Growth response and N uptake of two soybean varieties on inoculation of Bradyrhizobium sp. in Ultisol Binjai, Sumatera Utara

Ultisol problem is having acidic pH which makes soybean difficult to grow and symbiotic with Brady rhizobium sp. To fixate N. The aim of this research was studied the growth response and N uptake of two soybean varieties on inoculation Brady rhizobium sp. in Ultisol Binjai, Sumatera Utara. This research used Ultisol Binjai with pH 4.5 which was carried out with a pot experiment in the research field of Faculty of Agriculture, Universitas Sumatera Utara, using a Factorial Randomized Block Design with 3 factors. The first factor is Brady rhizobium sp inoculants consisting of without inoculant; BGR3 inoculant; and LP3 inoculant, the second factor is varieties consisting of Anjasmoro and Demas-1. The third factor is liming consisting of without liming and liming with a dose of 7.76 g/10 kg of soil (until pH 5.5). The results of the research showed that application of Brady rhizobium sp inoculant BGR3 was able to increase the N uptake of soybean in Ultisol with an acidic pH which was better than other inoculant. Shoot root ratio tended to increase in Anjasmoro without liming which were application of BGR3 inoculant about 14.15%.