eChapters

Introduction

Climate change is threatening food security globally. Countries like India are more vulnerable in view of the tropical monsoon climate and poor coping capacity of the small and marginal farmers. Several agricultural practices like indiscriminate use of agro-chemicals and crop residue burning contribute to emission of greenhouse gasses leading to warming of the atmosphere. Sequestration of carbon both in the vegetation and soil is the most effective means of mitigating GHG emissions. There are several strategies of soil carbon sequestration which can be adopted at farm level. These include: conservation agriculture, biomass recycling, crop rotations and use of organic amendments. One of the recent developments is the conversion of crop residue biomass into biochar and using the char as a soil amendment rather than directly using the crop residues. Several studies show that biochar has a long life in soil and is more effective in sequestering carbon besides improving other soil properties like water holding capacity and nutrient availability. In Indian conditions, there is an immense scope for converting millions of tonnes of crop residues which are not used as fodder into biochar and use the same for enriching soil carbon.

Introduction

Productivity has increased as a result of the significant industrialization that has occurred in India during the past 40 years. However, it has also had detrimental effects on the ecology, particularly in India where soil contamination is progressively becoming more severe. In addition to the effects of man and land use, soil is constantly adapting changes in environmental conditions. A characteristic of soil pollution is the decrease in soil productivity brought on by the presence of soil pollutants. Some changes in the soil will be temporary and reversible, while others will be permanent. Pollutants in the soil have a negative impact on the physical, chemical, and biological characteristics of the soil and decrease its production. Soil pollution is a result of a variety of factors, including pesticides, fertilizers, organic manure, chemicals, radioactive waste, abandoned food, clothing, leather goods, plastics, paper, bottles, tins, and corpses. Industrial waste contains chemicals including iron, lead, mercury, copper, zinc, cadmium, aluminum, cyanides, acids, and alkalis, among others, which either directly or indirectly enter the soil.

Introduction

Soil organic matter is an indispensible component of soil health management. It plays an important role in improving soil physical, chemical and biological environment. Soil health refers to the capacity of the soil in terms of physical, chemical and biological properties for maintaining ecosystem services. With respect to agricultural lands, soil health implies the capability of the soil towards improving crop growth and yield, while also supporting environmental sustainability. Some important determining properties of soil health maintenance are soil reaction, salinity or alkalinity, soil organic matter, soil texture, soil structure/aggregation, water holding capacity, porosity, internal drainage, and nutrient retention capacity. Simultaneously, the key properties maneuvering soil health are soil aeration, internal drainage, nutrient cycling, susceptibility to erosion etc. Except some of the basic properties (soil texture) and processes (soil erosion), most of the determinant properties and processes are maneuvered by the presence of soil organic matter. A healthy soil must have strong resistance to degradation processes and able to recover following a perturbation because of inherent resilience (Magdoff 2001).

Introduction

Rice straw is produced as a by-product of rice production at harvest. Agricultural Waste Burning (AWB) is a major contributor of air pollution in many countries, particularly in South Asia. Exposure to fine particulate matter less than 2.5 μm (micrometer), also known as PM 2.5, released by AWB can cause premature mortality due to respiratory and cardiovascular diseases (Brauer et al.,2012). Combine Harvesters used on the spring rice crop leave behind stubble and straw on the field (Sidhu et al., 2007). Farmers burn the rice residue while preparing the field for wheat sowing season that follows. Further, migrant labour from neighbouring states of Bihar and Uttar Pradesh has decreased (Sirhindi, 2019), and resulted in an increase in the cost of agricultural labour during the rice harvest season (Sharma,2018). Farmers find it both convenient and economical to burn residue to clear and prepare their fields for the next crop. In 2018, over 20 million metric tons of rice residue was generated in Punjab, of which almost 10 million metric tons was subject to open-air burning (MoA, 2019). The time window between rice harvesting and wheat sowing is just 20 to 30 days towards the conclusion of the Kharif season, which is one of the primary reasons of crop waste burning (Balwinder et al., 2016).

Introduction

Microbial diversity is one of the main factors characterizing natural ecosystems; soil is considered one of the best storehouses of useful microorganisms in the world. Although the role of most of these microorganisms is still unknown, scientific progress is providing a better comprehension of the specific ecological functions of soil microorganisms (Ahmad, I.et al., 2008). Microorganisms in the rhizosphere soil play a key role in maintaining the soil fertility (Yadav et al. 2015), which is key for successful natural crop production to meet the increasing global organic food demand. Soil acts as a reservoir of air, water, and nutrients that is essential for plant growth. Only a few grams of soil contain hundred million to billion microorganisms. Bacteria are the most abundant microbes in soil followed by fungi; however, the actinomycetes are ranges in between bacteria and fungi. Other microbes that are found in smaller numbers are algae, cyanobacteria, protozoa, and nematodes. Soil gives the necessary support for anchorage to plant roots (Yadav et al. 2012; Bhaduri et al. 2015).

