Effect of tillage on growth, yield and nutrient uptake in wheat after rice in the Indo-Gangetic Plains of India

A 3-year field study was conducted during 1998/99-2000/01 on the effect of tillage on crop growth, yield and nutrient use in wheat (Triticum aestivum L.) grown after different methods of rice (Oryza sativa L.) seeding. Treatments comprised three methods of rice seeding, viz. direct seeding (unpuddled), manual transplanting and mechanical transplanting by self-propelled rice transplanter as main plots and three tillage levels in wheat (conventional tillage (CT), reduced tillage (RT), zero tillage (ZT)) as subplots. Results indicated that tillage significantly decreased soil bulk density (1·59 Mg/m3) over the zero tillage system (1·69 Mg/m3). Greater root density in terms of root dry weight (7·50 Mg/20 cm row length) was recorded in CT and the lowest root dry weight (5·80 Mg/20 cm row length) was obtained in ZT during 2000/01. Significantly higher dry matter accumulation (254 g/m row) and leaf area index of wheat (3·04) were consistently recorded under direct seeding of rice, which was statistically different from the other methods of seeding adopted in the preceding rice crop. CT resulted in significantly higher dry matter (253 g/m row) and leaf area index of wheat (3·02) than RT and ZT respectively, during 2000/01. The highest mean yield of wheat (6·02 Mg/ha) was obtained in direct seeding of rice, followed by mechanical and manual transplanting. Among different tillage levels, CT recorded the highest mean yield of wheat (5·90 Mg/ha) followed by RT (5·82 Mg/ha) and ZT (5·40 Mg/ha). The yield reduction was in the order of 11·28 and 6·31% under ZT and RT, respectively. Soil chemical analysis showed that available soil N, P and K contents were affected significantly due to seeding method and tillage after each cycle of rice-wheat sequence. Significantly greater available soil N, P and K were recorded under direct seeding of rice followed by manual and mechanical transplanting. CT recorded significantly lower values of available soil N and higher values of soil P and K whereas ZT recorded higher values of available soil N and lower values of available soil P and K during the 3 years of study.