eChapters

5.1 Introduction

A reservoir that collects and harvests in-situ rainfall as well as runoff from the catchment area can be used for many purposes: the most important of which is the supply of water to crops as supplemental irrigation. The water of the reservoir can be used for domestic and industrial uses. It is also a good source for recreational use. Total water demand of the reservoir including irrigation to different crops in different seasons, domestic and other non agricultural uses are to be assessed. While estimating the crop water requirement and irrigation requirement, various crops to be grown in the service area of the reservoir, their water requirements, crop duration, extent of coverage and water management practices followed are to be taken into consideration. Multiplying the irrigation requirement with crop coverage area, volumetric irrigation water requirement of crop can be found out. Summation of irrigation requirement of all crops grown in service area of the reservoir gives total irrigation demand of the reservoir.

Small farm reservoirs are normally used for irrigation to crops as well as to meet the live stock water demand. Normally the large live stocks like horse, cattle require 20 thousand litres of water per head per year whereas the small live stocks like sheep, goat, pigs require 2 thousand litres of water per head per year. Adding the irrigation demand to the livestock demand, total water requirement of the reservoir is calculated. In addition to this, water used for industrial, domestic and other sectoral purposes are to be added to irrigation and livestock demand to estimate the total water demand of the reservoir.

Introduction

The eastern states of India comprising of Bihar, West Bengal, Odisha, Chhattisgarh, Jharkhand, Assam and eastern Uttar Pradesh occupy about 21.85% geographical area and supports 34% human and 31% livestock population of the country. Agriculture is the mainstay of economy in these states, since 83% population living in rural areas depends on it for their sustenance. The region has about 2.73 M ha of total area under reservoirs, ponds, tanks, lakes, brackish water, etc. besides 15046 km length of rivers and canals constituting about 18 percent of country’s utilizable water resources. The average rainfall in eastern region varies from 1091 to 2477 mm with a regional average of 1526 mm, which is sufficient and substantial for growing a variety of crops. However, the irrigated area in the region is 39% as against 45%, the national average.

1.1. Status of irrigation in Tamil Nadu

Geographical area of 13 million hectares is ranked eleventh in size among the Indian states.

Net area sown is about 6 million hectares.

3 million hectares or 50% get irrigation facilities.

Introduction
Given increasing demands, dwindling resources, and climate-induced uncertainties, water resource management is a critical challenge in the 21st century. Integrating Information Technology (IT) into water resource management offers transformative solutions to optimize water usage, monitor resources, predictshortages, and enhance distribution efficiency. IT tools such as remote sensing, geographic information systems (GIS), artificial intelligence (AI), Internet of Things (IoT), and big data analytics are at the forefront of this evolution, enabling more effective planning, decision-making, and resource sustainability.

1.1 Introduction

Climate change is evident from the observation of increase in global average air and ocean temperatures, precipitation and extreme rainfall, widespread melting of ice, storms / storm surges flooding and rising global mean sea level, as recorded in the Fourth Assessment Report of IPCC. Eleven of the last twelve years (1995-2006) rank among the twelve warmest years in the instrumental record of global surface temperature (since 1850). 

10.1 Land and Water Resource

India has got the world’s 2.45% area and 16.87% of population with only the 4% of available fresh water (Table 11.1). This indicates the necessity of development of water resources and optimal use of it. India at macro level does not have short of water. But the shortage of water is due if not properly managed by conservation and sector wise utilization.

The water resource potential of the country has been assessed by different agencies in different time (Table 11.1). It is observed that the latest estimate of 1869bcm (1993) are within the little variation of the estimates since 1954. The utilizable water resources of the country are assessed 1123bcm by CWC (1993) of which 690bcm from surface water and 433bcm from ground water sources. This 690bcm can be harnessed if matching storage structures are built. The surface water utilizable potential may increase by 220bcm if inter-basin transfer

10. 1 Land and Water Resource

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

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

Land and water resources are central to agriculture and rural development, and are intrinsically linked to global challenges of food insecurity, land degradation , poverty, climate change adaptation and mitigation that affect the livelihoods of millions of rural people across the world. Current projections indicate that world population will increase from present figure of 6.9 billion to 9.1 billion in 2050. As a result, the world food demand will increase. Since, both land and water resources, the basis of our food production, are finite and already under heavy stress, so future agricultural production will need to be more productive and more sustainable at the same time. The largest contribution to increases in agricultural output will most likely come from intensification of production on existing agricultural land. This will require widespread adoption of sustainable land management practices, and more efficient use of irrigation water through enhanced flexibility, reliability and timing of irrigation water delivery. The prevailing patterns of agricultural production needs to be critically reviewed.