Introduction

Ideal plant health and productivity of a cropping system depends on an adequate amount of plant nutrients. Fertility of the soil refers to its capacity to support the production of crops. A productive fertile soil can support optimal plant growth, seed germination to plant maturity by providing adequate soil volume for plant root development, essential plant nutrients to meet the nutritional requirements of the plants, and encourage for the consequent plant structure. These attributes of the soil can be distinguished as inherent or dynamic soil quality indicators.Optimum plant health and productivity of a cropping system depends on an adequate supply of plant nutrients. The quantity of nutrients required by plants varies depending on many interacting factors including:

• Agronomic effects

• Soil properties

• Climatic condition

• Management practices

Nitrogen

Most commonly, complex organic compounds, ammonia, molecular nitrogen, nitrite, and nitrate are the forms of nitrogen found in soils. The physical and chemical conditions of the soil control the majority of the microbiological interconversions that change nitrogen.

Ammonia build-up, ammonia loss by volatilization, denitrification, nitrogen f ixation, and leaching losses of nitrogen are the primary changes that occur in submerged soils. The nutrition of rice is significantly impacted by these changes. Given the favourable circumstances for quick soil transformations and nitrogen loss, it is obvious that rice soils are nitrogen deficient.

Introduction

At a present time, Organic farming has an important priority in different areas due to worldwide in look of the growing need for pure and nutritious agriculture food and keep up the feasible and environmental pollution on long time associated with indiscriminate use of chemical fertilizer. The use of synthetic inputs in crop cultivation is necessary to meet the growing need for agriculture food in world. The natural fertilizers are made containing living or veiled cells or their strains of N2 fixation, P2 O5 solubilization bacteria. The biofertilizers are used for seed cramming, soil or vermicomposting region with the objective of rising quantity of such microbes and further those microbial processes which augment the obtainability of nutrients that can be easily digest by plants. Biofertilizers are playing higher role in increase soil productivity by f ixing atmospheric nitrogen, both, in relationship with plant roots and without it, solubilise and insoluble soil phosphorus and produces many plant growth substances in the soil.

Introduction

Manures are obtained from the plant residues, green manure, compost and animal wastes that are used as source of plant nutrients. They release nutrients after their decomposition. They essentially function as sustenance to the crops. They help in the proper cultivation of crops. The addition of manure enables the soil to hold more water. Organic manures have acids that dissolve the nutrients in the soil and make them available to the plants. manures can be grouped into bulky organic manures and concentrated organic manures. Brief dissection about manure given blow flow chart.

Bulky Organic Manure

Bulky organic manures are those materials of plant and animal origin, which contain small percentage of nutrients when added to the soil have tendency to decrease bulk density and to increase soil volume, thus providing better physical conditions for plant growth especially in coarse textured soils and also provide essential nutrients in smaller quantities than the chemical fertilizers. Characteristics of bulky organic manures:

Introduction

Problem soils are those that impede agricultural productivity owing to mineral stress, dryness, acidity, sodicity, waterlogging, etc. Vertisol, acid sulphate soils, saline-sodic soils, peat soil, and fine textured alluvial soils were the categories Beek et al., (1980) used to group the problematic soils. In addition to vast areas where deficiencies of zinc, phosphate, and iron, or excesses of iron, aluminium, and manganese limit rice yields, Ikehashi and Ponnamperuma (1978) observed that approximately 100 million hectares of land that are physiographical and climatically suitable for rice lie idle due to the soil toxicities caused by salt, alkali, acid, or organic matter. Problem soils can be broadly defined as those that have unfavourable conditions whether natural or artificially created that severely restrict the successful development of crops. Soil profiles with high groundwater levels and a less permeable argillic layer, degraded soils, sandy soils with low fertility, coastal soils that frequently flood, and laterites could all be categorised as problem soils. Without taking into account related soil functions, soil health is evaluated independently. It is also based on the f indings from a few soil tests for different criteria. 2015 has been recognized the International Year of Soils by the 68th UN General Assembly in recognition of the importance of soil health in all dimensions.

