eChapters

10.1. Introduction

Irrigation facilities are created by the Government at huge cost for supplying water to the farmers for raising crops to increase agricultural production. The major and medium irrigation projects are planned, constructed, managed, operated and maintained by the Irrigation Departments, wherein certain procedures and rules are evolved and followed to the delivery schedule of canals, frequency of supply and distribution of water to the farmers, and closing of canals. The creation of such facilities resulted in ushering the green revolution in the sixties and seventies in the production of food grains and also employment generation in the country, thereby improving the socio-economic condition of Indian farmers. However, optimized management of irrigation water is the key to the sustainable development of agriculture and livestock. Since management of water for irrigation is highly location-specific, depending upon agro-ecological and socio-economic conditions, type of irrigation project and land use pattern, it differs from project to project and region to region in the country.

Natural resources conservation and their management hold key to sustainable agriculture and livestock production. It is all the more crucial for countries with predominant agrarian economies where development of sustainable agriculture is essential for overall growth, redressal of poverty and security. Conservation of both soil and rain water as very crucial and basic resources have been practiced since ancient times in India. However, there has been renewed emphasis on conservation and efficient utilization of these resources in the recent past. The fact that 70% of the arable area of India is rainfed with precarious supply of water and that rainfed agriculture supports 44% of India’s human population and contributes 90 per cent of coarse cereals and pulses, 80 per cent of oilseeds and 65 per cent of cotton and growing realization that further gains in productivity of crops and livestock will emanate from rainfed regions, leave no room for complacency in this regard.

Year after year, the fate of a vast majority of Indian farmers hangs in balance, as success with rainfed agriculture continues to be a gamble. It is evident that crop yields in semi-arid areas depended more on rainfall distribution than on total rainfall and lack of serious efforts to create the water supply for crops through scientific management of rainwater is a factor favoring this avoidable uncertainty. In rainfed agriculture no other input can perhaps enhance the yield without effectively tackling of the rainfall aberration related sub-optimal moisture availability. Therefore a prerequisite for substantial improvement in the agriculture production in the semi-arid region is to manage runoff water and to use it either at the time of moisture stress even during the monsoon or in next season. It has been reported that only one supplementary irrigation at proper stage can double of rabi crops. But supplemental water is a developed resource and is more expensive than the natural resources. Hence, it is all the more necessary to use this water judiciously and efficiently. Standardization of techniques by which as much of precipitation as possible can be conserved for crop use, either directly in the soil profile through infiltration or through runoff collection and recycling is an area of priority in research.

Land, water and weather are natural resources that are critical for survival. Modern agriculture requires precise information on various agro-climatic parameters like soil, crop, climate and water resources for formulating efficient agricultural planning. Out of these, water is considered most scarce input in agriculture because its availability is reducing drastically for agriculture as well as drinking purposes. Besides, declining water tables and deteriorating quality of water resources caused pollution and sewage and effluents have further multiplied the problems.

Natural resources conservation and their management hold key to sustainable agriculture and livestock production. It is all the more crucial for countries with predominant agrarian economies where development of sustainable agriculture is essential for overall growth, redressal of poverty and security. Conservation of both soil and rain water as very crucial and basic resources have been practiced since ancient times in India. However, there has been renewed emphasis on conservation and efficient utilization of these resources in the recent past. The fact that 70% of the arable area of India is rainfed with precarious supply of water and that rainfed agriculture supports 44% of India’ s human population and contributes 90 per cent of coarse cereals and pulses, 80 per cent of oilseeds and 65 per cent of cotton and growing realization that further gains i n productivity of crops and livestock will emanate from rainfed regions, leave no room for complacency in this regard.

Year after year, the fate of a vast ‘majority of Indian farmers hangs in balance, as success with rainfed agriculture continues to be a gamble. It is evident that crop yields in semi-arid areas depended more on rainfall distribution than on total rainfall and lack of serious efforts to create d water supply for crops through scientific management of rainwater is a factor favouring this avoidable uncertainty. In rainfed agriculture no other input can perhaps enhance the yield without effectively tackling of the rainfall aberration related sub-optimal moisture availability. Therefore a prerequisite for substantial improvement in the agriculture production in the semi-arid region is to manage runoff water and to use it either at the time of moisture stress even during the monsoon or in next season. It has been reported that only one supplementary irrigation at proper stage can double of Rabi crops. But supplemental water is a developed resource and is more expensive than the natural resources. Hence, it is all the more necessary to use this water judiciously and efficiently. Standardization of techniques by which as much of precipitation as possible can be conserved for crop use, either directly in the soil profile through infiltration or through runoff collection and recycling is an area of priority in research.

