Influence of Cobalt, Water Quantities, and Crop Sequence on Growth and Yield of Common Bean in Nematode-Infested Soil

Abstract

Egyptian agriculture faces a number of accelerating concerns to satisfy food security for over-population increase, avoid lack in the available water resources, challenge expected climatic changes, and manage crop pests and diseases. Hence, horizontal and vertical expansion in Egyptian agriculture is desperately needed. The present study assessed the effect of three components of such an expansion on growth parameters and yield of common bean (Phaseolus vulgaris) planted in reclaimed land. Bean plants irrigated once with cobalt sulphate at concentrations 0, 8, 12, 16, and 20 ppm promoted plant growth parameters and pod yield. Nevertheless, the highest cobalt concentration, 20 ppm, indicated inferior growth parameters (P ≤ 0.05) relative to one or more of its other applied concentrations. The standard amount of water usually required to irrigate common bean planted in reclaimed land mostly showed better (P ≤ 0.05) plant growth parameters and yield than low amounts; i.e. 80 and 60% of the standard water supply. Cobalt supplement under different moister levels (100%, 80%, and 60%) gave better yield than untreated check. As cobalt concentration increased and/or water supply decreased, abscisic acid contents in plants were enhanced. Plantparasitic nematode levels were not detectable before bean cultivation probably due to fallowing and sanitation practices which preceded bean cultivation. Also, the levels of the root-knot nematode, RKN (Meloidogyne arenaria), as devastating pathogen of common bean worldwide, were low or non-detectable at harvest but reached a damaging level on broad bean in adjacent field. Given the country's ambition to dramatically expand agriculture horizontally via such reclaimed lands which favor RKNs, an example of crop rotation system with possible modifications and guidelines to manage the nematodes was presented.