Introduction

 Salinity is a form of salt that occurs naturally within soils or water. When soil

becoming salty form that is called salinization, it can be caused by mineral

weathering called as natural process but it can be caused by irrigation called

as artificial process. Saline or salty soil have a high salt content like sodium

chloride (NaCl also called table salt). Salinity is like- abiotic stress for plants

and reduced the plant growth but not for all because some of them crops are

survive in better way for growth and development such as barley, sugerbeet,

cotton and mustard etc. Basically, stress are two types-biotic and abiotic

stress. Abiotic stress are also called nonliving stress like- drought, salinity,

submergence, heat, cold and temperature that are affect to plant life cycle so

that are called as abiotic stress. Natural water and all types of soil both contain

soluble salts. Amount of salt affected to weather of soil, when excessive salt

present in soil and it adversely affects to crop growth and developments. Salt

affected soils exist under arid and semi-arid climates. Major constitutions of

soluble salt in soil are the cations and anions. Cations are containing sodium,

calcium, magnesium and anions are contains chloride, sulphate, carbonate and

bicarbonate. Saline soil have <8.5 pH, >4EC (dS/m) and <15 ESP. where EC

is eclectical conductivity that is measure of soil salinity and ESP stand for

Exchangeable sodium percentage.

Soil pH

 Soil reaction is measured by pH (Puissance de Hydrogen) of a suspension of

soil in water. The word “pH” has originated from the French word “pouvoir

hydrogen” which means powers of hydrogen. The acidity, neutrality or

alkalinity of a soil is measured in terms of hydrogen ion activity (active

concentration) of the soil water system. Most of the agricultural soils have

a pH varying from 4.5 to 8.5. The active concentration of hydrogen ion is

termed as ‘active acidity’ which is 1/50,000 or 1/1,00,000 times lesser than the

exchange acidity or exchangeable hydrogen.

 Soil pH is a measure of the activity of ionised H (H+) in the soil solution. The

pH of a solution can be defined as the negative logarithm to base 10 of the H+

ion activity or the logarithm of the reciprocal of the H+ ion activity.

pH = -log10

 a[H

 +] = log10

 1/[H

 +]

 There is difference between activity and concentration. Activity and

concentration are related by the mathematical expression

 a

 c

 F

 = where a = activity of a species (moles L-1)

 c = concentration of that species (moles L-1), f = activity coefficient

 a = c for dilute solutions, f = 1

 Activity coefficient of an ionic species is the degrees of freedom of that species

to participate in an equilibrium reaction or to maintain its charge under an

ionic environment.

Introduction

 India, situated between the latitude of 08004’ and 37006’ N and longitudes of

68007’ to 97025’ E, has a geographical area of 329 Mha. Physiographically, it

can be divided into three broad regions, viz., Peninsula (a triangular Plateau in

the Deccan and South of the Vindhyas), Mountain region of the Himalalayas

(Extra-Penninsula), and the Indo-Gangetic Plain separating these two regions.

Geologically, a great part of the Penninsula is occupied by the gneiss, schists

and other rocks of diverse nature. Red soils (Alfisols) generally predominate in

this region. The western and central parts predominate in basaltic rock having

Black cotton soils of different thickness (Vertisols, Inceptisols). The mountain

region shows the development of marine sediments of all ages, especially, in

north of the Himalayas. The vast Indo-Gangetic and other plains of Pleistocene

origin are composed of alluvium of the great river systems flowing in this

region. The alluvial soils of this region depend on the age of alluvia and degree

of development.

Climatically, India shows three distinct seasons:

 i) Cool and mainly dry winters from November to February

ii) Hot and mainly dry summers from March to June

iii) Monsoon rainy season from mid-June to September.

Introduction

Soil resource catalogue provides an insight into the capability and the constraint

of mapped area for its optimum exploitation towards developmental planning.

For this motive soil survey series as an essential tool. Soil survey is essentially

a study and mapping of soils in their natural environments and systematic

examination, description, classification and mapping of soil of area.Soil survey

contains a group of compound operation involving

•             To study important properties of soils and associated land features.

 •            Define taxonomic units through correlation and classifications of soils.

•             To establish and draw a border of different kinds of soils on standard

topographical base map through mapping of soils.

 •            Transfer of technology from research farm to farmer ‘s field under

different soil condition and management practices.

Cation Exchange of Clay Minerals in Soil

The term “clay mineral” refers to phyllosilicate minerals and to minerals which impart plasticity to clay and which harden upon drying or firing. Clay minerals are layer silicates that are formed usually as products of chemical weathering of other silicate minerals at the earth’s surface. Clay minerals in soil play a significant role in exchanging cations, which are positively charged ions, and in regulating soil fertility and nutrient availability. Cation exchange capacity (CEC) is a measure of a soil’s ability to exchange cations and is influenced by the type, abundance, and charge properties of clay minerals in the soil. Clay minerals have a high CEC due to the presence of charged surfaces (silanol and alumoxane groups) that can exchange cations with the soil solution. The most common cations exchanged by clay minerals are hydrogen (H+), calcium (Ca2+), magnesium (Mg2+), potassium (K+), and sodium (Na+). When a soil solution comes into contact with clay minerals, cations in the soil solution are adsorbed or attracted to the charged surfaces of the clay particles.

