Effects of sugarcane (Saccharum officinarum) cultivation on soil quality in the semi-arid tropics of Sudan

Abstract

This study was carried out to determine the effects of cultivation period of sugarcane on some quality parameters of a vertisols. Samples were collected from the 0-30 and 30-60 cm depths of fields (subjected to burning during harvest of cane) cultivated for 29, 25 and 10 years and also from an adjacent fallow area. The samples were analyzed for pH, electrical conductivity (ECe), saturation percentage (SP), bulk density (BD), organic carbon (OC), total N (TN), particle size distribution, dry aggregate stability (DAS), soil organic matter (SOM) associated with sand size fractions (POM) and mineral N (NH4 +-N and NO3 - -N) accumulation during decomposition of soil organic matter. Results showed that cultivation or cultivation period significantly decreased SP, OC, DAS, clay content and amount of soil organic matter size fractions, while cultivation period showed no significant effect on either amount, or content of C and N of these fractions. During early weeks of mineralization of SOM, mineral N was significantly lower due to cultivation as such or in fields subjected to extended periods of cultivation. It is quite evident that the quality of heavy clay soils (e.g. vertisols) would be recovered more easily if the crop residues during harvest of the cane are incorporated into the soil. This is possibly due to the greater physical protection (due to high clay content) of organic matter against break down, thereby, improving their chances of sequestration. It is also concluded that long-term cultivation enhanced removal of fine clay particles, which might results in the long-term creation of a hard pan.

Keywords: Sugarcane, vertisols, soil quality, semi-arid tropics, Sudan