eChapters

ABSTRACT

Survey and research trial conducted for the selection of promising tree based farming system in Paonta valley region of H.P. have been summarized in the manuscript. Tree based farming innovations with intercropping, their planting technology and geometry around field/ farm, pure plantation , block plantation of trees grown with agricultural/fruit crops for better productivity per unit of land have been suggested for improving socio-economic condition of the regional farmers.

ABSTRACT

A long term study was conducted to evaluate different aonla based silvipastoral systems for compatibility, productivity and conservation effects. Three grass species viz. dholu, hybrid napier and perennial arhar were evaluated for 14 years for degraded lands of Shivaliks. Hybrid napier because of its vigour growth adversely affected the growth of aonla but effect on yield turned non-significant. Arhar could survive only during pre-bearing state. Studies on soil losses and runoff for decades showed that Embilica officinalis + Chrysopogon fulvus was the best silvipastoral system for soil conservation. This system saved rainwater and soil in a range of 4.88 to 30.66 cm and 862-2818 kg ha^-1 respectively over sole plantation. The combination of Embilica officinalis + Chrysopogon fulvus proved to be the most effective silvipastoral system for reclamation of degraded lands and improving economic status of people in Shivalik foot hills.

ABSTRACT

Tree component of agroforestry systems produce large biomass of varying nutrient concentration to serve as alternative to inorganic fertilizers under integrated nutrient management or organic farming. Additionally, agroforestry systems proved effective in conserving soil and rainfall and brought down soil loss up to 0.2 t ha^-1 and runoff up to 1.8 per cent of rainfall. Introduction of grasses in aonla conserved up to 31 cm of rainwater, 28 q ha^-1 of soil, 11 kg ha^-1 of N and 2 kg ha^-1 of K₂O. Conservation coupled with ameliorative capacity of agroforestry systems helped in building organic carbon and nutrients and improving soil physical, chemical and biological properties.

ABSTRACT

The lower Shivaliks of Jammu and Kashmir comprise 12% of the total area of Jammu region. The productivity of the soils is not only low but highly unstable. High intensity monsoonal rains coupled with rolling topography, low organic matter and coarse nature of the soils are primarily responsible for soil erosion in the region. Soil loss due to erosion depletes the soil nutrients and, is primarily responsible for land degradation, low productivity and poor economic status of the farmers in the region. Further, the adoption level of the farmers regarding modern conservation techniques is also low. Though soil erosion can be controlled or minimized through agronomical and/or mechanical techniques but agroforestry intervention is one such option which can be used for managing the land in the problematic conditions. Agroforestry systems have proven potential of conserving soil and water besides enrichment of soil through biomass additions. Agroforestry systems, therefore, help curtail soil erosion both by intercepting the rain and minimising its erosivity as well as by reducing the erodibility of the soil. Tree based cropping systems enhance the organic content in soils and therefore, create more stable aggregates, which provide more resistance to erosive forces. The chapter discusses the importance of agroforestry in the fragile Shivaliks of Jammu and Kashmir and suggest how to conserve and restore degraded lands in the region.

ABSTRACT

The paper discusses the problems of soil and water erosion in the Shivalik foot hills and suggests strategies for improved land use planning and the role bamboo species can play in mitigating the problems. The paper also discusses the various bamboo species of the Shivalik foothills, their regeneration, planting practices, management and utilization pattern in detail.

ABSTRACT

The Shivalik range of Himalayas, represent the most fragile ecosystem in India. In order to see the impact of land treatment, five hilly micro watersheds typical of the region having catchment area from 0.813 to 4.750 ha were selected for study. All the five watersheds were brought under study during 1966. Temporal changes in water yield from hilly catchments of Shivalik were monitored for twenty eight years (1966-1993). The watersheds were treated with annual burning (LT1), contour trenching +afforestation (LT2), cutting of trees, shrubs and over grazing (LT3) and over grazing alone (LT4). One watershed (LT5) was kept as control without any interference. As a result of burning, cutting and grazing there was significant increase in runoff as well as peak flow in the initial years, however, after increase in vegetation through protection from 1977 onwards resulted in decrease in runoff and soil loss.

ABSTRACT

Among the challenges of 21^st century, to make the food supply sustainable, the impact of climate change is largely unconceivable. The climate on earth has increased by 0.74° C over the past 100 years. Best estimate for low scenario of global warming is 1.8°C and for high scenario is 4°C. Last decade recorded the hottest in the century and 2009 has been rated hottest since 1900. Retreating glaciers have been confirmed in various parts of the world. Further, the current greatest challenge is to perceive the biological impact of such climate changes. Efforts have been initiated by Intergovernmental Panel on Climate Change (IPCC) to assess the impact of climate change on biological systems across the globe. Since 1950’s, the change in carbon dioxide content in the atmosphere is being monitored. Almost a decade later, computer models were employed to assess the possible impact of change in temperature and enhanced CO₂. By the 1980’s consensus was almost achieved on possible doubling of atmospheric CO₂ concentration due to emission from fossil fuels and rise in the global temperature. Since then quantitative estimates on the biological impacts of climate change have been taken up by scientific community world wide. Presently, ample of evidence on impact of climate change from marine to terrestrial environment, from species to communities, ecosystems and hierarchies have been gathered for both flora and fauna (Walther et al., 2002I). Parmesan and Yune (2003) reported that meta-analyses of 334 species and global analyses of 1,570 species revealed highly significant and regular patterns of change in relation to observed warming with more than 95 per cent confidence, as fingerprints of climate change.

