Evaluation Of The Response Of Two Soybean Varieties To Rhizobia Inoculation For Improved Biological Nitrogen Fixation.

Soybean Glycine max .L is an important food crop in Rwanda and has recently been identified as one of the priority crops for the Crop Intensification Program CIP for the country. However its productivity is low standing at about 0.8 tha against the potential of 3-5 tha depending on the varieties used. The use of organic and inorganic fertilizers to increase soybean productivity is constrained by their high cost to most small scale farmers. Use of farm yard manure is also limited by the unavailability of livestock to most soybean growers. In this regard the most viable alternative to fertilization would be deployment of Nitrogen-fixing microorganisms to soybean farming systems. These however need to first be tested on the available soybean varieties. A field experiment was carried out in Nyarubaka sector of Kamonyi District to evaluate the response of two soybean varieties Peka6 and SB24 to Rhizobium inoculation without limitation of phosphorus. The experiment was laid down in completely randomized block design with three replicates. The results obtained showed significant differences P 0.05 in grain yields and nodules mean score between inoculated and no inoculated treatments. The variety Peka6 responded to the Rhizobium inoculants more than SB24. Although further studies need to be conducted to obtain conclusive information on these Nitrogen fixers the study indicates that Peka6 in combination with the right Rhizobia inoculants could be recommended to replace conventional fertilization for our poor farming households