The rice-wheat belt is home to 600 million people and more than 240 million residing here consume these products yielded from the cropping system.

In South Asia farmers use this system on over 13 million hectares which includes Pakistan, northern India, Nepal and Bangladesh. China has additional 10 million hectares of rice-wheat area.

In Pakistan this system consumes around 1.7 million hectares. Punjab covers 70 per cent of the total rice area of the country. Around 80 per cent of it is covered by fine Basmati varieties which mature in November.

Farmers remain busy in harvesting, thrashing and handling of rice straw until early December. This along with land preparation delays wheat sowing. The best time to plant wheat after rice is from November 1-21. Thereafter, delay of one day results in yield reduction by 30-35kg per hectare.

The Directorate, On-Farm Water Management, Punjab, initiated the sowing of wheat after rice with zero tillage drill in the Punjab belt. Its advantages are reduction in delayed sowing of wheat, cut in cost of preparatory tillage, saving of "rauni" irrigation, and increase in yield due to early planting. Inspite of the obvious advantages of zero tillage drill, many questions are raised due to the lack of knowledge.

The Agricultural Extension Department of Punjab opposes zero tillage technology on the ground that it would increase rice borer attack on the following rice crop and increase weed population in wheat crop sown after rice.

Field studies in Punjab have shown that rice stem borer larvae do not survive in winter and hence there is no increase of stem borer attack on the subsequent rice crop as compared to the traditional planting system. Zero till drill reduces population of weeds like phalaris minor up to 40 per cent in the first cycle.

To control Kharif weeds in wheat crop a pre-seeding application of herbicides such as glyphosate and paraquat is enough to kill all weeds. Weeds of rice die towards the maturity of rice or in winter and hence poses no major threat to zero tilled sown wheat.

Ratoons of rice do not affect wheat because sprouts begin to die in November. If soil moisture is lost due to strong winds then the farmers should advance irrigation by a week to ensure a good crop.

If soil is relatively dry and pre-sowing irrigation is likely to further delay seeding, it will be best to place seeds within surface 2-3cm and apply a light irrigation immediately after zero till planting to quicken seed germination. Pre-sowing irrigation promotes weeds ahead of crop which can decrease the yield. Weeds should be controlled by herbicides.

The question of burning rice stubbles before seeding wheat causes air pollution and loss of precious nutrients, besides depriving soil from the residual stubble mulch essential for soil and water conservation. This adversely affects microbes, fauna and wheat yield.

Zero tillage has increased from nothing in mid nineties to 0.56 million hectares in 2002-03 in South Asia. Farmers in India, Bangladesh and Nepal are increasingly using this technology as it gives more yield at less cost, saves labour and time.

Farmers who practice this technology overcome the biases but unfortunately in Pakistan this is encouraged due to lack of communication, training, feedback. Farmers should, themselves use this technology and observe the advantages over conventional methods.

The Department On-Farm Water Management should form a group for the introduction of this technology through education, training and demonstration. The department should encourage import of two-wheeler 12 horsepower tractor for preparing soil.

Seeds should be sown in one operation. Bangladesh and Nepal imported 600,000 and 600 of these tractors, respectively by 2001-02. This number has further increased. These are also being manufactured in India with improvements which are suitable under local conditions.

Though, multiple zero tillage technology has been developed for sowing rice, maize, pulses and other crops in many countries but in Pakistan even sowing of wheat after rice has been made a controversial issue. For example, wheat is now seeded after sugar cane.

A disk harrow is used for easy working of zero tilled drill for avoiding damage to drill from hard sugar cane rootstocks. Again, zero-till-fertilizer-seed drill fitted with punch planting openers easily eliminates problems of sugar cane rootstocks or its residues.

The aforementioned facts should be seriously considered by the agricultural managers for developing an effective agricultural policy, especially for small, subsistent and below-subsistent level farmers who cultivate about 62 per cent of the total area.