Synergic effect of N and moisture on biochemical property of nodules and seed yield in chickpea

Water stress often has a negative effect on nodulation and seed yield in legumes but this effect can be minimized through N management. This study determined the synergic effect of water stress and N fertilization on the biochemical property of nodules, biomass partitioning among shoot, roots and nodules, and seed yield in chickpea. The cultivar ‘CDC-Frontier’ inoculated with and without Mesorhizobium cicer was grown at various rates of N fertilizer under high (90% field capacity), medium (60%) and low (30%) moisture levels in controlled environments. There was a significant synergic effect of N and moisture on nodulation and productivity. The seed yield of non-inoculated chickpea receiving zero N (0N) was reduced by 174% at high, 90% at medium, and 50% at low moisture levels compared to chickpea receiving 60 kg N ha-1(60N). As soil moisture declined from high to low, the seed yield of inoculated chickpea supplied with 20 to 40N were reduced by 25%, significantly less than the yield loss of 58% for the plants supplied with 0N. Presence of N allowed a lower accumulation of amides in nodules and more N were kept in the nodules. The use of N fertilizer reduced the negative effect of water stress by partitioning more biomass to roots. Stronger root systems allowed plants to absorb more water for the transport of fixed N. In practice, yield losses from ineffective nodulation due to water stress can be minimized with the use of low doses of fertilizer N in chickpea.