Nature is dynamic. It causes inheritable changes in all living organisms. For thousands of years, farmer around the world have been selecting and conserving varieties of different crop plants that they cultivated. This process has generated a rich wealth of varieties in each crop plant, seen to be most abundant in countries near the equator and India is no exception. In the world there are Mega centers of biodiversity of which aware present in India. This is because in India, the different soils and agro-climatic situations are present. So Indian farmers grow a large number of crops. Generation of Indian farmers, with their continued selection and conservation, has created a rich wealth of varieties in many crops. Therefore India is the original home of many crops such as rice, little and kodo millets, red gram, moth bean, jute, pepper, cardamom, many vegetables and fruit species. These plants were identified from the wild, selected and cultivated by Indian farmers over hundreds of years. The present wealth of varieties in India includes both crops that originated in the country and those that were introduced from the other countries during the distant and recent paste are soybean, sunflower, oil pail and kiwi fruit.
The Indian economy is predominantly rural & agriculture oriented. In agriculture, 85% of the holdings are less than two hectares and the declining trend in the average size of the farmer holdings, poses a serious problem. Majority of them are dry lands, which depend on erratic monsoon rains. The rest of the area is cultivated with supplemental irrigation. The farmers concentrate mainly on crop production, which is invariably subjected to a high degree of uncertainly income and employment.
In India the cultivable land is 143.8 million hectares and there is very little possibility of extending it further. Therefore, to meet the requirement of food grains for increasing population, the only option open is through time and effective space utilization in agriculture. The time concept relates to increasing the intensity of cropping under assured irrigated conditions, whereas space utilization pertains to building up of vertical dimension through multi-tier cropping and farming system approach. Thus by making use of these time and space concept either in irrigated or in rained areas, the productivity per unit area per unit time can be substantially enhanced. Therefore the only way to increase an agricultural production in the small/marginal units of farming is to increase is to increase the productivity per unit time and area. This may be achieved of quicker maturing varieties with equal yields or by improving techniques of culture, fertilizer use, weed and pest control.
The green revolution in mid sixties stirred by research based new technological developments involving new materials, models and ways of organizing farm inputs (water, fertilizer, chemical etc) and government’s policies transformed the agriculture dramatically. The outcome chewed a many fold increase in production and productivity viz. food grain production of 211 million tones ( which was only 74.23 million tones in 1966-67 ) and food grain productivity of 1697 kg/ha ( which was only 644 kg/ha in 1966-67 ). The country thus became self sufficient in food production despite tremendous pressure to sustain 16% of world human population and 10% of cattle population with just 2.4% of total land.
However modern crop production technology has considerably raised output but has residues in farm produce, gene erosion of fossil fuel based inputs such as fertilizer, pesticide, herbicides and labour spacing but energy intensive farm machinery.
Land water and plant (bio diversity) are the natural resources and conservation of these natural resources is vital important. As far as resources degradation is concentrated, India is facing top soil depletion, falling ground water table and contamination of water, ecological imbalance due to deforestation and healthy hazards linked to increase use of toxic agro- chemical because of increase in food consumption. The adverse soil loss is estimated to be over 16 tones/ha/year, which is layer of top soil. Annual top soil loss is 6000 million tones, which carries about 8.4 million tones of nutrients and it is more than what we are using today. Similarly tat energy research institute ( TERI ) reported that more than 10% of GDP is being lost annually on account of environment and around 11-26% of country’s apicultural output is lost on account of soil degradation.
The rate of human induced land and degradation is very high. Out of total geographical area of 329 million ha, 187 million ha, representing almost 57% of total geographical area of the country are reported to have degraded of which 162 million ha is way of wind and water related degradation.