eChapters

Introduction

The need for water for human consumption and the industry keeps spiraling up in the cities in the wake of rural diaspora and urban sprawl. Groundwater is exploited at an unsustainable rate leading to depletion of aquifers. Worse still is the intrusion of salt water from adjoining coast into the aquifers leading to total wastage of remaining water.

Introduction

Accumulation of excess soluble salts in the root zone of soils resulting in partial or complete loss of soil productivity is a worldwide phenomenon. The problems of soil salinity are widespread in the arid and semi-arid areas but salt-affected soils also occur extensively in the sub-humid and humid climates particularly in the coastal regions where the ingress of sea water through estuaries and rivers and through ground water movement causes large scale soil and water salinisation. Soil salinity is also a serious problem in areas where ground waters of high salt content are the only source of water available for irrigation. By far the most serious problems of salinity are being faced in the irrigated, arid and semi-arid regions of the world. Our ability to manage salt-affected soils and waters both in the irrigated and in the unirrigated regions will constitute a major effort in meeting potential food requirements. The magnitude of the problem can be appreciated from the following.

Next to the mineral frame work the salts in the soil deserve consideration. In fact these salts constitute the main food material of plants besides what the root hairs can get out of the mineral framework in the form of basic materials already dealt with. We are, however, not concerned with the plant food materials, but salts that are in excess and which alter the properties of the soil to such an extent as to influence its behaviour profoundly.

Soil testing is a useful tool that can help to ensure the efficient use of applied plant nutrients. Soil tests provide a means for assessing the fertility status of a soil, but soil tests do not provide a direct measure of the actual quantity of plant available nutrients in the soil. Instead, soil tests measure the quantity of a nutrient element that is extractable from a soil by a particular chemical extracting solution. The measured quantity of extractable nutrient in a soil is then used to predict the crop yield response to application of the nutrient as fertilizer, manure, or other amendment. As soil test levels increase for a particular nutrient, the expected crop yield response to additions of that nutrient decreases. A soil-testing programme has four phases as follows:

1.Collection of soil samples,

2.Chemical analysis of soil samples,

3.Calibration and interpretation of the results of chemical analysis, and

4.Nutrient/Fertilizer Recommendation.

Abstract
 
Mention about the Great Himalayan river of Vedic Period (10000-8000 BC) is found in ancient Indian literature. The river called as ‘Saraswati’ in India and ‘Hakra’ in Pakistan, was flowing with full majesty through Thar Desert around 6000 BC and dried up during 3000 BC due to climatic and tectonic changes in Himalayan region. The relict of this lost river is still found as palaeochannels in this region. Large numbers of archaeological sites of Harappan civilization occur along the dry river bed. 

Abstract

This paper sets out to describe key results and experiences obtained during the assessment of the crop response to water which varies strongly from crop to crop depending on its specific genetic characteristics and adaptation to ecological conditions. The specific crop water information for the different crops is compiled in a crop-based data base. This includes crop water parameters, yield response to water, as well as selection of economy crops. Existing natural water resources can sustain the crop production with high yield as well as economic value with minimal environment impact. Most of the crop varieties get all of its required water from rainfall- water but due to climate change there is always a demand of irrigation water from the ground water resources. Thus, there is a need to evaluate the crop water information in relation to ground water extraction as a source of irrigation.

Digital image processing is the use of computer algorithms to perform image processing on digital images. As a subcategory or field of digital signal processing, digital image processing has many advantages over analog image processing. It allows a much wider range of algorithms to be applied to the input data and can avoid problems such as the buildup of noise and signal distortion during processing. Since images are defined over two dimensions (perhaps more) digital image processing may be modeled in the form of multidimensional systems. Introduction to image processing 
Image processing is a method to convert an image into digital form and perform some operations on it, in order to get an enhanced image or to extract some useful information from it. It is a type of signal dispensation in which input is image, like video frame or photograph and output may be image or characteristics associated with that image. Usually image processing system includes treating images as two dimensional signals while applying already set signal processing methods to them.
Image processing is a method to perform some operations on an image, in order to get an enhanced image or to extract some useful information from it. It is a type of signal processing in which input is an image and output may be image or characteristics/features associated with that image. Now-a-days, image processing is among rapidly growing technologies. It forms core research area within engineering and computer science disciplines too.

