A glasshouse technique (using Phaseolus vulgaris L.) to study canopy competition at equal root volume

Abstract

A glasshouse technique is described which avoids interactions between root volume and nutrient uptake. This technique can be used to study the canopy effects among widely different plant spacings and among one or several cultivars. The technique uses tall thin tubes (pots) for plant support. These tubes allow very close spacing between plants. Continuous nutrient supply promotes growth while constant removal of leached nutrients prevents uneven distribution among plants. The system was successfully tested by conducting several trials in which navy beans (Phaseolus vulgaris L.) were grown at spacings of 36, 225, 400 and 625 cm2 per plant. The yield and some yield components are presented. Yields ranged from 266 to 863 g/m2 for the low to high plant density respectively. This testing phase indicated that several important points need attention. Nutrient type and amount for
each plant type need clarification. Growth behaviour under non-limiting conditions should be known. Most importantly the whole system should receive maximum protection against disease and insect pests.