Root System Architecture and Symbiotic Parameters of Summer Mung Bean (Vigna Radiata) under Different Conservation Agriculture Practices

Abstract

Root system architecture plays a vital role in plant growth, development, and adaptation by absorbing water and nutrients and providing mechanical support for growing plants. Unfortunately, little information is available in the literature on the root dynamics of summer mung bean under conservation agriculture conditions. In this study, field experiments were conducted during the summer seasons of two consecutive years (2020 and 2021) to investigate the root system dynamics of summer mung bean under different conservation agriculture practices. The highest stem and system width, depth to width length, number of nodal roots, taproot diameter, secondary root length (both right and left) of summer mung bean were recorded in the Soybean (permanent bed; PB)-Wheat(PB)-Summer mung (PB)(+Residual; +R) based cropping systems, followed by Maize(PB)-Wheat(PB)-Summer mung (PB)(+R), while, the lowest values of above parameters were recorded in the Puddled Transplanted Rice–Conventional till (PTR-CT)Wheat-Summer mung (-R). Further, the pod length, number of seeds per pod, number of pods per plant, seed yield and symbiotic parameters (including number of nodules per plant, leghaemoglobin content) and root dry weight were recorded highest in Soybean (PB)-Wheat (PB)-Summer mung (PB)(+R). Interestingly, the yield of summer mung bean increased around 13.4–29.5% when residues were retained on the soil surface with treatments involving residual removal. The soil dehydrogenase enzyme activity increased significantly under Soybean (PB)-Wheat (PB)-Summer mung (PB)(+R) based cropping system as compared to PTR-CT Wheat-Summer mung (-R). In addition, the number of pods per plant exhibited a significantly positive correlation with yield during both crop seasons. Overall, this study suggests that the inclusion of summer mung in soybean-based cropping systems may substantially improve the root architecture and soil quality and increase crop yield under conservation agriculture.