Dr. Parveen Kumar, Dr. Anil Kumar
Agriculture in the country has largely been done by conventional methods. These conventional methods are largely crude which depleted our natural resources, require more labour, inputs and money. Despite more labour and inputs the production is not optimum besides a huge damage to soil and human health and loss of biodiversity. Greater stress is now being laid on adopting practices which conserve the natural resources, do not compromise with the soil health, does not harm the diverse flora and fauna and also give adequate yields. This set of resource conserving technologies is now being adopted under the term ‘Conservation Agriculture’. Conservation Agriculture (CA) refers to set of soil management practices that minimise the disruption of the soil’s structure, composition and natural biodiversity. This agriculture has proved its potential to improve crop yields, while improving the long-term environmental and financial sustainability of farming. The Food and Agriculture Organization (FAO) of the United Nations (UN) defines it as a concept for resource-saving agricultural crop production that strives to achieve acceptable profits together with high and sustained production levels while concurrently conserving the environment. It is basically the use of resources in a manner that safely maintains a resource that can be used by humans as well as for future use. Conservation has become critical because the global population has increased over the years and more food needs to be produced every year without disturbing the agro-ecology of the regions. Conservation Agriculture works on certain key
principles.
Zero/No Tillage: Tillage operations in soil are considered very essential for sowing the next crop and it is believed to increase soil fertility through mineralization. Today tillage is largely being perceived as destroying organic matter that is largely found within the soil cover. But the lesser known fact is that tillage also leads to soil erosion and formation of crusts which decrease soil fertility besides increasing time and labor for producing that crop. Under the new paradigm, the soil is not ploughed but disturbed to the least possible extent. There is a specially designed drill for sowing of seeds in zero/no till soils. At the time of seeding, fertilizers can also be applied simultaneously. It thus helps to minimize mechanical soil disturbance which is essential to maintaining minerals within the soil, preventing erosion, and preventing water loss from occurring within the soil. Food and Agriculture organization reports that no till farming saves soil organic levels for a longer period and at the same time allow the soil to be productive for longer periods. When no-till practices are followed, the producer sees a reduction in production cost for a certain crop. Tillage also requires more money in order to fuel tractors or to provide feed for the animals pulling the plough. There is also a reduction in labor as the farmer need not to be in the fields as long as a conventional farmer. zero/no till has been reported to save rupees 3000-4000 per hectare for land preparation, advances sowing in wheat by 10-12 days through direct drilling after rice harvest with 5-10 per cent yield advantage and reduction in weed infestation particularly Phalaris minor. The water requirement is also reduced by 1-2 cm per irrigation at later crop growth stages.
Management of Top Soil: Managing the top soil in order is also necessary to create a permanent organic soil cover that can allow for growth of organisms within the soil structure. This growth breaks down the mulch that is left on the soil surface which in turn produces a high organic matter level that acts as a fertiliser for the soil surface. Studies in an article entitled ‘The role of conservation agriculture and sustainable agriculture’, reveal that the layer of mulch that is built up over time acts like a buffer zone between soil and mulch and helps reduce wind and water erosion. The soil surface also gets protected when rain falls on the ground. This type of ground cover also helps keep the temperature and moisture levels of the soil at a higher level rather than if it was to be tilled every year.
Crop Rotation: Practicing crop rotation with more than two species does not allow insect/pests and weeds to be set into a rotation with specific crops. When crops are rotated, these act as a natural insecticide and herbicide against specific organisms. The rotation does not allow insects or weeds to establish a pattern and this helps to eliminate problems with yield reduction and infestations within fields. Crop rotation also help build up soil infrastructure. Establishing crops in a rotation allows for an extensive buildup of rooting zones which will allow for better water infiltration.
Raised Beds With Residue Retention: Crops are grown in raised beds and the beds can be broad or narrow. The irrigation is being provided through furrows. The beds made once can be used subsequently for other crops but a reshaping is necessary once in a year. It also results in reduction of weed population. The furrow irrigated raised bed system of wheat saves 25-40 per cent of seed, water by 25-40 per cent and nutrients by 25 per cent without affecting the yields. Also reduces the lodging in crops as crop is not in physical contact with the irrigated water.
Brown Manuring: It is done using plant species like Dhiancha (Sesbaania). Dhiancha is allowed to grow along with rice for about 25-30 days. When Dhiancha is 25-30 days old, it is turned down by application of suitable chemicals. 2, 4-D or bispyribac-Na @20-25g/ha are effective. With a fresh biomass of 10-12 t/ha about 15-20 kg of N/ha is being provided to the soil enriching its fertility thereby providing better yields.
Laser Land Leveling (LLL): The technique was for the first time introduced in Uttar Pradesh at the farm level in 2001. Basically at the field level also there are variations in soil moisture, nutrient status and other parameters in the fields. The LLL gives us the inter field variations and then plan as per the field conditions. The technique of LLL has been reported to increase about 3-4 per cent of net cultivable area as there is fewer requirements for bunds and channels, increase water application efficiency by 50 per cent, crop yields by 15-20 per cent, increases nutrient use efficiency by 15-25 per cent and also reduces weed problems.
Besides these integrated techniques like integrated weed management, integrated disease management, integrated nutrient management are also an important part of conservation agriculture. These techniques make the best possible use of chemical physical, biological and cultural methods to control diseases, weeds and nutrient uptake by the crops. Studies have revealed that If Conservation Agriculture practices had been in use for many years, enough organic matter would have been built up at the surface and a layer of mulch would have been formed which would further prevent soil erosion and damage to the profile of the soil.
(The authors are from Advanced Centre for Rainfed Agriculture (ACRA); SKUAST-J)