eChapters

4.1. Black gram, green gram, lablab and cowpea

4.1.1. Bean aphid: Aphis craccivora (Aphididae: Hemiptera)

1. Host range: Groundnut, redgram, peas, beans, safflower, lablab, niger

7.1. Early shoot borer: Chiloinfuscatellus snellen

1. Damage symptoms

2.1. Causes of pest outbreak

Activity of human beings which upsets biotic balance of ecosystem is prime cause for pest outbreak.

pH is defined as the negative logarithm of hydrogen ion concentration. The amount of the acidic gas CO2 significantly affects the pH of natural water body. Fish have usually blood pH levels of 7.4, but little deviation has been observed, perhaps 7.0 to 8.5pH range is more suitable for the growth and reproduction of the fish. However, pH range 4.0 to 6.5 and 9.0 to 11.0 cause fish death in water pH less than 4.0known as acidic death point or even more than 11.0 known as alkaline death point. The pH of fresh water more fluctuating as compare to sea water due to release and consumption of CO2 and O2 respectively by bacterial oxidation and respiration. However, the pH of marine water often constant at 7.8-8.3 due to presence of buffer like HCO3-, CO2 -, CO3-2 etc.
Principle
The estimation of hydrogen (H+) ion activity through sensing electrode. Electrode composed of a narrow glass bulb with fixed concentration of HCI solution inside it. A wire made of an Ag-AgCI placed in to the bulb which work as electrode to fix voltage. Potential difference forms between the solution in the glass bulb and the sample solution when the electrode immersed into solution.

Introduction

Agricultural produce are being sun dried since ages as the first step to preserve the product for future consumption. It is still practised being most inexpensive over mechanical and other advanced drying systems. The most prevailing disadvantage of open sun drying is the quality losses due to insect infestation, enzymatic reactions, microorganism growth, and mycotoxin development. On the other side, sun drying is also a highly labor intensive and time consuming process prone to theft and damage by birds. It also suffers with the lack of process control and treatment uniformity (Bansal and Garg 1987, Bansal, 1987).

To overcome these disadvantages several types of solar dryers have been developed over the years (Ekechukwu and Norton 1999). These dryer may be identified into three group namely active, passive and hybrid. As regards their structural arrangement three generic subclasses were also identified: direct-modes (the solar-energy collection unit is an integral part of the entire drying system), indirect-modes (the solar collector and the drying chamber are separate units) and mixed-modes solar dryers. Natural convection solar dryers have become more suitable for rural sector and remote areas, as they work on single energy option and do not require any other external energy source (Pangavhane et al. 2002).

Introduction

As the most of the conventional resources are depleting and can last only for about a few 30 to 50 years. Scientists worldwide are looking for alternative energy resources and they have come to an agreement that solar energy can provide much of our energy needs in the future. The major challenge before them is to store this energy. The radiation falling on the earth surface can be tapped and stored in no of ways. However, the most efficient way is done through the latent heat storage through PCM. The PCM has many added advantages i.e. high energy density, isothermal behavior, non-polluting and low cost. Nowadays, it gaining popularity worldwide and now seen as the most efficient way of thermal energy storage. There is a large number of PCM at use i.e. organic, inorganic, eutectic and salt hydrates. Their utilization depends on the user’s requirement technological constraints. They also serve the purpose of energy availability at night beside the uninterrupted supply during the day. They are seen as the materials for ensuring the environmental sustainability

