eChapters

Precautions to be taken while working in the laboratory for personal safety and to prevent any hazards.
    1.    Be vaccinated against dangerous viruses viz., rabies and hepatitis B as persons can contract infection while working with these organisms.
    2.    Use eye protection viz., goggles, spectacles etc to avoid splashing microbes into the eyes. 
    3.    Do not rub eyes with contaminated hands or objects.
    4.    Do not eat or drink anything in the microbiology laboratory as it will contaminate the laboratory.

INTRODUCTION

Indigenous knowledge is the knowledge of the indigenous people inhabiting different geographical regions of the world with their own language, culture, tradition, belief, folklore, rites and rituals. In course of their close interactions with nature and natural resources, they are to make a certain decisions as to solve their problems they encounter in their day to day life while managing the land and environmental resources for survival.

Several researchers explained traditional knowledge as holistic, encompassing many fields of scientific knowledge, such as climate, hydrology, soils, plants and animals (Howes and Chambers, 1980, Jungerius, 1985, Wilken, 1987, Agrawal, 1995). Therefore, indigenous knowledge so developed is based on necessities, instinct, curiosity and observations of ethnic groups to mitigate the immediate problems. Several logical observation was used by them in the decision making process as to how, when and where to act depending on the situations.

INTRODUCTION

Knowledge is a familiarity with someone or something, which can include facts, information, descriptions, or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject. It can be implicit (as with practical skill or expertise) or explicit (as with the theoretical understanding of a subject); it can be more or less formal or systematic.While many would agree that one of the most universal and significant tools for the transfer of knowledge is writing (of many kinds), argument over the usefulness of the written word exists nonetheless, with some scholars skeptical of its impact on societies. People are often internalizing new information which they perceive to be knowledge but in reality fill their minds with false knowledge.

Introduction

Sustainable exploitation of fish stocks and conservation of fish habitat are matters of concern for fishery scientists and administrators all over the world. Worldwide there is a declining trend in natural fish catch (FAO, 2002) and India is no exception. Increasing harvest pressure, destructive fishing operations, introduction of exotics, are examples of factors from within the sector responsible for increasing pressure on fish stocks. The decline in open water catch has been a serious issue in fisheries as millions of rural households depend on fishing to maintain their livelihood incomes, and because fish is a major protein source in the globe. However, the government in several countries is addressing the issue in a number of ways, such as: (i) moving towards biological management from revenue-oriented management; (ii) involving resource users in capture fisheries management to maintain natural productivity; and (iii) starting programs such as rehabilitating of degraded habitats (FAO, 1999).

Introduction

North East India, a mega-biodiversity centre and a hotspot (Myer et al., 2000) occupy 7.7% of India’s total geographical area supporting 50% of the flora (ca. 8000 species) (Rao, 1994), of which 31.58% (ca. 2526 species) are endemic (Nayar, 1996). It is a transitional zone between the Indo-China and Indo-Burma–Malaysian regions. This region is also a part of the vavilovian centre of biodiversity and origin of many important cultivated plant species and some domesticated animals (Agarwal, 1996). North Eastern Hilly (NEH) region of India supports a rich biodiversity spanning from tropical rainforests to alpine scrubs.  Takhtajan (1969) described the region as the “Cradle of Flowering Plants” because of its diversified angiosperms.  This rich biodiversity has a significant role to balance the ecosystem and has been used ethnologically by locals for various socio-economic and developmental purposes (Yumnam, 2008).

INTRODUCTION

The North Eastern Hill (NEH) Region of India comprising the states of Arunachal Pradesh, Assam, Meghalaya, Mizoram, Manipur, Nagaland, Tripura and Sikkim lies between 20º5’ to 29º30' latitude and 89º49' E to 97º3' E longitude. The region possesses a great diversity in soil and climate as influenced by varied altitudes ranging from 18m MSL to more than 3000m MSL. In the entire region due to high rainfall (1800 mm to 3000 mm/year) humidity is very high (50-100%). The average minimum and maximum temperature is also comparatively low and ranges from below 0°C to a maximum of 35ºC. This region is very rich in natural resources with diverse flora and fauna.