Introduction

Soil aeration status involves the rate of such ventilation, as well as the proportion of pore space filled with air, The composition of that soil air and the resulting chemical oxidation or reduction potential in the soil environment. Water provides the base for food, nutritional and environmental security. Soil water plays a significant role in controlling the energy balance of the soil and its overlying micro-environment by modifying its radiation exchanges and thermal properties. Soil temperatures affect plant and microorganism growth and also influence soil drying by evaporation. It is a central maximum of ecology that “everything is connected to everything else.” This interconnectedness is one reason why soils are such fascinating and challenging objects of study. In this chapter we shall explore three aspects of the soil air, water and temperature.

Introduction

The interest in soil as a natural body originated from its ability to produce and sustain crops. The scientific study of soil probably started in the mid-nineteenth century and was dominated by geologists, chemists and plant physiologists. Justus von Liebig (1840) in his famous publication, Chemistry Applied to Agriculture and Physiology, put forward the theory that plants assimilate mineral nutrients from soils which varied in their capacity of nutrient supply. The ‘Law of Restitution’ propounded by him states that whatever is being taken by plants from the soil needs to be restored to maintain the nutrient supplying capacity of the soil.

Statistics: Collection of methods for planning experiments, obtaining data,

and then organizing, summarizing, presenting, analyzing, interpreting, and

drawing conclusions.

Sir R.A. Fisher: Father of modern statistics.

Population: All subjects possessing a common characteristic that is being

studied.

Sample: A subgroup or subset of the population.

Parameter: Characteristic or measure obtained from a population.

Statistic: Characteristic or measure obtained from a sample.

Karl Pearson: Study of correlation and chi-square test of goodness of fit.

W.S.Gosset: Student’s t-test for small sample

Francis Galton: Regression analysis.

Descriptive Statistics: Collection, organization, summarization, and

presentation of data.

Statistics: Collection of methods for planning experiments, obtaining data,

and then organizing, summarizing, presenting, analyzing, interpreting, and

drawing conclusions.

Sir R.A. Fisher: Father of modern statistics.

Population: All subjects possessing a common characteristic that is being

studied.

Sample: A subgroup or subset of the population.

Parameter: Characteristic or measure obtained from a population.

Statistic: Characteristic or measure obtained from a sample.

Karl Pearson: Study of correlation and chi-square test of goodness of fit.

W.S.Gosset: Student’s t-test for small sample

Francis Galton: Regression analysis.

Descriptive Statistics: Collection, organization, summarization, and

presentation of data.

Inferential Statistics: Generalizing from samples to populations using

probabilities. Performing hypothesis testing, determining relationships

between variables, and making predictions.

The term ‘Management’ derived from word ‘manage’ derived from French

word menage means ‘housekeeping’.

According to Knootz and Weihrich 1988, ‘Management as the process of

designing and maintaining an environment in which individuals, working

together in groups, efficiently accomplish selected aims’.

According to Louis E.Boone and David L.Kurtz ‘management as the use of

people and other resources to accomplish objectives’.

POSDCORB is an acronym widely used in the field of Management and

Public Administration., it first appeared in a 1937 staff paper by Luther Gulick

and Lyndall Urwick. The acronym stands for steps in the administrative

process: Planning, Organizing, Staffing, Directing, Coordinating, Reporting

and Budgeting.

Rural Development: The economic betterment of people as well as greater

social transformation. The efforts for rural development comprises the direct

and indirect involvement of people at the grass root level for development of

agriculture/animal husbandry, industry, communication, education, health and

allied sectors.

Democratic Decentralization: To ensure people’s participation in rural

development programmes, democratic decentralization has been the core

principle of the government since 1957. In the process, people’s participation

in all developmental activities has been the unique phenomena to find out the

solutions of their problems.

Panchayat Raj: On the principle of democratic decentralization, Panchayat

Raj institutions were launched in 1957 as per the recommendations of Balwant

Rai Mehta Committee. Under this, the government has derived its authority

from the people, and distribute to some extent to the people for decision and

action at the local level called Panchayat Raj.

Extension teaching methods: Methods by using them new information can

pass freely between the extension worker and rural communities. Extension

education is mainly concerned with the dissemination of useful and practical

information relating to rural life and helping the rural people in the practical

application of such knowledge to rural situations. Extension teaching methods

can be classified on the basis of:

Some Definition

Farmer’s call: Call made by a farmer or homemaker at the working place of

the extension agent for getting information.

Adoptive/minikit trial: It is a method of determining the suitability of a new

practice in farmer’s situation.

Farm clinic: It is a facility developed for diagnosis and treatment of farm

problems and provides specialist advice to individual farmers.

Field day/ Farmer’s day: Methods of motivating the people to adopt a new

practice by showing what has actually been achieved by applying the practice

under field condition.

