种群密度调控下大豆生物量分配以及产量的响应OA

In this study,a field experiment was conducted in the Hexi arid region of Gansu Province using six density gradients(90 000,135 000,180 000,225 000,270 000,and 315 000 plants·ha-1).The relationship between the biomass(Y)of various soybean(Glycine max)organs and plant density(X)was analyzed using the allometric growth equation Y=aXᵇ,and the variations in the scaling exponent(b)were explored.The results indicated that:1)Plant density significantly affected soybean plant height,basal diameter,and the biomass of different organs(P<0.05).Organ-specific biomass significantly decreased with increasing planting density,indicating clear regulation by density-dependent mechanisms.2)The allometric exponents of the biomass-density relationship varied among organs in the order of reproductive organs(-0.833)<leaves(-0.807)<stems(-0.725)<roots(-0.561).This sequence indicates that the rate of change in response to density was greater in belowground biomass than that in aboveground biomass.3)Soybean yield initially increased and subsequently decreased with increasing plant density,peaking at a density of 225 000 plants·ha-1.4)The biomass allocation patterns among soybean organs did not fully conform to the optimal allocation theory.Plant density significantly altered the biomass allocation ratios of leaves and roots(P<0.05).With the increas of plant density increased,leaf biomass allocation initially increased and then decreased,whereas root biomass allocation showed the opposite trend.However,biomass allocation to the stem and reproductive parts was not significantly affected.Therefore,a planting density of 225 000 plants·ha-1 is optimal for soybean cultivation in this region.Overall,this study provides a valuable reference for the high-yield and efficient cultivation of forage soybean.