Nodulation, nutrient accumulation and yield of rainfed soybean in response to indigenous soybean-nodulating Bradyrhizobia in the Himalayan region of Kashmir-Pakistan

Abstract

<span>The use of efficient and effective nodulating Bradyrhizobia strains considered as an<br /><span>ecologically and environmentally sound management strategy for soybean production. A 2-yr<br /><span>(2009 and 2010) field experiment was conducted to evaluate the effects of seven indigenous<br /><span><em>Bradyrhizobium </em><span>strains, one exotic TAL-102 and three N fertilizer rates, i.e., 25, 50 and 100<br /><span>kg N ha<span>-1 <span>on the productivity and N<span>2 <span>fixation of rainfed soybean [<span><em>Glycine max </em><span>(L.) Merr.] grown<br /><span>in the Himalayan region of Rawalakot Azad Jammu and Kashmir (AJK), Pakistan. The<br /><span>experiment was conducted in a randomized complete block design with three replications.<br /><span><em>Bradyrhizobium </em><span>inoculation accelerated plant growth by increasing shoot length (26-47%), root<br /><span>length (45-73%) and shoot dry weight (58-104%). Seed yield in the control was 861 kg ha<span>-1 <span>that<br /><span>significantly increased to 1450–2072 kg ha<span>-1 <span>with <span><em>Bradyrhizobium </em><span>strains. Seed yields under<br /><span>indigenous NR<span>20 <span>and NR<span>22 <span>strains was 24 and 28% higher than that recorded from the exotic<br /><span>TAL-102. Number of nodules, nodules dry weight and acetylene reduction assay with<br /><span><em>Bradyrhizobium </em><span>strains were 55–123%, 94–178% and 38–103%, (respectively) higher than<br /><span>the non-inoculated control. The higher N rate (N<span>100<span>) depressed nodulation and N<span>2 <span>fixation.<br /><span>A significant variation in the symbiotic effectiveness and yield potential showed that inoculation<br /><span>response was site/strain specific. Two indigenous strains NR<span>20 <span>and NR<span>22 <span>were found highly<br /><span>efficient and displayed superiority over the exotic strain TAL-102. Multi-locational trials are<br /><span>required to check the suitability of these isolated isolates for other agro-climatic conditions<br /><span>before using as inoculants or bio-fertilizers.</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span><br /><br class="Apple-interchange-newline" /></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>