eChapters

Bioconversion refers to the recycling and reprocessing of organic waste materials using the system of biological decomposition or biodegradation into value added products. Composting is one way of conversion of organic waste into manures. It is defined as a method of solid waste management whereby the organic component of the solid waste stream is biologically decomposed under controlled conditions to a state in which it can be handled, stored or applied to the land without adversely affecting the environment.

Composting provides a partial solution to an issue of great concern in many communities. All around the world, landfills are filling up, garbage incineration is becoming increasingly unpopular, and other waste disposal options are becoming ever harder to find. Composting provides a way not only of reducing the amount of waste that needs to be disposed of, but also of converting it into a product that is useful for agriculture. Composting reduces waste, makes us less dependent on landfills, and decreases greenhouse gas emissions. Composting recycles essential nutrients back into the soil and promotes a prolific soil ecosystem.

Introduction

More than a third is covered by drylands in the terrestrial land surface, which have a harsh and vulnerable natural condition (Maier et al., 2014). Due to insufficient water availability, dry areas have a scant population of vascular plants, as well as poor availability of the nutrient turnover with poor availability of the resources as a result of severe temperatures (Adeel, 2008). Biological soil crusts or Biocrusts commonly protects the soil surface in dry environments and it is considered “ecosystem engineers” of arid and semiarid areas, as well as signs of ecosystem health (Briggs and Morgan, 2011; Bowker et al., 2008). They are connected in dryland ecosystem restoration level or degradation (Assouline et al., 2015). When compared to chemical or physical crusts, biocrust is the largest word that explicitly implies that these are the crusts which are dependent on the living organisms’ activity.

Pesticides are the chemical substances that kill pests and herbicides are the chemicals that kill weeds. In the context of soil, pests are fungi, bacteria, insects, worms, and nematodes etc. that cause damage to field crops. Thus, in broad sense pesticides are insecticides, fungicides, bactericides, herbicides and nematicides that are used to control or inhibit plant diseases and insect pests. Although wide-scale application of pesticides and herbicides is an essential part of augmenting crop yields; excessive use of these chemicals leads to the microbial imbalance, environmental pollution and health hazards. An ideal pesticide should have the ability to destroy target pest quickly and should be able to degrade nontoxic substances as quickly as possible.

The ultimate “sink” of the pesticides applied in agriculture is soil. Soil being the storehouse of multitudes of microbes, in quantity and quality, receives the chemicals in various forms and acts as a scavenger of harmful substances. The efficiency and the competence to handle the chemicals vary with the soil and its physical, chemical and biological characteristics.

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

Introduction

Organic farming is basically a holistic management system, which promotes and improves the health of the agro-ecosystem related to biodiversity, nutrient biocycles, soil microbial and biochemical activities. Organic and bio-dynamic farming emphasises management practices involving substantial use of organic manures, green manuring, organic pest management pratices and so on. It has also come to mean that it is a system of farming that prohibits the use of artificial fertilisers and synthetic pesticides.

Biodynamic agriculture is an advanced form of organic farming system that is gaining increasing attention because of its added advantage of soil health and food quality. It is an alternative variant where the chemical fertilisers are totally replaced by microbial (biological) nutrient givers such as bacteria, algae, fungi, mycorhiza, actinomycetes. Biological Pest management of crops is undertaken by employing predators, parasites and other plethora of natural enemies of pests, in addition to all the rest of option that help to avoid resorting to chemical pesticides. These agents could be augmented into farms or promoted through such activities that favour their flourished activities. Composting, Green manuring, crop rotations. Intercropping, mixed cropping etc. as well as bird perches, trap crops promote such biological activities.

Biodynamic Farming introduces biodynamic preparations used within holistic approaches to soil and crop management. The chapter systematically presents formulations BD-500 and BD-501 and the compost preparations BD-502 to BD-508, prepared from materials such as yarrow, chamomile, stinging nettle, oak bark, dandelion, valerian, and horsetail. Cow Pat Pit is also included. The discussion emphasizes the preparation and intended agricultural role of these formulations within biodynamic farming systems. By presenting each preparation separately, the chapter provides students and practitioners with an organized reference for understanding traditional and biodynamic inputs and their place within broader sustainable, ecological, and natural farming practices. for reference.

