eChapters

Soil is a major source of nutrients needed by plants for growth. The three main nutrients are nitrogen (N), phosphorus (P) and potassium (K). Together they make up the trio known as NPK. Other important nutrients are calcium, magnesium and sulfur. Plants also need small quantities of iron, manganese, zinc, copper, nickel, chlorine, boron and molybdenum, known as trace elements because only traces are needed by the plant. The primary nutrients are nitrogen, phosphorus and potassium, because they are required in larger quantities than other nutrients. These three elements form the basis of the N-P-K label on commercial fertilizer bags. As a result, the management of these nutrients is very important. However, the primary nutrients are no more important than the other essential elements since all essential elements are required for plant growth. Remember that the ‘Law of the Minimum’ tells us that if deficient, any essential nutrient can become the controlling force in crop yield.

Introduction

Increase in population in our country with decrease in cultivable land is putting the challenges to the scientists and policy planners for increased food supply. There is very little scope for horizontal increase in cultivable land. Hence, the way to meet the need for providing food to ever increasing population is to increase the production of food per unit area of cultivable land.

Farmers, generally apply fertilizer to soil on blanket recommendation. Sometimes, the addition of nutrients is inconsistent. Sometimes, the application of fertilizer is much higher than the recommended dose. Imbalanced application of fertilizer to soil results in low nutrient use efficiency and low crop yield. There is need of site specific nutrient management for increased crop yield and for achieving higher nutrient use efficiency. Proper care should be taken for selection of fertilizer, method of application of fertilizer, rate of fertilizer application and also time of nutrient supply to the soil. Excess application of fertilizer has an adverse effect on soil health.

Traditional tillage may affect physico-chemical as well as biological properties of soil. Change in tillage practice from conventional tillage to conservation agriculture method may have an impact on soil properties and nutrient dynamics. Conservation agriculture affects soil health, proper fertilizer application, both rate and time, along with efficient use of soil moisture improves nutrient use efficiency. For obtaining a good crop yield nutrient should be available for plants in adequate quantity and in right proportion. Nutrients removed by the crop should be replenished by application of inorganic fertilizers alongwith incorporation of organic manures. Soil test is an important tool for determining the quantity of nutrients available in the soil. Based on soil test values and nutrient requirement of the crop rate of fertilizer to be applied in the soil for the plant is determined. Ample quantity of farm yard manure is not available nowadays. Hence, other organic manure such as town waste, green manure etc should be used.

Plants require altogether 17 essential elements to nourish themselves and to complete their reproduction and life cycle. Among them nine elements are required in large amounts for their growth, the so called macro nutrients like C, H, O, N, P, K, Ca Mg and S.  The former three elements (C, H and O) are available to the plants through air and water over which we have relatively little control either in their application rates or uptake into plant system.

Salt affected soils occupy 962.2 m ha globally which accounts for 33% of the arable land. In India 8.373 m ha is affected with salts. Of which 2.359 m ha are alkali soils, 3.829 m ha are saline soils and 2.185 m ha coastal saline soils. Reclamation of these soils provides additional area for food grains production and employment.

The requirement of micronutrients is always in low amounts while their moderate decrease causes the deficiency symptoms and a moderate increase causes toxicity. In other words, there is a narrow range of concentration at which the elements are optimum. Any mineral ion concentration in tissues that reduces the dry weight of tissues by about 10 per cent is considered toxic. Such critical concentrations vary widely among different micronutrients. The toxicity symptoms are difficult to identify. Toxicity levels for any element also vary for different plants. Many a times, excess of an element may inhibit the uptake of another element.

Soil is the fundamental resource in the agricultural production systems and monitoring its fertility is critical to the sustainability of agriculture. Plant nutrients undergo different transformation processes through which they are converted from unavailable to available forms. Nutrient cycling thus involves the transformation and availability of nutrients and is mediated by microbial action. Understanding the dynamics of nutrient and soil organic matter transformations requires an understanding of the biological, chemical, and physical processes involved.

7.1. Soil Nitrogen

The objective of nutrient use is to increase the overall performance of cropping systems by providing economically optimum nourishment to the crop while minimizing nutrient losses from the field and supporting agricultural system sustainability through contributions to soil fertility or other soil quality components. NUE addresses some but not all aspects of that performance. The most valuable NUE improvements are those contributing most to overall cropping system performance. Therefore, management practices that improve NUE without reducing productivity or the potential for future productivity increases are likely to be most valuable. An excellent review of NUE measurements and calculations was written by Dobermann (2007). Table  is a summary of common NUE terms, as defined by Dobermann, along with their applications and limitations. The primary question addressed by each term and the most typical use of the term are also listed below.

Fill in the Blanks

1.The highest amount of rain is received in India by _______ Monsoon

2.Country with largest irrigated area in the world is _______

3.The major source of irrigation water in Andhra Pradesh is _______

4.The annual water budget of India is about _______ million ha meters

5.Ultimate irrigation potential in India is _______ m. ha.

