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Barley is believed to be originated from Asia and Ethiopia. Its Sanskrit name ‘Yava’ is mentioned in ‘Veda’ and use of barley in religious ceremonies has been described which shows that barley has been grown in India since ancient times. It is widely believed that the ‘Near-East region’ is the probable place of origin of barley around 8000 BC (Harlan, 1968). There are two theories regarding the origin of barley. 

Cereals are cultivated grasses grown for their edible starchy grains. Larger grains used as staple food – Rice, wheat, maize, barley, oats etc.

ABSORPTION (of light): A process by which light is taken-up by another material. Examples include soot consisting of tiny black particles, which absorb all visible light; and nitrogen dioxide, a pollutant mostly from diesel and gasoline engines, that absorbs blue light resulting in air with a brown tint.

AIRBORNE SENSING: Remote sensing from an airplane. (Related words: airphoto, aerial)

ACCELERATED EROSION: Erosion in excess of natural rates, usually as a result of anthropogenic activities.

AERATION, SOIL: The exchange of air in soil with air from the atmosphere. The air in a well aerated soil is similar to that in the atmosphere; the air in a poorly aerated soil is considerably higher in carbon dioxide and lower in oxygen.

ACID SOILS: Acid soils with pH below 6.5 are widespread. Main limitations of these acid soils are low pH, low CEC, low status of bases, especially Ca, Mg, and K along with toxicity of Al and Mn. Use of acidifying fertilizers aggravates this situation.

ABSORPTION ACTIVE: Movement of ions and water into the plant root as a result of metabolic processes by the root, frequently against an electrochemical potential gradient.

ALLIC: soil family class term used in Oxisols as a calcareous and reaction class category. Soils placed in the allic class are acid and have low CEC with high amounts of KCl-extractable aluminum in a layer at least 30 cm thick within the control section. If used for agriculture, these Oxisols require large inputs of lime to displace the aluminum and raise pH.

ACID-FORMING FERTILIZER: A term applied to commercial fertilizers which leave an acid residue in the soil. The amount of calcium carbonate required to neutralize the acid residue is referred to its equivalent acidity.

AGRICULTURAL WASTE: The characteristics of the agricultural waste materials make them important in respect of their use and economic value. Agricultural wastes can he put to use because (1) Farm development (improvement of soil health, soil fertility, soil physical conditions and plant protection), it is the source of energy and power, (3) it acts as animal feed and fodder, (4) it is the human food

ACTIVATION ENERGY: The energy required before the reaction of concern will proceed. Often, heating will supply the needed energy. Enzymes or other catalysts lower the activation energy of a reaction.

ABIOTIC FACTORS: Environmental influences produced other than by living organisms for example, temperature, humidity, pH and other physical and chemical influences. Contrast it with ‘biotic factors’ - meaning effects due to biological components.

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

The word mulch was coined by Wagganor in 1960. It is derived from the German word ‘molsch’ means “easy to decay,” and mulches have widely been used for vegetable production since ancient times (Lightfoot 1994). Therefore the term mulching refers to the practice of covering the soil surface with different organic and inorganic materials, known as mulch materials to reduce moisture loss, balance wide variations in diurnal soil temperatures especially in the root zone, control weeds, insect-pests and diseases and finally enhance crop yield (Nalayini 2007; Kader et al. 2019).

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).

Due to continuous pressure on our food security even after independence, the cultivation has been expanded to marginal and sub marginal lands that are prone to different types of erosion. Though the rainfed farming is based on the erratic and uneven rainfall, it contributes nearly 50% food grain, 90% oilseeds and pulses and 65% cotton production.

Rainfed agriculture occupies about 1.22 billion hectare (Bha) area worldwide, which is about 82% of total area (1.5 Bha) under agriculture (Yadav et al., 2006) and contributes nearly 58% to the global food basket. It is practiced under a wide variety of agro-climatic, edaphic and socio-economic conditions and globally, rainfed agriculture accounts for more than 95% of farmed land in sub-Saharan Africa, 90% in Latin America, 75% in the Near East and North Africa; 65% in East Asia and 60% in South Asia (Singh et al., 2018). 

Drought is a recurrent feature of climate or climatic anomaly or weather related natural disaster. It occurs when the precipitation remains deficient over an extended period of time, usually for a season or more and affects water shortage in water bodies, streams, soil moisture, ground water etc. resulting into low crop production and economic performance of large regions or entire country. Drought occurs in virtually all regions varying its severity, low and high from regions to regions.

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.

Out of 329 m ha geographical area in the country, 187.8 m ha or 53% is affected by various forms of degradation process which include 148.9 m ha affected by water erosion, 13.5 m ha by wind erosion, 13.8 m ha by chemical deterioration and 11.6 m ha by physical deterioration. The annual loss of topsoil is nearly 16.0 t/ha/year resulted in to 8.4 m t/year total nutrient loss. 

