drivers. Growing external demand has increased its contribution to exports. The demand for processed food has also led to increasing requirements for agricultural inputs, hybrid seeds, machinery and fertilizers. Investment opportunities in storage infrastructure and agrochemicals also present immense opportunities. Organised retail has made India attractive for multinationals. The industry has a combination of multiple organisational forms, like associations, co-operatives, government (departmental) undertakings, foreign entities, trusts and companies, private and public. Unlisted companies encompass a vast range (private limited companies, family business, group-owned firms, and joint ventures are major actors.) The form and complexity of business ownership highlights Corporate Governance (CG) debate. Given this background, our objective is to understand the CG characteristics of unlisted agricultural and allied companies operating in India, the driving forces for improving CG practices, and the need for a policy framework in supporting good CG. We propose to examine the extent of control in the various types of entities and explore the mechanisms that contribute to the development of an efficient CG framework. Using data from the Prowess database, on 2,879 firms, from 2012-2013 to 2016-17, we analysed how CG problems are caused and how it can be alleviated. The results provide stakeholders and agri entrepreneurs with an overview of the policy and managerial issues that arise in the debate on CG of companies in this key sector. Finally, we conclude how the unlisted companies are likely to stimulate growth and development if CG mechanisms are enhanced.

Abstract

Trade Related Agreements on Intellectual Property Rights (TRIPS) widely affects the agricultural sector which is largely unorganised in India. At the same time this sector remains the bread winner for majority of the population of the country. The Intellectual Property Rights (IPRs) affect the extensive and intensive margins in agricultural trade. This paper draws attention of enterprises in the field of agricultural biotechnology which has genetic modification (GM) as one of its core activity. GM is of benefit in terms of value additive features but also of great concern for the community in conservation of biodiversity. Food & Agricultural Organisation (FAO), being aware of the pitfalls of implementing IPRs in agriculture, constituted an expert panel to study the issues pertaining to the sector. They came up with very clear directives to the FAO on the course of action. This paper aims to focus on this area to identify the micro-level dynamics of IPRs in agriculture and its effects on the rural enterprises in India. The impact of IPRs and its ramifications, the issues of agricultural productivity and its future trajectory, are to be understood from the perspective of an entrepreneur’s policy decisions. This will lead to identification of policies that would help in harnessing IPRs for the growth of Indian agriculture.

Abstract

Among the 29 Indian states, 14 are linked with 585 regulated mandis with electronic national agricultural market. Across the states, 7.35 million farmers with 53,163 commission agents are registered in these regulated mandis. Every year Government of India announces modified agricultural policies to safeguard the interest of the farming community. Amongst the policies, one of the mechanisms to protect the producers from price fluctuations is Minimum Support Price (MSP). While determining MSP, government takes into account cost of production, cost of living, as well as economic and socio-political factors. For the past two decades, it has been observed that one MSP graph is moving upward but still the farming community seems dissatisfied. The reasons behind MSP variation among states include offering bonus prices additionally with MSP by some states, due to variation in government procurement procedures and policies. As a result, MSP is playing an important role in manoeuvring of prices amongst the various state markets. MSP deviation provides chances for the private sector to take undue advantage and the farmers are adversely affected. The study analyses existence of deviation in mandi prices of staple food between two states from year 2007 to 2018. It will disclose whether centralized price system reduce the cost of government and aid the farmer to get fair valuation.

Abstract

Entrepreneurship essentially involves economic and dynamic activities, risk- assuming and idea generation that help in developing, organising and managing a business opportunity for profits. Entrepreneurship in agriculture is not merely confined to farm activities but also involves activities interlinked and interdependent with core and peripheral agricultural activities. Impediments in the pathway of agricultural entrepreneurship in West Bengal are characterised by fragmented landholding, low financial resources and thereby debt stickiness & dependence on short-term agricultural loan. Though disbursements of short-term credit have increased substantially, the rate of increase is low. For most farmers, insurance for financial or crop crisis is unheard or have hardly any implication. The paper tries to explain the performance of various agricultural insurance schemes in terms of coverage and the benefits being delivered in India and in West Bengal. The paper analyses whether the recipients consider the schemes as an effective risk mitigation tool or merely a habit of credit-dependence in West Bengal through a diffusion model. The paper concludes with the focus on possible entrepreneurial opportunities that may offer more customised agri-insurance policies, where regional disparities could be considered and individual interests be given little more importance.

Abstract

Packaging industry is considered to be one of the world’s largest industrial sectors. In the past few years, food processing has undergone several paradigm changes with respect to production, distribution, storage, processing and retailing. This increasing dynamism in the food industry, while on one hand placing a lot of challenges on the packaging industries, is on the other hand opening up opportunities for entrepreneurs to foray into food processing and also packaging industries and develop appropriate solutions in response to the needs of the market and environment. This study aims at exploring the state of packaging industry and packaging technologies in developing countries, with special emphasis on India, against the backdrop of increasing concern for prevention of food losses and therefore highlighting the need for new innovative ideas for food packaging. The authors posit that customer awareness about safety of processed food has given rise to tremendous possibilities of entrepreneurship opportunities in the area of safe and hygiene packaging. However market preferences, state reputations and cost benefit analysis play major roles in packaging of processed food products.

Abstract

More than one-third of food is lost or wasted in post-harvest operations in India. Decreasing the post-harvest losses (PHL) may be a sustainable solution to increasing food availability and improving farmers’livelihoods. As per Associated Chambers of Commerce of India, India loses approximately US$ 14.33 billion annually on account of PHL (ASSOCHAM, 2017). The objective of this study is to analyse the agricultural wastes that are produced in the value chain for a modern trade retailer, identify their causes, and discuss methods for minimising field wastages. A case study approach has been used to depict the agricultural value chain (vegetable segment). A field visit was conducted to a farmland and a privately operated Collection Center in Barasat area of West Bengal. The author discusses solutions towards minimising harvest wastages in the farm by focusing on waste reduction. Post-harvest wastages beyond the farm can be reduced by undertaking measures that focus on waste management. Going forward, adoption of technologies by farmers may lessen inefficiencies such as wastages and improve their income. Further scope for research lies in exploring joint interventions by private players, government agencies, non-profit organisations and entrepreneurs through public-private partnership models or through development of clusters for creating sustainable value chains and achieving greater profitability.

Abstract

Access to reliable and affordable irrigation is one of the most important enablers to increase agricultural productivity and income for farmers. An innovative Manual Axis Tracking Solar Pump model and its utility in providing affordable irrigation has been discussed in this paper. The proposed Manual Axis Tracking Solar Pump can increase output on an average 8%-12% more than fixed panel and is much cheaper than automated tracking. This paper deliberates upon the technical features that make the Manual Axis Tracking Solar Pump an advantage over its nearest competitor, the diesel pump. Government of India has already introduced various subsidy-based solar pump schemes and most of them are not popular because of low discharge issue. The low discharge issue can be solved by this proposed optimum tilt-based Manual Tracking Solar Pump, whose sustainable market penetration is suggested through various strategies in the paper, supported by case studies. The proposed entrepreneurship model not only opens a new era of agricultural business but also helps to reduce the GHG emissions.