Use of biofertilizers in agriculture and their advantage
 
Bio-fertilizers or bio-inoculants

These are productions containing living organisms such as nitrogen fixers or phosphorus solubilises which are useful for agricultural production. Biofertilizers play a significant role in improving soil fertility and plant growth. By fixing atmospheric nitrogen both in association with plants and without plants solubilize insoluble soil phosphates into soluble phosphates there by increasing the availability of phosphorus secrete growth promoting substances and supplies to the inoculated plants.

Boost to crop production has been the ultimate goal of researchers involved in agriculture so as to feed the ever-increasing human and domestic herbivorous animal populations. Crop production is not only constrained by the limited inherent potential of available varieties currently in use, but is also largely affected by the limitations of soil nutrient availability and damages by diseases, insects and weeds. To counter later challenges, augmentation of soil nutrients through use of biofertilizers in integrated nutrient management programmes and restricting the use of chemical pesticide by integrating biopesticides in plant protection programmes has received much attention in recent years because of consumer’s preference for organic food.

Introduction

Biofertilizers are microbial preparations containing living or latent cells of efficient strains of nitrogen fixing, phosphate solubilizing and cellulose decomposing microorganisms intended for seed or soil application and designed to improve soil fertility and plant growth by increasing the number and biological activity of beneficial microorganisms in the soil.

The objects behind the application of biofertilizers /microbial inoculants to seed, soil is to increase the number and biological / metabolic activity of useful microorganisms that accelerate certain microbial processes to augment the extent of availability of nutrients in the available forms which can be easily assimilated by plants. The need for the use of biofertilizers has arisen primarily due to two reasons i.e. though chemical fertilizers increase soil fertility, crop productivity and production, but increased / intensive use of chemical fertilizers has caused serious concern of soil texture, soil fertility and other environmental problems.Use of biofertilizers is both economical as well as environment friendly. Therefore, an integrated approach of applying both chemical fertilizers and biofertilizers is the best way of integrated nutrient supply in agriculture.

Biofertilizers, thus include i) Symbiotic nitrogen fixers- Rhizobium sp. ii) Non-symbiotic, free living nitrogen fixers- Azotobacter, Azospirillum etc. iii) Blue Green Algae (BGA) inoculants- Azolla-Anabaena, iv) Phosphate solubilizing microorganisms (PSM)- Bacillus, Pseudomonas, Penicillium, Aspergillus etc. v) Mycorrhiza vi) Cellulolytic microorganisms

Biofertilizers act as complementary and supplementary sources of plant nutrients. Biofertilizers help in increasing the biologically fixed atmospheric nitrogen and enhancing phosphorus availability to the crops. Among the biofertilizers for increasing nitrogen supply, nitrogen fixing bacteria (Rhizobium, Azotobacter and Azospirillum), blue green algae (BGA) and Azolla are important. The availability of phosphorus is improved by phosphorus solublizing microorganisms (PSM) and mycorrhizae (VAM).

Rhizobium is of vital importance to various pulses and some of the oilseeds and fodder legumes as 80–90 per cent of their nitrogen requirement is met through biological nitrogen fixation (BNF). Rhizobium fixes atmospheric nitrogen ranging from 50–60 kg per ha in groundnut, 100–300 kg per ha in alfalfa. In pulses it is estimated at 50–110 kg/per ha. Field studies indicated a yield increase of 14–53 per cent due to Rhizobium inoculation. Nitrogen left over the demand of legumes in combination with the nitrogen present in roots of the legumes will enhance the soil fertility. Consequently the nutrient needs of the subsequent crop from applications will be reduced.

Biofertilizers focuses on microbial and biological resources that enhance nutrient availability and support crop nutrition. The chapter covers nitrogen-fixing organisms, phosphorus-solubilizing microorganisms, phosphate-mobilizing mycorrhizae, mineral-solubilizing biofertilizers, and plant-growth-promoting rhizobacteria. It explains applications, importance, liquid biofertilizer methodology, mass production, packaging, storage, and multiplication of bacterial, mycorrhizal, cyanobacterial, and Azolla-based inputs. By connecting microbial activity with nutrient cycling and plant growth, the chapter demonstrates the practical role of biofertilizers in reducing dependence on synthetic fertilizers and strengthening soil fertility. It provides an applied foundation for students, researchers, extension workers, and practitioners of sustainable agriculture. under diverse soil and climatic conditions and practice for field application in natural farming.

