SOIL-MANAGEMENT OPTIONS FOR ALFISOLS IN THE SEMIARID TROPICS - ANNUALAND PERENNIAL CROP PRODUCTION

A field experiment was conducted in the semi arid tropics to study the effects of soil structural modification on cropping systems. The aim was to improve crop production and land resource protection using inno vative soil management practices. Tillage, mulch and perennial/annual rotational based systems were compared for 5 years in an Alfisol at IC RISAT in India. Crop yield parameters, including grain and biomass yie ld, leaf area index, crop cover, and plant height were measured. Resul ts indicate significant benefits to annual crop yield (maize, sorghum) from improved water supply due to mulching with farmyard manure or an d rice straw, and due to rotation with prior-perennial crops. Grain yi elds were 16 to 59% higher in mulched treatments compared to unmulched treatments, with similar increases for fodder yields. Annual crop yie lds after 4 years of perennials were 14 to 81% higher than unmulched t reatments, except for low fertility maize grown after buffel grass. Th e interaction with chemical fertility was less clear than for water su pply. The results have implications for soil management throughout the semi-arid tropics. (C) 1997 Elsevier Science B.V.