Abstract

Sustainable development and success in any field, agriculture being one of them, goes hand in hand with Innovation. To tackle the current growing problems in the agricultural sector, and long-term sustainability of the agri-ecosystem, agricultural innovations are needed that might bring new products or processes or open up new markets, thereby optimising the use of the limited resources to attain maximum benefits. The authors discuss innovation from the perspective of two dimensions: Technology and Market to illustrate four different kinds of innovation - incremental, architectural, radial and descriptive. This paper deals with the concept of innovation in agricultural field [referred to as agri-innovation] using illustrations of two innovative products namely Dragon Fruit and Water Hyacinth, both of which have significant role in the agri-ecosystem of India. The introduction of Dragon Fruit in a new market is illustrated as an agri-innovation. Efforts by state and private sector of introducing Dragon Fruit, a popular production in South & South East Asia to Indian markets are an example of Architectural Innovation. Also the most common weed Water Hyacinth is considered to be used in news forms so that it can be modified as a new product for a new market. The paper thus documents the suitability of these innovative agri-products in the current Indian market scenario.

Abstract

The upsurge in global population rates has triggered a significant escalation in food demand across the world. This is accompanied by urbanisation and a pressing need for sustainable agriculture. In this context vertical cultivation of plants as well as breeding of livestock on vertically inclined surfaces, such as in skyscrapers and other high-rise buildings in urban regions has gained prominence. The dynamics of urban agriculture is captured through the case study of Urbagrow Aquaponics, an urban, aquaponic, soil-free, food garden based in Kolkata. The garden exhibits an assortment of aquaponic systems for growing a variety of vegetables as well as the tilapia and catfish. The systems make use of less water, require less work in man-hours and can grow vegetables in greater density than a traditional soil based food growing endeavour. A feasibility study has been conducted to explore the potential of scaling such a venture across myriad other high-rise buildings across Indian cities.

Abstract

This chapter will look at the major reasons why farmers in India are unable to take advantage of Agricultural profession as a mode of generating income and suggest ways to change this by employing new technologies. Agriculture has basic processes which require identifying the season for planting the seeds at the right time, watering the plants to the required level, undertaking maintenance for the different plants and then finally harvesting at the right time to ensure that the effort that has been put into the agricultural process results in useful output. In business terms the output when it is valued in terms of money, should enable the farming business to sell their output at a certain price that will enable them to pay off the money that has been used for setting up the crop for that cycle. This chapter will underscore the valuable contribution of remote sensing data in farming to enhance operational decisions. We will look at how low-cost technologies can be implemented into the existing agricultural extension activities and help farmers make better decisions that will enable them to be more business oriented. It is envisaged that incorporating high technology-based data into simple to understand terminology willhelp reduce the burden on farmers. This is due to the lack of knowledge but also due to the low volume of information that is possible to be fed to the farmers through the agriculture extension network in the country. However, due to the varied nature of farming in India it is difficult for extension officers to specialise but concentrate their efforts on widely utilised crops in an area. The following figure below explains in simple terms how the cycle of activities occur in a farmer’s world and where business decisions are taken that will have an impact on the profitability.

2.1 Some Useful Formulas Related to Farm Power

1.1 Some Useful Formulas Related to Farm Machinery

Climate change mitigation is urgent, and adaptation to climate change is crucial, particularly in agriculture, where food security is at stake. The gases contributing to the greenhouse effect mainly include carbon dioxide (CO₂), nitrous oxide (N₂O) and methane (CH₄). These gases have varying global warming potentials, which can be expressed in CO₂ equivalents.

Agriculture, currently responsible for 2030% of global greenhouse gas emissions (counting direct and indirect agricultural emissions), can however contribute to both climate change mitigation and adaptation. The main mitigation potential lies in the capacity of agricultural soils to sequester CO₂ through building organic matter. This potential can be realized by employing sustainable agricultural practices, such as those commonly found within organic farming systems. Examples of these practices are the use of organic fertilizers and crop rotations including legume leys and cover crops. Mitigation is also achieved in organic agriculture through the avoidance of open biomass burning, and the avoidance of synthetic fertilizers, the production of which causes emissions from fossil fuel use.

Organic agriculture is associated with higher carbon sequestration as many organic practices help to improve soilquality and carbon sequestration. The most common organic practices that increase soil organic carbon are the use of organic fertilizers (such as the composted waste products from livestock husbandry), crop rotation involving legumes and the planting of cover crops.

Organic farming offers several ways to mitigate climate change when compared to conventional agriculture:

Primarily, organic farming, through its key practices of organic fertiliser use and crop rotations with forage legumes, tends to increase soil organic carbon levels resulting in carbon sequestration.This contributes to climate change mitigation, as it absorbs CO₂ from the atmosphere and stores the additional carbon in the soil. However, depending on soil type and climatic conditions, this process usually comes to a halt after some decades, when soil organic carbon levels have reached a new equilibrium and soils arethus saturated with respect to organic carboncontents. Furthermore, this storage of organiccarbon is reversible and the carbon can again be released into the atmosphere as carbon dioxide when switching to unsustainable practices.

Regeneration capacity of the soil is enhanced with the sowing of MVS which provides ideal condition for regeneration. It creates green cover / dry leaf cover in the top soil (35-40 cm height) which will facilitate the multiplication of inoculated beneficial microbes in the soil.

Multi Varietal seeds sowing techniques

MVS contains seeds of three to four crops belonging to each category viz., cereals, pulses oilseeds, nitrogen fixing green manures and spices and condiments. The seeds of above crops may be mixed in different proportion based on their growth habit and seasonal requirement. For example in the summer the following mixture can be practiced with each of 1-1.5 kg each.

Optimal quality organic produce that combines the desired textural properties, sensory shelf-life, and nutritional content results from the careful implementation of recommended production inputs and practices, careful handling at harvest, and appropriate postharvest handling and storage. This section will focus on an overview of general postharvest handling considerations unique to the marketing of registered or certified organic produce.

Maturity index for fruits and vegetables

The principles dictating at which stage of maturity a fruit or vegetable should be harvested are crucial to its subsequent storage and marketable life and quality. Post-harvest physiologists distinguish three stages in the life span of fruits and vegetables: maturation, ripening and senescence. Maturation is indicative of the fruit being ready for harvest. At this point, the edible part of the fruit or vegetable is fully developed in size, although it may not be ready for immediate consumption. Ripening follows or overlaps maturation, rendering the produce edible, as indicated by taste. Senescence is the last stage, characterized by natural degradation of the fruit or vegetable, as in loss of texture, flavour, etc. (senescence ends at the death of the tissue of the fruit). Some typical maturity indexes are described in following sections.

