Effect of Tillage on Soil Fertility and Sunflower Yield in Southwest Nigeria

The study investigated response of sunflower (Helianthus annus L.) to tillage methods and soil properties in the rainforest zone of southwest Nigeria. Soil and plant nutrient omposition and yield of sunflower determined for soils produced by Zero Tillage (ZT), disc Ploughing (PL), Ploughing plus harrowing (PLW), Ploughing plus Ridging (PLR), Ploughing plus two passes of Harrow (PLHH) and two Ploughings (2PL) were compared. Tilled soils had less moisture content but higher organic matter, N,P,K, Ca and Mg contents compared with ZT soil. Seed weight of sunflower was not significantly different among tillage treatments. Soil and plant nutrient contents increased in the order ZT, PL, PLH, PLR, PLHH and 2PL.