Communication word comes from Latin ‘Communis’ - Common

Communication: The communication is the process of human interaction in

which one person communicates a message/idea to another person.

Diffusion: It is the process by which an innovation/new idea/new technique

spreads.

According to Rogers (1983) ‘Communication is the process by which the

message is transmitted from the source to the receiver’.

Function of communication

1. Informative

2. Instructive/Command

3. Influence/Persuasive

4. Integrative

Communicator: Person who starts the process of communication OR he is the

sender of message

Message: It is the information the communicator wishes his audience to

receive, understand and act upon

Encoding: It is a process of interpreting the message

Decoding: It is a process of receiving the message

Research: The word research is composed of two words “Re” and “Search”.

“Re” - ‘Again or over again or a new’.

“Search” - ‘To examine closely and carefully’ or ‘to test and try’.

Research is a careful, systematic, patient study and investigation in some field

of knowledge undertaken to establish principles / policies.

Science: It is a systematized knowledge derived through observation,

experimentation or any other systematic method or procedure in order to

determine the nature of phenomenon or process being studied or the causes

behind specific events.

Research Methodology: The study of conducting research is research

methodology.

Pure/Basic/Fundamental Research: Gathering, knowledge is termed as

‘pure’ or ‘basic’ research. Just to gather knowledge in order to formulate or

generalize theories or policies. Pure research involves developing and testing

theories and hypotheses that are intellectually challenging to the researcher but

may or may not have practical application at the present time or in the future.

Father of sociology: Auguste Comte

The term sociology was coined by Auguste Comte (1789-1875).

Sociology word comes from two roots i.e. Latin word ‘socius’ meaning companion Greek word ‘logos’ meaning speech or reasoning.

Sociology: Sociology is the scientific study of human social behavior and its origins, development, organizations, and institutions. It is a social science that uses various methods of empirical investigation and critical analysis to develop a body of knowledge about human social actions, social structure and functions.

Rural sociology: The study of social life of peoples lives in rural areas.

Social organization: The study of the various institutions, social groups, social stratification, social mobility, bureaucracy, ethnic groups and relations, and other similar subjects such as education, politics, religion, economy etc.

Social psychology: The study of human nature as an outcome of group life, social attitudes, collective behavior, and personality formation.

Social change: Alteration in the structure and function of society. It may be structural, functional and cultural changes and it deals with the study of such current problems in society such as juvenile delinquency, criminality, drug addiction, family conflicts, divorce, population problems etc.

The Constitution of India related to women

Guarantees to all Indian women equality: Article 14

No discrimination by the State: Article 15(1)

Equality of opportunity: Article 16

Equal pay for equal work: Article 39(d)

Securing just and humane conditions of work and for maternity relief: Article 42

The All India Women’s Education Conference was held in Pune in 1927

The National Policy For the Empowerment of Women came was passed in 2001

In 2010 March 9, Rajya Sabha passed the Women’s Reservation Bill requiring that 33% of seats in India’s Parliament and state legislative bodies be reserved for women.

Women perform 2/3 of the world’s work

Women earn 1/10 of the world’s income

Women comprise 2/3 of the world’s illiterate

Women own less than 1/100 of the world’s property

Father of Extension: James Stuart •

Word Extension: Derived from Latin roots “ex” - Out “tensio” - Stretching

Extension term originated in England as University Extension in 1866.

The term Extension Education first used in 1873 by Cambridge University.

Philosophy of Extension (Kelsey and Hearne, 1967): How to think.

Binet test: Intelligence test (IQ)

Function of Extension: Change in Attitude, Skill and Knowledge of an individuals.

Extension Education Process: Extension education is a participative and continuous process

Learning Situation: It is a condition or environment in which all the elements necessary for promoting learning are present.

Elements of effective learning situations in Extension are:

 

About two-thirds of the developing world’s three billion rural people live in about 475 million small farm households, working on land plots smaller than two hectares. Many are poor and food insecure and have limited access to markets and services. Their choices are constrained, but they cultivate their land and produce food for a substantial proportion of the world’s population. Besides farming, they have multiple economic activities, often in the informal economy, to contribute towards their small incomes. These small farms depend predominantly on family labour. In China, nearly 98 percent of farmers cultivate farms smaller than 2 hectares – the country alone accounts for almost half the world’s small farms. In India about 80 to 85 percent of farmers are small. In Ethiopia and Egypt, farms smaller than 2 hectares constitute nearly 90 percent of the total number of farms. In Mexico, 50 percent of the farmers are small; in Brazil smallholders make up for 20 percent of the total number of farmers (Rapsomanikis, 2019).

