Improvement of Soybean Growth and Yield (Glycine max L.) by Inter-row Stripe Tillage in Upland Fields Converted from Paddy Fields

Abstract

We adopted ‘inter-row strip tillage’ (IST), which involves conducting tillage between rows and sowing on no-tillage soil, to cultivate soybeans in upland fields converted from paddy fields (UFCP) and examined the effect on soil water content, growth and soybean yield. The three phase of no-tillage soil in IST differs from soil harrowed via conventional tillage, which shows lower solid and liquid phases. No-tillage soil in IST showed a larger water content under drought conditions and less fluctuation of the liquid phase between conditions of drought and excess moisture compared to those of harrowing soil in conventional tillage. The plants in IST had more root nodules and showed higher SPAD values. They were also longer, with more nodes on the main stem, and a larger dry weight at the flowering stage. The IST yield exceeded that in conventional tillage, due to the higher number of pods and 100-kernel-weight. The factors of superior growth and higher IST yield were attributed to the property of the no-tillage soil in IST, which alleviates the fluctuation of the soil water content in UFCP. The relationships between soil permeability and property remain to be evaluated, while there is also a need to improve the IST operational efficiency.