This study was conducted to determine the effects of soybean cultivation on yield and other characters in a newly reclaimed soil. Four factors - ① plant density ② compost application ③ innoculation of nodule bacteria (Rhizobium japonicum) combined with lime application ④ NPK application-were examined in a 24 factorial experiments arranged in randomized complete block design with 4 replicates. Kangio variety was used and the results obtained are summarized as follows;
(1) Dense plant population, Application of Compost and application of fertilizer (NPK) gave the yields 1.7, 1.4 and 2.1 times the check respectively. The Combinations of, dense population×compost, dense population×fertilizer (NPK), compost×fertilizer(NPK), and dense population×compost×nodule bacteria with lime×fertilizer (NPK) increased the yields by 2.0, 3.0, 2.6 and 5.4 times than the check respectively. But little effect on yield was noted in the treatment inoculated with nodule bacteria with lime.
(2) In the case of higher yield, the increased weight of 100 seeds was found.
(3) A markedly increased PH was observed in all of the plots under study after the. completion of experiment.
(4) The compost treatment and the ferttilizer (NPK) treatment greatly increased the organic matter, total nitrogen and the available phosphorus in the soil.
(5) The variation in the grain yield appeared to have a close correlation with the content of available P₂O_5 in the soil.
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