Defoliation of Autumn Planted Maize Hybrids for Sustainable Intensification of Maize – Soybean Intercropping System

Abstract

In maize-soybean intercropping systems (ICS), the morphophysiological growth traits and grain yield of component crops (CC), especially of soybean suffer adversely owing to the dominance of maize in acquiring growth resources and shading effect. Thus, a field trial was conducted entailing maize hybrids (H1= YH-1898 and H2= YH-5427) and defoliation treatments (R1= removal of top two leaves, R2= removal of top four leaves, R3= removal of top six leaves, and R4= no removal of leaves) for boosting soybean (cv. AARI-soybean) growth and yield. The response variables included plant height (PH), 1000 grains weight, grain yield (GY), and biological yield (BY) along with the physiological growth traits (leaf area index LAI, leaf area duration LAD, crop growth rate CGR, and net assimilation rate NAR) of CC. The H1 hybrid of maize outperformed the other hybrid by recording 8% and 9% higher PH and BY, respectively, while the H2 hybrid depicted 18% and 6% greater 1000 grain weight and GY, respectively along with NAR. Additionally, R1H2 exhibited the maximum LAI, LAD, and CGR at 30, 60, 90, and 110 days after sowing (DAS). Contrastingly, soybean recorded 11% higher PH in intercropping with the H1 hybrid under R4 defoliation treatment along with significantly higher 1000 grains weight (13%), GY (57%), BY (10%), and NAR (157%). Moreover, soybean exhibited the maximum physiological growth in response to the R4H1 treatment combination. Based on recorded findings, the H2R1 treatment combination could be recommended for boosting maize yield, whereas H1R4 could be adopted to bolster the growth and productivity of soybean intercrop, but at the cost of a significant reduction in maize yield.

Keywords

• biological nitrogen fixation
• row intercropping
• crop growth rate
• leaf removal
• net assimilation rate