Biodiversity encompasses the different kinds of life we find in one area— the variety of animals, plants, fungi, and even microorganisms like bacteria that make up our natural world. Each of these species and organisms work together in ecosystems, like an intricate web, to maintain balance and support life. Biodiversity refers to all species and living things on Earth or in a specific ecosystem. Biodiversity brings together the different species and forms of life (animal, plant, entomological and other) and their variability, that is to say, their dynamics of evolution in their ecosystems. Traditionally, there are three levels of biodiversity: genetic diversity, species diversity, and ecosystem diversity. But what does each of these levels really mean.

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).

Marginal and sub marginal lands are being brought under cultivation to meet the demand of human and livestock in terms of rising demand of 6F viz., food, fodder, fuel wood, fibre and fertilizer. These in lands are unable to sustain productivity. Cultivation on such lands leads to imbalance in the ecosystem. In order to meet the above said demands and to conserve the natural resources, a diversified land use system needs to be adopted in different agro-ecological regions of the country as an alternative to conventional cropping systems. Through this approach, the biological productivity and quality of resource base of degraded lands can be significantly enhanced. Land use systems which are alternatives to crop production are called by the term ‘Alternate Land Use Systems’.

Dryland agriculture is a more vulnerable system in view of its high dependency on monsoon rains which are of aberrant nature. The risk of crop failure and poor yields always restrain farmers from investing on new technologies and input use.

Concept of resilience

Resilience is used to describe the magnitude of a disturbance that a system can withstand without crossing threshold into a new structure or dynamic. Resilience is defined as “the ability of a system and its component parts to anticipate, absorb, accommodate, or escape from unacceptable standards of living due to the effects of a hazardous event, in a timely and efficient manner”. In other words, resilience describes the capacity of communities in a given context or landscape to maintain and improve their livelihoods—despite stresses and shocks—through the sustainable management of natural resources while maintaining key ecological functions

In India since ages, the dryland farmers adopted a kind of mixed farming involving traditional annual crops and livestock consisting of one or two cows / bullocks and few poultry birds. This traditional system though of small scale provided some kind of risk minimisation particularly in the years of scanty rainfall causing agricultural drought. (https://coabnau.in/uploads/1587050523_ Agriculturalheritage.pdf) Discouraged by their marginal impact on farm economy, dryland farmers switched over to the lure of ‘productive’ mono-cropping with certain commercial crops like cotton etc. The continuous mono-cropping resulted in impoverishment of soils and low crop yields which took farmers into the labyrinth of poverty.

Historical perspective: Planting of single crops or mono-cultural agriculture—is a recent invention of the industrial agricultural complex (Hirst, 2019). While unequivocal archaeological evidence is difficult to come by, it’s believed that most agricultural field systems in the past involved some form of mixed cropping. That’s because of even botanical evidence of plant residues such as starches or phytoliths of multiple crops are discovered in an ancient fields (Hirst, 2019). Mixed cropping, also known as polyculture, or co-cultivation, is a type of agriculture that involves planting two or more crop plants simultaneously in the same field so that they grow together. The primary reason for prehistoric multi or mixed cropping probably had more to do with the needs of the farmer’s family and perhaps to avoid crop failure. It’s possible that certain plants adapted to multi-cropping over time disappeared as a result of the domestication process (Hirst 2016).

Dryland agriculture limits the crop growth to a part of the year due to lack of sufficient moisture (Peterson et al., 2006). According to the Fourth five-year plan of India, dry lands are defined as areas which receive rainfall ranging from 375 mm to 1125 mm and with very limited irrigation facilities. Dry lands are economically fragile regions which are highly vulnerable to environmental stress and shocks. Degraded soils with low water holding capacities along with multiple nutrient deficiencies and depleting ground water table contribute to low crop yields and further leading to land degradation. In a country like India, 44 per cent of the total food production is supported by dryland agriculture, thereby playing a critical role in nation’s food security. With the increasing population, food production has to be increased. A real need to second green revolution has been envisioned, which can be achieved by improving the dryland agriculture.

Rainfed farming has a distinct place in the Indian agriculture, occupying 67 % of cultivated area contributing 44 % of food grains to our national food basket, supporting 40% of human and 65% of livestock population. The system is characterized by resource poor farmers, poor infrastructure and low investment in technology inputs. Even when full irrigation potential of the country is realized, 50% of the net sown area is continued to be rainfed. The important problems encountered in rainfed areas are unfavorable weather, limited choice of crops and varieties, low cropping intensity and unstable productivity. The research work done by the net work of AICRPDA (All India Co-ordinate Research Project for Dryland areas) centres and SAUs (State Agricultutal Universities) indicated that the production in rainfed environment could be enhanced by 200 % compared to the productivity of farmers’ field by adopting improved cropping systems and agro techniques.

