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Azolla is a free-floating water fern that floats in water and fixes atmospheric nitrogen in association with nitrogen fixing blue green alga Anabaena azollae. Azolla fronds consist of sporophyte with a floating rhizome and small overlapping bi-lobed leaves and roots. Rice growing areas in South East Asia and other third World countries have recently been evincing increased interest in the use of the symbiotic N2 fixing water fern Azolla either as an alternate nitrogen sources or as a supplement to commercial nitrogen fertilizers. Azolla is used as biofertilizer for wetland rice and it is known to contribute 40-60kg N/ha per rice crop. The agronomic potential of Azolla is quite significant particularly for rice crop and it is widely used as biofertilizer for increasing rice yields. Rice crop response studies with Azolla biofertilizer in the People’s Republic in China and in Vietnam have provided good evidence that Azolla incorporation into the soil as a green manure crop is one of the most effective ways of providing nitrogen source for rice.

The role of leguminous plants in improving the soil fertility is known for centuries. The nitrogen uptake in legumes by some unknown process was demonstrated through agronomic experiments by J.B Boussingault in 1838, which was opposed by Liebig and others. The presence of bacteria in the roots nodules of legumes was observed by P.G Lachmann (1858). M. Woronin (1866) further examined and observed them to be rod-shaped and motile.

Under agricultural conditions, the nitrogen removed is usually greater than the nitrogen input. To maintain fertility, nitrogen must be returned to the soil. This takes place mainly by biological nitrogen fixation, which is responsible for the major reduction of dinitrogen to ammonia that is used by the plants. Biological nitrogen fixation accounts for most of the fixation of atmospheric nitrogen in to Ammonium, thus representing the key entry point of molecular nitrogen into the biogeochemical cycle of nitrogen (Fig.4.1). Some bacteria can convert atmospheric nitrogen into ammonium. Most of this nitrogen fixing prokaryote is free living in the soil.

Biofertilizers can be defined as the preparations containing strains of micro-organisms which can augment the microbiological process viz. nitrogen fixation, phosphate solubilization or mineralization, excretion of plant growth promoting substances or cellulose or lignin biodegradation in soil, compost or other environments. Biofertilizers can be divided into nitrogen fixing bacteria, phosphate solubilizing and mobilizing microorganisms and organic matter decomposers as (Table 3.1 and Fig. 3.1):

On the basis of Nitrogen Fixation: On the basis of N₂ fixation, they are divided in to two sub categories as

2.1 Introduction

Microbes are the oldest form of the life on earth. These organisms date more than 3 billion years to a time when they were discovered with oceans. They are so tiny in size that million microbes can fit into the eye of a needle. Without microbes, we can’t live. Thus, understanding microbes is vital to understanding past and future. Microbes play many roles in the earth’s environment recycling dead plant and animal matter through the soil, removing CO2 from the atmosphere by photosynthesis in the oceans and nitrogen from the atmosphere to form nitrogenous fertilizers plants. Microbes play an important role in nutrient recycling, management, organic matter, decomposition and increasing the crop productivity and quality and protection against diseases (Panwar et al., 2009). Over the past century, many of the basic scientific principles of plant nutrition and soil fertility have been explained. In developed countries, inorganic chemical fertilizers have been widely accepted as a major source of improving and maintaining soil fertility.

Agriculture is undoubtedly the largest livelihood provider in rural India. As we enter a new post WTO Scenario and IT revolution, new inventions are happening day by day in every sphere. Agriculture is not culture now, it is agri business! Agriculture constitutes over 25% of India’s GDP. In recent years, much emphasis has been given by the Ministry of Agriculture on commercializing agricultural production in the country. Adequate production and distribution of food has become a high priority and global concern. In the fast changing world and increasing competition in a globalized economy, there is a need for exploiting the available resources to the maximum level and use of best technologies available world over, to cope up with domestic demand of food and also to target export market. This will be particularly relevant in South India, where farmers grow a number of crops, but have technical constraints in enhancing production and productivity because of inadequate exposure to high technology & inputs coupled with advanced production practices, logistics and marketing. In addition, shortage of labour is a major concern for progressive farmers of South India who are ready to offer more wages to labourers. Therefore, they are forced to become machinery-dependent in their farm operations. As a result, Southern India is emerging as one of the hottest destinations as well as a strong market with buying potential for farm machinery and equipment.