In general, any business directly involved in food production can be certified, including seed suppliers, farmers, food processors, retailers and restaurants. Requirements vary from country to country, and generally involve a set of production standards for growing, storage, processing, packaging and shipping organic certification ensures:

• Avoidance of synthetic chemical inputs (e.g. Fertilizer, pesticides, antibiotics, food additives, etc) and genetically modified organisms;
• Use of farmland that has been free from chemicals for a number of years (often, three or more);
• Keeping detailed written production and sales records (audit trail);
• Maintaining strict physical separation of organic products from non-certified products and
• Undergoing periodical on-site inspections.

In some countries, certification is overseen by the government, and commercial use of the term organic is legally restricted. Certified organic producers are also subject to the same agricultural, food safety and other government regulations that apply to non-certified producers.

Farming system approach addresses itself to each of the farmer enterprises; inter relationship among enterprises and between the farm and environment. Thus farming system research has the objective of increasing productivity of various enterprises in the farm. Farming system approach introduces a change in farming technique for high production from a farm as a whole with the integration of all the enterprises. The farm produce other than the economic products for which the crop is grown can be better utilized for productive purposes in the farming system approach. A judicious mix of cropping system with associated enterprises like dairy, poultry, piggery, fishery, sericulture etc. suited to the given agro-climatic conditions and socio economic status of farmers would bring prosperity to the farmer.

Combination of Integrated farming system (IFS) along with organic farming so called integrated organic farming system (IOFS)appear to be the possible solution to the continuous increase of demand for food production, stability of income and improvement of nutrition for the small and marginal farmers with limited resources. Integration of different enterprises with crop activity as base will provide ways to recycle products and waste materials of one component as input through another linked component and reduce the cost of production of the products which will finally raise the total income of the farm. This becomes quite essential as crop cultivation is subjected to a high degree of risk and provides only seasonal, irregular and uncertain income and employment to the farmers. With a view to mitigate the risk and uncertainty in agriculture, IOFS serves as an informal insurance.

Production of agricultural crops, vary in response to changes of the seasons. In the recent period stable income of agricultural crops has become unstable. Redressing these by integrating crops with agro-based industries like livestock farming is essential. An integrated organic farming system applies the concept of “Low External Input Sustainable Agriculture” (LEISA) and this system develops the livestock business and the crop business in one location or area using local resources to optimize inputs. Designing a farming system to tie together principles of sustainability and productivity is complex. Organic farmers must consider how the various components of their system - rotations, pest and weed management, and soil health - will maintain both productivity and profitability. This section outlines the major principles incorporated into organic farming systems.

Organic farming is a crop production method respecting the rules of the nature, targeted to produce nutritive, healthy and pollution free food. It maximizes the use of on -farm resources and minimizes the use of off – farm inputs.

The general guidelines on organic production of crops are prepared based on National Programme for Organic Production (NPOP) launched by Government of India. These guidelines enable the growers to attain more or less the same level of the productivity of conventional farming within a few years and at the same time maintain the fertility of the soil and protect the ecological balance.

Agricultural scientists and policy makers have understood that continuation of modern agriculture might lead to severe ecological and economic problems. We are also convinced that modern agriculture may not be able to meet the requirements of the ever increasing population in the future. So, we are searching for alternative technologies. Several alternatives have been proposed such as low external input agriculture, sustainable agriculture, organic farming, biodynamic farming etc. However, they require, some times little or considerable external inputs whose availability may be uncertain in future.

Hence for the developing countries, the other alternative viz., traditional methods have special advantages over modern agricultural techniques. Also the capital and technological skill requirements in the use of traditional technologies are generally low and their adoption often requires little restructure of the traditional societies. The traditional technologies are nothing but indigenous technical knowledge. By adopting such indigenous knowledge, our ancestors did not face any problem of large-scale pest out break or economic crisis unlike the today’s farmers.

From an ecological perspective all organisms are part of nature, irrespective of what they do. To a farmer, all organisms that reduce the yields of their crops are considered pests, diseases or weeds. Insects, birds or other animals are also pests whenever they cause damage to crops or stored produce. Fungi, bacteria and viruses are also recognized as disease causing organisms when they lead to conditions that interrupt or modify the vital functions of growing plants or stored produce. All unwanted plants that grow within crops and compete with them for nutrients, water and sunlight are considered weeds. Such plants can also be hosts for pests and diseases.Presence of these organisms in crop fields is not a problem until their numbers increase beyond a level where they attack, and cause substantial reductionin field crop yields or quality of harvested and stored produce.

The organic approach to plant pest, plant disease and weed management makes reference to the four principles of organic agriculture: the principle of health, the principle of ecology, the principle of fairness, and the principle of care. Generally, organic farmers aim at sustaining and enhancing the health of their soils, plants, animals, humankind and—in the widest sense—the planet. The health of individuals and communities cannot be separated fromthe health of ecosystems. Therefore, by providing healthy soils and a diversified natural environment, farmers are able to produce healthy crops that foster the health of animals and people.

Healthy plants are also able to resist and tolerate physiological disruption and damage from disease-causing organisms and pests. Thus, organic farmers aim at optimizing the growing conditions for their crops to make them strong and competitive. At the same time they encourage natural control mechanisms to prevent pests, diseases and weeds to develop in a way that they cannot damage the crops. They, therefore, give priority to preventive measures to prevent and limit the spread of infections, instead of relying on direct control measures. Direct control measures are mainly applied when pathogens have already developed.

Soil is a living system and soil fertility is the key to agricultural productivity. Any input that destroys this living system and undermines soil health basically undermines the agricultural productivity. The maintenance of the fertility of soil is the primary step in any permanent system of agriculture.

Fertile land and sufficient water are vital for sustaining agriculture and livelihoods. Fertility of a soil is defined by its ability to provide all essential nutrients in adequate quantities and in the proper balance for the growth of plants – independent of direct application of nutrients – when other growth factors like light, temperature and water are favorable. This ability does not depend on the nutrient content of the soil only, but on its efficiency in transforming nutrients within the farm’s nutrient circle.

In transformation of nutrients soil organisms play a key role. They break down biomass from crop residues, green manures and mulch and contribute to build up of soil organic matter, including humus, the soil’s most important nutrient reservoir. They also play an essential role in transferring nutrients from the soil organic matter to the mineral stage, which is available to plants. Soil organisms also protect plants from disease and make the soil crumbly.

