Effects of isoxaflutole on the growth and nodulation of chickpea ('Cicer arietinum') under different soil nitrogen rates

Abstract

The growth and nodulation response of one isoxaflutole tolerant and one sensitive chickpea cultivar was assessed with differing soil nitrate levels and isoxaflutole rates. The sensitive cultivar was more susceptible to isoxaflutole damage with increasing herbicide rate and nitrate levels but detrimental effects of isoxaflutole occurred with both cultivars. Some damage was observed with the tolerant cultivar at the highest herbicide rate and nitrate levels. In general, isoxaflutole decreased shoot and root dry weight, nodule number, and nodule dry weight of the sensitive cultivar. Herbicide applied at the recommended rate reduced nodule dry weight of chickpea by 51% at 6mM nitrate level. Nodule number of the tolerant cultivar declined by 30% at the recommended herbicide rate. Nodule dry weight declined with increasing nitrate levels without herbicide application, and addition of herbicide caused a further reduction.