INTRODUCTION

North East India is a rich storehouse of indigenous agricultural practices and local varieties of crops. The region comprising of the states of Arunachal Pradesh, Assam, Meghalaya, Manipur, Tripura, Mizoram, Nagaland and Sikkim can be physiographically categorized into the Eastern Himalayas, Northeast hills (Patkai-Naga Hills and Lushai Hills) and the Brahmaputra and Barak Valley plains. At the confluence of the Indo-Malayan, Indo-Chinese and Indian biogeographically realms, the NE region is unique in providing a profusion of habitats, which features diverse biota with a high level of endemism (Chatterjee et al., 2006). The northeastern region is rich in biological diversity and contains more than one-third of the country’s total biodiversity. This biodiversity and variability of the ecosystem are used and conserved by traditional communities through various informal institutions and using traditional ecological knowledge systems. Ethnic communities of the region practice their traditional cultivation practices of diverse crop suitable in different ecosystems solely on organic conditions without any external inputs to the system; and value the land and the environment for the sustainability of the system for future generations. There is no systematic record to describe what they are, what they do and how they do, how they can be changed, their operations, their boundaries and their applications.

INTRODUCTION

Ethno-Veterinary Medicine (EVM) or Veterinary Anthropology refers to holistic and interdisciplinary study of traditional knowledge, skills, methods, practices and folk beliefs of the people about the health care of animal husbandry and production of livestock (McCorkle, 1986). It encompasses information on diseases and their control; remedies and clinical practices for treatment and prevention; management, feeding and breeding strategies; spiritual elements; and the use of human resources that hold the information and experience (Mathias, 2004).

INTRODUCTION

The fermented products probably came into existence at least before the British Era in Northeastern states of India [before 1824, The Yandabu Agreement between British Govt. and Burma (now Myanmar)] when the British first introduced salt in the region. Interestingly, in all the fermented fish products of this region no salt is used as ingredient which is a major difference with the other fish based fermented fish products of Southeast Asian countries such as Nuac-mum of Vietnam, Budu of Malaysia, Patis of the Philippines etc. Even after the British Era, people used to treat salt as a highly valued and scarce commodity and they used to take an alternative commodity, for example khar in Assam, made from banana plant or papaya. Hence, they could not afford spending salt in fish preservation and they were bound to preserve fish in their own cheaper and easier way.

INTRODUCTION

Jewellery has been a favorite form of adornment since time immemorial in all parts of the worlds and Indian is not an exception. The significance of jewellery in the country is evident from the fact that on many auspicious occasions, jewellery forms a part of gifts. Jewellery has not only been considered for the purpose of adoration, but it can also be sold to overcome the economic crisis. This way, jewellery also serves the purpose of insurance, which can be depended upon. To accentuate their feminine beauty, women use jewellery made of gold, silver and diamonds. Traditionally, jewellery has always been linked with wealth, power and status.

INTRODUCTION

Ethno-entomophagy is the term used to describe the practice of consumption of insects as food by native human populations. Insects are an important source of protein for humans, either through direct consumption or as food supplements for livestock (DeFoliart, 1989). They are nutritious in terms of protein (40–75 g/100g dry weight) and minerals. Their protein is of high quality and has high digestibility (77–98%) with good concentration of essential amino acids (46–96% of the nutritional profile) (Verkerk et al., 2007). The biochemical composition and chemical analysis have revealed that they are comparable with other foods enriched with high proteins, fats, lipids, vitamins and mineral salts (Prasad, 2007). Insects generally have higher food conversion efficiency than other animals. They show a food conversion efficiency of about twice as efficient as pig and boiler chick and more than five times as efficient as beef cattle (Durst and Shono, 2010). Some of the important edible insects include grasshoppers, caterpillars, beetle grubs, adult winged termites, bees, wasps, winged ants, cicadas and a variety of aquatic insects.

INTRODUCTION

Over the past decades, as concerns about declines in local habitats, species, and livelihoods related to agriculture and allied sectors have increased, the potential contributions of local and traditional knowledge (LTK) to ecosystem research and management have been increasingly recognized (Thornton and Scheer, 2012). North Eastern region is well known as one of the 18 hotspot areas of the world and hence is blessed with rich biodiversity and fish fisheries resources. With more than 90% of population being fish eaters, there is heavy demand of fish but a wide gap exists between supply and demand. The region produces over 0.214 million tonnes of fish annually, with almost 50% coming from aquaculture.