Soil and water are the basic resources in drylands. Soil supports plant life by providing a medium for their growth and development. It is a non-renewable natural resource and susceptible to rapid degradation through various forms of erosion processes. Worldwide, around 52% of total productive land has been degraded by various kinds of degradation processes and almost 80% of the terrestrial land is affected by water erosion .Further, annually ~10 million hectares (Mha) of cropland becomes an unproductive at the global level due to soil erosion with an average rate of 30 t ha−1 year−1 soil erosion .In India, out of 328 million hectares of geographical area, 68 million hectares are critically degraded while 107 million hectares are severely eroded. Soil degradation in India is estimated to be occurring on 147 million hectares (Mha) of land, including 94 Mha from water erosion, 16 Mha from acidification, 14 Mha from flooding, 9 Mha from wind erosion, 6 Mha from salinity, and 7 Mha from a combination of factors (Battacharya et al., 2015).

Moisture deficit causing shortfalls in crop production is the characteristic feature of dryland agriculture. Other adverse factors viz., decline in soil fertility together with play of biotic stresses add to the complexities of dryland crop production. Added to the proven agronomic management to combat the problem of drought in dryland agriculture, there is the need to tailoring of suitable crop varieties which can yield reasonably well under conditions of moisture deficit (Varshney et al., 2021). In this context, the appropriate developmental rhythm along with the combination of the constellation of characters of the crop plant matching with the rainfall and the soil moisture availability patterns of the zone are the important considerations together with stability of yield (Hanson and Nelsen, 1980). This task being a complex one, the problem should be approached through multidisciplinary strategy that should buffer the genetic and breeding efforts.

The world’s drylands include hyper-arid, arid, semi-arid and dry sub-humid areas where rainfall is highly scanty and variable. Droughts are common in areas / zones where water is the principal limiting factor for agriculture (https:// www.fao.org/3/t0122e/t0122e03.htm) . Dryland soils are characterized by low levels of moisture, organic matter, and biological activity, consequently such soils are very poor in fertility devoid of plant nutrients. When, these soils suffer further degradation in fertility, resulting in erosion, desertification, and salinization when crops are grown on such soils inappropriately without any scientific basis. However, the major factor limiting agricultural production on drylands is the lack of adequate moisture for crop growth or drought.

Multipurpose trees and shrubs are defined as all woody perennials that are purposefully grown to provide more than one significant contribution to the production and/or service functions of a land-use system that they occupy. In agroforestry systems, different species of trees and shrubs can be planted with many types of crops in a variety of patterns. Thus, it is required to know about the methods of propagation and nursery raising, planting and other silvicultural management practices along with the diverse uses of multipurpose trees and shrubs of tropical and subtropical areas before their selection for forestry and agroforestry activities. It is important to select the most suitable tree species since it is not easy to replace them once they have been planted.

Trees have been used in cropping systems since the beginning of agriculture. Throughout the world, at one period or another in its history, it has been the practice to cultivate tree species and agricultural crops in intimate combination. In the tropics, human beings underwent a transition from hunting/gathering to the use of domesticated plants and livestock. As a part of the process, they cut down trees, cleared the debris by burning and sowed crops in the ashenriched soil. It was the ‘slash-and-burn’ agriculture, a primary forerunner of the present-day agroforestry and a practice that might have originated in the Neolithic period, around 7000 BC. There are innumerable examples of traditional land-use practices involving combined production of trees and agricultural species on the same piece of land in many parts of the world. Trees were an integral part of these farming systems and they were deliberately retained on farmlands to support agriculture. These practices are now known as agroforestry. However, the ultimate objective of these practices was not tree production but food production.

Farmers have been growing trees for different purposes for thousands of years. Tree species that are grown to provide more than one significant function are called multipurpose trees. These functions may be productive such as producing fuelwood, timber, fibre, fodder, food, medicine, etc. and/or protective such as soil conservation, shade, shelterbelt, microclimate amelioration, land sustainability, biodiversity preservation, etc. All trees are multipurpose; some, however, are more multipurpose than others. Tree species can be multipurpose in two ways. 1. A single tree can provide more than one function. For example, Gliricidia sepium is grown as living fences that provide fuel, fodder and green manure for agricultural crops - all at the same time. 2. Trees of the same species, when managed differently, can provide different functions. For example, Leucaena leucocephala is managed so that some trees will mainly yield wood while others mainly produce leaf fodder.

Management approaches to soil, including problems of soil degradation and low soil fertility, have recently undergone major changes. The earlier concept was to concentrate on achieving high levels of production from the more fertile areas, leaving the marginal lands for extensive use only. Steeply sloping and highly drought-prone areas were mostly left without any cultivation as production from these areas was hardly cost effective. Soil constraints were to be overcome by inputs like improved crop varieties, fertilizers, chemical control of pests and diseases, and the use of irrigation. The approach of use of newly developed high yielding crop varieties, improved agronomic management practices, use of chemical fertilizers, efficient water management and timely plant protection measures has been successful in achieving large increases in crop productivity in recent years. On the other hand, continuous application of fertilizers at higher rates leads to environmental problems. Yield responses to fertilizers have declined because of soil physical degradation and micronutrient deficiencies.

