MAIZE GROWTH-RESPONSES TO DEEP TILLAGE, STRAW MULCHING AND FARMYARD MANURE IN COARSE-TEXTURED SOILS OF NW INDIA

The effects of deep tillage, straw mulching and farmyard manure on mai ze growth in loamy sand and sandy loam soils were studied in experimen ts lasting three years. Treatments included all combinations of conven tional tillage (10 cm deep) and deep tillage (35-40 cm deep), two farm yard manure rates (0 and 15 t/ha) and two mulch rates (0 and 6 t/ha), replicated three times in a randomized block design. Deep tillage decr eased soil strength and caused deeper and denser rooting. Mulching dec reased maximum soil temperature and kept the surface layers wetter res ulting in better root growth. Farmyard manure also improved root growt h, and the crop then extracted soil water more efficiently. All three treatments increased grain yield in the loamy sand, but in the sandy l oam only tillage and farmyard manure increased yields significantly. D eep tillage and straw mulch effects varied with soil type and amount o f rainfall in the growing season. In the loamy sand the mean responses to deep tillage and mulching were largest in a dry year. A tillage-mu lch interaction was significant in the loamy sand.