INTRODUCTION

Fishing is one of the oldest professions of humans. As the day went by, the fish farmers carry out their own indigenous technology as a common practice through natural resource management. In this line, different traditional fishing communities of West Bengal gained a vast experience in every sphere of aquaculture. Their innovation is based on their own knowledge derived from their day to day effort of solving problems. Actually this indigenous knowledge is the accumulated information, skill and technology of the local farmers derived from the close interaction with the nature. The intimate interaction of the farmers with aquatic ecosystems through their age old practices has developed huge expertise which is essential to be documented and disseminated. It will be helpful for aqua resource management as they can be shared in a, cost effective, eco-friendly as well as socio economically viable proposition.

INTRODUCTION

The origin of fish culture in India probably dates back to 2000 years. Possibly, fishery activity started when the human settlement moved away from the riverbanks to the hinterland. As the days went by, the Indian fish farmers practice their own indigenous technology as a common practice through natural resource management (National Commission on Agriculture, Gov. of India, 1976). The close and intimate observation of farmers through their age-old practices has developed the expertise of acquiring knowledge in aquatic ecosystem in particular. Admittedly, the multifarious knowledge and skill possessed by local people can substantially contribute to productive efforts and endeavors (Dasgupta, 1993).

INTRODUCTION

The enemies of plants have been harming the organized agriculture ever since man started depending on plants for food. Fossil evidence indicates that plants were affected by disease since 250 million years ago. Conditions of food shortage and famines have been created by these enemies of plants. Naturally, the man had been obvious of their presence and proposed explanations and methods of combating them according to the knowledge available at that time all over the world. It is not true that attention to plant diseases was first given in the western countries. In the ancient Indian literature many plant diseases and their remedies were mentioned.

INTRODUCTION

Assam is a heartland of indigenous groups. Since hundreds of years, many indigenous groups have been living in the state, maintaining their originalities in every sphere of life with difficulties. The tribal-indigenous groups constitute almost 12.4% of the total population of Assam. (Sentinelassam.com). Fishing is one of the major livelihood option of many indigenous fishers as the state is blessed with huge water resources with about 3.91 lakh hectare of water area in the form of rivers, beel, derelict water bodies and ponds and tanks. Besides swamps and low-lying areas, two major rivers and their tributaries have a high growth potential for fishing and could play a pivotal role in the socio-economic development and employment generation in the state. Indigenous fishers have developed a close and unique connection with the water resources and its environment in which they are depended for generation to generation for their livelihood. They have generated unique system of knowledge, innovation and skills relating to the uses and management of fishing activities. Over centuries, people have learnt how to get food and to survive in different environment. Farmers are very keen to observe the problems arising during fishing and seek solutions to adjust to their local environmental conditions. They continuously adapt and manage their fishing systems and in this way, they develop a rich storehouse of practical knowledge on their situation.

INTRODUCTION

Northeast India comprises the contiguous seven sister states.viz., Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland and Tripura and the Himalayan state of Sikkim. The Northeastern states of India are blessed with diversified fish fauna which assumes special interest due to the fact that the region is grained by two important drainages viz., Brahamaputra-Barak and Chindwin Irrawaddy. (Gurumayum and Choudhury, 2009). Riverine fisheries resources of Northeastern States comprise of 19,150 km of streams and rivers. Except the Brahmaputra and Barak Valleys in Assam and Imphal Valley in Manipur, the Northeast mainly comprises of Hills and Mountains which form 65% of its territory (Suguman, 1998).

INTRODUCTION

Fish is a dependable source of animal protein in developing countries like India. In recent years, with the rapid development of the aquaculture enterprises, the infectious diseases caused by fungus, bacteria, virus and parasites became more severe, resulting in huge economic losses. Due to certain unavoidable problems for diagnosing and treating diseases, losses are being born by the poor fish farmers of the country.

The issue is more relevant to rural area like north-east India, where soil and water are highly acidic due to the high content of ferrous ions and high rainfall and their management needs high inputs. The situation gets shoddier when the farmers do not get the access to water and soil laboratory to test their pond samples. It is very hard for the rural farmers to monitor their culture pond condition without any scientific tools and technical knowledge. Moreover, stresses due to over-crowding, wide temperature fluctuations, cold stress, global warming, microorganism, pesticides, insecticides, chemicals, contaminants etc.

