Abstract
Field trial was conducted under low fertile sand soil conditions to follow up the role of organic additives with presence and absence of compatible bacterial inoculum in enhancement of peanut growth and yield. Bradyrhizobium spp. (foreign strain USDA 3456), inoculation resulted in relative increase of seed yield, as average, by about 5% over the un-inoculated plants despite of organic additive source. Similarly, organic additives had increased the seed yield, in average, over the non-treated plant which relatively accounted for 5%, 16% and 37% as affected by animal manure, leuceana residues and quail feces, respectively. On overall means basis of N uptake by seeds, comparison between organic additives indicated the superiority of animal manure over both of leuceana residues and quail feces.
Nitrogen derived from mineral fertilizer seems to be higher in absence of organic manure and tended to decrease with addition of different organic amendments. Accordingly, the portion of fertilizer-N remained in soil after harvest was, in general, very low especially under organic amended soil and in absence of bacterial inoculation. Nitrogen derived from air by different plant parts on the basis of overall means indicated higher records accounted for 45.22 kg ha-1 with treatment leuceana residues followed by quail feces (45.22 kg ha-1) and animal manure (32.89 kg ha-1), respectively but all of them were superior over the un-treated treatment. Portion of N derived from organic sources was higher in seeds and straw than roots and seed cover, respectively.