Minimum Tillage and Soil Surface Cover Reduced Weed Density but Not Diversity Over Four Growing Cycles

Abstract

This study investigated use of cultural practices to address weed challenges that present one of the highest costs to farmers. The parameters explored included the effects of tillage and soil cover practices on weed density and diversity, evaluated in a split plot experimental design. Increasing rainfall amounts significantly increased weed density and weed diversity. Minimum tillage significantly suppressed weeds with a density of 80/m2 compared to conventional tillage density of 124/m2. Soil cover practices similarly suppressed weed density (p<0.05) compared to sole crops without soil cover intervention. Maize with mulch had the lowest density (64/m2) followed by maize intercropped with one line of soybean between maize being more effective in weed suppression (92/m2 vs 113/m2). Sole maize and sole soybeans treatment both had a density of ~121/m2. Weed diversity, as measured by Shannon-Weiner index and Simpsons index were not statistically different across treatment (p>0.05). However, weed species count was higher in minimum tillage by 05% compared to conventional tillage, hence it calls for investment in minimum tillage and intercropping practices to allow a more diverse weed community that will be less competitive, less prone to dominance by highly adapted weeds, hence promoting ecological sustainability.