1. Introduction

The agricultural sector plays a pivotal role in driving economic development in India, a nation with a population of 1.39 billion, making it the world’s second most populous country according to the United Nations’ World Population Prospects 2019. With 54.6 percent of the workforce engaged in agriculture as per the 2011 Census, and contributing 18.6 percent to the Gross Value Added (GVA) in 2021-22, its significance cannot be overstated. Notably, women play a substantial role in this sector, with rural females exhibiting a higher workforce participation rate of 41.8 percent compared to 35.31 percent for urban women (MoSPI, 2017). In rural communities, agriculture and allied sector is the primary source of livelihood that includes 80 percent of all economically active women, out of which 33 percent constitute agricultural labour force and 48 percent are self-employed farmers. Rural women are engaged at all levels of the agricultural value chain; i.e., production- pre-harvest, post-harvest, processing, packaging, marketing to increase productivity in agriculture (Nilam Patel etal, 2022). As per Pingali et al. (2019), the ratio of women to men working in the agricultural sector has increased over the time and made a greater amount of contribution to GDP per capita. They are the momentous demographic group for a sustainable food system (FAO, 2011). Empowering women in agriculture through reforms aimed at ensuring equal access to resources, skill development, and opportunities is projected to increase agricultural output in developing countries by 2.5 to 4 percent (FAO, 2011).

Plant growth is resultant of all the environmental factors – climatic, physiographic, edaphic and biotic factors.

For a particular field – it is primarily a function of climate with temperature and light – being the most important factors. – Close relationship exists between plant phenology and both latitude and altitude.

Introduction

Mosquito-borne diseases such as malaria, filariasis, Japaneseencephalitis, chikungunya and dengue hemorrhagic fever cause extensive morbidity and take heavy toll of life in the developing nations particularly in the tropics. Every year about 300-500 million people are estimated to be affected by malaria alone (WHO report, 2000). In India around two million cases of malaria are being reported annually although real burden is many fold higher (Kumar et al. 2007). Similarly, lymphatic filariasis caused by Wuchereria bancrofti affects about 120 million people worldwide. India contributes about 40%  to  the total global burden of filariasis and accounts for about 50% of the people at risk of infection (ICMR bulletin, 2002). Anopheles stephensi is recognized as a major vector for urban malaria in India (Kumar 1997).

Semiochemicals are chemical substances that mediate communication between organisms.

Classified into pheromones (intra specific semiochemicals) and allelochemicals (inter specific semiochemicals).

Acid and alkaline phosphatase enzymes are among the extensively studied phosphatases and classified so because of their optimum activities in acid and alkaline pH ranges, respectively. Acid phosphatase is predominant in acid soil while alkaline phosphatase is dominant in alkaline soils. The colorimetric assay of phosphatase is based on release of p-nitrophenol from hydrolysis of p-nitrophenyl phosphate byaction of phosphatase enzyme in buffered soil solution (buffer pH 6.5 for acid and 11 for alkaline phosphatase assay).

Introduction

Increased population pressure, reduced length of fallow, deforestation and improper agricultural practices have led to widespread soil degradation in many parts of the developing world which has culminated in appearance of determinative manifestations of environmental damage in form of inadequate replenishment of soil nutrients and organic matter. Phosphorus is second major plant growth limiting nutrient and despite being in abundance in soil (organic and inorganic form), P deficiency is becoming critical in many soils throughout world as these soils have free available P concentration (generally) not higher than 10mM even at most soluble slight acidic pH (Arnou, 1953). Moreover, consistent P deficiency threatens to disturb the use efficiency of applying other nutrients. Hence to preserve the sustainability of agriculture it is foremost to rebuild soil fertility and maintain/improve the soil biodiversity to reap hiked current levels of productivity and farm income.

Phosphorus (P) is the second most important essential nutrient limiting crop/ plant growth, next only to nitrogen (N). Phosphorus is an important component of nucleic acid like deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is needed for energy storage and transfer, which is the single most important essential function of P. Phosphate compounds act as “energy currency” within plants. The most important common P energy currency is adenosine diphosphate (ADP) and adenosine triphosphate (ATP). The ATP transfers energy for synthesis of ADP. Life is not possible without P. It is the source of energy that powers practically all energy-requiring biological processes in plants. Phosphorus is present in plant as phospholipid such as lecithin and cephalin which appears to be involved in the structural framework of protoplasm. Phosphorus is involved in many important processes such as photosynthesis, cell division, tissue development, and growth in plant. Requirement of P by the crops is less, compared to N and potassium (K). It is present in plant tissues. It is reported that for 5-6 t ha^-1 of wheat grain yield, it removes about 100-120 kg N, 20-30 kg P₂O₅ and 150-180 kg K₂O from soil.