The diets of over two-thirds of the world’s population lack one or more essential mineral elements. This can be remedied through dietary diversification, mineral supplementation, food fortification, or increasing the concentrations and/or bioavailability of mineral elements in produce (biofortification) involving aspects of soil science, plant physiology and genetics underpinning crop biofortification strategies, as well as agronomic and genetic approaches currently taken to biofortify food crops with the mineral elements most commonly lacking in human diets: iron (Fe), zinc (Zn), copper (Cu), calcium (Ca), magnesium (Mg), iodine (I) and selenium (Se).

At this moment, the majority of energy is obtained from fossil fuels and requires switching over to alternative energy sources is the need of the hour. Fossil fuels are nonrenewable energy source and also have seriously negative impacts on the environment. The use of fossil fuels cause excessive global climate change because emissions of greenhouse pollutants and the formation of compounds CO_x, NO_x, SO_x, C_xH_y, ash and other organic compounds that are released into the atmosphere. The increase in greenhouse gas emission will result in global warming, climate change, environmental degradation and health problems.

Biofuel, any fuel that is derived from biomass - that is, plant or algae material or animal waste. Since such feedstock material can be replenished readily, biofuel is considered to be a source of renewable energy, unlike fossil fuels such as petroleum, coal, and natural gas.

1. Concept of Conservation Farming

Conservation farming represents a paradigm shift in agriculture, moving away from conventional practices that often degrade the environment and compromise long-term productivity. Expanding on the principles of conservation farming provides deeper insights into the multifaceted benefits and challenges associated with this approach.

Conservation farming aligns closely with the principles of agroecology, emphasizing the integration of ecological concepts into agricultural systems. The concept recognizes that agriculture is not separate from the natural environment but rather an integral part of it. By minimizing soil disturbance, conservation farming promotes the preservation of soil structure and the intricate network of microorganisms that contribute to nutrient cycling and plant health.

Fixation of elemental nitrogen in the atmosphere by the microorganisms through a reductive process into ammonia is called biological nitrogen fixation (BNF). Molecular nitrogen (N₂) is the major component (approximately 80%) of the earth’s atmosphere. The element nitrogen is an essential part of many of the chemical compounds, such as proteins and nucleic acids, which are the basis of all life forms. However, N₂ cannot be used directly by biological systems to build the chemicals required for growth and reproduction. Before its incorporation into a living system, N₂ must first be combined with the element hydrogen. This process of reduction of N₂ commonly referred to as nitrogen fixation (N-fixation).

N₂is transformed into reactive N via lightning discharge (5 teragrams (Tg) N / year; 1 Tg equals 1012 g) and by biological N fixation (100 -140 Tg N /year ). Conversion of dinitrogen to ammonia in the industrial process requires temperatures of 400 - 500^o C and high pressures (Haber-Bosch process). Biological nitrogen fixation is much more important as it contributes to more than 70 % of the input in to the world’s soil and water nitrogen. It has been estimated that 100 to 175 million tones of nitrogen are fixed annually by the process of biological nitrogen fixation.

The process of N₂ fixation is mediated by the enzyme, called nitrogenase (which reduces N₂ to ammonia). The overall reaction is as follows.

The biochemical oxygen demand is a chemical procedure for determining the amount of dissolved oxygen needed by aerobic organisms in a water body to break the organic materials present in the given water sample at certain temperature over a specific period of time. BOD of water or polluted water is the amount of oxygen required for the biological decomposition of dissolved organic matter to occur under standard condition at a standardized time and temperature. Usually, the time is taken as 5 days and the temperature is 20°C. microbes
C6H12O6 + 6O2 ¾¾¾¾®CO2 + H2O
Principle
The test measures the molecular oxygen utilized during a specified incubation period for the biochemical degradation of organic material (carbonaceous demand) and the oxygen used to oxidize inorganic material such as sulfides and ferrous ion. It also may measure the amount of oxygen used to oxidize reduced forms of nitrogen (nitrogenous demand).
Procedure
Fill two BOD bottles with sample (or diluted sample); the bottles should be completely filled.

Chemical pesticides though extremely effective in controlling pest population suffer from disadvantages. They have a broad toxic range and potentially toxic to non target organisms. Other constraints that have emerged with the use of chemical pesticides such as development of resistance and resurgence in insects, residual toxicity, secondary outbreak of minor insect pests, etc., In this juncture, the biopesticides have proven to be effective tool in managing the devastating insect pests of various crops.

