eChapters

Organic manures

Anand Swarup (1992) stated that application of green manures along with rice husk increased the concentrations of N, P, Zn, Mn and Fe and decreased the Na concentration of rice in a reclaimed sodic soil. Kolambe and Patel (1994) reported that application of organic amendments along with phosphorus increased the uptake of phosphorus at different growth stages of rice.

Talashilkar and Chavan (1997) reported that incorporation of 10 t of Glyricidia ha^-1 and application of 100 per cent RDF recorded the highest total N uptake by rice over three successive years. Mishra and Sharma (1997) found that application of 100 per cent NPK + 10 t FYM ha^-1 resulted in highest total uptake of NPK by rice. Mahapatra etal. (1997) revealed that application of 80 kg N ha^-1 through green manure alone or through combined use of green manure and urea increased the total uptake of N by rice over application of fertilizers alone.

In the global scenario, the increasing energy crisis and consequent escalation of chemical fertilizer prices along with increasing risk associated with soil degradation have reviewed interest in bio-resources for attaining soil health and sustainable crop production. The use of organic manures, bio-fertilizers and chemical fertilizers will augment the efficiency of combined application of nutrients to maintain a high level of soil productivity and rice production (Thakuria et al., 1991; Prasad et al., 1995). Several experimental evidences showed that the combination of various bio-resources with chemical fertilizers improved the rice production in sustainable way (Roy and Jha, 1987; Subba Rao, 1995; Mahapatra et al., 1997; Suresh et al., 2001).

Secondary nutrients

Secondary nutrients includes Calcium, magnesium, and sulfur. Crop plants requires secondary nutrients in moderate quantity for crop growth and yield. Their requirement by plant is less than the macro nutrients. Sulphur and Magnesium requirement of crops are very similar to the Phosphorus needs. Calcium is required in higher amount than Phosphorus. Calcium and magnesium are mostly deficient in acid and alkali soils. In India S deficiencies are found in almost 40 per cent of the cultivated soil. Under intensive cropping system, the use of higher amount of nitrogenous fertilizer without secondary and micro nutrients and lesser use of organic manures are the major reason for the secondary and micro nutrient deficiency in soil.

It is generally observed that N, P and Zn content in soil decreases with increasing soil salinity. Nutrient imbalances created by continuous use of chemical fertilizers, particularly nitrogenous fertilizer alone, combined with sub optimal rates of other nutrients or total omission of other nutrients are the primary causes for unsustainable yields of crops in saline soil. A sustainable approach for nutrient management in salt affected soils should therefore include balanced use of organic, inorganic and biological sources of nutrients (Bandyopadhyay and Rao, 2001). Organic amendments are known to facilitate the reclamation of sodic soils and better nutrition of crops (Anand swarup, 1992).

Experiments at Central Soil Salinity Research Institute (CSSRI), Kamal, India showed that alkali soils are not always high in available P and rice and wheat significantly responded to addition of P (Pathak et al., 1975).

The availability of phosphorus in soil either native or added is limited by fixation and precipitation mechanisms. The organic acids released during decomposition of organic matter influences the soil pH, form stable complexes with cations responsible for P fixation and thus increases the availability (Tiwari et al., 1980).

The use of bulky organic manures (Maurya and Ghosh, 1972; Chaudhary et al., 1981) and green manures (Prabhakar et al., 1972; Sharma et al., 2000) has been found very beneficial for P management of saline and alkali soils as these improve the soil physical condition and the availability of soil phosphates.

Potassium availability in most of the coastal salt affected soils of India is rich except when the soils are low in clay content (Bandyopadhyay et al., 1985). Plants grown under high salinity may show K deficiency due to the antagonistic effect of Na on K absorption and / or disturbed Na / K ratio. Under such conditions application of K is also known to reduce the adverse effect of salinity and sodicity on crop growth (Qadar, 1995). Singh et al. (1980) reported that the addition of FYM increased the K concentration in the soil. Swarup (1987) reported that the incorporation of green manure increased the available N, P and K status of the soil. Available P and K remarkably increased to a tune of 30 and 44 per cent respectively by the application of coir waste (Santhi et al., 1991).

The uptake of Mg by rice plant was highest when fertilizer was applied in combination with vermicompost (Jadhav etal, 1997). Pattanayak etal. (2001) also reported the highest Ca uptake in the treatments that received green manuring of dhaincha. Sriramachandrasekharan (2001) who reported the highest Fe uptake of rice with green manuring of Sesbania aculeata.