A fertile soil is easy to work, absorbs rainwater well, and is robust against siltation and erosion. It filters rain water and supplies us with clean drinking water. It neutralizes (buffers) acids, which pass through contaminated air to the soil surface, and decomposes pollutants such as pesticides rapidly. And last but not least a fertile soil is an efficient storage for nutrients and CO₂. In this way a fertile soil prevents the eutrophication of rivers, lakes and oceans and contributes to the reduction of global warming.

In the context of biological agriculture soil fertility is thus primarily the result of biological processes, not of chemical nutrients. A fertile soil is in active exchange with the plants, restructures itself and is capable of regeneration. The biological properties can be observed in the soil’s conversion activity, in the presence and the visible traces of the organisms in it. The communities of microorganisms are robust and active at the right moment. In the self-regulating ecological equilibrium animals, plants and microorganisms all work for each other.

It is the responsibility of farmers to understand soil ecology to the point that they can create or restore the conditions for a robust balance in the soil. If a soil does not regularly bring good yields, farmers should investigate the reasons for it.

The increasing awareness of the deleterious effects of indiscriminate use of artificial inputs in agriculture such as chemical fertilizers and pesticides hasled to the adoption of organic farming as an alternative method for conventional farming. Farmers are adopting organic farming due to the advantages like,

• It is self-sustaining and socially and ecologically superior over the conventional farming.
• It makes use of cost effective management practices involving the use of farm inputs produced within the farm.
• It is less expensive.
• It is environment friendly as there is no pollution of soil and water.
• It enriches the soil and the local ecology.
• The produce is free of contamination from chemical residues has better taste, flavour and nutritional value.
• Seeds have more vitality and are good for successive generations.
• Growing markets for safe food

The word biodiversity refers to the variety of living organisms (flora and fauna). Biodiversity or Biological diversity is defined as the variability among all living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and ecological complexes of which they are part. Wilson, 1988 defined ‘Biological diversity’ or ‘biodiversity’ as that part of nature which includes the differences in genes among the individuals of a species, the variety and richness of all the plant and animal species at different scales in space i.e. local, regional, country wise and global, andvarious types of ecosystems- both terrestrial and aquatic-within a defined area.

The diversity of agro-ecosystems

Biological diversity deals with the degree of nature’s variety in the biosphere. This variety can be observed at three levels i.e., genetic, species and ecosystem.

a) Genetic Diversity

Genetic diversity refers to the variation at the level of individual genes. Tremendous amount of genetic diversity exists within individual species. This genetic variability is responsible for the different characters in species. Genetic diversity is the raw material from which new species arise through evolution. Today, the genetic diversity is made use to breed new crop varieties, disease resistant crops.

Organic producers, on the other hand, are looking for varieties that are suited to their local climatic and soil conditions and are not susceptible to disease and pest attack. Research has shown that in general these characteristics are more likely to be found in the older native cultivars. For example, conventional wheat grown in an organic system will have reduced protein content, whereas the selection of a variety suitable for the particular growing conditions will provide higher protein, and thus higher baking quality wheat to be grown. Research has also indicated that yields and disease resistance are better in native cultivars as opposed to modern varieties for vegetables (tomato, cucumber and melon) grown in an organic system.

The Tenth Five Year Plan (GoI 2002), for 2002 through 2007, has put emphasis on natural resource management through rainwater harvesting, groundwater recharging measures and controlling groundwater exploitation, watershed development, treatment of waterlogged areas. With regard to application of agricultural inputs like fertilizer and pesticides, the Plan stated that factors such as imbalanced use of nitrogenous (N), phosphatic (P) and postassic (K) fertilisers, increased deficiency of micronutrients and decreased soil organic carbon would be addressed through a holistic agri-environmental approach stressing Integrated Plant Nutrient and Pest Management. Further, the Tenth Plan document recognizes organic farming as a ‘thrust area’ in the sustainable use and management of resources in agriculture.

The trajectory of Indian agriculture and its associated environmental problems has brought about recognition that future agricultural growth and productivity will have to occur simultaneously with environmental sustainability. The environmental challenges, especially in terms of land degradation and groundwater depletion, water logging and excessive use of chemical inputs are posing problems for the future of Indian agriculture. To address the problems, policies have laid emphasis on promoting sustainable agriculture including organic farming. Differential approaches and policy instruments, however, will be required to address these problems. The shift from input-intensive to sustainable, particularly organic farming is a difficult task as it involves a number of policy measures dealing with a variety of issues ranging from the transfer of information and technology to the development of markets. Another difficult task, and perhaps more difficult, relates to marginal and small farmers – which comprise a substantial part of Indian agriculture. Although these marginal and small farmers have been considered organic by ‘default’, severe resource constraints make a shift to the modern sense of organic farming prohibitive.

The Indian government has been undertaking measures to promote organic farming with the aim to improve soil fertility and help to double the farmers’ incomes by the year 2022. The Prime Minister had visited Sikkim—which is India’s first organic state—and encouraged other states to replicate the “Sikkim model”. Some of the policy initiatives to promote organic farming and exports include development of an organic regulation for exports by the Agricultural and Processed Food Products Export Development Authority (APEDA), removal of quantitative restriction on organic food exports, providing subsidies to farmers under the Paramparagat Krishi Vikas Yojana (PKVY) in partnership with the state governments, and other schemes such as the Mission Organic Value Chain Development for North Eastern Region. Despite these initiatives, a recent survey-based study covering 418 organic farmers across different states of India suggests that a move to organic farming methods may not be that easy and organic farmers are not getting the expected premium price for their produce.

Agriculture in India is not of recent origin, but has a long history dating back to Neolithic age (7500–6500 B.C). It changed the life style of early man from nomadic hunter of wild berries and roots to cultivator of land. Agriculture is benefited from the wisdom and teachings of great saints. The wisdom gained and practices adopted have been passed down through generations. The traditional farmers have developed the nature friendly farming systems and practices such as mixed farming, mixed cropping, crop rotation etc. The great epics of ancient India convey the depth of knowledge possessed by the older generations of the farmers of India. The modern society has lost sight of the importance of the traditional knowledge, which had been subjected to a process of refinement through generations of experience. The ecological considerations shown by the traditional farmers in their farming activities are now a days is reflected in the resurgence of organic agriculture.