INTRODUCTION

The medicinal values of plants are known since prehistoric times. Interestingly, 13000 BC old drawing on Lascaux caves in France suggests that humans were using plants for medicinal purposes. Ancient Egyptians chewed willow bark to relieve fever and headaches; and thousands of years later, scientists discovered that the bark contains salicylic acid- the active ingredient in aspirin. History reveals that in most of the countries natural products including plants, animals and minerals have been the basis of treatment of diseases both in human and veterinary medicines.
 
Plants as a source of medicine has been an ancient practice and is an important component of the health care system in India. The health management of people and domestic animals is based partially on the exploitation of natural resources, which needs proper documentation and research.

INTRODUCTION

The North Eastern Region of India comprises of eight states, viz., Assam, Arunachal Pradesh, Manipur, Meghalaya, Tripura, Nagaland, Mizoram and Sikkim. These north eastern states are home to myriad tribals and several ethnic groups. Most of the people of the north-eastern region of India belong to the Mongolian race and the food habit of the region is fairly similar with that of South-East Asian countries. Fermented foods form an intrinsic part of the diet of these people. Fermentation has been an age long traditional practice of preserving various food products in the region. These fermented products are used as condiments in the preparation of various traditional sauces, strews and dishes (Saisithi, 1994).

INTRODUCTION

In the emerging global knowledge economy, a country’s ability to build and mobilize knowledge capital is equally important for sustainable development like the physical and financial capital (World Bank, 1997). The basic component of any country’s knowledge capital is its indigenous technical knowledge (ITK). ITK is the social capital of the local people, their main asset to invest in the struggle for survival, to produce food, to provide for shelter or to achieve control of their own lives. It is the unique, traditional, local knowledge existing within and developed around specific condition of men and women indigenous to a particular geographical area (Ghosh and Sahoo, 2011). It helps to increase the sustainability of development efforts because of its integration process with mutual learning and adaptation, which in turn contributes to the empowerment of local communities.

INTRODUCTION

Fish are one of the main exploitable resources of the aquatic ecosystems that provide a cheap source of protein which help solving the problem nutritional security particularly NE region of the country. The rapid development of fishing technology in India during the recent years has paved the way for increased production availability of new synthetic materials, evolution of new designs of fishing crafts and gears and avoidance of ignorant harmful fishing techniques etc. It is to be taken into account that any developmental activity adopted should also be base rooted in the objective of uplifting the economy of the fishing communities. This implies that the improvisation of the existing tools and techniques and introduction of new ones to enhance fishing efficiency need a careful study of the traditional infra-technologies. Further selection of fishing methods and gear are influenced by various factors such as physiographic of the water body, nature of fish stock, characteristics of the material from which gear are fabricated and standard of living. Therefore, variation in application of fishing devices can be observed in different type of water bodies, which have characteristic of their own due to unique nature of the water resources of the region.

Introduction

North East India constitutes the states of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Tripura and Sikkim which reflects ecological and cultural contrasts between the hills and the plains. It is one of the most biodiversity regions in the world, with more than a hundred and fifty tribes forming a melting pot of variegated cultural mosaic of people and races constitute a vital component in this region (Dutta and Dutta, 2005).
 
More than 70% people of the region are engaged in agriculture while rice is the staple food crop (Bhattacharjee and Ray, 2010). The farmers from different ethnic diversity of the region have developed their own systems of cultivation of various crops (Islam et al. 2004). These indigenous traditional knowledge systems are quite endemic to this region (Deka et al. 2006).

INTRODUCTION

Traditional knowledge is the knowledge, innovations and practices of indigenous and local communities around the world. Developed from experience gained over centuries and adapted to the local culture and environment, it is transmitted orally from generation to generation. It tends to be collectively owned and takes the form of stories, songs, folklore, proverbs, cultural values, beliefs, rituals, community laws, local language. Sometimes it is referred to as an oral tradition for it is practiced, sung, danced, painted, carved, chanted and performed down through millennia. Traditional knowledge is mainly of a practical nature, particularly in such fields as fisheries, health, horticulture, forestry and environmental management in general. Appreciation of the value of traditional knowledge is growing. This knowledge is valuable not only to those who depend on it in their daily lives, but to modern industry and farming as well. Many widely used products, such as plant-based medicines, health products and cosmetics, are derived from traditional knowledge. Other such valuable products include agricultural and non-wood forest products as well as handicraft. Traditional knowledge can make a significant contribution to sustainable development.