6.The portion of the total rainfall that is retained in the soil directly for evapotranspiration is _______ M ha m

7.The first irrigation commission was constituted in the year _______

14.1 Introduction

An oil spill (or slick) is the intentional or unintentional release of oil into the natural environment as a result of human activity. The term often refers to marine oil spills where oil is released into the ocean or coastal waters (Fig. 14.1).

Oil can refer to many different materials, including crude oil, refined petroleum products or by-products, oily refuse, oil mixed in waste, or oily ballast. Oil is also released into the environment from natural geologic seeps on the seafloor, as along the coastline. The fate, behavior, and environmental effects of spilled oil can vary depending upon the type and amount of material spilled. In general, lighter refined petroleum products such as diesel and gasoline are more likely to mix in the water column and are more toxic to marine life, but tend to evaporate relatively quickly and do not persist long in the environment. Heavier crude or fuel oil, while of less immediate toxicity, can remain on the water surface or stranded on the shoreline for much longer. Oil from the Exxon Valdez and Gulf War oil spills, while weathering over time, has persisted along the shoreline for years after the spill.

7.1 Introduction

The practice of rainwater storage in the pond is quite common but still there is a need to improve its design. Most of the ponds used for rainwater storage are designed on thumb rule: either they are under or over designed. An over designed farm pond can meet the supplemental irrigation needs of the crop but it may not be economical. On the other hand, an under designed pond though economical, may not be able to meet the irrigation needs of the crops at all times. It is reported that in some case up to 20% of the farm area is used for construction of farm pond. These farm ponds are found not to be optimal. Although these ponds are able to meet the crop water demand at most of the stress periods, but considering the economics, they are observed not to be optimal. The big size farm ponds need large areas to be wasted for the digging of the structures. They need huge investment for their construction and lining. Hence, proper scientific studies are needed so that its storage becomes adequate to save the crops from the adverse effects of the drought in monsoon and to assure the possibility of growing a second crop in the winter and at the same time, it is economical also. Simulation studies by daily water balance models of both the crop field and the pond help to understand the availability of water in the pond to meet the supplemental irrigation demand of the crops.

Successful orchard establishment requires careful planning of site, climate, soil, water, planting material, spacing, and crop architecture. This chapter explains principles of orchard planning and establishment, including site evaluation, land preparation, layout, pit preparation, planting systems, and selection of suitable cultivars and rootstocks. Traditional and modern planting systems, including high-density and ultra-high-density systems, are discussed in relation to light interception, productivity, mechanization, and efficient resource use. Proper orchard design also facilitates irrigation, fertigation, pruning, harvesting, and plant protection. The chapter emphasizes long-term planning because perennial horticultural crops remain productive for many years and early establishment decisions strongly influence future orchard performance.

Introduction

Organic farming is a comprehensive approach to production management that promotes and improves Agro-health, ecosystems including biodiversity, biological cycles, and soil biological activity. It prioritizes management approaches above off-farm inputs, and agronomic, biological, and mechanical farming procedures are used rather than synthetic resources (Ajibade, Ayinde, and Abdoulaye 2020). The term “organic farming” refers to a production technique that excludes the use of artificially formulated fertilizers, pesticides, or growth regulators for agronomic practices or the use of different chemicals for livestock production, i.e., feed additives, growth promoters and antibiotics, etc. (M. Singh 2021).

The organic constituents of soils or soil organic matter is the most essential components of soil consisting of plant and animal residues at various stages of decomposition, cells and tissues of living or nonliving organisms and the substances synthesized by their decomposition. Soil organic matter exerts profound effect on soil productivity as it acts as source and sink of plant nutrients especially nitrogen and sulphur. It also involves in major biochemical processes to transform or release of plant nutrients into their available forms. Thus, it plays vital role in soil fertility maintenance, through increasing cation exchange capacity and improving soil physical properties, such as bulk density, aggregation, water retention capacity and also supports all kinds of biological activities in soil. The soil organic matter mostly concerns only with dead organic fractions formed from the decomposition of original plant and animal residues using as a source of food and energy by the soil microorganisms. It can be distinguished into –

There is no doubt that after independence, particularly during 1966-68, the use of hybrid and composite seeds of various crops, chemical fertilizers and pesticides resulted in an increase in the Indian agricultural output leading to ìGreen Revolutionî. But quite soon, the deleterious effects of farming based on chemical Organic Farming for Sustainable Agriculture 105 methods came to fore.

1. Introduction to Organic Farming

Definition and Principles of Organic Farming

Organic farming is not merely a set of agricultural practices; it is a profound philosophy that seeks to redefine humanity’s relationship with the land. At its core, organic farming is an intricate dance with nature, a commitment to fostering biodiversity, ecological balance, and sustainability.

Defining Organic Farming

Organic farming is a departure from conventional agricultural methods that rely heavily on synthetic inputs. It is an agricultural system that embraces natural and traditional approaches to cultivation.

