Department of Soil Science, G. B. Pant University of Agriculture and Technology, Pantnagar, U.P.
Online published on 25 January, 2012.
Inoculation of seeds of soybean cultivar Bragg with 7 days old broth cultures of SB-16, UPAU-3 and USDA-110 strains and their combinations resulted in increase in yield, nodulation, bacterioid number, leghaemoglobin synthesis and nitrogen fixation by the legume over uninoculated control. Combination of all the three strains recorded the highest nodulation followed by yield and nitrogen fixation by the plant. The efficiency of the composite culture (SB-1+UP AU-3+USDA-l 10) was tested on five spring soybean varieties, viz., Black Hark, Goldsoy, Portage, Harrow Manchu and Grant varieties. The uninoculated control also recorded nodulation which may be due to the presence of native rhizobia in soil. Among different spring soybeans, the variety Goldsoy recorded highest nodulation, bean yield and nitrogen fixation over the other varieties. Negative nitrogen fixation was recorded at 30 days of crop age in all the varieties.
The efficiency of Pantnagar composite culture was compared with other composite cultures obtained from Indian Agricultural Research Institute, New Delhi; J. N. Krishi Vishwa Vidhyalaya, Jabalpur; University of Agricultural Sciences, Bangalore and U. P. Institute of Agricultural Science, Kanpur on two soybean varieties, Bragg and Lee, under field conditions. Variety Lee gave significantly lower yields, nodulation and nitrogen fixation than Bragg. The maximum yield and nitrogen fixation was seen with IARI-1 composite culture closely followed by JNKVV and Pantnagar composite cultures. The effect of the inoculation treatments on the yield of wheat variety Kalyansona was also studied. It was found that the inoculation treatments with majority of composite cultures brought significant increase in grain yield over that of uninoculated treatment except with JNKVV-2 composite culture where the grain yield was not statistically different. Organic amendments like farm yard manure and poultry manure to soil increased the bean yield and nitrogen fixation by soybean to an appreciable extent.
