Effects Of Selected Conventional And Conservation Agriculture On Soil Moisture Content, Infiltration And Maize And Pearl Millet Grain Yield In Liselo And Mashare: Namibia

Abstract

This study focused on the results from the 2016/17 and 2017/18 cropping seasons from two trials, one in Liselo and the other in Mashare in the Kavango East and Zambezi regions of Namibia, respectively, on the effects of Conventional and Conservation Agriculture (CA) practices and principles on soil moisture content and infiltration. Conventional mouldboard ploughing (CTa), Sub-soiling with a Magoye ripper (SS-M) and Manual direct seeding with a Dibble stick (MDS-M) were the primary treatments of interest in the CA Systems Trial. In Both seasons, average soil moisture content, total water infiltration and runoff were not significantly affected by tillage systems treatments. The treatments of interest in the Component Trial were Conventional tillage (CT), Minimum tillage (MT), Minimum tillage, mulch (MT-M), Minimum tillage, rotation (MT-R) and Minimum tillage, mulch and rotation (MT-MR) were. Significant differences (p=0.000) were observed with regard to soil moisture content in the 0-30cm and 0-60 cm soil depths on the Component Trial at both sites.MT-M plots had the highest soil moisture content of 14.5mm and 39.8mm at Liselo Research Station (LRS) and 44mm and 134.5 mm at Mashare Irrigation Training Center (MITC) for the 0-30cm and 0-60cm soil depths, respectively over the study period. Conventional Tillage (CT) with a mouldboard plough in both localities LRS and MITC had lower average soil moisture content in both 0-30cm and 0-60cm soil depths than most CA treatments. Regarding the Component Trial, a significant difference on grain yield was only observed at MITC in the first season (p=0.0496) and in the second season at LRS (p=0.0206). CT(1783.0 kg ha-1) had the highest pearl millet grain yield, followed by MT-M (1562.0 kg ha-1) and MT (1520.8 kg ha-1) had the lowest pearl millet grain yield. CT (3852.3 kg ha-1) had the highest maize grain yield and MT (2524.0 kg ha-1) had the lowest maize grain yield. Results suggest CA has the potential to increase water conservation and contribute to reduction of risk of crop failure, as was observed at MITC where CA plots had more soil moisture content than conventionally tilled plots.

Keywords: Conventional Tillage, Conservation Agriculture, grain yield, run-off, soil moisture content, total infiltration