The biopesticides are types of pesticides derived from natural materials such as microorganisms, plants, animals and certain minerals. They are living organisms or their products or byproducts, which can be used for the management of pests that are injurious to crop plants. Biopesticides have a vital role in crop protection, although most commonly in combination with other tools including chemical pesticides as part of integrated pest management (IPM). Microorganisms help to regulate the abundance of many pests or potential pests without any cost to society. Microbes can be increased artificially and thereby achieve faster, higher and more consistent control of the target pests that will occur naturally. Insect pathogens that are transmissible in nature from one host to another offer an important bonus effect that chemical insecticides do not have. A pathogen will kill pests exposed and many continue killing them by natural transmission from one individual host to another through subsequent host generation.

Biopesticides generally have several advantages compared to conventional pesticides. While chemical pesticides are responsible for extensive pollution of the environment, a serious health hazard due to the presence of their residues in food and development of resistance in targeted insect pest populations, biopesticides, in contrast, are inherently less toxic to humans and the environment, do not leave harmful residues, and are usually more specific to target pests. The agents employed as biopesticides, include parasites, predetors and disease causing fungi, bacteria and viruses, which are the natural enemies of pests. Utilization of naturally occurring parasites, predators and pathogens for pest control is a classical biological control. These bio agents can be conserved, preserved and multiplied under laboratory condition for field release. Once these bio-agents are introduced in the field to build their population considerably, they are capable of bringing down the targeted pest population below economic threshold level (ETL).

Biopesticides presents biologically derived pest-management products as alternatives or complements to synthetic pesticides. The chapter explains their advantages, including biodegradability, target specificity, compatibility with Integrated Pest Management, reduced resistance risk, and comparatively favorable environmental characteristics. It classifies biopesticides into biochemical and microbial groups and describes mechanisms such as hyperparasitism, competition, antibiosis, parasitism, and volatile-compound production. Particular attention is given to neem and other botanical sources, including chinaberry, tobacco, pyrethrum, rotenone, and Melia toosendan. Their pest-control uses and preparation approaches demonstrate how botanical and microbial resources can contribute to sustainable crop protection and natural farming systems. for integrated crop protection effectively.

Introduction

Soil pollution is anything that causes contamination of soil and degrades the soil quality. It occurs when the pollutants causing the pollution decrease the quality of the soil and convert the soil inhabitable for micro and macro organisms living in the soil. Soil pollution can occur either because of human activities and/or natural processes. However, mainly it is due to human activities. The soil contamination can occur due to the presence of chemicals such as ammonia, pesticides, lead, herbicides, mercury, nitrate, naphthalene, petroleum hydrocarbons, etc. in an excess amount.

Soils can be polluted with several organic and inorganic pollutants. Organic pollutants contain hazardous persistent organic compounds viz. polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzodioxins (PCDDs), polychlorinated biphenyls (PCBs), polychlorinated naphthalines (PCNs) and other persistent organic compounds. Inorganic pollutants contain heavy metals like lead (Pb), cadmium (Cd), mercury (Hg), zinc (Zn), copper (Cu), arsenic (As) and nickel (Ni) as well as some radioactive compounds or radionuclides. The major sources of soil pollutants are anthropogenic. It contains mainly two sources, point and diffuse; the point sources contains industrial wastes, municipal wastes, domestic wastes, medical wastes, agrochemicals, agricultural wastes, composts and sludges and nuclear wastes. Organic and inorganic soil pollutants can be toxic for plants, animals soil organisms and others. Some compound of the soil pollutants enter into the food chain and can adversely affect on human health. Soil pollutants can be also transferred to surrounding air and water through leaching, volatilization, runoff and dust storms. Quality of air and water adversely affected can be degraded. Thus, remediation of polluted soils has become an awful necessity in many areas of the world.

The bio-resources application in the soil is known to improve the biological properties of the soil. Several earlier reports show a spur in microbial populations or increased microbial biomass carbon and the enhanced enzymatic activities with the incorporation of bio-resources in soil (Perucci, 1990; Goyal et al., 1993; Bonde et al., 2004).

Microbial populations

Indigenous microbial populations in soil are of fundamental importance for an eco system functioning, through determining nutrient cycling, organic matter decomposition and energy flow (Doran and Zeiss, 2000).