Soil Management Practices
The intrinsic capacities of natural resources become sub- optimal due to united introduction of degradative process. (Salinization). Overstraining natural resources beyond their carrying capacity can also cause damage. Arable farming in soils of land capability IV and above, or the bid to produce super yields artificially through high intensity farming and their inefficient use can also lead to non- sustainability of the farming enterprises.
Soil degradation is decline in the productive capacity of land due to process induced mainly by human activities. According to national Bureau of soil survey and land use planning, out of a total geographical area of about 328- M ha, 187 ha (57 % ) are sufficient from different soil degradation problems. Water erosion is the major problem causing loss of soil in 132 M ha.
Soil and Water Conservation Technology:
It has been estimated that about about 5334- M ha. Of soil is loss through erosion annually from agricultural lands include contour farming, agronomic, cultural, and biotic conservation measures, runoff recycling and mechanical measures such as contour bunding, graded bunding contour ditches ( CCT ) and bench terracing. Alternate land use system such as pasture, fuel – fodder- timber etc. are to be followed on non agricultural lands falling under land capability classes V. VI, VII and VIII.
Watershed based Approach:
The certain biotic constraints that unsustiainning rained agriculture includes:
1. Low and variable rain off
2. Removal of vegetative cover and its non replacement,
3. Declining soil fertility,
4. Extension of cultivation of marginal lands,
5. Accerated land Degradation,
6. Socio- economic factors.
For the development of rain fed agriculture the watershed model provides an envelop through which many of the steps for sustaining agriculture can be implemented. The land scope watershed unit can be efficiently subdivided into discrete hydrological units. Since the watersheds are specially laid from ridge to valley, the most effectively conserve land and water resources. And help secure water availability through out the crop – growing season. The land area of the watershed drain into a common point. Hence, the drainage water can be easily stored in above alternative to capturing the runoff water and recycling it for stabilizing and sustaining the productivity of Rainfed crops.
Soil- fertility management: There is net negative balance of soil nutrient in relation to the total uptake of nutrients by crops and the nutrients added to the soil. Progressive soil fertility depletion will assume as one of the serious limitation in future for sustainable agriculture.
Integrated Nutrient Management:
In the year 1974 the need for integrated nutrient management (INM) was clucided. The INM philosophy combines economic and efficient traditional technologies to grain from the symbiosis and synergy of crop soil environment bio- interactions. The approach is flexible and minimizes use of chemical but maximizes use efficiency. The concept is for optimizing of the effect of all available resources of plant nutrient to improve soil fertility availing nature’s gift. Agriculture is the most important source of renewable wealth. Development of an integrated plant nutrient management system (INMS) should be able to maximize the use of residues for the farm waste, waste from the livestock and the house holds before supplementing them with chemical fertilizer. At the watershed level, this should take into consideration inventory organic resources available from plants and livestock, agro forestry system and availability of need based chemical fertilizer INMS include.
1. Recycling of Organic Waste:
such as crop residue, dung urine from domestic animal and waste form the slaughter house, human excreta and sewage, biomass of weeds, organic waste form fruit and vegetable production and household, sugarcane trash, oil cakes, press mud, fly ash from thermal power plant. Composting and vermicompost can better apply material not suitable for direct use.
2. Biologival Nitrogen Fixation:
Through Blue Green Algae (BGA) and Azolla for rice, Rhizobium for legumes. Azotobacter and Azospirillum for others, Bacillus subtitles and Aspergillus Niger (fungus) available as culture can solublise the unavailable phosphorus and increase its availability to plants.
3. Green Manuring:
Is an age- old practice for improving soil fertility and supplying part of nutrient requirement of crops. The system modduling green manuring plants, Sesbania rostrsrta can fix 10 to 25 kg/ha. In 45 to 50 days. Availability of non competitive season in cropping sequence and irrigation on water are the limitation to the spread of green manure. There is also great scope for green leaf manuring for paddy and other crops topping of various multipurpose trees.