Agroforestry systems are not simply systems where trees and crops or animals give useful products to the farmers, rather systems where trees and crops and/ or animals interact. Interaction literally means influence or mutual or reciprocal action. So component interaction refers to the influence of one component of a system on the performance of other component as well as the system as a whole. In agroforestry systems, trees are grown in close proximity to crops and pasture. Their performance would largely depend on their ability to share various growth resources in a given environmental situation. Various interactions take place between the woody trees and herbaceous plants (crops or pastures) which is referred to as tree-crop interface. These interactions take place through the media of soil and microclimate and may exert favourable or adverse effects on the crop. Study of interaction helps to know how the components of agroforestry utilize and share the resources of the environment, and how the growth and development of any of the components will influence the others. Interaction occurs both above and below the ground and includes a complex set of interactions relating to radiation exchange, the water balance, nutrient budget and cycling, shelter and other microclimatic modifications.

In agroforestry systems the various components like tree, crop and pasture exist in different proportions and orientations. It is difficult to find out which agroforestry system is the best suited for a given land situation. Similarly, it is to be decided which technologies are required for refinement and improvement of the existing agroforestry practices. But without sufficient knowledge of the existing system in a particular land situation, it is very difficult to set the research priorities for modification and development of this system. Diagnosis and Design (D & D) is a systematic and objective methodology developed by International Centre for Research in Agroforestry (ICRAF) to initiate, monitor and evaluate agroforestry programmes. D & D is based on the philosophy that knowledge of the existing situation (diagnosis) is essential to plan and evaluate (design) meaningful and effective programmes in agroforestry research for development. The methodology plays a strategic role in all the phases of the agroforestry research process. D & D in agroforestry is unique and it has been specially developed for the following purposes.

Agroforestry is a land use system that involves two or more plant species at least one of which must be a woody perennial. When perennial woody and herbaceous components are grown together on the same piece of land their performance would largely depend on their ability to share various growth resources in a given environmental situation. Due to difference in growth pattern and resource requirement of the components in agroforestry situation, a close interactive relation is obvious. Thus, careful management practices for the components are required to establish a successful agroforestry system. The characteristics of the trees and crops, and their interactions, can be modified with good management practices in order to take advantage of the positive characteristics and minimize the effects of the negative ones. Effective and efficient agroforestry management may be divided into two groups; tree management and agricultural crop management.

The words ‘system’, ‘sub-system’ and ‘practice’ are commonly used in agroforestry literature. In a broad sense, a system is defined as a group of associated elements forming a unified whole and working together in a well defined regular relation for a common goal. An agroforestry system refers to a type of agroforestry land-use that extends over a locality to the extent of forming a land utilization type of the locality. Sub-system and practice are lower-order terms in the hierarchy with lesser magnitudes of role, content and complexity. However, these terms are used loosely, and almost synonymously. Classification of agroforestry systems is necessary in order to understand and provide a practical framework for evaluating systems and developing action plans for their improvement. Any classification scheme should satisfy the following criteria (Nair, 2008).

A forest is a large area dominated by trees. Many definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing and ecological function. Although a forest is usually defined by the presence of trees, under many definitions an area completely lacking trees may still be considered a forest if it grew trees in the past, will grow trees in the future, or was legally designated as a forest regardless of vegetation type.According to the Food andAgriculture Organization definition, forests covered 4 billion hectares or approximately 30% of the world’s land area in 2006. Forests are the dominant terrestrial ecosystem of earth, and are distributed around the globe. Forests account for 75% of the  gross primary production  of the earth’s  biosphere, and contain 80% of the earth’s plant biomass.

Agroforestry is a new name for a set of old practices. The farmers have been practicing agroforestry since ancient times. 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. In fact, man’s association with forest is much older than with agriculture. First man was a food gatherer and hunter in forests. Then he realized that the seeds of the fruits he collected germinated, grew into plants and bore the fruits again and thus man started to cultivate foods. Man’s desire to live in a community created settled agriculture.

Among the various natural resources upon which all living organisms depend, soil is the unique because of its non-renewable in nature, heterogeneity in space and time and susceptibility to degradation inflicted by biotic as well as abiotic agents. Whereas, escalating population demands, in one way, to bring more land under the plough for providing food, fodder, fuel and fibre, simultaneously, on the other way, these finite natural resources are dwindling by leaps and bound, through overexploitations and mismanagement, the combined effect of which leads to land degradation, a serious global threat and major environmental issues in the present times.