ABSTRACT

Chamba and Kangra districts of Himachal Pradesh are abode to vast natural diversity. The people of the area had developed varied traditionl approaches to live with the nature so that natural resources can be protected for their sustained use. The present paper enumerates some of the ecofriendly life styles, agroforestry systems and water use practices being adopted by the farmers of the region.

ABSTRACT

The increasing level of green house gases in general CO₂ in particular has raised concerns about the vulnerability of human, animal and plant life. These concerns have prompted the Governments world over to take the appropriate measures to save them from perspective destruction. Forests though serve as source and sink of the CO₂, there is need to synthesize the impact of climate change on forests and the role of forests in global carbon cycle. Climate change needs to become part of decision making in forest management. Also, the agroforestry, a potential carbon sequestration activity is lagging behind, there is a growing interest in it in countries that have not only ratified Kyoto Protocol but also facing many other ecological problems on their private working land. The Clean Development Mechanism (CDM) offers benefits through sink credits and reduces the negative impact of climate change, therefore, necessary institutional arrangements should be put in place to use CDM projects effectively for generating resources through afforestation and reforestation projects for the well being of present as well as future generation. Forest/agroforestry scientists/managers need to realize the current degree of vulnerability and start thinking about their ability to cope with the impacts. Governments have initiated negotiations on policy actions to reduce the green house gases and addressed the vulnerabilities of the ecological, economic and social systems to climate change. It may be one of the least expensive ways for industries to off-set their carbon emission and tree growers to benefit through the carbon trade. Despite the fact that the certain aspects under Kyoto Protocol are still under clarification and negotiation, the forest plantations will play an important role in carbon sequestration and the implementation of Kyoto Protocol. Since the development of plantation is a slow process, the dividends will only be realized after a gap therefore the new plantation should be taken up without delay and the old one be managed as per their silvicultural rotation.

ABSTRACT

North-Western Himalayas have a large area which are degraded and bouldry. Such areas are not fit for crop production. These areas are generally kept unutilized and hence are invaded by uneconomic and invasive species. These lands can be brought under production though establishment of silvipastoral system which has a potential of fodder, fuel and timber production besides conserving natural resources. The paper discusses the techniques of establishment, management and production potential of silvipasture systems in north-western Himalayas.

Agriculture is derived from two Latin words Ager and Cultura. Ager means land or field and Cultura means cultivation. Therefore the meaning of the word agriculture is cultivation of land.

Definitions

Agriculture is defined in the Agriculture Act, 1947, as ‘‘including horticulture, fruit production, seed production, dairy farming and livestock breeding/keeping, the use of land as grazing land, meadow land, osier land, market gardens and nursery grounds, and the use of land for woodlands where that use is ancillary to the use of land for other agricultural purposes”.

Agriculture is defined as ‘purposeful work through which elements in nature are harnessed to produce plants and animals to meet the human needs’. It is a biological production process which depends on the growth and development of selected plants and animals within the local environment.

Agriculture is defined as the art, the science and the business of producing crops and the livestock for economic purposes.

As an art it embraces knowledge of the way to perform the operations of the farm in a skillful manner, but does not necessarily include an understanding of the principles underlying the farm practices. The skill is categorized as;

Physical skill: It involves the ability and capacity to plough the field in an efficient and quick manner, handling of farm implements, animals, sowing of seeds, fertilizer and pesticides application etc., For example: Taking a straight furrow.

Mental skill: It involves the ability of the farmer to take a decision based on his experience, he decides the correct and accurate timing of operation, such as i) time and method of ploughing ii) selection of crop and cropping system to suit soil and climate, iii) adoption of improved farm practices.

History is the continuous record of past events

Heritage is the inherited values carried from one generation to other generation

Agricultural heritage refers to the values and traditional practices adopted in ancient India which are more relevant for present day system.

Agricultural Heritage in India

Agriculture in India is not of recent origin, but has a long history dating back to Neolithic age of 7500-6500 B.C. It changed the life style of early man from ‘nomadic hunter of wild berries and roots’ to ‘cultivator of land’. Agriculture is benefited from the wisdom and teachings of great saints. The wisdom gained and practices adopted have been passed down through generations. The traditional farmers have developed the nature friendly farming systems and practices such as mixed farming, mixed cropping, crop rotation etc. The great epics of ancient India convey the depth of knowledge possessed by the older generations of the farmers of India. The modern society has lost sight of the importance of the traditional knowledge which had been subjected to a process of refinement through generations of experience. The ecological considerations shown by the traditional farmers in their farming activities are now-a-days is reflected in the resurgence of organic agriculture.