Phosphorus is 11^th most abundant element on the earth crust. However, it is the least mobile element among the major plant nutrients. Its complex chemistry in soil makes it highly deficient nutrient element in most of the arable soils across the globe. Only 0.1% of the total P in the soil is available for uptake by plants because of its fixation as various insoluble compounds depending upon the soil pH. About 43% of the world’s arable soil is P deficient which limits crop growth and production (Roy et al., 2018). In the Indian context, about 80% of the soils are reported to have low to medium available P content (Muralidharudu et al., 2011). Thus, application of P-fertilizers to maintain the soil fertility and sustain crop productivity becomes imperative in today’s input intensive agriculture.

Phosphorus is only second to nitrogen as an inorganic nutrient required by both plants and microorganisms. It stimulates growth of young plants, giving them a good and vigorous start. Phosphorus management and nutrition has both economic and environmental implications. Phosphate constitutes nearly 0.1% of the earth’s crust. They occur in soil in inorganic and organic forms. The organic phosphorus containing compounds are derived from plants and microorganisms and are composed of nucleic acids, phospholipids, lecithin, phytin and related compounds. In soil, 15-85 % of the total P is organic and soils rich in organic matter contain abundant organic P. The inorganic forms are derived from parent rocks or through fertilizers application and manuring with bone meal. They are soluble in water when present as phosphates of Na, K, Ca, Mg etc. Phosphorus exists mainly as apatites, with the basic formula M₁₀ (PO₄) ₆ X₂. Commonly the mineral (M) is Ca, less often Al or Fe. The anion (X) is either F^-, Cl^-, OH^- or CO^2- ₃. Diverse combinations of M and X results in 200 forms of P.

It is a major constituent of nucleic acids in all living systems essential in the accumulation and release of energy during cellular metabolism. This element is added to the soil in the form of chemical fertilizers, or in the form of organic phosphates present in plant and animal residues. In cultivated soils it is present in abundance (i.e. 1100 kg/ha), but most of which is not available to plants, only 15 % of total soil phosphorus is in available form. Both inorganic and organic phosphates exist in soil and occupy a critical position both in plant growth and in the biology of soil.

Phosphorus in soil present both in inorganic form and organic form. The inorganic P can be divided into different pools. The major active inorganic forms are: P bound to aluminium (Al-P), iron (Fe-P), calcium (Ca-P) and silicate minerals and relatively less active forms are occluded and reductant soluble forms of P. On the other hand the principal organic P compounds present in soil are (i) inositol phosphate, (ii) phospholipids, (iii) nucleic acid and other unidentified esters and phosphoproteins.

15.1. Determination of Available Soil P

The availability of soil P to plant varies greatly depending upon the reaction, minerological composition and amount of the soil colloid. Very little P is present in the soil solution except in recently fertilized or sodic soils. The type of phosphate ions present in the soil solution depends on the soil pH. In soils of neutral to slightly alkaline pH, HPO₄^2- ion is the dominant form. In slightly or moderately acidic soils, both H₂PO₄^- and HPO₄^2- ions prevail. At strongly acidic soil H₂PO₄^- ion tends to dominate, while above pH 9.0, the PO₄^3- ion becomes more important than H₂PO₄^-.

Phosphorus is present in soil both in inorganic form and organic form. The inorganic P can be divided into different pools. The major active inorganic forms are: P bound to aluminium (Al-P), iron (Fe-P), calcium (Ca-P) and silicate minerals and relatively less active forms are occluded and reductant soluble forms of P. On the other hand, the principal organic P compounds present in soil are (i) inositol phosphate, (ii)phospholipids, (iii)nucleicacid and other unidentified esters and phosphoproteins.

22.1 Determination of Available Soil P

The availability of soil P to plant varies greatly depending upon the reaction, minerological composition and amount of the soil colloid. Very little P is present in the soil solution except in recently fertilized or sodic soils. The type of phosphate ions present in the soil solution depends on the soil pH. In soils of neutral to slightly alkaline pH, HPO₄^2-ion is the dominant form. In slightly or moderately acidic soils, both HPO^-and HPO^2-ions prevail. At strongly acidic soil HPO 244 24 ion tends to dominate, while above pH 9.0, the PO₄^3-ion becomes more important - than H₂PO₄ .

