Dryland Grain Sorghum (Sorghum bicolor) Yield and Yield Component Responses to Tillage and Mulch Practices Under Subtropical African Conditions

Abstract

In the African subtropical zones, the choice of tillage practice is critical to sustainable rainfed crop production. Two season (2015 and 2016) field trials were conducted at Matopos Research Institute (20 240S; 28 290E, 1340 m above sea level) in southern Zimbabwe in order to determine dryland grain sorghum yield and 1000 kernel weight responses to tillage and mulch practices under African subtropical conditions. Sorghum grain yield was highest in planting basin tillage plots under 4 T ha-1 sorghum stover mulch application (3140.9 kg ha-1 for year 2015 and 3415.7 kg ha-1 for year 2016). The 1000 kernel weights in both years were least in ripper tillage and greatest in planting basin tillage field trial plots. The mass of 1000 sorghum kernels on planting basin tillage subplots under 2 T ha-1 sorghum stover mulching was 8.6 g (25.1%) and 8.4 g (24.2%) in excess of that recorded on mulched ripper subplots for 2015 season. For the season 2016, mass of 1000 sorghum kernels on planting basin tillage subplots under 4 T ha-1 sorghum stover mulching was 9.1 g (22.9%) and 8.4 g (21.1%) in excess of that recorded on mulched ripper subplots. The adoption of the planting basin tillage under sorghum stover mulching, a technology designed for smallholder farmers with limited access to animal draft power, can improve considerably the dryland sorghum grain yield and weight of 1000 kernels.