The Effect of Rhizobia Inoculum and Mineral Fertilizers on the Number of Root Nodes, Growth, and Yield of Groundnut

Abstract

Abstract This study was initiated to evaluate the effect of root inoculum or fractionation of mineral fertilizers on the number of root nodes, growth, and yield of groundnut. A field experiment was carried out in one of the fields located on the right bank of the Euphrates River in the city of Heet, western Iraq, during the summer season of 2022. A randomized complete block design (RCBD) was used with three replications. This study included five combinations of rhizobia inoculum with a percentage of mineral fertilizer as follows: Mineral fertilizer according to the fertilizer recommendation, inoculation with rhizobia bacteria only, rhizobia inoculum with 25% of the mineral fertilizer recommendation rhizobia inoculum with 50% of the mineral fertilizer recommendation, rhizobia inoculum with 75% of the mineral fertilizer recommendation. Rhizobia inoculum was prepared from root cuttings of field pistachio plants grown in pots before starting the field experiment. The results of the experiment showed that inoculation with rhizobium bacteria increased the average number of root nodes in the advanced stages of plant life, while the treatment of 50% mineral fertilization was superior in the early and advanced stages of plant life in the number of root nodes, in addition to its superiority in the number of pods per plant with an average of 123.5 pod-1. Thus, it was possible to replace 50% of the mineral fertilizer, reduce pollution, and save the price of mineral fertilizer.