Historical Perspective of Organic Farming

The available ancient literature includes the four Vedas, nine Brahnanas, Aranyakas, Sutra literature, Susruta Samhita, Charaka Samhita, Upanishads, the epics Ramayana and Mahabharata, eighteen Puranas, Buddhist and Jain literature, and texts such as Krishi-Parashara, Kautilya’s, Artha-sastra, Panini’s Ashtadhyahi, Sangam literature of Tamils, Manusmirit, Varahamihira’s Brahat Samhita, Amarkosha, Kashyapiya-Krishisukti and Surapala’s Vriskshayurveda. This literature was most likely to have been composed between 6000 B.C. and 1000 A.D. The information related to the biodiversity and agriculture (including animal husbandry) is available in these texts. Rig-Veda is the most ancient literary work of India. It believed that Gods were the foremost among agriculturists. According to ‘Amarakosha’, Aryans were agriculturists. Manu and Kautilya prescribed agriculture, cattle rearing and commerce as essential subjects, which the king must learn. According to Patanjali the economy of the country depended on agriculture and cattle-breeding. Plenty of information is available in ‘Puranas’, which reveals that ancient Indians had intimate knowledge on all agricultural operations. Some of the well known ancient classics of India are namely, Kautilya’s‘Arthashastra’; Panini’s ‘Astadhyayi’; Patanjali’s ‘Mahabhasya’; Varahamihira’s ‘Brahat Samhita’; Amarsimha’s ‘Amarkosha’ and Encyclopedic works of Manasollasa. These classics testify the knowledge and wisdom of the people of ancient period. Technical book dealing exclusively with agriculture was Sage Parashara’s ‘Krishiparashara’ in 1000 A.D. Other important texts are Agni Purana and Krishi Sukti attributed to Kashyap (500 A.D.).

Organic farming system in India is not new and is being followed from ancient time. It is a method of farming system which primarily aimed at cultivating the land and raising crops in such a way, as to keep the soil alive and in good health by use of organic wastes (crop, animal and farm wastes, aquatic wastes) and other biological materials along with beneficial microbes (biofertilizers) to release nutrients to crops for sustainable production.

Presently the farming situation urges need to develop farming techniques, which are sustainable from environmental, production, and socio-economic points of view. Modern agricultural production throughout the world does not appear to be sustainable in the long run.

Sustainable agricultural development “is the management and conservation of the natural resource base and the orientation of technological and institutional change in such a manner to assure the attainment and continued satisfaction of human needs for the present and future generations”. Such sustainable development in the agriculture, forestry and fishery sectors, conserves land, water, plant and animal genetic resources, is environmentally non-degrading, technically appropriate, economically viable and socially acceptable. Consequently these concerns imparted a way to organic farming. It is the need of the day to understand the prospects and problems of organic farming to launch a successful and flawless organic production programme in the farm environment.

There are many explanations and definitions for organic agriculture but all converge to state that it is a system that relies on ecosystem management rather than external agricultural inputs. It is a system that begins to consider potential environmental and social impacts by eliminating the use of synthetic inputs, such as fertilizers and pesticides, veterinary drugs, genetically modified seeds and breeds, immunity booster preservatives, additives and irradiation. These are replaced with site-specific management practices that maintain and increase long-term soil fertility and prevent pest and diseases.

The science of agrometeorology has great practical utility in protection against, or avoidance of adverse climate risks of crop production. Agrometeorological information can be used in efficient land use planning, determining suitable crops for a region, risk analysis of climate hazards and profit calculations in farming, production and harvest forecasts, and in adoption of farming methods and choice of farm machinery. Meteorological instruments are the equipments used to sample the state of the atmosphere at a given time. Meteorology does not use much laboratory equipments but relies more on field-mode in situ observation and remote sensing equipments. Rain was one of the first weather parameter to be measured historically. Two other accurately measured weather-related variables are wind and humidity.

An agrometeorological observatory or station is a place where all the necessary instruments and structures are installed and maintained to observe and record the weather parameters at stipulated time interval.

Climate, soil, input and management factors influence the crop yield. Weather is the most important natural input that affects the agricultural production and productivity. The agricultural activities starting from the land preparation to harvest and post-harvest storage are greatly influenced by the weather. The effects of weather on crops may be direct such as those of precipitation, solar radiation, humidity, temperature, etc., or indirect such as those of pest, diseases, weed competition, etc. Thus, the success or failure of a crop is determined by the prevailing weather conditions. Although influence of weather conditions on yield is well established, the quantitative assessment is not always straight forward and simple. The quantitative assessment of the effect of weather on crops is an important application of agrometeorology. The relationship between weather and crop production has been understood through crop weather modelling and study on this aspect through a systematic approach started a century ago. The aim of developing crop weather models is to ensure better utilisation of resources and hence a more environmental friendly and sustainable agriculture.

A model is a schematic representation of the conception of a system or an act of mimicry or a set of equations, which represents the behaviour of a system. Its purpose is usually to aid in explaining, understanding or improving performance of a system. Agricultural models are mathematical equations that represent the reactions occurring within the plant and the interactions between the plant and its environment. However, it is a difficult task to represent any system completely in mathematical terms because of the complexity of the system. Universal models do not exist for the agricultural systems and agricultural models are built for specific purposes and the level of complexity is accordingly adopted. Different models are developed for different subsystems and several models may be built to simulate a particular crop or a particular aspect of the production system. Crop weather models may be defined as a simplified representation of the complex relationships between weather or climate on one hand and crop performance such as growth, yield or yield components, on the other hand by using mathematical and/or statistical techniques

The word ‘remote sensing’ was coined by Evelyn L. Pruitt, an American Geographer in 1960. Remote sensing is defined as collection and interpretation of information about a target without being in physical contact with it. Remote sensing is the science and art of obtaining information about an object, area or phenomenon through the analysis of data acquired by a device that is not in contact with the object, area or phenomenon under investigation (Lillesand and Keifer, 1994).

The information needs a physical carrier to travel from the objects/events to the sensors through an intervening medium. Any force field such as gravity, magnetic or electromagnetic could be used for remote sensing. However, the electromagnetic radiation is conventionally used as an information carrier in remote sensing. Remotely sensed data may be gathered by different devices, including sensors, film cameras, digital cameras and video recorders. Instruments capable of measuring electromagnetic radiation are called sensors.

Remote sensing is nothing but opposite of astronomy. In astronomy, man looks from the earth to the sky to understand and gain more knowledge about the celestial objects. But remote sensing refers to going upward in the sky to look downwards to understand and gain more knowledge about terrestrial objects. In remote sensing, the aerial sensor technologies are used to detect and classify objects on earth by means of electromagnetic radiation.

Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location. Weather forecasts are made by collecting quantitative data about the past and current state of the atmosphere on a given place and using scientific understanding of atmospheric processes to project how the atmosphere will evolve on that place. Weather warnings are important forecasts because they are used to protect life and property. Forecasts based on temperature and precipitation is important to agriculture.

Agricultural production is highly dependent on weather, climate and water availability, and is adversely affected by weather and climate related disasters. In many developing countries where rainfed agriculture is the norm, a good rainy season means good crop production, enhanced food security and a healthy economy. Failure of rains and occurrence of natural disasters such as floods and droughts can lead to crop failures, food insecurity, famine, loss of property and life, mass migration, and negative national economic growth (Sivakumar, 2006).