Soil acidity is a major constraint for crop production. The production of acid in soils is a natural process, especially in the high rainfall areas. The removal of basic cations especially Ca and Mg, by leaching and erosion results in their replacement by acidic cations, H, Al and Fe on cation exchange sites and in the soil solution, which are in dynamic equilibrium with each other. Soils, that develop from weathered granite are likely to be more acidic than those developed from shale or limestone. Organic matter decay produces H+ in soils, which also contribute to soil acidity. Intensive cropping and use of hybrid & high yielding crop varieties remove large quantities of basic elements essential for their growth i.e. Ca, Mg and K & deplete the soils. Rate of acidification is also accelerated by  faulty fertilizer (especially Nitrogen) management practices.

Soil pH

Danish scientist Sorensen (1909) first used the term pH. The H+ concentration is usually small and is expressed in terms of pH, defined as the logarithm of the reciprocal of the H+ concentration, in moles per litre. The pH scale ranges from 0 to 14, with 7 being neutral. Soil acidity is the concentration of H+ in the soil solution. This is active acidity. Besides, there is a potential acidity, that includes the H+ adsorbed on the colloidal fraction of soil. The pH scale is derived from the dissociation constant of water, Kw:

Soil  is an interface of inorganic and organic componentsof the planet earth, which combines carbon and nitrogen from the atmosphere with different mineral elements of the lithosphere through millions of microorganisms, intercepting energy from the sun and moisture from the hydrosphere and atmosphere. It is a source as well as sink to adsorb, desorb, fix or release mineral elements and gases, decompose organic residues, simultaneously and support the growth of plants. All these natural processes are accompanied by runoff, percolation and evapotranspiration processes of the hydrologic cycle. Thus, soil is a dynamic body that acquires properties in accordance with the forces, which act upon it. Many soil properties emanate from physical, chemical and biologically mediated reactions, where the factors like climate, vegetation, topography and time  influences the processes. Soil reaction is one of the most important chemical characteristics of the soil solution,which has both direct and indirect effects on plant nutrition.

Acid soils are found in India in about 93 million hectares ( Table 1) and they occur in the Himalayan region, the great Indo-Gangetic and Brahmaputra plains, peninsular plateau and uplands and the coastal plains including island eco-systems under varying environmental conditions of landscape, geology, climate and vegetation. Conditions which are conducive for the formation of acid soils, such as high rainfall coupled with high temperature encouraging intense weathering and loss of alkali and alkaline earth metals with a simultaneous accumulation of iron and aluminium hydroxy compounds or the formation of free acidic substances in the humid forest foot hill regions, exist in some region or other in almost all the states in India.  A soil with pH less than 7.0 is deemed as an acid soil (Soil Survey Staff,1951). However, for characterization and classification, acid soils may be defined as those having pH less than 5.5 in 1:1 water extract (Soil Survey Staff, 1999).

Many farmer participatory field  experiments were designed and conducted in different states of India having large area under acid soils, with locally available soil ameliorants to study their effect on soil health and crop performance. This work was done during 2000 & 2005 under an ICAR network project on “Soil characterization and resource management of acid soil regions for increasing productivity”. The details of the field locations are presented in table 1.

The north eastern hill region covers a large share of acid soils of India occupying 14.95 m ha which is a major constraint for sustainable crop production. Acid soil limits the availability of calcium and phosphorus in soil, lowers base saturation and reduces microbial activities in soil adversely affecting the crop growth and yield. About 95 % of the soils of this region, except Nagaland (about 70 %) are acidic in reaction. About 84, 77, 76, 60, 57 and 47 per cent soils of Arunachal Pradesh, Manipur, Meghalaya, Mizoram, Sikkim and Tripura, respectively have soil pH below 5.0 and are considered strongly acidic (Panda, 1998). The soils are highly degraded because of heavy rainfall and removal of top soils. Land slides are also contributing towards land degradation. About 16 % of the area is affected by water erosion (www.india stat.com). About 53.8, 28.2, 42.6, 53.9, 89.2, 60, 33 and 59.9 per cent  area are degraded in Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim and Tripura, respectively. Including Assam, north-east constitutes 80 % of the total area under acid soils of the country. The land use pattern of north-east region is presented in table 1 and area, production, yield of foodgrains and fertilizer consumption are presented in Table 2.