The word agronomy has been derived from two Greek words, agros and nomos having the meaning of field and to manage, respectively. Literally, agronomy means the “art of managing field”. Technically, it means the “Science and economics of crop production by management of farm land”.

Definitions

Agronomy is the art and underlying science in production and improvement of field crops with the efficient use of soil fertility, water, labour and other factors related to crop production.

Agronomy is defined as “a branch of agricultural science which deals with principles and practices of field crop production and management of soil for higher productivity.

In general crop is an organism grown or harvested for obtaining yield. Agronomically crop is a plants cultivated for economic purpose.

Classification of Crops

Classification is done to generalize similar crop plants as a class for attaining better understanding of them. Field crops are classified in the following ways.

1. According to range of cultivation
2. According to the place of origin
3. Botanical classification
4. Commercial classification
5. Economic / Agricultural / Agrarian classification
6. Seasonal classification
7. Classification based on ontogeny

Internal Factors

The increased yield and other desirable characters are related to the genetic make up of the plant. They are :

• High yields under given environmental conditions.
• Early maturity (in some cases late maturity).
• Resistance to lodging.
• Drought, flood and salinity tolerance.
• Tolerance to insects and diseases.
• Chemical composition of grains (high percentage of oil, increase in protein quantity or quality, etc.)
• Quality of grains (fineness, coarseness, etc.)
• Quality of straw (sweetness, juiciness, etc.)

Soil is defined as the thin layer of earth’s crust made up of disintegrated and decomposed rocks, complex mineral compound, organic matter, water/air and living organism like bacteria, fungi, insects and worms and serves as the natural medium of growth of plants.

• It provides nutrients, moisture, anchorage (support) and provides air to root system.
• There are different soil groups found in varied regions of India.
• Each group differs from other in physical and chemical properties.
• The variation in behaviour is mainly due to the nature of the parent material from which the soils are formed.
• Parent materials are Igneous rocks, sedimentary rocks and metamorphic rocks.
• Physical properties like structure, texture, colour, water holding capacity, depth etc. are to be noted. Chemical properties like the presence of various plant elements, pH, EC, CEC, acidic or alkaline, etc. are considered.

Agricultural Seasons

Season is defined as “part of the year during which a distinguished type of weather prevails”.

A) Seasons of Temperate region

1. Spring (March – May) is the first season of the year in which plants being to grow and leaves emerge.
2. Summer (June – August) is the second and warmest season of the year out side the tropics during which plants flourish
3. Fall or Autumn (September – November) is the third season of the year in which leaves turn brown.
4. Winter (December – February) is the last and the coldest season of the year. Many trees loose their leaves.

For better understanding of different systems of farming it is essential to study certain terminologies.

Farm is a piece of land with specific boundaries, where crop and livestock enterprises are taken up under a common management.

Farming is the process of harnessing solar energy in the form of economic plant and animal products or it is the business of cultivating land, raising livestock etc.

System refers to an orderly set of interdependent and interacting components none of which can be modified without causing a related change elsewhere in the system.

There are three district systems of farming as wetland system of farming, garden land (irrigated dry land) system of farming and dryland system of farming.

Wetland: Pertaining to soils flooded or copiously irrigated through lake or pond or tank for a least several weeks in each year (or) to crop growth in such soils. The water is not entirely under the control of the farmer.

Tillage operations in various forms have been practiced from the very inception of growing plants. Primitive man used tools to disturb the soils for placing seeds. The word tillage is derived from the Anglo-Saxon words tilian and teolian, meaning to plough and prepare soil for seed to sow, to cultivate and to raise crops. Jethro Tull, who is considered as father of tillage suggested that thorough ploughing is necessary so as to make the soil into fine particles.

Seed is a fertilized ripened ovule consisting of three main parts namely seed coat, endosperm and embryo which in due course gives rise to a new plant. Seed is the nucleus of life. Endosperm is the storage organ for food substance that nourishes the embryo during its development. Seed coat is the outer cover that protects or shields the embryo and endosperm.

Importance

Plants reproduce sexually by seeds and asexually by vegetative parts. Grains which are used for multiplication are called seeds while those used for human or animal consumption are called grains. Good stalks of planting materials are basic to profitable crop production. The seed or planting material largely determines the quality and quantity of the produce. A good seed or stalk of planting material is genetically satisfactory and true to type, fully developed and free from contamination, deformities, diseases and pests.

Crop Stand Establishment

Good crop establishment is one of the most important features in better crop production. The better crop establishment is in turn expressed as optimum plant population in fields.

Plant population is the number of plants per unit area in a cropped field. It indicates the size of the area available for individual plant.

Optimum Plant Population

It is the number of plants required to produce maximum output or biomass per unit area. Any increase beyond this stage results in either no increase or reduction in biomass.