Farming in many parts of the world, especially in the arid and semiarid regions is risky, because climate is highly variable. In some developing countries as much as 80% of the variability in agricultural production is due to the variability in weather conditions. This production variability in agriculture has immediate and important macroeconomic impacts. A timely seasonal forecast of favourable conditions could permit farmers to adjust cropping patterns and input use in order to benefit fully from these conditions. Also, a timely forecast could give the marketing system and downstream users, such as the food processing industry, time to prepare for a bountiful harvest (Arndt et al., 2000). It is important to remember that under rainfed conditions, even a less reliable, but earlier forecast may be more valuable than an accurate but late forecast (Mjelde et al., 1998).

Many aspects of the global climate are changing rapidly. Evidence for changes in the climate system abounds, from the top of the atmosphere to the depths of the oceans. The climate system is the highly complex system consisting of five major components; the atmosphere, the hydrosphere, the cryosphere, the land surface and the biosphere, and the interactions among them. The climate system evolves in time under the influence of its own internal dynamics and because of external forcings such as volcanic eruptions, solar variations and human-induced forcings such as the changing composition of the atmosphere and land-use.

The term ‘climate variability’ is often used to denote deviations of climatic statistics over a given period of time (e.g., a month, season or year) from the long-term statistics relating to the corresponding calendar period. In this sense, climate variability is measured by those deviations, which are usually termed anomalies.

‘Climate change’ refers to a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). Climate change may be due to natural internal processes or external forcings, or due to persistent anthropogenic changes in the composition of the atmosphere or in land use. The United Nation’s Framework Convention on Climate Change (UNFCCC) defines ‘climate change’ as ‘a change of climate behaviour which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’. The UNFCCC thus makes a distinction between ‘climate change’ attributable to human activities altering the atmospheric composition, and ‘climate variability’ attributable to natural causes. Climate change is a long-term shift in weather conditions measured by changes in temperature, precipitation, wind, snow cover, and other indicators. It can involve both changes in average conditions and changes in variability, including, for example, changes in extreme conditions.

A key difference between climate variability and change is in persistence of ‘anomalous’ conditions. In other words, events that are used to be rare occur more frequently, or vice versa. Occasionally, an event or sequence of events occurs that has never been recorded before, such as the exceptional tsunami in the Indian Ocean in 2004 or hurricane season in the Atlantic in 2005. Yet even that could be a part of natural climate variability. If such a season does not recur within the next 30 years, by looking back it could be called as an exceptional year, but not a ‘climate change’. Only a persistent series of unusual events taken in the context of regional climate parameters can suggest that a potential change in climate has occurred.

Weather and climate have great influence on farm animal production. The environment in which an animal lives is referred to as its habitat. A habitat includes both biotic (living) and abiotic (nonliving) components of the animals’ environment. Abiotic components of an animal’s environment include temperature, humidity, oxygen, wind, soil composition, day length and elevation. Knowledge of how potential environmental stressors (ambient temperature, humidity, thermal radiation, air speed, etc.) can directly and adversely affect animal performance, health and wellbeing is also required for a successful animal farming. The indirect consequences of weather include their impact on feed quality and availability.

Birds and mammals are warmblooded (endotherms or homeotherms), possessing a thermoregulatory system that maintains a stable body temperature and uniform internal environment (homeostasis) by converting food energy into heat. All metabolic processes generate substantial heat and much of this is retained within the body of homeotherms by insulating layers of fat, feathers or fur. Dairy cattle, like other warmblooded animals, function most efficiently in environments where they can maintain their body temperature at around 38° C. Tissue and cellular metabolism and the underlying biochemical reactions that sustain life and productive functions need body temperature to be maintained within very narrow limits. Relatively small increases in body temperature result in the breakdown of body protein and a significant depression in production.

Climate change, particularly global warming has complex impacts on domestic animal production system affecting feed supply, challenging thermoregulatory mechanism resulting thermal stress, emerging new diseases due to change in epidemiology of diseases and causing many other indirect impacts. So, climate change will have farreaching consequences for dairy and meat production, especially in vulnerable parts of the world where it is vital for nutrition and livelihoods. Due to poor availability of good quality feed and fodders in India, animals are generally maintained on poor quality grasses available in the pastures or are stallfed, mainly on crop residues. India is already deficit in feed and fodder. These shortages would be further aggravated by the adverse effects of global warming on fodder crop production.

Many diseases, nematodes, insects and weeds affect crop production, causing severe yield loss. Weather is the most important factor that determines the geographical distribution of these crop pests. The local weather patterns have a significant impact on the abundance of diseases and insect pests in the crops. The severity of disease and pest development depends on the combination of weather conditions during the growing season and is variable from season to season. The weather conditions include temperature (both the maximum and the minimum), light, rain, humidity, dew, cloudiness, sunshine, wind, air currents, evaporation, snow and atmospheric pressure. However, among these weather parameters, temperature and humidity play the major roles in infection of crops due to insect pests and diseases.

Different crops are grown over a wide range of agroecosystems. Though the crops are raised in varied climates, ranging from very hot to very cold, and very wet to very dry, across temperate, tropical and semiarid zones, they are very sensitive to climate. The crop production is dependent on climatic parameters like rainfall, light, temperature, relative humidity and carbon dioxide concentration. Each kind of cultivated crop plants has its own optimum growth requirements. Breeding and selection of new cultivars have allowed for a greater adaptability to less favourable growing conditions than was possible in the past, but the inherent climatic requirements of a specific kind of crop have not changed materially. Crop management is therefore very much about managing climate risk so as to have financially viable and sustainable agricultural systems. Professor Henry Nix of the Australian National University posed three questions that need to be addressed when considering what crop can be grown where (Nix, 1981).

Climate classification systems are ways of classifying the world’s climates. One purpose of climatic classification is to group together places with similar climatic characteristics. That means if an area or region is categorised under a particular climatic type, it possesses broadly uniform characteristics with respect to climate. Classifications have been based on climatic elements such as temperature and precipitation, which are measurable, and on differences in tree species, soil characteristics, topography, etc. The varied nature of earth’s surface and the many interactions that occur among atmospheric processes give every location on the earth a distinctive climate.

Although the delineation of distinct climates may seem likely a very straightforward job, establishing the criteria by which climates are delineated requires considerable subjectivity. There are many ways of classifying the climate depending on the user and the level of understanding of the climate system at a given time. Different regions of the same climate type constitute isoclimatic regions. Identification of isoclimates helps in the transfer of agro-technology and suggesting new cropping pattern. Climatic classification is based on two approaches, viz., generic or empirical approach and genetic approach. In the generic approach the classification is based on the observed climatic elements or their effects on the phenomena, usually vegetation or humankind. The genetic classification is based on climatic controls such as general circulation, net radiation and moisture fluxes.