1. Introduction to Water Resources in Agriculture

Water, the quintessential life force for agriculture, intricately intertwines its significance throughout the fabric of global farming practices.

1.1 Significance of Water in Agricultural Practices

1.1.1 Sustenance of Plant Life

• Beyond its role as a life sustainer, water emerges as the very essence that propels plant development. It acts as the vital catalyst for photosynthesis, the engine of plant growth. This intricate process is the heart of the plant’s ability to convert sunlight into energy, driving robust development from seed germination to harvest.

Introduction

Water is a precious natural resource vital, for sustaining all life on the earth. It is in a continuous circulatory movement - hydrologic cycle. It is not uniformly distributed in time and space. Due to its multiple benefits and the problems created by its excesses, shortages and quality deterioration, water as a resource requires special attention. On a global scale, total quantity of water available is about 1600 million cubic km. The hydrological cycle moves enormous quantities of water about the globe. However, much of the world’s water has little potential for human use because 97.5% of all water on earth is saline water. Out of remaining 2.5% fresh water, most of which lies deep and frozen in Antarctica and Greenland, only about 0.26% flows in rivers, lakes and in the soils and shallow aquifers which can be readily used. Sustainable water management in India is fast becoming a necessity, with the looming crisis over water resources in the country threatening the security and livelihood of the population and the environment over the coming decades. Managing water resources, river catchments, and coastal zones are outstanding challenges of today and tomorrow’s. Global changes ask for a comprehensive scientific approach, an international multi-disciplinary orientation and require a new mind-set towards water and coastal management problems.

2.1. Introduction

Water plays a pivotal role in this earth system. The withdrawal of water for irrigation is about 70% of the global freshwater. Water use efficiency is less than 50% in many countries. It has been forecasted by the Food and Agricultural Organization (FAO, 2015) that global water requirements will be increased by 50% by the year 2050 to meet the demands of agricultural water use. This is so because food demand will be higher for the growing human population. We have entered into an earth system where everything living has evolved and developed (Cosgrove and Loucks, 2015). There has been a new geological scenario, some say Anthropocene (Crutzen, 2002; Williams et al., 2011). Consequently, freshwater will increasingly be a scarce and the costliest resource in the future, which needs to be managed properly.

Surface Water Resources

Surface water is a general term describing any water body which is found flowing or standing on the surface, such as streams, rivers, ponds, lakes and reservoirs. Surface water originates from various combinations of sources:

1. Direct precipitation - rainfall which falls directly in the surface water body;
2. Surface runoff - rainfall which has fallen onto the surrounding land and that flows directly over the surface into the water body;
3. Interflow - excess soil moisture which is constantly draining into water body; and
4. Water table discharge - where there is an aquifer below the water body and the water table is high enough, the water will discharge directly from the aquifer into the water body.

The quality and quantity of surface water depends on a combination of climate and geological factors. The recent pattern of rainfall, for example, is important in enclosed water bodies such as lakes and reservoirs where water is collected over a long period and stored. The water storage in streams and rivers is in a constant stage of movement and depend on the weather conditions.

4.1 Introduction

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

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

4.1 Soil Moisture Tension

Soil moisture tension is a measure of the tenacity with which water is retained in the soil and shows the force per unit area that must be exerted to remove water from soil. The tenacity is measured in terms of the potential energy of water in the soil measured, usually with respect to free water. It is usually expressed in atmospheres, the average air pressure at sea level. Other pressure units like cm of water or cm or mm of mercury are also often used (1 atmosphere = 1036 cm of water or 76.39 cm of mercury). It is also sometimes expressed in bars (1 bar = 106 dynes / cm² = 1023 cm of water column. 1 millibar = 1/1000- bar).

