Abstract
As part of a program to develop a weather-driven model to predict yield and quality of green beans that also describes the accumulation and distribution of nutrients by these plants, we required information on the evolution of the N, P and K content and concentration within the crop. A field experiment with three widely grown green bean cultivars ( Phaseolus vulgaris L. cv. Carlo, Cleo and Mutin) was made with eight sowing dates over 2 years. Water and nutrients were supplied to ensure that they would not limit plant growth. Weather data was collected hourly. Dry matter accumulation and the concentrations of N, P and K in the shoots were determined each week. The concentration of N was related to thermal time by a logistic equation, while P concentration was linearly related to thermal time in the early stages of development but became constant later on. A model that combined the effects of developmental stage and temperature, or saturation vapour pressure deficit, explained the concentration of K. Upper and lower boundary lines were adjusted to total uptake of nutrients, representing the maximum or minimum amount of each nutrient present in the above-ground tissues in relation to thermal time. The harvest index of nutrients depended on the partition of dry matter between pods and shoots, according to a logistic function, and the concentration of nutrients in the pods and shoots.
Published Version
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