Productivity Enhancement of Soybean Through Appropriate Planting Geometry and Canopy Manipulation in Maize-soybean Intercropping to Mitigate Changing Climate

Abstract

Soybean remains in stress due to shading effect of maize in maize soybean intercropping system especially during autumn crop cultivation. Appropriate planting geometry with canopy manipulation of maize would pave the way to improve productivity of soybean in maize soybean intercropping, thereby mitigating changing climate. Considering the aforementioned facts, study was conducted in the Agronomic Experimental Area, University of Agriculture Faisalabad in Autumn 2020-21; repeated in Autumn 2021-22. In the experiment, three planting geometries i.e. PG1: 60 cm apart double row bed plantation, PG2: 75 cm apart single row ridge plantation and PG3: 75 cm apart double row ridge plantation and four canopy manipulation techniques of maize i.e. CM1: No leaf removal and no detasseling of maize, CM2: Removal of 2 top leaves of maize, CM3: Detasseling of maize and CM4: Removal of 2 top leaves and detasseling of maize were implemented following RCBD in split plot arrangement under three replications having 3 m x 7 m gross plot size. The recorded data was statistically computed using Fisher's analysis of variance procedures, and the means of the treatments were compared using the Least Significant Difference (LSD) test at the 5% probability level. Results revealed that during both study years, most of the yield and growth-related metrics of soybean were significantly influenced by planting geometry (PG) and canopy manipulation (CM) of maize in maize-soybean intercropping, its maximum stem diameter (0.42 cm and 0.41 cm), pods per plant (44.33 and 41.66), seed yield (1.01 t ha^-1 and 0.99 t ha^-1), biological yield (3.40 t ha^-1 and 3.33 t ha^-1), seed protein contents (38.69% and 38.09%), CGR and NAR were observed with the treatment PG3CM4. However minimum values of all above mentioned soybean parameters were observed with treatment PG2CM1. Overall, during both the years (Autumn 2020-2021 and Autumn 2021-22), maximum BCR (1.96 and 1.89 respectively) values were also recorded with PG3CM4. It was concluded that 75 cm apart double row ridge plantation of maize (intercropped with soybean) with removal of 2 top leaves and detasseling is a feasible and economical strategy for soybean to attract the farming community of maize belt.