Data collection is a tedious and time consuming work, particularly from remote places. So many times the collected data is noisy. But data is the base for future planning and management of water resources. Planning based on noisy data could lead to failure. The modern data collection and subsequent control system i.e. telemetry and SCADA, are introduced in this chapter.

Knowledge of structure is a basic element of biological research. Understanding structures of various degrees of complexity contributes to a better understanding of function, ontogenetic and physiologic processes, as well as phylogenetic relationships. In biological sciences, ultrastructure refers to the nanostructure of a biological specimen, such as a cell, tissue, or organ, at scales smaller than can be viewed with light microscopy. Electron microscopy (EM) has a great impact on our knowledge and understanding of ultrastructure.

Scenario of Bioinputs reviews the broader market, production, consumption, and regulatory context surrounding bioinputs, with particular attention to biopesticides. The chapter discusses global availability and registration, major categories, market outlook, research needs, and industrial support. It then examines production infrastructure and consumption trends in India, including contributions from government organizations, agricultural institutions, private companies, and local laboratories. State-wise patterns and regulatory considerations are also addressed. By combining technical agriculture with market and institutional perspectives, the chapter helps readers understand the evolving bioinput sector, its production ecosystem, policy environment, commercialization potential, and opportunities for expanding sustainable crop-protection technologies. for stakeholders today.

Scheduling irrigation is the process of determining when to irrigate and how much to irrigate. Selecting the appropriate time span in between two irrigation and applying the required volume of water in each irrigation, ensures saving of water, minimize energy use, higher crop yield and lower production costs. Irrigation applied earlier than due date causes loss of water through evaporation or deep percolation and later causes water stress to plants and thereby affects the growth and yield of the plants.

Scheduling of irrigation may be required in two field conditions: (i) when available of water is adequate, (ii) when availability of water is limited.

In the places where water is adequate scheduling of irrigation follows full   irrigation with time sequence of minimum number of irrigation to ensure maximum yield and high water use efficiency. When water is limited its use is rationalized by using at the sensitive stage

Irrigation Scheduling: Approaches and Advantages
Efficient irrigation scheduling aims to optimize crop yields while maximizing water use efficiency and minimizing soil damage. This involves determining the correct timing and amount of water to apply for each irrigation event. Several criteria can be used for scheduling irrigations, broadly classified into climatological, soil water regime, and plant-based approaches. The most suitable criterion depends on specific soil, plant, climate, and management factors.
Climatological Approach
Under conditions where soil water is readily available, the potential rate of water loss from a crop primarily depends on the atmosphere’s evaporative demand. This approach uses potential evapotranspiration (PET) or cumulative pan evaporation (CPE) over short periods as an index for irrigation scheduling.
Penman (1948) defined PET as the water transpired by a short, uniformly green crop completely covering the ground and never lacking water. He also noted that PET is generally a fraction of pan evaporation under the same conditions. PET can be estimated using various techniques, including lysimeters, energy balance calculations, aerodynamic approaches, and empirical formulas. Based on PET or crop water use rates over short periods, irrigation can be conveniently scheduled. Lysimeters isolate the crop root zone, allowing accurate determination of water balance components by controlling and measuring difficult-to-assess processes.
Soil Water Regime Approach
This approach uses the available soil water held between field capacity and the permanent wilting point in the effective crop root zone as a guide for irrigation scheduling. Soil moisture tension, which reflects how tightly water is held by soil particles, can also serve as an indicator.