Debele et al. (2001) reported that the application of FYM enriched with 10% rock phosphate + gypsum with PSB and PSF @ 500 g inoculums t^-1 of FYM increased the nutrient uptake of maize. The higher nutrient uptake of 227 kg N ha^-1, 59.5 kg P ha^-1 and 227 kg K ha^-1 recorded with the application of enriched FYM @ 2 t ha^-1.

Biostimulants examines substances and microorganisms that enhance plant physiological processes, growth, development, and tolerance to environmental stress. The chapter distinguishes non-microbial and microbial biostimulants and discusses plant extracts, protein hydrolysates, animal-derived hydrolysates, humic substances, seaweed and macroalgal extracts, and secondary metabolites. Microbial examples include nitrogen-fixing and nutrient-solubilizing organisms, arbuscular mycorrhizal fungi, Trichoderma, Bacillus, Pseudomonas, microalgae, and cyanobacteria. Their implications for germination, metabolism, root development, crop quality, growth promotion, and abiotic-stress tolerance are described. The chapter provides a framework for understanding biostimulants as complementary tools within sustainable crop production and natural farming systems. in modern sustainable crop production for farmers worldwide under diverse agricultural production conditions.

Introduction
Biotechnology represents a transformative force in modern agriculture, offering innovative solutions to enhance crop production, improve resistance to diseases, and address the global challenges of food security and climate change. Chapter 9 delves into the multifaceted role of biotechnology, particularly in the realm of genetic innovation, and how it is reshaping the agricultural landscape. The chapter begins by exploring the various applications of biotechnology in crop improvement. This includes the development of genetically modified organisms (GMOs) and transgenic crops, which have been engineered to exhibit desirable traits such as increased yield, pest resistance, and enhanced nutritional content. These advancements have significantly contributed to the global food supply, particularly in regions facing harsh climatic conditions or limited agricultural resources. A detailed examination of genomic tools and techniques follows, highlighting the sophisticated methodologies employed in biotechnology. Techniques such as CRISPR -Cas9 gene editing, marker-assisted selection, and genomic sequencing are discussed, showcasing their pivotal role in accelerating the development of improved crop varieties. These tools have enabled scientists to manipulate genetic material with unprecedented precision, paving the way for more efficient and targeted crop breeding programs. The chapter also addresses the role of biotechnology in crop protection, emphasizing its importance in developing crops that are resistant to pests, diseases, and environmental stresses. By enhancing the natural defense mechanisms of plants, biotechnology reduces the need for chemical pesticides, thereby promoting more sustainable agricultural practices and minimizing the environmental impact of farming. The importance of biotechnology and genetic engineering in ensuring food security is a central theme of this chapter. As the global population continues to grow, the demand for food is expected to increase dramatically. Biotechnology offers a viable solution to meet this demand by enabling the production of higheryielding and more resilient crops. This section also explores the ethical and regulatory considerations surrounding the use of GMOs and other biotechnological innovations in agriculture.

Stress is an intrinsic part of biological systems, and successfully adapting to stimuli that induce stress is essential for the survival of dryland crops and farm animals kept in a complex and ever-changing environment. Here the biotic stresses of crop plants are treated and not that of farm animals to avoid the expansion of the volume of the chapter. Biotic stress in plants is caused by living organisms, specifically viruses, bacteria, fungi, nematodes, insects, arachnids, and weeds. In contrast to abiotic stress caused by environmental factors such as drought and heat. Biotic stress agents directly deprive their host of its nutrients leading to reduced plant vigour and, in extreme cases, death of the host plant. In agriculture, biotic stress is a major cause of pre- and postharvest losses. Plants respond to biotic stress through a defence system (Atkinson and Urwin, 2012).

Introduction

Black cotton soils are formed by the solidification of molten magma; it covers a large area of the Deccan plateau. The depth of this soil is very high in the lower part of the Krishna – Godavari basin. The clay fraction is very high which is responsible for the heavy waterlogging in the area of heavy rainfall and become more vulnerable to soil erosion. The fine fraction of soil not allows draining out through the soil profile and at the same time the rate of evaporation is low. During summer soils suffer from moisture stress and it becomes very hard but at the same time during the rainy season moisture content very high. this imposes severe constraints on conventional agriculture use as a result most of the land remains fallow and subjected to soil erosion due to heavy rain. The nutrient status of the soil is quite good in Vertisol but these constraints limit crop production. To manage black cotton soil for crop production it is advisable to use animal-powered devices for surface soil drainage, Counter cultivation, adoption of a new cropping system will be helpful for better crop production.

