Effect of Three Different Nitrogen Rates and Three Rhizosphere N2- Fixing Bacteria on Growth, Yield and Quality of Peanuts

Abstract

Raising prices of organic fertilizers, environmental relation of their usage and need for global foodstuff, placed a topic of universal interest in cultivation of legume plants for human nutrients and soil fertility supplementation. Three rates of N fertilizer were studied in the field: 0, 20 and 40 kg N/ha. Three bacterial strains were identified and inoculated in the experiment: Enterobacter asburiae (E. asburiae), Klebsiella quasipneumoniae (K. quasipneumoniae) and Enterobacter cloacae (E. cloacae). The soil samples were taken before and after experiment for chemical attributes analysis. The effect of N2 fertilizer and 3 bacterial strains was on soil chemical properties, yield components and yield of peanut plant. The results of present study showed that application of different N2 fertilizer rates was a little influence on the N2-fixing ability of rhizosphere bacteria, but high effect was significant at the peanut nodule number. In the 3 N fertilizer rates and 3 bacteria, which only had N2 fertilizer rate of 40 kg N/ha and E. asburiae significantly raised the maximum yield component and yield of peanut, while there was the lowest yield component and yield of peanut was observed in N fertilizer rate application of 0 kg N/ha and E. cloacae inoculation. The differences in rhizosphere bacterium strains between different N fertilizer rates was better than that caused by the nitrogen fertilizer amount. This could be due to the substantial improvement in soil chemical attributes at different soils, especially in, pH, OM and total N, as these significantly impacted the soil structure. HIGHLIGHTS Increasing pH, organic matter and total nitrogen of soil were statistically significantly different by 3 N2 fertilizer rates. There is a positive interaction between nitrogen rates and RNFB increasing yield of peanut. Number and weight of peanut nodules obtained the maximum value without applying N2 application compare to other treatments. The maximum yield components of peanut were inoculated with asburiae to compare with K. quasipneumoniae and E. cloacae and applied weight of 40 kg N/ha. The maximum yield of peanut was inoculated with asburiae to compare with K. quasipneumoniae and E. cloacae. GRAPHICAL ABSTRACT