Effects of soil management practices and tillage systems on soil moisture conservation and maize yield on a sandy loam in semiarid Kenya

Maize is an important crop in the high and medium rainfall areas of Kenya and thus, there is a need for additional information on the effect of tillage and soil management practices on water conservation and yield of maize. The objective of this study was to determine the effects of seven soil management practices: bare with conventional tillage (BC), bare with minimum tillage (BM), incorporated mulch with conventional tillage (IMuC), manure with conventional tillage (MaC), manure with minimum tillage (MaM), surface mulch with conventional tillage (SMuC), and surface mulch with minimum tillage (SMuM) on water conservation and yield of maize. Soil water content was greater in minimum tilled plots than in the conventionally tilled (hand hoeing) plots during the study period. This was demonstrated by the manure with minimum tilled treatment, which had the highest soil moisture (7.6% and 9.3%) both at 0-7 cm and 7-23 cm depth. However, when organic matter additions were analyzed separately, it was observed that manure irrespective of tillage had the highest soil moisture in both depths (7.6% and 8.1%). The differences within the treatments occurred when soil water contents were highest shortly after the rains. When the amount of soil water for each management practice was averaged for all the seasons, a significant difference was found at P = 0.0001. Manure (Ma) and surface mulched (Smu) treatments had significantly higher soil moisture content than the other treatments. The higher moisture content found under these treatments was attributed to higher infiltration rates, better cover that reduced the rainfall kinetic energy, and to better structural stability contributed to by higher organic carbon. Compared with the traditional form of hand hoeing, minimum tillage increased available soil water content drastically and crop performance was improved. Grain yields were greatest in manure and lowest in bare treatments. There were significant differences in grain yield in all treatments.