Jharkhand state lies between 21º58’2" to 25º8’32" North latitude and 83º19’05"to 87º55’03" East longitude covering an area of about 7.97 m.ha. and accounts for  2.4 per cent of  the total geographical area (TGA) of the country. It is bound on the east by West Bengal, on the west by Chhattisgarh, on the north by Bihar and on the south by Odisha. Reliable information on the location, extent and quality of soil and land resources is the first requirement in planning for the sustainable management of land resources. The components of land i.e., soils, climate, water, nutrient and biota are organised into an eco-system, which provides a variety of services that are essential for the maintenance of the life support system and the productive capacity of the environment.

The state of Odisha located in the Coromondal coast of India has a tropical monsoon climate characterized by high humidity, high rainfall (1497 mm) and short and medium winter. It is the 10^th largest and 11th most populous state accounting about 5% of the geographical area and 4% of the population of the country. The geographical area of the state is 15.57 m ha, out of which 0.62 m ha is arable land. Agriculture contributes 28% to  state domestic production and employs 64% of the work force.

Acid soils occupy one fourth of the land in India. The formation and distribution of acid soils depend upon several factors like temperature, vegetation, parent material and hydrological conditions etc. For this reason, these soils have low pH, poor base saturation, high sexquioxide content, which affects the transformation and availability of plant nutrients.  Secondary and micronutrient deficiency as well as toxicity are major problems in cultivation of crops in acidic soils. These soils are generally deficient in Ca, Mg and S and adequate in Fe, Mn and Cu. Apart from the secondary nutrients, Zn, B and Mo deficiencies affect crop production. In lowlands, rice crop suffers from toxicity of Fe. Aluminum toxicity, common in highly acidic soils, also pose major problems in crop production. Management of secondary and micronutrients in acid soils for agriculture is a national priority to achieve food sufficiency and sustainability.

Soils become acidic due to natural  and artificial (anthropogenic) reasons. The natural reasons include their origin from acidic parent materials namely granite, rhyolite, pegmatite and dacite etc. and areas under high rainfall  (rainfall  exceeding evapotranspiration) removing  basic cations through leaching and erosion particularly in coarse textured soils with undulated, hilly and sloping topography. Under natural condition, accumulation of organic matter and its decomposition also releases organic acids into the soil system, turning soils  acidic. The anthropogenic factors    responsible for turning soils  acidic,  are (i) removal of basic cations through crop cultivation, (ii) continuous use of acid forming fertilizers and (iii) acid rain in industrial areas.

The adjustment and maintenance of soil pH at a value suitable for optimal crop production is the first step in soil management, because soil pH affects soil properties, nutrient availability and plant nutrition. In India, about 30M ha cultivated  land  suffer from high soil acidity (pH < 5.5). These soils are critically degraded and are of poor health producing crop yields, which are often less than 50% of that in normal soils. Due to this, farmers use much less fertilizers for crops (50 to 80 kg NPK ha^-1), since this is not profitable.

Livestock production is an integral part of agriculture and plays a significant economic role in most developing countries. It contributes to poverty alleviation, food security and provides elements that are essential to the national economy. Livestock production accounts for 40% of the gross value of the agricultural production globally and this figure is likely to go up, as the demand of livestock products is increasing rapidly with the increase in income and urbanization (FAO, 2012). For poor farmers, animal ownership ensures varying degrees of sustainable development and economic stability. Livestock provide a stable cash reserve independent of inflation and are an important source of traction. Livestock are closely linked to the social and cultural lives of several million people. Quality and quantity of feed is essential for optimum animal productivity. Inadequacy of quality animal feed resources is most often the crucial factor for livestock production. The success of livestock is greatly dependent on continuous supply of good quality nutritious feed at competitive price. Poor nutrition of animals has been identified as the major constraints to animal production across the developing world (FAO, 2000). Feed is the major input cost in animal production system, accounting for 65-70% of the total rearing cost.