The market of organic products is growing globally every year. This organic market expansion makes it possible for farmers to reap the benefits of a trade with relatively high price premiums. Organic farming is carried on in almost all countries of the world. The share of organic farms in overall farmland and in terms of numbers of holdings is growing continuously. The market for organic products is also growing very rapidly, not only in Europe, North America and Japan, where the largest markets are to be found, but also in many emerging economies in transition. In India, an organic movement is now emerging on different levels i.e. producer groups, trainers and advisors, certification bodies and processors and traders.

The organic quality is based on standards, inspection, certification and accreditation. All organic food is produced and handled according to strict rules called ‘Organic Standards’. Organic standards do not define a quality status which can be measured in the final products (e.g. quantity of pesticides residues, heavy metals, etc). They define the way of production (e.g. that no chemical pesticides and fertiliser are used).

The problem of insect-pest, disease and weed is acute in case of all the crops and especially so in case of commercial crops. Pesticides, fungicides or chemicals are meant to control harmful pests such as insects, nematodes, diseases, weeds etc. However, excessive use of pesticides, fungicides and herbicides not only leave residues in soil, water and air but also have adverse effects on the non-target organisms such as pollinators, parasitoids, predators and wild animals. This has adversely affected the ecological balance resulting in pest resurgence, development of resistance in the pest species, diseases and environmental pollution.

Plant nutrients are drawn up from soil for growth and development. There are more than 90 elements present in the soil. According to the criteria of Essentiality of Nutrients for plant growth, proposed by Arnon and Stout in 1952, only 16 are considered to be essential for plant growth. Out of these, C (Carbon), H (Hydrogen), O (Oxgen), N (Nitrogen), P (Phosphorus), K (Potassium), Ca (Calcium), Mg (Magnesium) and S (Sulfur) are called Macronutrients (required in large quantities) and the remaining 7 elements - Fe (Iron), Mn (Manganese), Cu (Copper), Zn (Zinc), B (Boran), Mo and Cl are called Micronutrients or trace elements (required only in very small quantities). Among the macro elements - N, P and K are called Fertiliser elements or primary nutrients as they are most often applied in the form of synthetic or mineral fertilisers, and Ca, Mg and S are called secondary elements which are applied in smaller quantities than primary nutrients and required subsequent to primary nutrients.

Organic food production is as much a state of mind as it is a production system. The organic farmer must understand how everything is interrelated and how one set of circumstances will influence other factors in how the plant grows. A strong, healthy plant is much more important in an organic system then a conventional system. A two to three year leaning curve must be accepted by anyone intending to switch from conventional to organic farming. What works one year may fail the next.

The need for organic farming in India arises from the unsustainability of agriculture production and the damage caused to ecology through the conventional farming practices. The present system of agriculture which we call ‘conventional+’ and practiced the world over evolved in the western nations as a product of their socio-economic environment which promoted an over riding quest for accumulation of wealth. This method of farming adopted by other countries is inherently self destructive and unsustainable.

Farming is the intervention of man in the growth cycle of plants, animals or birds to get utility products of choice at maximum levels and of highest quality. The growing and caring of plants is called Crop Husbandry, and that of animals is called Animal Husbandry. Farming is our most basic activity. It is considered as the backbone of Indian economy. Farming not only nourishes the whole population, but also provides a means of livelihood to more than 60 per cent of our population. Our history, culture and community values are embedded in farming. Today when we think of farming, what comes to our mind are long stretches of farm land, farmer tilling the field, pumping water into fields, applying fertilizers or pesticides, plants with so many fruits, tractors with loads of farm produce, cross bred cows, a farm chicken, aquaculture, fish and so on. A more advanced image on this subject will be of the small plantlets in conical flasks or test tubes, what we call Tissue culture, High Yielding Varieties (HYV), Genetically Modified (GM) crops, Green House farming and other techniques that increase the crop yields. So all these activities are considered as the products of science that our scientists were able to develop over a period of time and helped the growing population to meet their food requirements.

