The way vegetables are grown and handled after harvesting is truly appalling. High levels of pesticide residue, owing to indiscriminate and unsafe use of chemicals on vegetable crops, is just one problem, albeit the most critical one. Some farmers - and even vegetable traders - dip the harvested vegetables in chemicals to extend their shelf life, or use colouring agents to enhance their customer appeal, aggravating the menace of the toxic residue.
Such imprudent use of chemicals, besides being a health hazard, leads to drug resistance among pests by making them more aggressive. It also destroys beneficial micro and macro agents present in the soil and the local environment. Many vegetables, especially those dug out from the ground, such as carrots and radish, are often washed in nallah (drain) water, causing microbial contamination. Fertilisers, too, are applied arbitrarily and pollute both soil and subsurface water.
The Food Safety and Standards Authority of India is working on safety norms and quality standards, conforming to the sanitary and phyto-sanitary standards followed in the international market, to facilitate vegetable exports. Farm scientists, on the other hand, are evolving eco-friendly technologies for growing vegetables to minimise, if not wholly eliminate, the use of harmful chemicals. The Varanasi-based Indian Institute of Vegetable Research (IIVR) has a slew of such technologies to offer, many of which have, in fact, already reached vegetable growers. These techniques help raise bumper crops with lower cost, and without impairing the environment or posing health hazards.
The key technology here is the integrated pest management (IPM) that protects the crops from diseases and pests with least use of chemicals. In the process, it reduces damage to ecology and natural resources such as soil and water. While the key principles of IPM are the same across the board, their finer elements have been modified to suit individual vegetable crops.
The IPM methodologies broadly involve the use of healthy seeds of crop varieties resistant to major diseases and pests; treatment of seeds with biological infection control agents; application of herbal and other harmless plant protection substances; and judicious scheduling of crop planting and harvesting to escape pest attack. Besides, farmers are advised to rotate vegetable crops with cereals and other crops to break the breeding cycle of pathogens and pests.
This apart, IIVR has come out with numerous varieties of different vegetable crops possessing tolerance against diseases and pests. The production potential of many of these varieties is 10 to 25 per cent higher than normal. Some of them, notably the kashi kanchan variety of cowpea (lobia), kashi pragati of okra (bhindi) and kashi anmol of chilli, have clocked a yield advantage of 20 per cent over the commonly cultivated types. Reports from the fields suggest that seeds of some of these varieties are sold at a premium. The downside, however, is that many seed suppliers are offering the stuff that may or may not match the authentic seeds. It is, therefore, important for farmers to buy seed from reliable sources.
The most significant among the other environ-friendly vegetable production technologies are the "zero-tillage" or "minimum-tillage" system of sowing and soil solarisation (exposure to sun for killing the soil-borne pathogens). Agronomic practices like optimal plant spacing; need-based irrigation; covering of soils with polythene sheets or plant residues (technically called mulching) to reduce moisture loss; drip irrigation; and weed control have also been standardised for different crops. Impact studies have shown that "zero-tillage" technology, involving the sowing of vegetables on permanent ridges and retaining the leftovers of the previous crop in the fields, help slash cultivation cost by Rs 18,000 per hectare. The saving on the use of diesel under this system is estimated at over 60 litres per hectare in a year.
Though IIVR is trying to promote these technologies on its own and through other agricultural research organisations, including the Krishi Vigyan Kendras (farm science centres), the involvement of the government extension agencies is vital. The increased deployment of these techniques will be good for the environment and natural resources as well as farmers and consumers.