ROOT ARCHITECTURE AND RHIZOSPHERE DYNAMICS IN VEGETABLE CROPS: IMPLICATIONS FOR NUTRIENT USE EFFICIENCY AND PRODUCTIVITY

Abstract

Restricted ability to acquire nutrients deeply in the soil may be due to the use of shallow-rooting systems, high input of fertilizers, and the multiple irrigation cycles used in the production of vegetables. In varied subsurface soil moisture conditions, root system architecture and the related physiological processes help determine vegetable crops ability to acquire, translocate, and utilize nutrients. There are differences in the ability to acquire the three major nutrients i.e. nitrogen, phosphorus and potassium, due to root length density, the presence of laterals, root hairs, and the distribution of roots in the soil. Different crops (leafy, fruiting, and root) behave differently and have different strategies and fertilization requirements, therefore, distinct nutrient foraging patterns in the root system. The uptake of nitrogen is the result of the synergistic action of transporters and the allocation of carbon to the roots, while the acquisition of phosphorus is, the result of expanded root surface area and the ability of the root system to adapt to low phosphorus availability. Under intensive management, potassium uptake is essential for osmotic regulation, activation of enzymes, and stress tolerance. A concerted understanding of both the physiological and architectural elements on root systems, can provide ways to improve nutrient use efficiency, and at the same time, lower reliance on fertilizers. The ability of root systems in vegetable crops is understudied, and the relationships between root systems and productivity is poorly understood. Selection for root traits in breeding and management has the greatest untapped potential in the production of vegetables.