The concept of climate classification was originally brought out to delineate natural vegetation, which is dependent on rainfall and temperature. Climate classification is unique tool to find out different climate types across the globe, out of which isoclimates or homoclimates can be traced out.

The climate of a particular place is the function of a number of factors such as latitude and its influence on solar radiation received, air mass influences, location of global high and low pressure zones, heat exchange from ocean currents, distribution of mountain barriers, pattern of prevailing winds, distribution of land and sea, and altitude.

Meteorological hazards are severe and extreme weather and climate events that occur in all parts of the world, although some regions are more vulnerable to certain hazards than others. Meteorological hazards include cyclones, droughts, floods, hurricanes, hailstorms, heat waves and tornadoes. The hazard is distinguished from an extreme event and a disaster. An extreme event is simply an unusual event; it does not necessarily cause harm. A disaster is an event that does cause harm in significant amounts. Meteorological hazards are often called as natural hazards. The natural hazards become natural disasters when people’s lives and livelihoods are destroyed.

Hydrological hazards are the result of either excess or a severe lack of water, i.e., flood or drought. Hydrometeorological hazard is a process or phenomenon of atmospheric, hydrological or oceanographic nature that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage. Human and material losses caused by natural disasters are a major obstacle to sustainable development. By issuing accurate forecasts and warnings in a form that is readily understood and by educating people about how to prepare against such hazards, before they become disasters, lives and property can be protected.

Evapotranspiration is the combination of two separate processes named evaporation and transpiration. Evaporation accounts for the movement of water to the air from sources such as the waterbodies and soil. Transpiration accounts for the movement of water within a plant and the subsequent loss of water as vapour through stomata in its leaves. So evapotranspiration is a bio-physical process.

Evaporation

The change of state of water from liquid to the vapour and its diffusion into the atmosphere is referred to as evaporation. During evaporation, water molecules absorb energy which gives them the motion required to escape from the surface of liquid and become a gas. Since a certain amount of energy is consumed in the process of evaporation, the remaining liquid is cooled by an equivalent amount. Thus, the process of evaporation is always accompanied by a cooling effect.

As evaporation proceeds, the surrounding air becomes gradually saturated with water vapour and the process will slow down and might stop if the wet air is not transferred to the atmosphere. The replacement of the saturated air with drier air depends greatly on wind speed. Hence, solar radiation, air temperature, air humidity and wind speed are meteorological parameters to be considered when assessing the evaporation process.

In agrometeorology, evaporation is defined as the maximum possible loss of moisture from a wet, horizontal, flat surface exposed to weather parameters, which exist in the vicinity of plants. Evaporation is an essential part of the water cycle. It is the primary pathway through which water moves from the liquid state back into the water cycle as atmospheric water vapour. The oceans, seas, lakes and rivers provide nearly 90 per cent of the moisture in the atmosphere via evaporation, with the remaining 10 per cent being contributed by plant transpiration. A very small amount of water vapour enters the atmosphere through sublimation, the process by which water changes from a solid (ice or snow) state to a gaseous one, bypassing the liquid phase.

The word ‘monsoon’ is derived from the Arabic word mawsim meaning season. The Arabs during their travel towards India recognised that by June strong southwesterly winds commence over the Arabian Sea and bring a lot of rains to the subcontinent. The term was first used in English in British India and neighbouring countries to refer to the big seasonal winds blowing from the Bay of Bengal and Arabian Sea in the southwest bringing heavy rainfall to the area. In the Indian subcontinent, monsoon is one of the oldest weather observations, an economically important weather pattern over June through September every year, and the most anticipated weather event and unique weather phenomenon. Due to its effects on agriculture, flora and fauna, and other economic, social, and environmental effects, a monsoon is one of the most anticipated, followed and studied weather phenomena of the Indian subcontinent. It has significant impact on the overall well-being of subcontinent residents.

The term ‘monsoon’ is customarily used in India to refer to the rainy season during the northern hemisphere summer from June to September and is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. Now the term monsoon has been broadened to include almost all of the phenomena associated with the annual weather cycle within the tropical and subtropical land regions of the earth.

Precipitation is water in liquid or solid forms, falling on to the earth. In other words, precipitation is the deposition of atmospheric moisture on earth. Formation of clouds does not mean precipitation. Precipitation involves condensation, growth of hygroscopic nuclei, cooling of nuclei at different stages and their fall on to the earth’s surface. There may be several clouds but no precipitation. If the cloud particles are too small and remain suspended in the sky, they may not fall on the earth. Under certain conditions, water particles formed tend to fall but do not reach the surface since they get evaporated on the way. Only when the cloud droplets or ice crystals grow to certain size and can no more remain floating due to buoyancy of air, do they fall as precipitation.

Precipitation is the major source of water to all the living organisms on the earth. All the water sources on the earth depend on precipitation only.

Forms of precipitation

Precipitation form is the state that the moisture is in, i.e., liquid, freezing, or frozen (solid). Different forms of precipitation may occur together, such as mixed rain and snow; but such an occurrence is simply a mixture of forms, not a separate form of precipitation. Because atmospheric conditions vary greatly both geographically and seasonally, several different forms of precipitation are possible. All forms of precipitation are collectively termed hydrometeors. Hydrometeors have been classified into 50 specific types. Out of these precipitation forms, only rain (liquid form) and snow (solid form) make significant contribution to total precipitation. In many parts of the world, the term rainfall is used interchangeably with precipitation.

Clouds are visible mass of little drops of water or frozen crystals suspended in the atmosphere above the surface of the earth. The World Meteorological Organisation defined cloud as a visible aggregate of minute particles of water or ice or both, in the free air. This aggregate may include larger particles of water or ice and particles such as those present in fumes, smoke or dust.

Clouds are the most important form of suspended water droplets caused by condensation. The typical size of these water droplets and ice crystals range from less than 1 μm to 50 μm. When surrounded by billions of other droplets or crystals, they become visible as clouds. In the atmosphere sufficient moisture is required to allow condensation to take place. Then, moisture needs a suitable surface upon which it can condense. In free air, condensation begins on hygroscopic nuclei such as aerosols. These are microscopic particles and include dust, smoke, salts and chemical compounds. Nuclei range in size from 0.001 μm radius to over 10 μm. On an average, oceanic air contains one million condensation nuclei per litre and land air holds some 5 or 6 millions. On hygroscopic particles such as sea salts, condensation can begin before the air is saturated. Supersaturation in clouds rarely exceeds one per cent. On an average, clouds contain only four per cent of the total water in the atmosphere at any one time. Almost all clouds exist in the troposphere, although the tops of some severe thunderstorms occasionally extend to the stratosphere. Clouds move along with the wind and remain stationary in calm winds. They grow vertically and horizontally, depending on the temperature of the cloud and its ambient temperature. They may dissipate or precipitate. Under favourable atmospheric conditions, they burst and fall as rain.