Crop geometry is the pattern of distribution of plant over the ground or the shape of the area available to the individual plant, in a crop field.

Weeds are the plants, which grow where they are not wanted. Jethro Tull (1731) coined the word weed. Weeds can also be referred to as plants out of place.

Definition

Weeds are unwanted and undesirable plant that interfere with utilization of land and water resources and thus, adversely affect crop production and human welfare.

In organic agriculture weeds are treated as childrens of the soil.

In the world 30,000 species of weeds have been listed, of which nearly 18,000 cause serious damage to agricultural production. Eighteen weeds are considered as the most serious in the world and about twenty six species have been listed as principal weeds in crop fields of India, and are listed in annexure V

Irrigation

Irrigation is defined as the artificial application of water to the soil for the purpose of crop production in supplement to rainfall and ground water contribution.

Time of Irrigation

The time schedule which indicates when irrigation water is to be applied and the quantity of water to be applied at that time is called irrigation schedule. There are several approaches for scheduling irrigation:

1. Soil moisture depletion approach based on the available soil moisture in the root zone.
2. Climatological approach based on the amount of water lost by evapotranspiration.
3. Combination approach based on soil moisture depletion and climatological approaches.
4. Critical stage approach which indicates the growth stages at which moisture stress leads to yield loss. These stages are known as critical period or moisture sensitive period. In cereals and millets panicle initiation and flowering stages are moisture sensitive stages. In pulses and oilseeds, flowering and pod development stages are critical stages. In sugarcane active tillering or formative stage is critical and in cotton boll development is the critical stage.

Growth is the development of a plant as a whole or of a specific organ. Besides the genetic factors, the environmental factors grouped as climatic factors and soil factors influence plant growth. The supply of mineral nutrient elements to the plants is discussed in this chapter.

A complete analysis of plants detects large number of elements. But only certain elements are essential. An element is said to be essential if the plant cannot complete its life cycle without it, and if the malady (deficiency) that develops in plants in its absence can be remedied only by that element.

Earlier 16 elements were considered as essential for plant growth. They are carbon, hydrogen, oxygen, nitrogen phosphorus, potassium, calcium, magnesium, sulphur, iron, manganese, zinc, copper, molybdenum, boron and chlorine. Recently, sodium, cobalt, vanadium, silica, selenium, gallium, aluminium and iodine are added to the above list. One or the other of these elements (recently added) has been found to be essential for a particular species of plants.

Carbon dioxide, water and molecular oxygen are the forms in which C., H and O are assimilated by plants. Others are taken up by plants from the soil. Nutrient uptake by plants accounts for about 10 percent of total dry weight of crops, the remaining percentage being water. The chemical symbol and the ionic forms in which the essential elements are absorbed by the plants are as follows.

Harvesting: “Removal of entire plant or economic parts after maturity from the field" is called harvesting. It includes the operation of cutting, picking, plucking or digging or a combination of these for removing the useful part or economic part from the plants / crops. The portion of the stem that is left in the field after harvest is called as stubble. The economic product may be grain, seed, leaf, root or entire plant.

Harvest Index: (H.I): It is the ratio of the economic yield to the total biological yield expressed as percentage.

H.I = Economic yield / Biological yield x 100

Time of Harvesting: If the crop is harvested early, the produce contains high moisture and more immature ill filled and shriveled grains. High moisture leads to pest attack and reduction in germination percentage and impairs the grain quality.

Late harvesting results in shattering of grains, germination even before harvesting during rainy season and breakage during processing.

Abstract

Based on oxygen requirement, microorganisms have been classified into different groups, like facultative anaerobes, micro-aerophilic, aerotolerant and strict/obligate anaerobes. Obligate or strict anaerobes are the key components of anoxic environments and provide valuable ecosystem services like methanogenesis, sulphate reduction, metal reduction, degradation of pollutants etc. Apart from being valuable for the ecosystem, they are causative agents of human infections. They are the key players of human-gut microbiology, and can be used in bio-toilets, solid waste management, anaerobic digestion of waste, wastewater treatment processes and generation of waste to energy etc. Only few anaerobic microorganisms are pathogenic in nature. A mechanistic understanding about physiology and metabolism of anaerobic microorganisms is imperative for their industrial applications. Cultivation of these organisms is the first and very important step for the basic and applied study of anaerobes. Unlike cultivation of aerobic microorganisms anaerobic cultivation needs special care and facilities for successful handling of anaerobes. In the current chapter, We tried to incorporate the components and technicalities of anaerobic pre-reduced media preparation, cultivation and successful isolation of strict anaerobes. In addition, we also tried to discuss the different tools used for cultivation of anaerobes.