Submerged soils/Flooded soil

Submerged soils are the type of soils that are saturated with water for a sufficiently long time in a year. This gives the soil the following distinctive gley horizons resulting from oxidation-reduction processes:

The soil is intermittently saturated with water, oxidation of organic matter is slow and it accumulated within the “A” horizon. Fe and Mn are deposited as rusty mottles or streaks if the diffusion of O2 into the soil is slow in the second horizon, whereas if the diffusion is rapid, they are deposited as concretions.

Types of submerged soils

1. Waterlogged soils- Waterlogged soils are saturated with water for a sufficiently long time annually to give the soil the distinctive gley horizons resulting from oxidation-reduction processes. Saturation with water may be due to impermeability of the soil material, or the presence of an impervious layer, or a high water table.

2. Marsh Soils- These types of soils are more or less permanently saturated or submerged. Freshwater marshes can be classified according to their origin into upland, lowland, and transitional. Upland marshes are poor in bases and have pH 3.5-4.5 because they receive mainly rainwater. Lowland marshes are saturated or submerged with water-carrying bases and have pH 5.0-6.0.

Water Scarcity Issues
The world is running out of clean water. The subsurface water table decreases and surface runoff rises as a result of deforestation. The amount of water stored underground is decreasing as wells are being dug deeper and deeper. As a result of desertification and deforestation, perennial rivers are turning seasonal. There is not enough potable drinking water because of abuse and overuse.
Conserving Water
• In certain situations, manipulating plants, harvesting water, and other techniques might increase the availability of water supplies.
• Water use reduction achieved by the application of water efficiency or conservation techniques; alternatively,
• Better techniques for managing water can either decrease or increase the useful use of water.
• Any activity, behavioral modification, tool, technology, or better design or procedure used to lower water loss, waste, or use is referred to as a water conservation method.
• One method of conserving water is water efficiency.
Among the Objectives of Water Conservation Initiatives
• The goal of sustainability is to guarantee that water extracted from an ecosystem will not be lost faster than it naturally replaces itself for future generations.
• The pumping, delivering, and treating of water results in energy conservation.
• Habitat conservation includes limiting the amount of water used by humans, which lessens the need to construct new dams and other water diversion infrastructure while also preserving freshwater habitats for nearby species and migratory waterflow.

Soil, climate and water decide the nature of crop to be grown in a particular region. While soil and climate can be manipulated to certain extent, there is no substitute of water. Water is governed by the hydrological cycle. The major source of water is rainfall which has been reduced over the years due to climate change. The per capita water availability in India was 4944 m3 in 1955 which has been reduced to 1750 m³ now and is expected to come down to 1500 m³ by 2025.

Abstract

In the emerging era of wide spread use of IT tools, up-to-date information on water resources is the key to support economic development, conserve the nature as well as to improve the quality of life. Due to rapid rise in population  and food demand, growing economy and improving living standards; the pressure on our water resources is increasing and it will become scarce in the coming decades if not managed at this stage in a integrated way. Water resources management requires a multi-disciplinary approach that combines a collection of technical tools and expertise along with stakeholders of diverse interests and priorities in planning and management and an operational water resources information system at national level is the first requirement.

Increasing population, declining natural resources, changing climate and political stability are the major threat to our food, nutritional as well as environmental security. It is expected that India’s population will boom to 1.5 billion by 2030 and to feed them we need approximately 341mt food grain including 315 mt cereals and 26mt pulses) (Kumar et al., 2016).

Water is a critical input for agricultural production and plays an important role in sustainable agriculture and food security. Agriculture is the principal user of water, accounting for around 70% of total withdrawals. Producing each calorie of food requires approximately one litre of water.