Silage is the material produced by controlled fermentation of forages or crop residues with high moisture content. The objective of silage making is to preserve the harvested forages by anaerobic fermentation in which soluble carbohydrates are converted into acids. Due to acid produced, pH of a well-ensiled product becomes so low that all life processes come to a halt and the material remain preserved so long as it remains in airtight storage. Soluble carbohydrate present in forage is converted to lactic acid which drops the pH to a level sufficient to inhibit any further biological activity in the ensiled forage mass (McDonald, 1991). Fresh forage crops, such as maize, grasses, legumes, wheat and Lucerne, can be preserved by ensiling. It is essential to have a good microbial fermentation process to produce high quality silage. Good silage is achieved by discouraging the activity of plant enzymes and undesirable micro-organisms and encouraging the dominance of lactic acid bacteria. A good fermentation process is not only dependent on the type and quality of the forage crop, but also on the harvesting and ensiling technique. Silage-making is a managemental tool that allows producers to match feed resources (forages, crop residues, agro-industrial byproducts, etc.) with feed demand for a dairy herd.

Ensiling is the term given for all physical and chemical changes that take place when forage with sufficient moisture content (60-65%) is stored in the absence of air for silage preservation. Silage fermentation is an exceptionally complex process involving biochemical interactions among the forage, microbial populations and the ensiling environment. Successful silage production depends upon the promotion of the fermentation brought by beneficial bacteria. The process is based on spontaneous lactic acid fermentation under anaerobic conditions. The lactic acid bacteria ferment the water-soluble carbohydrates in the crop to lactic acid, and to a lesser extent to acetic acid. Due to the production of these acids, the pH of the ensiled material decreases and spoilage micro-organisms are inhibited. The ideal characteristics of material for silage preservation are: DM content above 20% and an adequate level of fermentable substrate (8-10 percent of DM) in the form of water soluble carbohydrate. The ensiling material should also ideally have a physical form that allows easy compaction in the silo. Materials such as maize stover, sorghum stover and grass can be ensiled successfully, while crop residues such as rice and wheat straw, with low water soluble content, do not fulfill these requirements, and therefore pre-treatments, such as fine chopping or use of additives, or both, may be necessary.

A silo is an airtight to semi-airtight structure designed for the purpose of preservation and storage of high moisture feeds as silage.
 
Role of the silo in silage making

Silo has only three functions in the ensiling process:
    1.    To provide a solid surface to permit compaction of the mass to eliminate air;
    2.    To protect the ensiled materials from air and water during the storage period;
    3.    Where desired, to aid in the removal of silage by providing a base for unloading equipment.

Successful preservation of high-moisture forage and other crops depends upon the controlling the activities of microbes, particularly bacteria. Ensiling generally controls microbial activity by a combination of an anaerobic environment and a natural fermentation of sugars by lactic acid bacteria on the crop. The silage microflora plays a key role in the successful outcome of the conservation process. Therefore, it is important to understand both the microorganisms that are present on the crop at ensiling and how ensiling preserves the crop, inhibiting detrimental microorganisms. The crop at ensiling contains both aerobic and anaerobic microorganisms and a range of both bacteria and fungi that affect silage quality.

Silage fermentation is a complex process involving biochemical changes by microbial populations and the ensiling environment. The chemistry and microbiology of silage fermentation are linked, but the microorganisms are the dominant factor in the fermentation process, and they have the main influence on the quality of the end product. Many species of microorganisms are involved in the fermentation process, and their relative importance varies according to the prevailing conditions. As these conditions change during the fermentation process, the microorganism population changes accordingly. Lactic acid bacteria and clostridia are two main categories of microbes responsible for biochemical changes in silage.

Silage fermentation is a dynamic process that is affected by variety of factors. The primary goal of making silage is to maximize the preservation of original nutrients in the forage crop for feeding at a later date. Unfortunately, fermentation in the silo is a much uncontrolled process usually leading to less than optimal preservation of nutrients. In order to assist in the fermentation process, various silage additives have been used to improve the nutrient and energy recovery in silage, often with subsequent improvements in animal performance (Henderson, 1993; Bolsen et al., 1996; Muck and Kung, 1997; Kung and Muck, 1997; Muhlbach, 2000). Their main functions are to either increase nutritional value of silage or improve fermentation so that storage losses are reduced. The benefits obtained from silage additives depend upon their influence on the silage fermentation process. These benefits are usually measured by the reduction in fermentation losses and/or improvement in silage quality and feeding value.