PGPR have shown potentiality against pests and diseases oc curring on crop plants. Wilt and collar rot diseases are caused by soilborne pathogens viz., Fusarium oxysporum fsp. lycopersici (FOL) and Sclerotium rolfsii respectively in vegetables. An attempt was made to manage the diseases with PGPR microbes and 142 PGPR strains were isolated from different vegetable crops. Among them two isolates viz., Bacillus amyloliquefaciens (BA1) and B. subtilis (BS2) were found highly effective in controlling the diseases.  Apart from the disease control, the isolates BA1 and BS2 also registered enhanced crop growth and yield in cowpea under field conditions. Species level identification of BA1 and BS2 was done through PCR amplification and sequencing of 16s rRNA. Both BA1 and BS2 clustered with Bacillus amyloliquefaciens and B. subtilis respectively.

Mastitis is a global problem as it adversely affects animal health, quality of milk and economics of milk production. Bovine Mastitis is reported to be the most costly disease of dairy cattle, causing huge economic losses in terms of reduced milk yield, milk discard after treatment, cost of veterinary services and premature culling. While reviewing status of mastitis in India, subclinical mastitis is more important (10–50%) than the clinical mastitis (1-10%). Estimated annual economic losses incurred due to mastitis estimates to Rs.7165.57 crores to dairy farmers (Bansal and Gupta, 2009).

Investigations were undertaken to isolate the fluorescent pseudomonads from the soil and root samples collected from Western Ghats regions of Chikkamagalur district of Karnataka. A total of nine isolates were obtained from 10 sampling sites. All the nine isolates were subjected for morphological, physiological and biochemical characteristics and were tentatively identified as Pseudomonas fluorescens. Isolates were examined for different agriculturally important functions like production of plant growth promoting substances (PGPS), solubilization of TCP and biocontrol activity. Results of the study indicated that, five out of nine isolates found positive for IAA production and the amount of IAA production ranged from 1.92 to 6.75 mg per ml.

Introduction

The rumen ecosystem is essentially a fermentation system that houses a vast array of different microbes. Ruminants typically browse low energy forages, such as grasses or other plant material, rich in fibre but not easily accessible to the ruminant without rumen fermentation. These forages are literally food for the microbes present in the rumen first and then, in turn, the products of these microbes are the feed for the ruminant. Microbes break down forage in the anaerobic rumen environment and the products of microbial fermentation provide the ruminant with metabolisable compounds, such as short chain fatty acids, while the microbes themselves account for around 90% of the amino acids entering the lower intestine. There are many significant challenges to investigate rumen ecology.

One of the integral components of human and animal liveli hood is food and water without which life cannot sustain on  earth. However, due to high nutritive value of foods and ubiquitous nature of microbes, it is always at risk of microbial spoilage and contamination. World Health Organization (WHO) defined “food-borne illnesses” as diseases, usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. Every consumer is at risk of food-borne illness but conversely every incidence of foodborne illness is potentially preventable. Several bacterial pathogens in particular are responsible for foodborne infections and intoxications.

Globally, 2 billion children under the age of five suffer from diarrhoea, of which, more than 50% of the cases being in South Asia and sub-Saharan Africa, where the disease is more likely to be fatal (UNICEF-WHO, 2009). It has been also estimated that the great majority of acute diarrhoeal illnesses in children over the age of two years is attributable to bacterial pathogens (Carpenter, 1980). Amongst the various enteric bacterial pathogens, diarrheagenic strains of Escherichia coli are considerably responsible for causing bacterial diarrhea (Nataro and Kaper, 1998).

Microbial diversity is the key to human survival and economic well being. It provides a huge reservoir of resources which can be utilized for our benefit. Yeasts have been isolated from many sources for industrial purposes. The impact of yeasts on food and beverage production extends many fold beyond the popular notions of bread, beer and wine fermentations by Saccharomyces cerevisiae.

Diverse dynamic mixed populations of prokaryotic and lower eukaryotic microorganisms govern the fermentation and maturation processes and, finally, impact the quality of wine. Both of these parameters apparently contribute to regional differences in the quality of produced wines and characterization of regional wines should involve the study of microbial populations and their members active in the given region.