Boron (B) de?ciency has been realized as the second most important micronutrient constraint in crop production after that of Zn in the world (Ahmed et al., 2012). However, in Nepal, B de?ciency is more wide-spread than Zn de?ciency, as 80 to 90% of soil samples were de?cient in B, 20 to 50% in Zn and 10 to 15% in Mo (Anderson, 2007). In India, B de?ciency has increased from 2% of the soil samples de?cient in B in 1980s (Katyal and Vlek, 1995) to 52% soil samples in 2000s (Singh, 2012). Total B content in Indian soils varies from 7 to 630 mg kg^–1 soil (Kanwar, 1976); being the highest in arid regions of the country and the lowest in wet humid regions of the country (Behera et al., 2009; Prasad et al., 2014). Boron de?ciency is most in the heavy rainfall areas of Western Ghats of Maharashtra, Karnataka and the eastern states of Bihar, Odisha, Jharkhand and Chhattisgarh states of India (Fig.13.1). The wide-spread de?ciency of B in India can be seen from the fact that B fertilization recorded the highest bene?t : cost (B : C) ratio in rice–wheat cropping system at Palampur (Himachal Pradesh), Ludhiana (Punjab), Faizabad, Modipuram and Varanasi (Uttar Pradesh), Pantnagar (Uttarakhand) and in rice–rice cropping system at Maruteru (Andhra Pradesh), Karjat (Maharashtra) and Jorhat (Asom) (Singh and Goswami, 2014). Response of wheat to B fertilization is also reported from Bangladesh (Halder et al, 2007).

Introduction

Man’s intervention in the evolution of plants, to adapt them to suit his needs, constitutes the practice of plant breeding. Historically regarded as an art and still too empirical to be accepted universally as a science, it has recently been described as a technology (Riley 1978). Whether art, science or technology, it certainly draws on a wide range of disciplines and embodies all those principles of organisation and management that determine success in any production-oriented programme.

Perhaps the biggest contribution that the plant breeder has made to increased production during the past 50 years has been in helping to alleviate the effects of natural hazards such as lodging, pests and diseases on crop production. While most of this progress has been through the manipulation of biotic stresses, much is still to be achieved under non-biotic stresses such as drought, salinity, temperature, etc. This argument is strengthened by the fact that in spite of the spectacular achievements made possible by the ‘Green Revolution’, the productivity level of most crop plants, including wheat and rice, has remained both low and static under stress conditions. Concerted efforts are needed through an approach of interdisciplinary research, since not much has been done to define criteria for stress assessment and evolving breeding approaches for incorporating stress tolerance in crop plants.

Expression of genetic potential for growth and yield of a crop variety is directly dependent upon the environment comprising both climate (weather) and soil components. As discussed in the preceding chapter, the term ‘salt-affected soils’ encompasses a broad group of adverse but distinct soil conditions, namely, saline, alkali (sodic) and acid soils with further variations such as coastal and inland locations as well as arid and water-logged situations (Swaminathan 1977; Bresler et al. 1982). Factors limiting growth and yield of crop plants in various categories of problem soils are different and specific. Likewise, adaptive strategies evolved by plants to cope with the prevailing edaphic stresses, such as salt stress, also vary a great deal as indicated in Table 1. It is not unexpected therefore, that even varieties within a crop often show notable differences regarding tolerance to adverse soil conditions (Epstein et al. 1980; Devine 1982; Shannon 1984; Sayed 1985). Hence, it is essential that the breeder must understand the inherent charaderistics of the problem soil with which he is concerned and should also simultaneously appreciate that basically it is the sensitivity of crop variety, rather than the soil parameters per se, that essentially determines the occurrence as well as the magnitude of actual soil problem (Rana 1977). Since the degree of tolerance (adaptation) of crop varieties to different kinds of salt affected soils is genetically controlled, it is axiomatic that it can be improved through genetic manipulations by adopting suitable breeding procedures.

Introduction

Calcareous soils are those that contain high levels of calcium carbonate (CaCO3 ) that affects soil properties related to plant growth, such as soil water relations and the availability of plant nutrients (Elgabaly, 1973), and give effervescence visibly releasing CO2 gas when treated with dilute 0.1 N hydrochloric acid. The pH of calcareous soil is > 7.0 and also regarded as an alkaline (basic) soil.