Soil moisture tension is brought about at the smaller dimensions by surface tension (capillarity) and at the higher dimensions by adhesion. Buckingham (1907) introduced the concept of ‘capillary potential’ to define the energy with which water is held by soil. This term, however, does not apply over the entire moisture range. In a wet soil, as long as there is a continuous column of water, it might be called ‘hydrostatic potential’, in the intermediate range the term ‘capillary potential’ is appropriate. In the dry range the term ‘hygroscopic potential’ would be suitable. However, the term ‘soil moisture potential’, ‘soil moisture suction’ and ‘soil moisture tension’ are often used synonymously to cover the entire range of moisture (Khonke, 1968).

Water is an essential component of all living things. Although once believed as a resource with a never-ending supply, it has now been understood that water is becoming increasingly scarce and therefore a proper management is necessary to keep a sustainable food production (Kannan & Anandhi, 2020). A continuous and safe supply of water is indispensable for the food industry where it has numerous applications along the agriculture and food production processes.

Riboflavin or Vitamin B₂
Introduction

Riboflavin (synonymous with lactoflavin, vitamin G and vitamin B2) is a yellow green, fluorescent, water soluble pigment widely distributed in plant and animal cells. The organic formula of riboflavin is (6, 7-dimethyl)-9-(D,1-ribtyl)-iso-alloxazine. The empirical formula is C₁₇H₂₀N₄O₆. Riboflavin is very sensitive to both visible and ultraviolet light. All manipulations with riboflavin or riboflavin containing materials should be carried out in subdued light or in low actinic glassware. Even subdued daylight may be destructive but artificial light of an intensity of 6 candles per squarefeet or less is permissible. Irradiation of alkaline solutions yields lumiflavin (6, 7, 9-trimethylis-alloxazine) and in acid solutions lumich rome (6.7 dimethyl alloxazine) is formed, which is characterised by a blue fluorescence. One of the distinguishing properties of riboflavin is its yellow-green fluorescence in neutral solutions which reaches a maximum at pH 6.7 to 6.8.

Water Requirements

Dairy plant requires large quantities of water on a daily basis for processing and cleaning purposes. Normally the specific water consumption ranges from 1000-5000 litres per 1000 litres of milk processed. The actual requirement can vary between dairies and is a function of 
    a)    Manufacturing process or manufacturing profile.
    b)    Auxiliary processes such as steam generation, design of the refrigeration processes and extent of social services.
    c)    Multiple use/reuse.
Water is a very valuable basic natural resource  and needs careful consumption. The water supply system in a dairy plant should be designed in such a way that consumption for each manufacturing department and auxiliary processes can be determined. This makes it possible to influence water consumption directly, and major losses can be determined very rapidly.

4.1 Introduction

A farm pond is basically small scale water harvesting and water recycling structure. It harvests water mainly in the rainy season when there is abundant rainfall producing sufficient runoff and the harvested water may be used for single or multiple cropping. When there is deficient supply of water to the crops it may supplement as supplemental irrigation. The leftover water in the pond can be used for growing another crop in winter when there is no or less rainfall. Ij addition, the stored water in the pond can be used for domestic and other uses and rearing fish. Thus it serves as viable medium for integrated farming system in rainfed farming ecosystem. Before designing a pond in a given location, it is very important to estimate the total quantity of water supply to the pond. The two main sources of water supply to pond are (i) in situ rainfall and (ii) runoff (some times called as discharge) generated from the catchment and conveyed to the pond. Some times there is groundwater contribution to the pond when the pond is unlined and the underlying groundwater table with reference to the ground level is at lower elevation than the depth of water in the pond such that there is a hydraulic gradient in the direction of underlying groundwater level to the water level in the pond.

The demand for nutrients is rising, along with the population, which is rapidly expanding. The sustainability of life on earth now places a high focus on protecting the sources of sustenance. In this regard, aquaculture has a crucial role to play. The regulated raising of fish and other breeds in a particular environment is known as aquaculture. The natural resources and other elements required for sustainable development can be preserved using this method. The promotion of the value of nutrients and the expansion of employment prospects in the future are both made possible by aquaculture. Biofloc fish farming, which has set trends in fish farming all over India, facilitates recycling and reusing of the nutrients in the culture medium by filtering the unwanted substances and metabolites and converting them into nutrients, which benefits the zero exchange of water.