Zero tillage technology for planting wheat after rice is presently gaining popularity amongst
the farmers in the Indo-Gangetic Plains of India, Pakistan, Nepal and Bangladesh due to its apparent
advantage of timely planting of wheat within short turn–around time and reduction in cost of
production. The conservation tillage had been a common practice in Arkansas, USA by rice growers
primarily for economic and soil conservation reasons. It has also been widely adopted over the past
20 years in Australia and several other countries. Conservation tillage has been found to influence
the population of soil fungi and nematodes occurring in rice-wheat system. Many plant pathogens
increase to damaging level under zero tillage conditions and become major constraints to efficient
profitable farming while others are reduced to a considerable extent or not affected at all. Leaving
plant debris on the surface or partially buried in the soil may allow a number of pathogens to
overwinter or survive until next crop is planted but conditions favourable for biological control of
plant pathogens may also be increased (Sumner et al., 1981).