Abstract

Microbes are key ingredients of various ecosystems and backbone of modern biotechnology and industry. In addition to their cultivation, purification and characterization, preservation of microorganisms is equally important. Different preservation methods and protocols have been developed for long term preservation of microbes. Microbial Resource Centers (MRCs) are providing active services in the field of life sciences. National Centre for Microbial Resource (NCMR) at National center for Cell Science (NCCS), Pune is one of the MRCs. Unlike aerobes little work has been done in the area of cultivation and preservation of anaerobic microbes. In the previous chapter we have discussed the technicalities and problems of anaerobic cultivation. The aim of current chapter is to provide the recent overview of preservation of anaerobic microorganisms like methanogens, sulfate and metal reducers and the obligate anaerobes of clinical and industrial importance with fermentative mode of life style.

Abstract

Anoxygenic phototrophic bacteria (APB) are having the genetic potential of converting radiant energy into chemical energy useful for growth and metabolic activities without evolving oxygen. They are physiologically, metabolically and phylogenetically versatile group of organism spread in five distinct phyla; Proteobacteria (purple bacteria), Chlorobi (green-sulfur bacteria), Chloroflexi (green non-sulfur bacteria), Fir micutes (heliobacteria) and Acidobacteria. Different group of APB harbors distinct photosynthetic pigments, carotenoids, and a photosynthetic reaction center. These group of bacteria succeeds in a natural environment with light availability and presence of anoxic conditions as the pigment, and the molecular oxygen inhibits bacteriochlorophyll synthesis whereas few APB can grow in hypooxic as well as in aerobic conditions. Calvin-Benson-Bassham (CBB) pathway, reverse tricarboxylic acid (rTCA) cycle, and hydroxypropionate cycle are reported pathways for carbon assimilation in APB to fix carbon dioxide. Photosynthesis occurs in either intracytoplasmic membrane (ICM) or membrane bound chlorosomes and in the cytoplasm for few APB. APB have a wide range of potential applications including removal of H₂S from wastewater and gas streams, hydrogen production, degradation of xenobiotic, toxic metals and radioisotopes, work as host for the production of challenging membrane proteins, source of carotenoids and terpenoids, single cell protein, extensive applications in agriculture and production of bioactive compounds with antimicrobial, antioxidant and anticancer activity. The chapter is focused on the diversity of different types of APB, habitats, their growth requirements, photosynthetic machinery and biotechnological applications of APB.

Abstract

The anaerobic fungi are one of the early organisms in evolution which are commonly found in the digestive tract of ruminating and non-ruminating animals, (including herbivores) deep sea and earth, dumping sites, etc. In animals, these are considered the primary colonizers of the plant biomass ingested by them. Still their taxonomy was unclear for a long period of time. However, with the help molecular techniques, they are now classified under a separate phylum Neocallimastigomycota. There are 38 species known so far belonging to 11 genera. These have been identified based on both morphological data (like thallus, rhizoids, flagella per zoospore, etc.) and phylogenetic analysis. There is a need to explore the undiscovered anaerobic fungi and look for their potential in industrial applications and solutions to the present environmental problems. It can be achieved by improving techniques of sampling, isolation, maintenance and long term preservation. Animals like herbivores do not have the ability to produce enzymes for degrading the plant biomass and anaerobic fungi help them by producing a range of extracellular enzymes. This ability of anaerobic fungi are of use to humans in bioenergy (biogas production) and biomass degradation (by producing cellulases). Recent advances in metagenomics coupled with new methods of cultivation are helping immensely to know the uncultivated anaerobic fungal populations from the animal gut. The present book chapter discusses the past and present of anaerobic fungi, lacunaes and need for more work on this group of fungi, It focuses on the progress in sampling, isolation and preservation techniques, simultaneously discussing the advances in the application these fungi in biotechnology.

Abstract

Microorganisms that produce methane as their metabolic end product are known as methanogens. Methanogens are prokaryotic, unicellular, obligate anaerobes having fastidious growth requirements making them difficult to isolate and preserve. They catalyse the terminal step in anaerobic breakdown of organic substances. Even though methanogenic archaea or methanogens show very limited metabolic diversity, they are one of the most phylogenetically and ecologically diverse group of Archaea. Methanogenic community varies greatly with respect to temperature. Methanogens have been reported from permanently frozen habitats like permafrost to hyperthermophilic environments such as hydrothermal vents. However, the metabolic and phylogenetic diversity of methanogens in these habitats vary greatly. Methanogens are the biocatalysts, having the ability to provide a solution to help solve energy crisis by producing methane as storable energy carrier. Methane being a flammable gas, can act as a clean and renewable source of energy. The biogenic methane gas thus produced may serve as an efficient alternative for fossil fuels in the future.