The coastal agro ecosystem is very important among the different agro ecosystems of our country both economically and environmentally. It spans over a length of 8129 sq. km. covering 9 states and 2 Island ecosystems. Agriculture and allied activities constitute the single largest component of India’s economy, contributing nearly 27 per cent of the total Gross Domestic Product (GDP) in the year 1999-2000 (TERI, 2002). Agriculture exports accounts for 13 to 18 per cent of total annual exports of the country (MoF, 2002). However, given that 62 per cent of the cropped area is still dependent on rainfall (MoEF, 2002). Coastal agricultural region comprises of hinterland, which has a varied geometric and topographical features of mountains valley, coastal plains, riverine systems, climatic conditions, different soils and water bodies, vegetation ranging from rich tropical rain forests to coastal mangroves and a wide range of crops that are cultivated in this region (Table 1). The agro climatic conditions of the coastal zones are congenial for growing various field and horticultural crops.

Water management in agriculture is a critical component of ensuring sustainable food production and environmental conservation. This article explores various strategies for conserving water in agricultural practices, examining both traditional methods and modern technological innovations. It addresses the challenges posed by climate change, population growth, and resource scarcity, highlighting the importance of efficient water use. Key strategies discussed include irrigation optimization, soil moisture management, rainwater harvesting, and the adoption of drought-resistant crops. The article also considers policy measures and community-based approaches that support water conservation. By implementing these strategies, the agricultural sector can contribute to sustainable water management and enhance food security.

Introduction

Indian agriculture was contributing 70% to total GDP of the country at pre-independent time, but it decreased drastically year by year and contributed 66.8% in 1960, 55.6% in 1994, 27.1% in 1997 and now a days, it reached only to 25% in 2001. With the advancement of civilization our population is increased, whereas, the cultivable lands is decreased side by side, thus, on an average income of agriculture is decreased.

Gujarat is the leading state to concern with the productivity, production and the area of the some crops like Groundnut, Castor, Cotton, etc. in India. The major part of the state is surrounded by sea coast border, which is 1600 km. Gujarat is popular for production of oilseed crops like groundnut, cotton ; horticultural crops like mango, chiku, coconut, banana, papaya, citrus; spices crops like chili, cumin, funnel etc.

1.0 Introduction

Population in dry lands of the world is increasing; more fresh water is required in order to meet the growing demands. To meet this challenging situation developing new technologies for identification of potential sites for rainwater harvesting (RWH) is an important step towards maximizing water availability in semi-arid areas.

Pulses can be grouped into kharif and rabi pulses according to their temperature requirements. In India chick pea, pea, lentil and beans require relatively less temperature and are grown in rabi season, whereas others are confined to kharif season. However, kharif pulses can also be grown in pre-rabi on stored soil moisture or as irrigated crops in rabi and summer seasons.

Pulse crops have long tap root system which extracts soil moisture from deeper layers. Water uptake across the depth of rooting zone is not uniform. In general 40 per cent of the total water uptake occurs from first one fourth of the rooting zone, 30 per cent from the second, 20 per cent from the third and remaining 10 per cent from the last one-fourth region of total rooting depth (Nageshwararao and Writ, 1994). Plants often maintain higher root length densities than required in the surface layers to facilitate rapid uptake of recent rain/irrigation before it evaporates.

4.1. Introduction

Globally, rice is cultivated on about 165 million ha of land, which provides around 787 million tons of paddy annually (FAO, 2023). In Asia, 708 million tons of paddy is produced from nearly 143 million rice-cultivated areas. Rice crop is grown in a wide range of climates, varied soil types, and hydrological situations. Rice is the lone cereal crop that grows well in floods.

The rice habitat can be divided into four groups based on the hydrology of the rice field: irrigated lowland rice (79~80 million ha), rainfed lowland rice (54~55 million ha), upland rice (14~15 million ha), and flood-prone rice (11~12 million ha) (Table 4.1) (Bouman et al., 2006).

