Tillage effects on selected soil physical properties in a maize-bean intercropping system in Mwala District, Kenya

A field study was carried out to evaluate the effects of tillage practices on soil physical properties in Mwala district, Eastern Kenya, duringthelongrains(LR)andshortrains(SR)of2012/13.Thetreatmentswerediscploughing(DP),discploughingandharrowing (DPH), ox-ploughing (OX), subsoiling-ripping (SSR), hand hoeing with tied ridges (HTR), hand hoeing only (H). These were investigated under three cropping systems of sole maize, sole bean, and maize-bean intercrop in a split-plot design with four replications. Soil physical properties were monitored at different weeks aſter planting (WAP) throughout the growing seasons. A four-season average shows that soil moisture content was significantly (푃 < 0.05) higher in OX > SSR > DPH > H > HTR > DP with values ranging from 13.1 to 14.1%. Soil surface roughness and crust strength varied significantly (푃 < 0.05) over time within the growing seasons, between the tillage practices, and across the different seasons with values ranging from 26 to 66% and 1.21 to 1.31MPa, respectively. Tillage practices and cropping systems did not significantly affect bulk density, porosity, or 퐾sat values. It is apparent that long term tillage experiment (>4 seasons) would be required to detect changes in soil physical properties as a result of the soil management practices.