Quality of silage is determined by nutrients content and intake potential of the silage. High quality silage is a stable feed, made from high quality pasture, which is preserved in the absence of oxygen by a high quality fermentation, to minimize any loss of feeding value. It is not possible to produce high quality silage from low quality pasture, no matter how good the fermentation is. The silage quality is generally used to indicate the success of fermentation and not to evaluate the feeding value of the silage. However, the fermentation quality and nutritional value of the silage are usually highly correlated because a poor fermentation can result in great loss of the digestible nutrients (Sutoh et al., 1970; Uchida and Sutoh, 1973). Therefore, both the quality of the ensiled pasture and the quality of the fermentation must be considered.

Silage fermentation is a dynamic process involving interactions among the forage, microbial populations and the ensiling environment. A good fermentation process is not only dependent on the type and quality of the forage crop, but also on the harvesting and ensiling technique. There are various factors that influence the fermentation process and ultimately the nutrient composition and quality of ensiled feed. These are as follows:

1. Plant Factors

Forage characteristics at the time of ensiling are the predominant factor which determines the final quality of silage. Factors such as type of forage to be ensiled, maturity, DM content and WSC content of that forage, all influence the ease of ensiling and ultimately the quality of silage that is produced.

It is recognized in developed countries that the production of silage of high quality cultivated forage can be a valuable component for the development of a high-performing and low-cost system of animal production, using a relatively low level of purchased concentrates. However, this appears inappropriate for smallholders in tropical countries, primarily due to lack or high cost, or both, of equipment for harvesting and conservation and production of cultivated forage being often limited due to lack of available land. Many agricultural, agro-industrial and fishery by-products have potential as animal feeds. Most farmers in developing countries rely for their food security on the cultivation of cereals, root crops and high-value crops such as fruits and vegetables, which understandably take priority in the allocation of land. Fruit, vegetables and root crops are increasingly integrated in the farming system and play a key role as staples in the human diet in most developing countries.

Objective of the conservation of forage is to preserve as much as of the crop nutrient as possible. However, during ensilage loss of nutrients occurs. There are five sources of loss. Theses are:
 
    (a)    Field losses 
    (b)    Oxidation or respiration losses 
     (c)    Fermentation losses
    (d)    Effluent losses 
    (f)    Aerobic deterioration

Feeding silage is also an important part of the process. Silage can be fed to all kinds of animals. Silage is suitable for feeding 6-7 weeks after ensiling. Purposes of silage feeding are drought feeding, production increases, an aid to pasture or crop management, utilization of excess growth, balancing nutrients in the diet, and the storage of wet feed products. Silage is most likely to be profitable when used to increase productivity or balance nutrient content of the diet.
 
Feeding value of silage is defined as the product of the nutritive value and potential voluntary intake of the forage (Wheeler and Corbett, 1989).

Forage preservation as silage is a key component of high input (zero-grazing) systems (Mannetje, 1999). It has allowed producers to intensify the productivity of the land and the productivity of the livestock. Large quantities of forage can be conserved in a short time, forage conservation is less weather dependent and thirdly, silage is well suited to mechanization. However, a major disadvantage associated with silage making is that the feeding value of the resultant forage is reduced relative to that of the original crop. Ensiling offers many advantages over haymaking.

Feeding of green and succulent fodder is of utmost importance to farm animals. Grazing fresh forage year round at the optimal stage of maturity would supply the highest quality and most palatable form of feed in any livestock operation. In most part of the world, green fodder is limited to a particular season only. Because of fluctuations in seasonal growth and plant maturity, excessive biomass in the spring, it is necessary to harvest and store forages to maximize both quality and productivity. One of the important form of conservation practiced on a wide scale is hay making. Hay making is an art in which the fodder is kept for future use in lean period. Since it contains large quantity of moisture it is to be dried properly to increase its keeping quality without reducing its nutritive value. The objective of hay making is to achieve a rapid moisture loss after cutting so that the forage can be romoved from the field with minimum losses from weathering and microbial degradation (Bareebam, 1992).

Hay quality really means feed value. The ultimate test of hay quality is animal performance. Quality can be considered satisfactory when animals consuming the hay give the desired performance.
 
Characteristics of Good Quality Hay

    1.    Hay should be nutritious therefore prepared form plants cut at an appropriate stage of maturity when it has the maximum nutrients.
 
    2.    Good hay should be leafy. The leaves are generally richer in proteins, minerals and vitamins then other parts of the plant.

    3.    Hay should be green in colour. The green colour indicates the amount of carotene which is precursor of vitamin A. The green colour should be preserved by minimizing the bleaching, leaching arid fermentation losses.