Abstract

Methane is the second most important green-house gas and has a major role in global warming. Aerobic oxidation of methane is known for more than 100 years. Anaerobic methane oxidation (AOM) was recently discovered before ~25 years, first in marine sediments. The first discovered AOM was found to be mediated by anaerobic methanotrophic archaea (ANME) in association with sulphate reducing bacteria (SRB) and termed as sulphate dependent anaerobic methane oxidation (S-DAMO). Three main groups of ANME are present which perform methane oxidation by reverse methanogenesis pathway. Later on, methane oxidation by using nitrate or nitrite as the electron acceptor was discovered from a freshwater sediment. N-DAMO or nitrate/ nitrite dependent AMO can be carried out by an archaeal or a bacterial member, respectively. Members of Ca. Methylomirabilis oxyfera are bacteria, and use nitrite as the electron acceptor and methane monooxygenase to carry out methane oxidation. Whereas, members of Ca. Methanoperedens nitroreducens are archaea, and use reverse methanogenesis coupled to nitrate reduction. Metals like FeIII or Mn IV can also be used as electron acceptors for AOM, a process recently discovered (M-DAMO). In this case, one archaeal partner and one bacterial partner could be involved, although more research is going in this area. S-DAMO is the main methane oxidation process in the marine sediments and accounts for the major methane oxidation in the marine sediments. In fresh water sediments, aerobic methane oxidation and processes like N-DAMO seem to play an important role.

Abstract

Anaerobic sulfur compound reduction processes make use of sulfur, thiosulfate, trithionate, tetrathionate, and sulfite during the reduction process. Complete reduction of these sulfur compounds leads to production of H₂S. Isolation of sulfur compound reducers requires a suitable electron donor and one of the sulfur compound as a sole electron acceptor during the reduction process carried out in anaerobic conditions. Anaerobic sulfur, thiosulfate and tetrathionate reductases identified to date are molybdopterin binding oxidoreductases that extract out electron during the reduction process. The electron transport chain during the reduction process involves cytochromes and menaquinones. Dissimilatory sulfite reductases include conventional siroheme dissimilatory sulfite reductase and the nonconventional sulfite reductases including ASR sulfite reductase, F₄₂₀ dependent sulfite reductase and the MccA sulfite reductase. Anaerobic sulfur compound reduction process are almost ubiquitous in nature and are important part of the biogeochemical cycle. They occurs in aquatic systems, are found in extreme environments such as hydrothermal vents, acid mine drainage sites and are also found in important human and animal pathogens.

Abstract

Grazing animals have developed symbiotic relationship with anaerobic microorganisms, which survive in their rumen and help in the oxidation of complex molecules of feed containing lignocellulosic materials into volatile fatty acids. The consortium comprises anaerobic bacteria, fungi and protozoans. The rich microbial diversity of rumen remains constant after its establishment and does not get affected by intruding contaminants along with feed or water. The rumen contains a wide range of microbes such as Fibrobacter spp., Ruminococcus spp., Clostridium spp., Prevotella spp., Eubacterium spp., Methanobacterium spp., Treponema sp. Lachnospira sp., Bacterioides s pp., fungi: Anaeromyces s pp., Neocallimastix spp., and protozoa: Enoplastron sp., Eudiplodinium spp., Ostracodinium sp. They often have a variety of enzymes, glucanases, xylanase, glucuronidase, pectinase and amylase, etc. These enzymes inhabit the microbes and even break down complex molecules into simpler forms like; glucose and volatile fatty acids. The present chapter discusses on the role of microorganisms of rumen.

Abstract

Hydrogen synthesis from bioprocesses a good approach for generation clean of fuel for world's development. Throughout the ancient and current periods, most of the developmental activities are completed by consumption of non-renewable fossil fuel energy that which has resulted in multiple environmental issues or challenges (Climate change and pollution by toxic gases or byproducts formation) at global level. Biohydrogen synthesis from anaerobic bacterial fermentation could be a good effort for sustainable energy production without any toxic byproduct formation. For production of hydrogen, lignocellulosic material can be utilized as cheap raw substrates. This would help the farmers in providing surplus benefits to farmer for their agriculture residues that normally burnt and cause the serious air pollution. Utilization of agro-waste residues can help in development of sustainable biofuels for world energy need. Burning of agrowaste residues by farmer's can be discouraged via utilization as raw carbon substrates thereby reducing air pollution.

Abstract

Rise in global energy demand has led to an increase in consumption of fossil fuels. In recent years, there has been an increasing awareness about the consequences of pollution and global warming caused by burning of fossil fuels. This has led to an increased interest in the search for sustainable energy. Transportation sector is a major consumer of world’s energy resources. n-Butanol is one of the most promising alternative bio-fuels which has various advantages over other biofuels. The microbial n-butanol is produced by anaerobic conversion of the substrate to n-butyric acid and subsequently utilized to form n-butanol. The present chapter explores the scope of bacterial butanol production as need of the hour and its use as an alternative biofuel.

Abstract

Solid Waste Management (SWM) has become a significant global concern, specifically for developing countries like India because of increasing population, rapid urbanization and high rate of municipal solid waste generation. Bio-composting and anaerobic digestion are the methods majorly used for solid waste management. Present chapter comprises detailed information on methods, microbiology involved and pros and cons of these methods to provide the detail information of solid waste management processes to the readers. Variable nature of substrates are available for bio-composting process. It includes sludge from effluent treatment plant (ETP), sewage treatment plant (STP) and bio-toilets, municipal solid waste, food waste and garden waste etc. Nutritional content, carbon /nitrogen (C/N) ratio of the substrate, available space and cost of the process are the main factors that affect selection method for waste management. Anaerobic digestion is the preferred method of solid waste management in comparison to other processes of composting due to methane generation as biogas and bioconversion of organic compounds to manure.

