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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 innovative soil management practices. Tillage, mulch and perennial/annual rotational based systems were compared for 5 years in an Alfisol at ICRISAT in India. Crop yield parameters, including grain and biomass yield, leaf area index, crop cover, and plant height were measured. Results indicate significant benefits to annual crop yield (maize, sorghum) from improved water supply due to mulching with farmyard manure or and rice straw, and due to rotation with prior-perennial crops. Grain yields were 16 to 59% higher in mulched treatments compared to unmulched treatments, with similar increases for fodder yields. Annual crop yields after 4 years of perennials were 14 to 81% higher than unmulched treatments, except for low fertility maize grown after buffel grass. The interaction with chemical fertility was less clear than for water supply. The results have implications for soil management throughout the semi-arid tropics. (C) 1997 Elsevier Science B.V.