RESPONSE OF TWO SOYBEAN CULTIVARS TO DIFFERENT LEVELS ORGANIC FERTILIZER (COMPOST)

Abstract

Two field experiments were conducted to study the response of two soybean cultivars to different levels of organic fertilizer (compost) on nodulation, nitrogen fixation, growth, yield and yield characters during two successive summer seasons of 2005 and 2006 at the experimental farm of Mallawi Agriculture Research Station, Minia Governerate, Egypt. The soybean cultivars used were Giza 111 and Crawford. Treatments were five different levels of compost, zero, 500, 1000, 1500 and 2000 kg compost/fed compared with the Bradyrhizobium inoculated soybean plus starter dose of nitrogen fertilizer (20 kg N/fed) or uninoculated soybean fertilized with the recommended dose of nitrogen fertilizer (70 kg N/fed). A split plot layout with four replications was used. Results showed that the inoculation with Bradyrhizobium in combination with compost gave significant increases in nodule number and dry weight as well as dry weight of shoots and nitrogen content compared with the inoculated plants without compost in Giza 111 and Crawford cultivars. Also, results showed the superiority of Giza 111 cultivar for increasing nodulation, growth, yield and its components (nodule number and dry weight, shoot dry weight, seed and straw yields/fed, plant height, branches number and pods number per plant, seed weight/plant and 100- seed weight,). As well as results revealed that all different levels of compost increased significantly growth, seed yield and its components as compared with the control. The highest increase was recorded with 2000 kg rate of compost /fed. followed by 1500 kg/fed. The highest values of plant height, branch number, pods number, seed yield/plant, 100-seed weight, seed and straw yields were obtained from the interaction between Giza 111x 2000 kg compost/fed. It can be stated that applying different compost levels to soybean plants was the recommended for raising soybean productivity and reducing the environmental pollution under condition of the present study.