Farmyard Manure is the manure prepared by using the mixture of dung and urine soaked litter by microorganisms.

Good farmyard manure is one

Before the discovery of chemical fertilizer in early 20^th century, organic manures and growing of legumes were the ways of replenishing soil fertility. The only other way was leaving land fallow for a few years before its re-cultivation, a practice followed in shifting cultivation (jhuming) (Garbyal, 1999). This was also true for India, where although the ?rst single superphosphate plant was set up in 1906 in Ranipet (Tamil Nadu), the real use of fertilizer started with the manufacture of urea, the ?rst plant for which was set up in 1959 at Sindri (Bihar) (Tandon, 2014). Organic manures could meet crop-nutrient needs in early days because the average grain yield of most cereals was about 1.5–2.0 t ha^–1, while the average yield of pulses was 0.5–0.75 t ha^–1. However, the crop production scenario changed rapidly after the introduction of dwarf, high-yielding varieties of wheat from Mexico, which led to the “Green Revolution” (Swaminathan, 2013). This was followed by the development of semi-dwarf, high-yielding varieties of rice and hybrids of maize, sorghum and pearl millet. These varieties/ hybrids of cereals needed 100–150 kg N ha^–1 in one growing season, and this could be met only by urea or other N fertilizers; organic manures had no chance and their use became almost nil over a period of next 25 years or so. Well-off young farmers cannot even think of making manure heaps or compost pits, the job is too hard and not a clean one. However, what is ignored is the fact, that organic manures not only supply plant nutrients but also build up soil organic matter, which improves soil physical properties, helps in storing moisture and is the elixir of life for the soil biota (Lal, 2014). A large numbers of reports are available on the effect of adding organic manures and crop residues on improving soil physical (Hati et al., 2007; Brar et al., 2015) and chemical and biological properties of soil (Prasad et al., 1999; Prasad and Mishra, 2001;Sharma et al., 2009; Prasad et al. 2014). Thanks for the organic farming (Prasad, 2005), the interest in organic manures and composts has increased in India and it is now a sought after material. However, it has not entered the main stream of crop production.

The soil microorganisms thrive on organic matter in soil by feeding readily on soluble substrates and rather slowly on insoluble substrates. Organisms derive carbon and energy during the process of organic matter decomposition and release organically-bound carbon, thereby decrease C :N ratio and utilize nutrients. Any decrease in organic matter content in soil is likely to affect the microbial biomass and their activities thereby influence the soil fertility and productivity. It is, therefore, imperative to recycle the organic matter in soil in whatsoever form it may be. The raw organic matter requires appropriate treatment to boost decomposition process.

Sustainable horticulture seeks to produce nutritious and economically valuable crops while conserving soil, water, biodiversity, and other natural resources. This chapter examines organic, natural, and broader sustainable production systems and their underlying principles. Topics include organic inputs, compost, biofertilizers, biological pest management, crop diversification, mulching, recycling, soil-health improvement, and reduced dependence on synthetic inputs. Certification systems and market requirements are also considered, including Indian and international organic standards. The chapter distinguishes different production philosophies while emphasizing practical sustainability. Successful systems must maintain productivity, profitability, environmental quality, and consumer confidence. Sustainable horticulture therefore combines ecological principles with sound crop management, market awareness, and responsible resource use

In addition to farm ponds, irrigation to crops can be met from other sources. The main sources can be broadly classified as: (i) Canal irrigation, (ii) Well Irrigation and (iii) Lift irrigation. In arid and semi arid areas, where availability of water is scarce, pitcher irrigation is practiced. These sources of irrigation are briefly mentioned as follows.

13.1 Canal Irrigation

To feed the world population of 8 billion in 2025 AD, it is necessary to bring more area under irrigation because irrigated farms typically get higher yield under provision of irrigation. The food production will have to increase by about 50 percent to feed some two billion more people by 2025 AD, and a large part of that increase needs to come from irrigated agriculture. It is reported that the yield of different crops are generally 2-3 times higher than the crops grown under rainfed conditions. Furthermore, it is possible to raise 2-3 crops round the year under irrigated agriculture whereas hardly a single crop is successfully grown in a year under rainfed condition. It is reported that about 40% of the world’s food production comes from only 17% of the irrigated land of the world (Sivanappan, 2000). Everybody is aware of the fact how the irrigation played a crucial role to make the Green Revolution in India successful. A major part of irrigation is achieved by canal irrigation through different irrigation schemes.

A project that makes use of weir or a barrage for providing irrigation to fields is called as direct irrigation scheme. On the other hand, a storage irrigation scheme makes use of storage reservoir by construction of dams. In order to provide irrigation by both the schemes, it is necessary to have a network of canal systems including main canals, branch canals, distributaries, minors and watercourses. It is imperative to design the canal systems properly for a certain realistic value of peak discharge that must pass through them so as to provide sufficient irrigation to the command areas. These canals have to be aligned and excavated either in alluvial soils or non-alluvial soils; depending upon which they are called alluvial canal or non-alluvial canal.