Reduced and zero-tillage options for establishment of wheat after rice in South Asia

Summary

One of the major constraints to higher production of wheat on the 12 million hectares of rice-wheat grown in the Indo-Gangetic flood plains of South Asia is late planting and resultant poor plant stands. Late planting results in a linear decline in yield potential equivalent to 1–1.5% loss ha^-1 d^-1 when planting occurs after November. Late harvest of the previous rice crop or long turnaround time from rice harvest to wheat planting are two major causes of late wheat planting. Reduced or zero-tillage options are proving effective in overcoming late planting and poor plant stands in the rice-wheat systems of Asia. This paper presents data on zero-tillage systems, ranging from surface seeding to planting with four-wheel tractor seed drills, resulting in higher yields at lower costs and savings in fuel use and tractor wear and tear. Reduced tillage systems include ‘data-using’ drills that combine land preparation and seeding in one operation. Both two and four-wheel tractors have been used to achieve good results. This paper concludes that conventional tillage systems can be replaced by more economic reduced tillage options. However, it is important with reduced tillage that soil moisture at seeding is maintained at a high enough level to keep soil strength low, as occurs in tilled soils. Some longer term research is needed to determine medium term positive or negative effects of reduced tillage on sustaining wheat yields.