1. The unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants. - Soil Science Society of America

Introduction

Attaining food and nutritional security for a growing population and reducing poverty while sustaining agricultural production under the current scenario of depleting natural resources, increasing cost of inputs and impending negative impacts of climatic change are the major challenges the country is currently facing (FAO, 2009). In addition to these challenges, decline in soil organic matter, consequent deterioration of soil health, large scale erosion of fertile top-soil are the other bottle-necks for increasing agricultural productivity from a finite land resource base. These constraints are evolving mainly due to: (1) intensive tillage induced soil organic matter decline, soil structural degradation, water and wind erosion, reduced water infiltration, surface sealing and crusting, soil compaction, (2) insufficient return of organic material to soil owing to prevalent crop residue removal and burning (Prasad et al., 1999) and (3) mono-cropping. Conservation agricultural (CA) is a panacea to address these challenges the farming community of this country is presently facing. The CA system incorporates a holistic approach to agriculture that results in improved soil health and water quality, lower water and nutrient consumption, reduced soil loss, strategic land use and healthy biodiversity. It involves minimum soil disturbance, permanent soil cover through crop residues or cover crops, and crop rotations for achieving higher productivity (Hobbs et al., 2008).

Introduction

Conservation of biodiversity and mitigation of global warming are two major environmental challenges today. In the context of climate change and the global carbon cycle, the relationship between plant biodiversity and soil organic carbon (SOC) sequestration has become a subject of considerable scientific interest. The Earth’s terrestrial vegetation plays a pivotal role in the global carbon cycle. Not only are tremendous amounts of carbon stored in the terrestrial vegetation, but large amounts are also actively exchanged between vegetation and the atmosphere. Anthropogenic perturbations exacerbate the emission of CO₂ from soil caused by decomposition of soil organic matter (SOM) or soil respiration (Schlesinger, 2000). The emissions are accentuated by agricultural activities including tropical deforestation and biomass burning, plowing, drainage of wetlands and low-input farming or shifting cultivation. In addition to its impact on decomposition of SOM, macroclimate has a large impact on a fraction of the SOC pool which is active. Conversion of natural to agricultural ecosystems increases maximum soil temperature and decreases soil moisture storage in the root zone, especially in drained agricultural soils (Lal, 1996). Thus, land use history has a strong impact on the SOC pool (Pulleman et al., 2000). The dynamic relationship between plant biodiversity and SOC depicts that any land use practices that increase vegetative cover, or reduce its removal, could have an influence on the global carbon budget by increasing the terrestrial carbon sink.

Introduction

Drought is one of the primary factors responsible for depressing rice yield in chronic areas and in destabilising rice production in drought-prone areas. It is a production constraint common to all rainfed rice cultures: wetland, upland, and deepwater (O’Toole and Chang 1979). Breeding for drought resistance, a major component of the International Rice Research Institute’s (IRRI) Genetic Evaluation and Utilization (GEU) Program since the early 1970s, aims at countering the adverse effects of drought in unfavoured rice production areas.

Rice germplasm has such remarkably rich diversity that a continuous spectrum of genotypes differing in the various physiological mechanisms can be found and is available for genetic manipulation (Chang et al. 1982a). However, effective evaluation methods are essential for unravelling the specific mechanism(s) involved and for devising eficient selection criteria in a breeding program. Moreover, the broad spread in growth duration among rice cultivars makes it impractical to obtain uniform evaluation of a large number of cultivars when they differ in physiological responses that are specific to certain growth stages. Methods that can accommodate large numbers are essential to breeding program.

Acid soils occupy one fourth of the land in India. The formation and distribution of acid soils depend upon several factors like temperature, vegetation, parent material and hydrological conditions etc. For this reason, these soils have low pH, poor base saturation, high sexquioxide content, which affects the transformation and availability of plant nutrients.  Secondary and micronutrient deficiency as well as toxicity are major problems in cultivation of crops in acidic soils. These soils are generally deficient in Ca, Mg and S and adequate in Fe, Mn and Cu. Apart from the secondary nutrients, Zn, B and Mo deficiencies affect crop production. In lowlands, rice crop suffers from toxicity of Fe. Aluminum toxicity, common in highly acidic soils, also pose major problems in crop production. Management of secondary and micronutrients in acid soils for agriculture is a national priority to achieve food sufficiency and sustainability.