Abstract

Anaerobes are a diverse groups of microorganisms which do not require oxygen or energy for respiration/metabolism and are one of the important components of nitrogen cycle. They are capable of using various other organic and even inorganic materials as electron acceptors during respiration. Anaerobic based wastewater treatment is a biological approach where microorganisms degrade organic contaminants (i.e. rich in carbon and nitrogen) in the absence of oxygen. In this chapter, the role of anaerobes in wastewater treatment has been discussed as it offers an alternative, cheap and eco friendly treatment technology among different biological treatment methods. Anaerobic biological treatment of wastewater is well developed, understood, and frequently used in anaerobic digesters to treat complex organic carbon and nitrogen compounds such as primary and secondary wastewater sludge. The anaerobic sludge contains diverse groups of anaerobic microorganisms that work together in association via a multistage processe consisting of the following biochemical reactions like hydrolysis, acidification, acetogenesis, and methanogenesis thereby converting the organic matter to biogas. The composition of biogas includes 70% methane (CH₄) and 30% carbon dioxide (CO₂) in addition to traces of other gases (e.g., H₂ and H₂S). The methane produced as a by-product can be used as an energy source. The potentiality of anaerobes in anaerobic based bioreactors for its maximum efficiency can be implemented in a variety of ways. The chapter discusses about the working principle, performance, treatment potential, and cost implication in the application of anaerobic treatment technology. The main bioprocess parameters such as pH, temperature, mixing, organic loading rate (OLR), and hydraulic retention time (HRT) have also been discussed in brief. Anaerobic treatment offers several benefits over aerobic treatment, including lower energy requirements, less chemicals, low capital, operation, and maintenance costs, and less sludge production. Hence, it saves money and the environment and overall simplifies the whole process.

Abstract

The normal human microbial flora comprises of both aerobes and anaerobes at various sites. Anaerobes are recognised as pathogens causing simple abscesses to life threatening human infections like gas gangrene. They are also incriminated in a large number of mixed bacterial infections and their diagnosis and specific therapy is important for better patient outcomes. The emergence of Clostridioides difficile as an important pathogen causing antibiotic associated diarrhoeas and its emerging resistance to antimicrobial agents has brought anaerobic microbiology into the forefront. Unfortunately, anaerobic clinical microbiology is difficult to practice with long turnaround time, difficult to grow pathogens, new genera and species being discovered based on 16S rRNA sequencing methods and increasing incidence of antimicrobial resistance being reported in anaerobes. This chapter delves into the important aspects required to improve utilization of anaerobic microbiology services and the variety of human infections we encounter in clinical practice due to anaerobic bacteria.

Abstract

Gastrointestinal tract (GIT) harbors mixed microbial community, these are highly diversified, as revealed by molecular and phylogenetic studies. It is also estimated that microbiota of the GIT is composed of over 35,000 species and play a crucial role in human health and diseases. Thus are now of great interest to both the industrial and scientific communities. The microbes exhibit health benefits are known as probiotics. Anaerobic bacteria dominate in the GIT environment and genera like Bifidobacterium, Clostridium, are strict anaerobes while Lactobacillus, Lactococcus, is facultative anaerobes implicated in the probiotic effects.

For developing anaerobic bacterial based bio-products, it is necessary to cultivate large-scale biomass production that could be done using a modern manufacturing practice. Information on detailed understanding of the perfect growth medium and other bioprocessing parameters for the growth and viability is must. Also high cell viability is a prerequisite during downstream processing and storage of probiotic formulation. In this work we review the latest information about the history, mechanism of action, benefits of probiotic, selection criteria, sources of anaerobic probiotic bacteria, industrial cultivation medium along with biomass production, downstream processing.

Abstract

Hundreds of bacterial taxa makes up human gut microbiota and it is comprised primarily of anaerobes belonging to four main phyla which are Firmicutes, Bacteriodetes, Actinobacteria, and Proteobacteria. Anaerobes colonizes the human body, including oral cavity, small intestine, vagina, skin but the majority of them are housed in the colon. The composition and distribution anaerobes varies along the length of gastrointestinal tract because of variation in oxygen gradient, anatomy of intestinal tract and other host physiological factors. Human gets colonized by anaerobes during the birth and these initial colonizers have impact on infant’s health status. The colonization and development of the gut microbiome is responsive to variety of factors including the mode of delivery, feeding methods, environment etc. The human gut microbiota plays an important role in healthy status of host. It plays an important role in nutrient metabolism and absorption, synthesis of vitamins and production of short-chain fatty acids (SCFAs). In turn these metabolites have positive effect on host immunity and overall host fitness. Studying, the anaerobes using culturing method remains critical in microbiology. However, culturomics approach, combined with sequencing technology, provides new insights in studying anaerobes of human gut microbiota. In this chapter we have discussed that, how human gut is an ideal habitat for the colonization and growth of anaerobes and their impact on host health. We also tried to shed light on latest technical advancement in sequencing culturing technology and their application in studying gut anaerobes.