Calcareous soils have often more than 15% CaCO3 in the soil that may occur in various forms (powdery, nodules, crusts etc.). Soils with high CaCO3 belong to the Calcisols and related calcic subgroups of other soils. They are relatively widespread in the drier areas of the earth. They occupy >30% of the earth’s surface, and their CaCO3 content varies from just detectable up to 95% (Marschner, 1995).

Formation of calcareous soils

Calcareous soils occur naturally in arid and semi-arid regions because of relatively little leaching. They also occur in humid and semi-humid zones if their parent material is rich in CaCO3 , such as limestone, shells or calcareous glacial tills, and the parent material is relatively young and has undergone little weathering. Some soils that develop from calcareous parent material can be calcareous throughout their profile. This will generally occur in the arid regions where precipitation is scarce. It has been estimated that these soils comprise over one-third of the world’s land surface area (Taalab et al. 2019, Aboukila et al. 2018).

Common elements of natural water that significantly contribute to its hardness include calcium and magnesium ions of these elements leached from rocks. Water hardness reduces the utility of water for domestic use. Calcium hardness sometimes may be helpful because it provides a coating in the pipes which protects them against corrosion.
Principle
When calcium and magnesium are present in the water, EDTA reacts with calcium first. EDTA can be used to directly measure calcium when the pH is raised to a point where magnesium hydroxide is mostly precipitated and an indicator that only combines with calcium is employed. At a pH of 12 to 13, several indicators change colour to indicate that all of the Ca has been incorporated by the EDTA. The variations between an aliquot titrated at pH 10 and one titrated at pH 12 or 13 are what define the amount of magnesium.

CALCIUM

Calcium is important in imparting structure and permeability to cell membrane. Deficiency produces general breakdown of membrane structure. Calcium enhances the uptake of NO₃ ^– N and interrelated with NO₃ ^– metabolism. It regulates cation uptake, required for cell elongation and cell division. Deficiency causes failure of terminal buds and apical tips of roots to develop. Blossom end rot of tomato, bitter pit of apples are due to calcium deficiency. Calcium is beneficial in imparting good soil structure.

It is immobile in plant. Very little translocation of calcium in the phloem is observed. Hence there is poor supply of calcium to fruits and storage organs. Downward translocation of calcium is also limited. Hence roots fail to enter the low calcium soils.

Canopy management is central to achieving balanced vegetative growth, efficient light utilization, flowering, fruiting, and high-quality produce. This chapter explains the principles and objectives of training and pruning in horticultural crops. Different training systems are related to crop architecture, growth habit, planting density, and production objectives. Pruning techniques are discussed for regulating shoot growth, removing undesirable branches, improving air circulation, and maintaining productive canopy structure. Light interception and distribution within the canopy are also examined because photosynthetic efficiency strongly influences yield and fruit quality. Modern high-density orchards require precise canopy management to balance productivity, plant size, mechanization, and long-term orchard sustainability.

Abstract

Traditionally remote sensing technology has been widely used in the mapping and change detection of vegetation features. Of late research has shown that remote sensing technology can be successfully employed for retrieval of biophysical parameters of vegetation, either by statistical techniques or by employing radiative transfer models (RTMs). This paper gives an introduction to leaf and canopy RTMs, especially about PROSAIL, which is the most commonly used model. It reviews different techniques for inverting RTM models, their merits and performance comparison. The main techniques briefly described are iterative optimization, look-up table, artificial neural network, genetic algorithm and support vector machine. At the end, it gives examples of applications which use canopy biophysical parameters retrieved by inverting RTM.

Keywords: Radiative transfer, PROSAIL, Inversion, Vegetation

1.0 Introduction

Accurate quantitative estimation of vegetation biophysical variables is useful for a large variety of agricultural, ecological, and meteorological applications (Houborg et al., 2007). The spatial and temporal distribution of these variables are important inputs into models quantifying the exchange of energy and matter between the land surface and the atmosphere, developing better yield prediction models and detecting abiotic stresses at regional scales. Among the many vegetation characteristics leaf area index, leaf chlorophyll content and leaf water content are of prime importance (Bacour et al., 2006; Houborg et al., 2007).

Soil microorganisms in true sense are one of natural safety valves that regulate biogeochemical transformations in soil ecosystem. They act as natural agents for the disposal of organic matter. The various essential biological elements such as C, N, S and P, apart from H and O, form the primary building blocks of cells and their constituent elements are recycled through tiny microorganisms present in soil. More they are in quality and quantity, better recycling is expected by them. The organically bound materials are converted to simpler inorganic forms to complete biological cycle initiated during photosynthesis and other anabolic processes.