As the P is drawn from soil solution largely through diffusion by the plant, it is replenished from solid phase pool of available P. P fertilizer is added to recharge this pool.

Phosphorus is essential for plant growth and is involved in important physiological processes, but its availability in soil is strongly influenced by soil chemical conditions. This chapter provides a systematic treatment of phosphorus management in irrigated soils. It begins with the functions of phosphorus and the classification of soil phosphorus into organic and inorganic forms. The behaviour of phosphorus in alkali soils is discussed along with phosphate fixation, which can substantially influence phosphorus availability to crops. The chapter examines the sources of soil phosphorus used by plants and the major types of phosphatic fertilizers used in agricultural production. Available and total phosphorus are distinguished, providing a basis for assessing soil phosphorus status. The behaviour of phosphate fertilizers after application is considered in relation to their efficiency and crop uptake. The residual value of phosphatic fertilizers is also discussed, highlighting the continuing contribution of applied phosphorus to subsequent crops. Overall, the chapter emphasizes efficient phosphorus management to improve nutrient availability, fertilizer-use efficiency and sustainable crop production in irrigated soils.

Phosphorus is the second important key element after nitrogen as a mineral nutrient in terms of quantitative plant requirement (Donahue et al., 1990), which is required in optimum amount for proper growth of plants and soil micro-organisms. Being a constituent of ATP, it is involved in various processes such as cell division, energy transduction through photosynthesis and biological oxidations and uptakeof nutrients. The average soil contains 0.05% phosphorus, but only one tenth (1/10) of this is available to plants due to its poor solubility and chemical fixation in soil (Barber, 1984). About 98% of Indian soils have inadequate supply of available phosphorus (Ghosh and Hassan, 1979). A survey of Indian soils showed that out of 363 districts, only 2.2% were high, 51.5% medium and 46.3% were low in phosphorus content (Ghosh, 1982).

Phosphorus is one of the essential plant nutrients, which is required in optimum amounts for proper growth of plants and soil biota. Being a constituent of ATP it is involved in various processes such as cell division, energy generation and transfer of genetic characteristics and regulation of metabolic pathways (Theodorou and Plaxton, 1993). Phosphorus constitutes about 0.2% plant dry weight (Schachtman et al., 1998). The average soil contains 0.05% phosphorus but only one tenth of this is available to plants due to its poor solubility and chemical fixation in soil (Narayansamy et al., 1981, Barber, 1984). About 98 percent of Indian soils have inadequate supply of available phosphorus (Ghosh and Hasan 1979, Hasan, 1994). A survey of Indian soils showed that out of 363 districts, only 2,2% were high, 51.5% medium and 46.3% were low in phosphorus content (Ghosh 1982).

The problem of P fertilization may become serious in coming years because of the fact that manufacture of phosphatic fertilizers requires the use of non renewable resources such as high grade rock phosphate and sulphur which are becoming costlier. The situation is further aggravated by the fact that P is readily fixed in the soil and the average utilization efficiency of added fertilizer P by plants ranges from 15-25% only (Gaur 1982, 1990). The recent report showed that 42 per cent of soil samples fell in low category, 38 per cent in medium and 20 per cent in high category (Motsara, 2002). It has been observed that the vast alluvial tracts of the country are either low or medium in available P. Hence they need P application at recommended rates.

Phosphorus (P) is a critical nutrient in crop production, due to its low bioavailability in soils (Feng et al., 2004). Phosphorus is the vital component of DNA, RNA, ATP and photosynthetic system and catalyses a number of biochemical reactions from the beginning of seedling growth through to the formation of grain and maturity. Many factors influence soil P availability like type of parent material from which the soil is derived, degree of weathering and climatic conditions. In addition to this, erosion, crop removal and phosphorus fertilization and soil phosphorus levels also affect P availability in soil. Rock phosphate is the key raw material used for manufacturing phosphatic fertilizers on which the food production depend.