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Sustainable development has caught the imagination and action across the world. Sustainable agriculture is necessary to attain the goal of sustainable development. The word “sustain,” is derived from the Latin sustinere (sus-, from below and tenere, to hold), to keep in existence or maintain, implies long-term support or permanence. As it pertains to agriculture, sustainable describes “Farming systems that are capable of maintaining productivity and usefulness to society indefinitely. Such systems must be resource-conserving, socially supportive, commercially competitive, and environmentally sound”. “Sustainable agriculture is the successful management of resources for agriculture to satisfy changing human needs while maintaining or enhancing the quality of environment and conserving natural resources” (FAO). All definitions of sustainable agriculture lay great emphasis on maintaining an agriculture growth rate, which can meet the demand for food of all living things without draining the basic resources. Over time, the International Alliance for sustainable agriculture and an increasing number of researchers, farmers, policy-makers and organizations worldwide have developed a definition that unifies many diverse elements into a widely adopted, comprehensive, working definition

2.1 Introduction

Microbes are the oldest form of the life on earth. These organisms date more than 3 billion years to a time when they were covered with oceans. They are so tiny in size that million microbes can fit into the eye of a needle. Without microbes, we can’t live. Thus, understanding microbes is vital to understanding past and future. Microbes play vary roles in the earth’s environment recycling dead plant and animal matter through the soil, removing CO₂ from the atmosphere by photosynthesis in the oceans and nitrogen from the atmosphere to form nitrogenous fertilizers plants. Microbes play an important role in nutrient recycling, management, organic matter, decomposition and increasing the crop productivity and quality against diseases. Over the past century, many of the basic scientific principles of plant nutrition and soil fertility have been explained. In developed countries, inorganic chemical fertilizers have been widely accepted as a major source of improving and maintaining soil fertility. Plants need sufficient nutrients in proper balance for normal growth and development. Seventeen plant nutrients are essential for proper crop development. Each is equally important to the plant, yet each is required in vastly different amounts. Our understanding of nutritional needs of crop plants begin from the famous five year willow tree experiment conducted by J.B. van Helmont (1579–1644).

The earlier products of bio-fertilizers were carrier (solid) based where lignite is usually added as a carrier material. Lignite is hazardous to the production workers. Also, the shelf life of carrier based bio-fertilizers is only 6 months and is difficult to transport. Liquid Biofertilizers (LBFs) on the other hand have a shelf life of minimum one year, with no health hazards to production workers and are easy to transport. Additionally, LBF can be used in drip irrigation and as a component of organic farming. The liquid Bio fertilizers are suspensions having agriculturally useful microorganisms, which fix atmospheric nitrogen and solubilize insoluble phosphates and make it available for the plants. The use of this biofertilizer is environment friendly and gives uniform results for most of the agricultural crops and directly reduces the use of chemical fertilizer by 15 to 40%. The shelf life of the liquid bio fertilizer is higher (in the range of one to two years) compared to that of solid matrix base biofertilizer.

3.1 Definition

Liquid biofertilizers are liquid formulation containing the dormant form of desired microorganisms and their nutrients along with the substances that encourage formation of resting spores or cysts for longer shelf life and tolerance to adverse conditions. The dormant form on reaching the soil, germinate to produce fresh batch of active cells. These cells grow and multiply by utilizing the carbon source in the soil or from root exudates.

“A preparation comprising requirements to preserve organisms and deliver them to the target regions to improve their biological activity” or “A consortium of micro-organisms provided with suitable medium to keep up their viability for certain period which aids in enhancing the biological activity of the target site”.

Earthworms have been on the earth for over 20 million years. In this time they have faithfully done their part to keep the cycle of life continuously moving. Their purpose is simple but very important. They are nature’s way of recycling organic nutrients from dead tissues back to living organisms. Many have recognized the value of these worms. Ancient civilizations, including Greece and Egypt valued the role of earthworms played in soil. The Egyptian Pharaoh, Cleopatra said, “Earthworms are sacred”

4.1 Earthworms

Earthworms belong to Phylum Annelida of animal Kingdom. They are long and cylindrical shape, length of earthworms vary from a few mm to nearly 3mtr as noted in case of Megas colex species found in Australia. The body of earthworms has a large number of grooves. Due to these grooves the body of the earthworm is divided into number of compartments called segments. In mature earthworms, few anterior segments appear swollen due to glandular thickening. This part is called as clitellum. The segments are not clearly seen in this part. There are 2500 to 3,000 species of earthworms in the world which are adapted to range of environment. More than 350 species have been identified in India. The species of earthworms are differentiated mostly on the basis of external features such as length of earthworms, number of segments, position of clitellum and external aperture present on the body. Earthworms were referred by Aristotle as “the intestines of earth and the restoring agents of soil fertility”