Abstract

Anaerobic microorganisms occur in oxygen-free environments as they possess biomolecules and metabolic processes that have adapted to sustain them in the stressed environments. These biomolecules and metabolic processes are harnessed and employed in various biotechnological applications. Anaerobes are abundant in various ecological niches such as freshwater or marine sediments, subsurface aquifers, deep thermal vents etc. where, in the absence or limitation of oxygen, they utilise reduced ions such as nitrate, sulphate, ferric, carbonate and certain organic compounds like degrading organic matter, fatty acids or alcohols as electron acceptors during respiration/fermentation to produce more or fewer reduced products such as, alcohols, ammonia, organic acids, hydrogen and carbon dioxide as the oxidised product. Diversity of substrates that can be fermented and the wide range of products that can be formed make anaerobic processes useful in biotechnological applications. Their substrate versatility and flexibility, for example, they can utilize simple sugars as well as many of them can utilise complex renewable biomass make their biotechnological applications sustainable and environment friendly. Anaerobes have been employed in food, chemical and material industries for the production of food items, preservative, additives, chemical intermediates, solvents, catalysts and polymers. They find widespread usage in energy sector for generation of various kinds of biofuels that can mitigate our reliance on non-renewable sources for fuel production. An emerging aspect of anaerobic biotechnology is waste valorization that involves treatment of any kind of waste (industrial, municipal, agricultural, pharmaceutical), where organic fraction of the waste is converted into valuable products. Anaerobes play key role in maintaining the global cycles of carbon, nitrogen, and sulfur, and also facilitate bioremediation by breakdown of persistent compounds. Lately, role of anaerobes in medicine and health care sector is widely explored as they are found to produce several bacteriocins, antibiotics, immunomodulators, vitamins and anti-tumor compounds. Some of the anaerobes have also been employed as probiotics. In the present chapter, we discussed these and many more biotechnological applications of anaerobes in white, green, red and blue biotechnology.

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 three and half decades ago and was promoted widely as a sustainability-enhancing practice that combines the best attributes of forestry and agriculture.

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).

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).

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 belowground 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.

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.

Farmers can grow multipurpose trees (MPT) in various combinations with other crops, as in agroforestry, in block plantations of trees or in naturally regenerating tree farms. In certain cases, multipurpose trees are grown and managed for only one purpose. For example, Gliricida sepium is grown only to provide shade in coffee plantations. The same species may be planted in some other places and is managed differently for a very different use.

Trees that provide materials for propagation are called mother trees. Selection of mother trees is important because the young trees will be expected to inherit the favourable characteristics from the mother tree, such as fast growth, upright or spreading shape of the tree crown, good flowering and fruiting, and tolerance of diseases or pests. There may be sexual propagation by seed or vegetative propagation by using other parts of the tree. The genetic make-up of the seeds differs due to recombination of the genes, resulting in seedling variation. Thus, all the seedlings may look like the mother tree in some respects, but no two seedlings are the same. In case of vegetative propagation through cutting, layering, grafting or budding, the genetic make-up of the young tree is exactly the same as that of the mother tree. Consequently, all new trees grown vegetatively from one mother tree have the same set of gene pairs and therefore the same characteristics; they form a so called clone. Differences between plants of a clone can only be caused by different growing conditions.

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 practice 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.

Ecology of a place is influenced by a number of biotic and abiotic factors. An agroecological zone is broadly homogeneous in climatic and edaphic factors, but not necessarily contiguous, where a specific crop exhibits roughly the same biological expression. On the other hand, the characteristics of an agroecological zone influence the crops and cropping patterns of the zone. Thus, there are considerable variations in the types and management practices of agroforestry systems being followed in different agroecological zones.

AGROFORESTRY FOR HUMID AND SUBHUMID TROPICS

Humid and subhumid tropical regions have much variation in biological, social and economical parameters. The characteristics of humid tropics include high mean annual rainfall of more than 1500 mm, dry season of less than four months in a year and mean annual temperature of more than 22oC. Rainfall usually exceeds the evapotranspiration. However, demographic pressure has caused excessive deforestation and overgrazing which developed soil related problems like low soil fertility, low organic matter, high acidity and high rainfall erosivity. The agroforestry practices designed for this region should aim for improved fallows, soil fertility improvement and conservation, food production, etc. Thus, the common agroforestry systems in this zone are taungya, homegardens, alley cropping, plantation-crop combination, windbreaks, silvipastoral systems and various intercropping systems. Shifting cultivation is a common practice in tropics which should be discouraged as it causes environmental degradation and ecological imbalance, soil erosion and soil nutrient loss.