Bread, cloth and house (Roti, Kapra and Makan) are the basic need of human life and linked directly with agriculture because agriculture provides livelihood for nearly two-thirds of the population in India and it currently accounts for 14.2% of the GDP and also employs 55% of country’s total workforce. The sharp fluctuations in agricultural growth are mainly attributed to the vagaries of monsoon. Rainfed agriculture is spread over 55% of net cultivated area, contributing over 40% to the national agricultural production.

Soil is generally defined as the upper layer of earth in which plants grow. It is regarded as a source of nourishment to all animals, moving or static. From agriculture or crop production point of view, soil is loose earth surface that supports vegetation, its quality, type and density. It is generally treated as a dynamic living entity and its physic-biochemical properties are responsible for its nutritional index. Precision production technology with suitable management is the key factors for its longer sustainability.

India comes in a tropical region and so it has a tropical monsoonal climate. The climate of India is governed by mountain ranges as well as direction of rain winds like south-west and north-east monsoon and alternate season is the main feature of Indian climate. Climate in South India is generally hotter and extremely humid than that of North India.

Water is essential for life and most of the civilization flourished on bank of rivers like Indus valley, Mesopotamia, May, INCA and also destroyed in lack of water. Scarcities and famines were the common phenomena of the world civilization. Systematic dry cultivation started around 1850 and improved techniques were started in use in USA. 

Rainfed agriculture constitutes 80% of global agriculture and plays a critical role in achieving global food security. However, growing world population, water scarcity, and climate change threaten rainfed farming through increased vulnerability to 1 droughts and other extreme weather events. Out of the total population of 7.3 billion, about 1 billion are food insecure and 60% of these live in South Asia and Sub Saharan Africa.

An atom consists of a positively charged nucleus surrounded by a cloud of negatively charged electrons. The positive nuclear charge is due to the presence of protons which carry a mass of 1 and a charge of +1. Besides protons in the nucleus, there are neutrons which are heavier than protons. They carry no charge. Comparatively electrons have no mass (1836 times lesser than that of a proton) but they carry a charge of –1. Hence, the whole mass of an atom is likely to be concentrated in the nucleus.

Research related to biochemical analysis has been greatly benefited due to the development of chromatographic technique, since this technique makes it possible to resolve mixtures of closely related substances on a milligram to picogram range and to identify individual components by comparison with reference standard compounds. Chromatography ‘gives information where other analytical means have failed’ [Tswett, M. (1906) The macro-chemical and micro-chemical detection of carotene. Ber. Deut. Botan.Ges. 24 : 384- 393].

Mass spectrometry (MS) is a powerful and versatile analytical technique through which mass of an atom, or a molecule is assessed. It helps for identification and structure elucidation of various complex compounds. The instrument used is known as Mass Spectrometer. It serves the purpose of qualitative identification, confirmation as well as the quantification of an atom or a molecule. MS identification is conclusive because the mass spectrum of each substance is unique. In general, MS instruments are composed of a sample inlet, an ionization source, a molecule accelerator, a detector, an amplifier, and a recorder (Figure 7.1)

Interaction of radiant energy, exhibiting the properties of both waves and particles, with matter is dealt in spectroscopy. Matter may be defined as material, existing in solid or liquid or gaseous phase, which is composed of molecules, atoms, or ions. Atoms, molecules, and ions, irrespective of their physical state, remain in constant motion in a matter. Molecules may rotate, vibrate, and move from place to place in space. While radiant energy interacts with matter, these molecular motions are influenced to some extent. It is observed that radiations from ultraviolet and visible range of electromagnetic spectrum lead to the movement of bonding electrons from lowest energy state (ground state) to higher energy state (excited state) in the molecules, while absorption of IR radiation causes the molecule to vibrate more. Such changes, referred to as transition, are responsible for changing the molecular energy level.

Electrophoresis is an important separation technique for the charged molecules. Biologically important molecules, such as amino acids, peptides, proteins nucleotides, nucleic acids which carry electrical charge as they possess certain ionizable functional groups may be separated and identified from a mixture with the help of this technique. Some compounds that are non-polar in nature and do not possess any charge may be transformed to charge carrying derivatives. Thus, phosphate derivatives of carbohydrates may be separated and characterized utilizing electrophoretic techniques.

Centrifugation is a technique that promotes accelerated settling of particles in a solid-liquid mixture by the application of centrifugal force. The device that accelerates the separation with the help of centrifugal force is known as ‘Centrifuge’. The centrifuge consists of a fixed base or frame and a rotating part in which the mixture is placed and is then spun at high speed.

Indicators are the natural or synthetic chemical compounds that are used to detect the equivalence point in a volumetric analysis where unknown compound in a solution form is quantitatively estimated with the help of a known standard solution. The equivalence point, also known as the stoichiometric end point, is the point or stage of a titration reaction where the equivalent amount of the reacting substances are mixed together, and this point is identified by monitoring the rate of change in pH, conductivity, flow of current, adsorption, fluorescence, changing of solution colour, occurrence or disappearance of turbidity, flocculation or deflocculation, etc.

