Influence of Soil Moisture and Fertilizer Potassium on the Vegetative Growth of Mungbean (Vigna radiata L. Wilczek) and Cowpea (Vigna unguiculata L. Walp)

Abstract

Tropical food legumes are grown in a wide range of environments, and water stress is considered the principal environmental factor limiting growth and yield. Potassium fertilizer mitigates the impact of water stress in plants. However, the benefits of potassium in overcoming stress in tropical food legumes have not been investigated in comparative studies. The purpose of this study was to determine the benefits of potassium in overcoming water stress in mungbean and cowpea, two important tropical food legumes with different adaptabilities to soil moisture regimes. The experiment carried out under controlled conditions placed emphasis on vegetative growth and selected physiological parameters. The impact of potassium was different in the two legumes grown at optimal and suboptimal soil moisture. Potassium increased shoot growth of mungbean to a greater extent than in cowpea under suboptimal moisture conditions. The roots of cowpea showed a greater response to potassium fertilizer than in mungbean under suboptimal soil moisture. The plant water relations and photosynthetic rates of mungbean were improved to a greater extent by potassium under suboptimal soil moisture than those of cowpea. Although differences were observed in the responses of the vegetative growth of these species to moisture and potassium, in overall terms potassium promoted growth of both species when subject to suboptimal soil moisture. While field studies are required to validate the results, the application of potassium fertilizer can be considered a significant factor in overcoming soil moisture stress in these legumes commonly grown in tropical cropping systems.

Invasiveness of Cut-Leaf Ground-Cherry (Physalis angulata L.) Populations and Impact of Soil Water and Nutrient Availability

“…Moreover, well-watered plants produced significantly more leaves in comparison with all other plants, probably because of more profuse branching. This significantly higher vegetative growth of well-watered cut-leaf ground-cherry plants is consistent with the concept found in many other plants of arid environments (including drought-tolerant species) where vegetative growth is significantly enhanced by the supply of adequate soil moisture (Sangakkara et al, 2001;Rahlao et al, 2010).…”

Salt stress manifestation on plants, mechanism of salt tolerance and potassium role in alleviating it: a review

“…Potassium is essential for protein synthesis, activation of enzymes and photosynthesis; osmoticum mediating cell expansion and turgor driven movements and competitor of Na + under salt stress (Hu, Schmidhalter, 2005). Several studies have shown that application of potassium mitigates the unfavourable effects of salinity through its role in stomatal regulation, osmoregulation, energy status, charge balance, protein synthesis and homeostasis (Sanjakkara et al, 2001;Mahmood, 2011).…”

Plant Water-Stress Response Mechanisms

“…The relative amounts of K + , Ca 2+ , and Mg 2+ increased considerably more in barley than in rye when water stresses were imposed [150]. Potassium contributes to osmotic adjustment as one of the primary osmotic substances in many plant species [161,162] and under water stress conditions, K + application is beneficial for plant survival with improved plant growth [163,164]. There are a few reports indicating that water stress favored increases in K + [147] in plants such as maize [145], drought-tolerant wheat varieties [160], creeping bentgrass [165] and Ammopiptanthus mongolicus (evergreen xerophyte shrub) [166].…”