Tillage and legume mulching effects on moisture conservation and productivity of rainfed maize (Zea mays)wheat (Triticum aestivum) cropping system

Abstract

A field experiment was conducted at Selakui, Dehradun from 2001 to 2004 to study the effect of tillage, viz. con- ventional tillage (CT) and minimum tillage (MT); and weed-control practices, viz. chemical and mechanical weed- ing along with legume mulching, viz. in situ grown sunnhemp (Crotalaria juncea L.) and subabul [Leucaena leucocephala (Lam.) de Wit] on soil moisture conservation, crop productivity and soil health in maize (Zea mays (Triticum aestivum L. emend Fiori & Paol.) cropping system. CT gave higher grain yield of maize (+0.11 to O. 17 t/ha), but wheat performed equally well under CT (2.48 tiha) and MT conditions (2.36 t/ha). Chemical weeding with herbicides (alachlor in maize and isoproturon in wheat) resulted in 7.8 and 9.9% higher yield of maize and wheat, respectively over mechanical weeding. Beneficial effect of live mulching with sunnhemp or Leucaena was similar (12.314.7%), while their combined application increased the maize yield by 19.1% over no mulching. Further, enhanced soil moisture conservation due to mulching at maize harvest led to greater productiv- ity of wheat by 16.1% with sunnhemp or Leucaena, and 27.0% with sunnhemp + Leucaena. Nitrogen uptake of maize and wheat increased significantly with chemical weeding and legume mulching, but tillage practices made no effect on wheat while in maize it was lower under MT. Wheat gave 45 times more net retums than maize, and the net B : C ratio of the system was > .O with chemical weeding and legume mulching. Tillage and weed-control practices made no effect on organic C and total N status of soil but legume mulching improved these parameters and reduced bulk density associated with increased infiltration rate. It was concluded that CT along with legume mulching in maize and MT in wheat, and chemical weeding of both the crops was beneficial for improving moisture and nutrient conservation, and achieving higher productivity and profitability of maizewheat cropping system un- der Doon valley conditions.