5.1. Importance of Secondary Nutrients in Agriculture

Secondary nutrients such as sulphur (S), calcium (Ca) and magnesium (Mg) are the macronutrients that are required in relatively large amounts for crop growth. Among the secondary nutrients, Ca is the 5^th most abundant element in the earth’s crust while, Mg and S are ranked 8^th and 13^th, respectively. The average S content of the earth’s crust ranges from 0.06 to 0.10%; whereas, Ca in soil solution of temperate region soils is 30 to 300 ppm and soils of tropical areas is 8 to 45 ppm (Tisdale et al., 1997). In case of Mg, its’ concentration ranges from 5-50 in temperate region and 120-2400 ppm in tropical region. The Ca and Mg are the most abundant cations occupying the exchange sites of the soil colloids. Thus, most soils with the possible exception of highly weathered, leached acid soils, contain enough Ca and Mg for crop growth. In soils, occurrence and reactions of S are different from those of Ca and Mg. The plant available S is SO₄^2- ion which is relatively mobile in soil solution. Like nitrogen (N), S is also subjected to chemical and biological oxidation-reduction reactions. On the other hand, Ca and Mg are much more stable and they exist in soil as Ca²⁺ and Mg²⁺ cations and present in association with soil colloidal fraction similar to that of K. In general, Ca and Mg are the most abundant cations occupying in the exchange site.

Secondary nutrients in soils may be lost due to several reasons such as (i) crop removal, (ii) leaching, (iii) erosion, and (iv) volatilization. The amount of Ca and Mg attain importance in areas where soils are either strongly alkaline or acidic. These soils are often deficient in Ca and Mg. The Ca deficiency is most widespread in acidic soils. The alluvial soils of the Indo-Gangetic Plains (IGP), being neutral to moderately alkaline in reaction, have sufficient bases on their exchange complex and Ca deficiency is, therefore, rarely found in these soils. However, alkali soils may contain inadequate quantities of Ca due to dominance of Na⁺ on the exchange complex. Magnesium deficiency is found in sandy soils with low exchangeable Mg²⁺, acid soils and those with high in native or applied K. Alkali soils have high exchangeable Na⁺. The Ca²⁺ is a suitable ion to replace this Na⁺ from the exchange complex when Ca²⁺ is supplied through gypsum (CaSO₄.2H₂O). The replaced Na⁺ forms Na₂SO₄ which is then leached down to remove the salt away from the root zone of the crops. Gypsum also reacts with Na₂CO₃ to form CaCO₃ and Na₂SO₄ which is leached down the profile. A thorough leaching of the soil with irrigation water should be done after application of gypsum to free it from Na₂SO₄.

Secondary nutrients are essential for balanced plant nutrition and sustained soil fertility in intensively cultivated irrigated systems. This chapter focuses on calcium, magnesium and sulphur, examining their sources, behaviour, availability and management in soil. Calcium is discussed in relation to its sources, fate in soil, crop removal, leaching and factors affecting its availability, including high sodium content, parent material and interactions with other cations. Calcium fertilizers and their practical importance are also considered. The chapter then examines magnesium, including its sources, behaviour in soil, uptake by crops, leaching and fertilizer management. Sulphur receives detailed attention through discussion of organic and inorganic forms, elemental sulphur and sulfides, sulphate behaviour and the different forms occurring in rice soils. Processes such as adsorption, leaching and immobilization influence sulphur availability and are therefore important under irrigated conditions. Practical aspects of sulphur management, sulphur-containing fertilizers and crop responses to sulphur fertilization are discussed, including effects on the nutritional quality of forages

Secondary nutrients is a triad of three essential plant nutrients namely, Calcium (Ca), Magnesium (Mg) and Sulphur (S). Of these three, Ca and Mg are taken up by plants as cations, while S is taken up as anion SO4 2–. Among the secondary plant nutrients, sulphur is emerging as a major plant-nutrient de?ciency in crops grown in the Indo-Gangetic Plains, spread over 13 million ha in Pakistan, India, Nepal, and Bangladesh (Khurana et al., 2008). From the Indian point of view, S de?ciency has emerged in a large part of the country and needs to be attended. Uptake of Mg and S by some crops is given in Table 10.1.