Water vapour changes to the liquid water through condensation process. Condensation is the direct cause of the various forms of precipitation. It occurs as a result of changes in air volume, temperature, pressure or humidity. Water vapour can also be converted directly into the solid form through a process called sublimation. The latent heat expended in evaporation is liberated in the process of condensation. Four mechanisms may lead to condensation.

Water is the only substance that exists in the atmosphere in all the three phases, i.e., solid, liquid and gas. The moisture on the earth’s surface is in a constant phase change. The moisture content of the atmosphere is about 0.035% of all fresh water. The atmosphere receives its supply of moisture from the earth’s surface through evaporation from oceans, lakes, rivers, damp soil, etc. and through transpiration from vegetation. Water vapour is the gaseous state of water and is invisible.

The amount of water vapour present in the atmosphere is called atmospheric moisture or humidity. It is a measure of the amount of water vapour dissolved in the air, not including any liquid water or ice falling through the air. While humidity itself is a climate variable, it also interacts strongly with other climate variables. The humidity is affected by winds and by rainfall. Moisture content is determined by the local rate of evaporation, air temperature and the horizontal transport of moisture. Humidity indicates the likelihood of precipitation, dew or fog. It also plays a major role in the heat budget and the weather phenomenon of the atmosphere.

A big layer of air called the atmosphere surrounds the earth. The air within this layer moves from place to place when it warms up or cools down. This moving air is known as wind. In other words, air in motion is called wind. Winds move moisture and heat around the world and also produce much of our weather.

The strength of the wind can vary enormously. Sometimes air moves slowly and the wind is barely noticeable. When the weather is clear there may be a gentle breeze. When the wind is still very light, but it can be felt and there may be rustlings by leaves. At other times, the air can move very quickly and become a gale or hurricane, blowing down trees and damaging electric poles and buildings.

Winds are part of a global air circulation system that acts to balance temperature and pressure around the world. Different parts of the world receive different amounts of heat from the sun. This differential heating in turn results in differences in temperature and air pressure around the world, which drives the world’s winds.

As equatorial areas are heated most, the air above them warms and rises as it becomes lighter than the surrounding air, causing an area of low pressure. In cooler areas, the air sinks because it is heavier and results in an area of high pressure. Winds will blow as air is squashed out by the sinking cold air and drawn in under the rising warm air. Any difference in temperature like this will always cause a difference in air pressure, and therefore winds will blow. These movements result in a global wind pattern, with air moving between different areas around the world and also at different heights in the atmosphere. Colder air from the poles tends to sink and move towards the equator closer to the surface of the earth. In contrast, warm air from the equator rises and moves towards the poles high in the atmosphere because it is lighter.

Atmospheric pressure is the force per unit area exerted on a surface by the weight of air above that surface in the atmosphere of earth. The gas molecules of the atmosphere are pulled towards the earth by the force of gravity and hence exert a force on earth surface. In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. Atmospheric pressure influences other weather elements in a significant way. Small changes in air pressure may not be felt, but they are important for bringing a change in weather. Atmospheric pressure can be calculated as the summed weight of all gas molecules between a horizontal plane and top of the atmosphere and divided by the area of the plane. Low pressure areas have less atmospheric mass above their location, whereas high pressure areas have more atmospheric mass above their location.

Measurement of atmospheric pressure

The standard unit of pressure in the SI system is the Pascal which is the name given to one Newton per square metre (N/m²). For meteorological purposes, standard sea-level pressure is 101325 pascal (Pa). To simplify this large number, the millibar unit (mb) has been adopted, which is equal to 100 pascals. Units like kiloPascal (kPa) or hectoPascal (hPa) are also used to measure pressure. 1 kiloPascal is equal to 10 millibars and 1 hPa is 1 millibar. The standard sea-level pressure is represented as 1013.2 mb or hPa.

Soil temperature is an important environmental parameter for plant growth and development. It has direct effects on microbial growth and development, organic matter decay, seed germination, root development, and water and nutrient absorption by roots. In general, the higher the temperature the faster these processes occur. Variation in soil temperature is much more pronounced because of varying characteristics and composition of soil.

The soil gains heat by absorption of solar radiation and longwave counter radiation from the atmosphere, downward transfer of sensible heat and horizontal transfer of heat from the surroundings. On the other hand, soil loses heat by longwave radiation to the atmosphere, upward transfer of sensible heat to air when the soil surface is hotter than air and with evaporation and horizontal transfer of heat from the column to surroundings.

Temperature is the physical property of an object that quantitatively expresses the hotness or coldness. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot. When a heat transfer path between them is open, heat spontaneously flows from bodies of a higher temperature to bodies of lower temperature. If no net heat flow occurs between two objects, the objects have the same temperature which are then said to be in ‘thermal equilibrium’. Temperature plays an important role in all fields of natural and applied sciences. Most of the weather parameters are dependent on it, directly or indirectly. It has important role to play in the development and growth of all living organisms in all stages of their growth.

Atmosphere receives the heat energy from the sun and its temperature increases. Due to different amount of heat energy receipt at different places, the air temperatures at different places also vary. The variation in air temperature basically results into air motion, so as to equalise the energy content of the different regions of the earth. Thus, atmospheric temperature is one of the basic elements of weather and climate.

Sun is the prime source of energy injected into the earth’s atmosphere. The sun is the nearest star to the earth. It is a hot ball of glowing gases at the heart of the solar system. Its radiant energy is practically the only energy source to the earth. Very small and insignificant quantities of energy are available from other sources such as the interior of the earth, the moon, and other stars. Without the sun’s intense energy and heat, there would be no life on earth.

The mean distance of the sun from the earth, also known as one astronomical unit (1 AU), is approximately 1.496 × 10⁸ km, though the distance varies as the earth revolves round the sun in an elliptical orbit. At this average distance, light travels from the sun to earth in about 8 minutes and 19 seconds. The energy of the sunlight supports almost all life on earth by photosynthesis, and drives earth’s climate and weather. The minimum sun-earth distance is about 0.983 AU and the maximum is approximately 1.017 AU. The earth is at its closest point to the sun (perihelion) on around January 3 and at its farthest point (aphelion) on around July 4.

The sun makes up about 99.86% of the mass of the entire solar system. The visible disk or photosphere has a radius of 6.599 × 10⁵ km, and the solar mass is 1.989 × 10³⁰ kg. The sun is a completely gaseous body. The chemical composition (by mass) of the outer layers of sun is 71 per cent hydrogen, 26.5 per cent helium, and 2.5 per cent heavier elements like oxygen, carbon, neon, and iron among others. Since the sun is not a solid body, different parts of the sun rotate at different rates. At the equator, the sun spins once about every 25 earth days, but at its poles the sun rotates once on its axis every 36 days.