Volumetric analysis, also known as titrimetric analysis, is an analytical method of estimating the concentration of a known solute (analyte) in a solution by measuring the volume of a second known solution of known concentration (standard solution), that reacts completely with the known solute of unknown concentration. The prerequisite of titration is that the two different analytes, present in solution form, must involve in a fast chemical reaction. The standard solution is more commonly known as ‘titrant’ and the solution whose concentration needs to be determined is frequently called ‘titrand’.

Acids are chemical substances that are sour in taste and highly corrosive. The term ‘Acid’ was derived from a Latin word ‘acidus’, meaning ‘sour’. They emit sharp odour and transform litmus colour from blue to red. They lose their properties when alkalis are added to them. However, in this process, alkalis also lose their alkaline properties.

Integrated farming system is a multidisciplinary whole farm approach, which enables the farmers to identify opportunities and threats and act accordingly. It is a dynamic approach which can be applied to any farming system around the world. It is very effective in solving the problems of small and marginal farmers.

Conservation agriculture is an approach to managing agroecosystems for improved and sustained productivity, increased profits and food security while preserving and enhancing the resource base and the environment. Food and Agriculture Organisation of the United Nations defines conservation agriculture as a farming system that promotes maintenance of a permanent soil cover, minimum soil disturbance (i.e. no tillage), and diversification of plant species.

Low external input agriculture developed as a response to the criticisms surrounding Green Revolution technology being neither sustainable nor feasible for many small-scale farmers around the world. The concept aimed to redesign the agricultural system by optimising the use of biological resources, keeping changes to the natural ecosystem as well as the use of external inputs at a minimum (Pimentel et al., 1989).

The Green Revolution started in the early 1960s that led to the attainment of self-sufficiency in food grain production. This has been considered as the greatest agricultural transformation in the history of humankind. The Green Revolution contributed to widespread poverty reduction, averted hunger for millions of people, and avoided the conversion of thousands of hectares of land into agricultural cultivation.

The objective of any cropping system is efficient utilisation of all resources such as land, water and solar radiation, maintaining stability in production and obtaining higher net returns. The efficiency is measured by the quantity of produce obtained per unit resource used in a given time.

In agriculture, the ideal management practices were developed for individual crops through regular research and feedback received from the farmers. However, farmers are growing various crops in different seasons based on their adaptability to a particular season.

In agriculture, crop production is the main activity. However, the income obtained from crops may hardly be sufficient to sustain the farm family throughout the year. Assured regular cash flow is possible when the crop is combined with other enterprises. These other enterprises or components are called allied components.

A ‘system’ is a set of interrelated, interacting and interdependent elements operating together for a common purpose and capable of reacting as a whole to external forces. It is unaffected directly by its own output and it has a specified external boundary based on the inclusion of all significant feedbacks. A ‘farm’ is a system because several activities are closely related to each other by the common use of the farm labour, land and capital, by risk distribution and by the joint use of the farmer’s management capacity.

The residues from production and processing of raw agricultural products such as fruits, vegetables, meat, poultry, dairy products and crops are called agricultural
wastes. The by-products of agricultural activities are also referred to as agricultural waste.

The livestock sector has emerged as a vital sector for ensuring a more inclusive and sustainable agriculture system. Livestock production can be an important
component of a sustainable agricultural system because it can provide a quality source of plant nutrients, be an income generator, and provide an environmentally
sound use of certain lands. Some farmland is just not suitable for crop production, but may be utilised sustainably for livestock production.

Organic farming is one of the several approaches found to meet the objectives of sustainable agriculture. It is often associated and sometimes confused with
‘sustainable farming’. However, policy and ethics-wise ‘organic farming’ is different from ‘sustainable farming’. Organic farming is based on various laws
and certification programmes whereas sustainable agriculture is the practice of farming using principles of ecology.

The general concept of agroforestry is to integrate trees and agriculture so as to create a more diversified landscape, while providing the producers with new
environmental and economic benefits. In other words, agroforestry is a method of farming that allows trees and shrubs to grow along with crops and/or livestock,
therefore blending agriculture and forestry in the same production system.

Integrated farming system is a multidisciplinary whole farm approach, which enables the farmers to identify opportunities and threats and act accordingly. It
is a dynamic approach which can be applied to any farming system around the world. It is very effective in solving the problems of small and marginal farmers.
The approach aims at increasing income and employment from small-holding by integrating various farm enterprises and recycling crop residues and by-products
within the farm itself.

A system is a set of components that are interrelated and interact among themselves. A system may be natural, social or artificial. Natural systems consist
of all the materials both physical and biological and are independent of human beings. Our role in relation to natural systems is to try to understand these
systems and make use of them as per our needs. 

Agriculture is an economic activity that is highly dependent upon weather and climate in order to produce the food and feed necessary to sustain human life. In spite of technological improvements that increase agricultural production, weather hazards have caused significant yield reductions in some years at different regions.