Agriculture has been very successful in addressing the food and fiber needs of today’s world population. However, there are increasing concerns about the economic, environmental and social costs of this success. Integrated agricultural systems may provide a means to address these concerns while increasing sustainability. Integrated agricultural systems have multiple enterprises that interact in space and time, resulting in a synergistic resource transfer among enterprises. In an integrated agricultural system, management decisions, such as type and amount of commodities to produce, are predetermined. Full integration of agricultural systems at the producer or community scale may help in slowing or reversing some of the detrimental environmental and economic problems associated with specialized industrial agriculture. Modern agriculture requires intensive inputs.

6.1 Introduction

India experienced an impressive growth and productivity gains in agriculture since Independence reflecting our farmers’ resilience against multiple odds and challenges. Despite a structural transformation post-Green Revolution, characterized by a consumer centric and food security policy objective, the regular distress and crises in the recent past pose a severe threat to income and livelihood security of farmers. The income realised from agriculture compared to nonagriculture, has been too low with a wide variation across regions. The average income of an agricultural household during 2012-13 has been estimated as low as at `6426 per month, marginally higher than the average consumption expenditure (`6223). Further, around 23 per cent of the farmers still live below the poverty line (DFI Committee, 2017a). Estimates from the Central Statistics Office’s (CSO) indicated that the annual growth in gross value added from agriculture has reduced drastically from as high as 6.9% (October-December, 2016) to a mere 2.3% (April-June, 2017) at 2011-12 prices in the recent past ten quarters. Shockingly, the growth was lower in nominal terms in comparison to real prices during the April-June, 2017 quarter indicating the creeping deflation in farm sector.

Technological change has been the major driving force for increasing agricultural productivity and promoting agriculture development across the world. In the past, the choice of technologies and their adoption was to increase production, productivity and farm incomes. Over many decades, policies for agriculture, trade, research and development, education, training and advice have been strong influences on the choice of technology, the level of agricultural production and farm practices. Agricultural production today faces several challenges: an increasing world population has to be fed, but at the same time the environment and animal welfare need to be protected. Globalisation has led to increasing international competition, while the agricultural sector is also under heavy economic pressure as a result of regulation. These conditions can perhaps only be met by innovation, be it on the technological or on the systems-level (OECD, 2001). Agriculture is becoming more integrated in the agro-food chain and the global market, while environmental, food safety and quality, and animal welfare regulations are also increasingly impacting on the sector. It is faced with new challenges to meet growing demands for food, to be internationally competitive and to produce agricultural products of high quality. At the same time, it must meet sustainability goals in the context of on-going agricultural policy reform, further trade liberalization and the implementation of multilateral environmental agreements as agreed to by the government.

India is on the progressive path of development and its rural population is an integral part of this growth trajectory. As India gears up for an era of increased digitalisation, the issue of holistic and inclusive economic growth remains a pivotal concern. Hitachi, one of the leading Japanese conglomerate with a global footprint and a forerunner in digital innovation, has been an active contributor in transforming millions of Indian lives, its services reaching far beyond citizens within city limits. While India is one of the world’s fastest-developing economy, equitable growth remains a critical imperative. The rural population today constitutes above 45% of the national income. In 2050, despite urbanization, over half of India’s population will still be rural. Prime Minister, Sh. Narendra Modi has prioritized radical digitalisation to induce economic inclusiveness through a host of initiatives. ‘Digital India’, ‘Make in India’ and ‘Skill India’ provide for impetus and opportunity to rural citizens, to ensure they are equal participants in India’s growth story. Digital transformation is the integration of digital technology into all areas of a business, fundamentally changing how you operate and deliver value to customers. It’s also a cultural change that requires organizations to continually challenge the status quo, experiment, and get comfortable with failure. In many developed countries, farming has been modernized by a wave of technologies, adopted at farm level.

Digital technologies are finding increasing use in the agricultural value system, and High-tech farming is becoming the standard, thanks to use of sensors, logic controlled systems, data analytics, etc. In India, the increasing availability of energy and internet connectivity to the large rural landscape is further accelerating such changes. Digitised information systems allow remote access to knowledge, has given rise to group sharing and continue even now to revamp how societal exchanges happen interpersonally, commercially and in the extension services system. The digital spectrogram can be compared against a large database and spectral analysis can diagnose the contents of the sample. This analysis can happen in the cloud, and results communicated to the farmers almost instantaneously. There exist various similar technologies where a sample from a field, gets converted into digital information, is promptly analysed to provide accurate results, which then allows farmers to take decisions best suited to the land they farm on. The availability of satellite imagery, infrared imagery, and a myriad of remote inputs allow for more accurate weather forecasts, advance warnings on pest infestation and similar, and more. Instead of traditional homilies about temperature and rainfall events, the farmers now consult and share the advisories and forecasts of the same.

