A Study of Negative Leaf Defoliation and Plant Population Density on Total Dry Matter Production and Yield in Soybean

Objectives of this research were to determine negative leaf defoliation and proper plant population density in order to increase productivity of the soybean. The research was conducted from June ? August 2013 at the experiment field in Faculty of Agriculture, Brawijaya University. This research applied Split Plots Design in randomized complete block with three replications. Plant population as main plot in row spacing included J1= 20 x 15 cm (666,666 plant ha-1), J2= 30 x 15 cm (444,444 plant ha-1), J3= 40 x 15 cm (333,332 plant ha-1), J4= 50 x 15 cm (266,666 plant ha-1); and negative leaf defoliation (D) was placed as sub plot that included D0 = without defoliation, D1 = Defoliation of 2 trifoliate leaves at the bottom part, D2 = Defoliation of 4 trifoliate leaves at the bottom part. The harvest yield per area unit increases along with the increasing population of the plants. Treatment of low population of plants (266,666 plants ha-1) has increased the harvest yield 22.75% in comparison with high population of the plants (666,666 plants ha-1). Such defoliation of 4 trifoliate at the bottom part will increase the production as it compares with 2 trifoliate defoliations and without defoliation.