5.1. Introduction

Rice-fallows are a rainfed rice mono-crop production system, where only a single crop (rice) is grown and these lands remain without any crop for the rest of the period of the year (fallow). An estimate shows that rice-fallow areas extended over 22.3 M ha in South Asia, maximum in India ( 88.3%) followed by Bangladesh (8.7%), Nepal (1.4%), Sri Lanka (1.1%), Pakistan (0.5%), and Bhutan (0.02%) (Gumma et al., 2016). The eastern part of India accounts for ~ 84% (9.7 million ha) of the country’s total rice-fallow area (i.e. 11.7 million ha) (Ali et al., 2014; Singh et al., 2017), despite high rainfall during rainy / monsoon season. The reasons are that after the rainy season, irrigation facilities are lacking, very fast depletion of the soil residual moisture due to temperature rise, the poor economic condition of the farmers, and a lack of awareness or knowledge of available technologies. Additionally, delayed harvesting of long-duration rice (150-160 days) results in late sowing of winter crops, which, in turn, exacerbates the temperature and moisture stresses in winter crops (Kumar et al., 2018a; 2018b). Overall, the challenges of growing another crop in rice-fallow areas are the lack of irrigation facilities including declining groundwater levels, the dominance of the long-duration rice varieties cultivation, higher evaporative loss of the residual soil moisture, degradation of soil quality, and poor financial conditions of the farming community with diminishing profit. Recently, climate change with erratic rainfall and delayed monsoon arrival added more challenges for these areas in several places. Deficit soil moisture imposes stress on the crops and negatively affects the winter crops productivity in the rice-fallow system, and several times it results in complete crop failure (Singh et al., 2012; Ghosh et al., 2016).

Introduction

Crop production system includes the components like soil, climate and plant (genetic) material. Within a particular genetic make up of the crop, productivity of the system is limited either by climatic factors, that is, radiation, temperature and rainfall (water), or by inherent edaphic environment that govern the root development and consequent uptake of water and nutrients. Where soils are cultivated over long periods, the edaphic conditions reach at its low levels. When water, nutrients and CO2 are plentiful, yield is determined by radiation and temperature regimes during the growing season. However, under actual field situations, the yields are limited by factors other than climate, which is water and nutrients. These are not only limited in amounts but also are becoming costlier every year. It is, therefore, important that available fertilizers be used efficiently.

Introduction
Water management is a critical aspect of agricultural science and environmental sustainability, influencing not only the efficiency of food production but also the health of ecosystems and the balance of global water resources. This chapter delves into the principles, techniques, and modern advancements in water management, emphasizing its significance in ensuring food security, conserving vital resources, and combating global warming. The chapter begins by exploring the foundational principles of irrigation, a key component of water management in agriculture. Various irrigation techniques, such as surface, sprinkler, and drip irrigation, are discussed in detail, along with the factors that influence irrigation efficiency, such as soil type, crop needs, and climatic conditions. The importance of optimizing irrigation practices to enhance water use efficiency and minimize waste is underscored. Water use efficiency and conservation strategies form the next major focus of the chapter. As global water resources face increasing pressure from population growth, industrialization, and climate change, the need for efficient water use in agriculture becomes ever more critical. The chapter discusses various methods to improve water use efficiency, including advanced irrigation technologies, crop selection, and soil management practices. Conservation strategies, such as rainwater harvesting, groundwater recharge, and the use of drought-resistant crops, are also explored. Effective drainage systems and waterlogging control are essential for maintaining soil health and agricultural productivity. The chapter provides an overview of drainage system principles, techniques for assessing soil drainage, and strategies for controlling waterlogging, a condition that can severely impact crop yields. The benefits of well-managed drainage systems, including improved soil structure, reduced salinity, and enhanced crop performance, are highlighted. Water quality and salinity management are crucial for sustaining agricultural productivity and preventing soil degradation. The chapter discusses methods for assessing water quality, the impact of salinity on soils and crops, and techniques for managing salinity, such as the use of salt-tolerant crops and soil amendments. Effective water quality management ensures that crops receive the nutrients they need while preventing harmful buildup of salts and other contaminants

Summary
 
This chapter explores different approaches to manage water in rain-fed and irrigated agricultural systems. The first methods support the retention of water and reduce soil erosion. These methods include mulching – the application of a surface coating over the soil – which is usually organic mater. This reduces the damage to soil caused by rain and wind and reduces water loss to evaporation and helps with infiltration. The other methods explored are bunding and terracing.  These approaches are about stopping the flow of water across land to increase the amount of water infiltration into the soil and to reduce or prevent soil run off.  These approaches are labour intensive. A less labour -intensive approach is contour ploughing. This approach is about encouraging farmers and tractor drivers to plough across sloping fields not up and down them. The second group of technologies refers to the introduction of water through irrigation methods.