Growth and yield response of chickpea to Rhizobium inoculation: productivity in relation to interception of radiation

Crop productivity may be increased by manipulating management practices that enhance resource capture and utilisation during yield formation. This study aimed at assessing the effect of Rhizobium inoculation on growth, yield and radiation use of two chickpea cultivars at Thohoyandou, South Africa in winter 2011 and 2012. Nodulation was determined at flowering, crop biomass and grain yield were determined at harvest maturity, intercepted total radiation was determined by measuring photosynthetically active radiation above and below the crop canopy at 7-days intervals using an AccuPAR ceptometer, and radiation use efficiency was calculated as ratio of yield to intercepted total radiation. Number and weight of nodules per plant were greater with inoculation compared with the control. There were no significant differences in crop biomass, grain yield, harvest index, intercepted total radiation and radiation use efficiency between Rhizobium inoculation and the non-inoculated control. The low yield and non-significant effect of Rhizobium inoculation suggest that (i) the productivity of chickpea was probably constrained by factors other than nitrogen deficiency; or (ii) there was no difference in nitrogen fixation between the inoculated and non-inoculated treatments. However, further field trials should be conducted, over several seasons, before any definite conclusions can be drawn.