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 and Agriculture Organization, forests covered four 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.

DEVELOPMENT OF MODERN FORESTRY

Systematic management of forests for a sustainable yield of timber began in Portugal in the 13th century when Afonso III, the king of Portugal planted the trees to prevent coastal erosion and soil degradation, and as a sustainable source for timber used in naval construction. His successor Dom Dinis continued the practice and the forest exists still today. Forest management also started in Germany in the 14th century and in Japan in the 16th century. The practice of establishing tree plantations in the British Isles was promoted by John Evelyn during second half of the 17th century.

During the late 19th and early 20th centuries, forest preservation programmes were established in British India, the United States and Europe. Sir Dietrich Brandis is considered the father of tropical forestry. He brought European concepts and practices to the tropical and semi-arid climate zones. The enactment and evolution of forest laws and binding regulations occurred in most Western nations in the 20th century in response to growing conservation concerns. Tropical forestry is a separate branch of forestry which deals mainly with equatorial forests that yield woods such as teak and mahogany. One of the applications of modern forestry is reforestation, in which trees are planted and tended in a given area.

Agroforestry is a new name for a set of old practices. 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.

The pressure on the agricultural lands has increased manifolds due to the increasing population, expansion of urban area and the industrialization process. The environment has also been disturbed. Soil is losing its productivity and the biodiversity is threatened. Farming community is trying all means to increase the land productivity. Chemical fertilizers and pesticides are applied in higher proportion, causing environmental pollution hazards. Under all these circumstances agroforestry has shown that besides sustainable agriculture it can also help promote a better environment. Trees have always played an important role in mankind’s survival. This relatively young science known as agroforestry was brought from the realm of indigenous knowledge into the forefront of agricultural research four decades ago and was promoted widely as a sustainability-enhancing practice that combines the best attributes of forestry and agriculture.

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 ash-enriched 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.

The words ‘system’, ‘sub-system’ & ‘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).

The word ‘social forestry’ was coined by Westoby and used in the ninth Commonwealth Forestry Conference at New Delhi in 1968. In India the term was first used by the National Commission on Agriculture, Government of India in 1976, to denote tree raising programmes to supply firewood, small timber and minor forest products to rural population. Prasad (1985) defined social forestry as forestry outside the conventional forests which primarily aims at providing continuous flow of goods and services for the benefit of people. This implies that the production of forest goods for fulfilling the needs of the local people is social forestry. Thus, conceptually it deals with the people to produce goods such as fuel, fodder, small timber, etc. to meet the needs of local community particularly the underprivileged section (Shah, 1988).

Urban forestry is not a new concept, but it is one which appears to have growing potential. With increasing urbanization in the 20th century, the incorporation of trees into urban settlements has also increased. The management of all trees within the urban area is considered a distinct discipline of forestry. Urban forestry was conceptualized in the late 1960s in North America, and grew out of what was initially termed environmental forestry. Trees and urban forests can make our cities cleaner, cooler, greener, safer, healthier, happier and nice places to live.

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. Above all, large numbers of poor farmers simply can neither afford high levels of fertilizers and other purchased inputs, nor do they have the capital to take on the risk involved in their use. Increasing the area under irrigation has also run into severe constraints in the form of limits to available freshwater resources.

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.

The success of an agroforestry system relies heavily on exploitation of the component interactions. In an ideal relationship, production of trees as well as crops or grasses in combination could be comparable to their sole performance. Agroforestry could be even more advantageous if the production of associated components is increased due to influence of trees. This is possible because trees are capable of improving productivity of soil in many ways. A large number of trees are known to fix nitrogen symbiotically. Nevertheless, instances of crop inhibition in association of trees are not uncommon. Such inhibitions are primarily caused by shade effect as well as competition for below-ground resources such as nutrients and water. In some cases, inhibitory effect may also result from allelochemicals secreted by some of the tree species.

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.

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.

FACTORS AFFECTING THE SELECTION OF TREE SPECIES

Trees in an agroforestry system contribute significantly to the total output of the system and therefore, success of the system depends on the selection of the tree species. The following factors are to be considered to choose the best tree species for the agroforestry systems in a particular site.