Study On The Effects Of Increasing Planting Density And Decreasing Fertilizer Application Of Different Dense-resistant Soybean Varieties

Excessive fertilization has become a very serious problem in intensive agricultural production system.To exploring the way to increase the density and fertilizer application to achieve the sustainable green soybean production mode,this test is to close type soybean varieties resistant Dennison,Liaodou 14,Shennong 28 and not resistant to dense type soybean varieties,Amsoy and Liaodou 11 as test materials,by setting the different planting density and fertilizer levels,research on the different planting density and fertilizer dense type soybean photosynthetic physiological resistance,the influence of yield and quality.The main research results are as follows:During the whole growth period,the leaf greenness of dense-resistant varieties was higher in density than in low density.At pod stage,the dense-resistant cultivars lost weight to 112.5kg/hm2 under the condition of high planting density.In the pod stage to grain stage,the leaf color value of dense-resistant cultivars decreased more slowly than that of dense-resistant cultivars under high-density planting conditions.The photosynthetic rate of dense-tolerant cultivars was higher than that of dense-tolerant cultivars,while that of dense-tolerant cultivars was higher than that of dense-tolerant cultivars.The photosynthetic rate of dense-tolerant cultivars decreased more slowly than that of dense-tolerant cultivars under the condition of high-density planting from pod stage to grain stage.The leaf area index under high density planting condition was higher than that under low density planting condition.Under the condition of high-density planting in pod bearing stage,leaf area index of all the four varieties except Liaodou11 reached the maximum under the treatment of weight loss to 112.5kg/hm2.With the increase of planting density,mechanical strength of stem decreased.Under the condition of high density planting,the mechanical strength of the resistant cultivars was greater than that of the non-resistant cultivars.The lodging rate under high density planting was significantly higher than that under low density planting.Under different density planting conditions,the lodging rate of dense-resistant varieties was significantly lower than that of dense-resistant varieties.At mature period,the accumulation of nitrogen,phosphorus and potassium was higher at high density than at low density under different planting conditions.The total accumulation of nitrogen and phosphorus in dense-resistant varieties was greater than that in dense-resistant varieties.The total accumulation of potassium in dense-resistant cultivars was less than that in dense-resistant cultivars.With the increase of planting density,the plant height and pod height of soybean increased significantly,and the stem diameter,branch number and pod number per plant decreased significantly.The 100-grain weight under low-density planting condition was higher than that under high-density planting condition.Under the condition of high density planting,the dry matter accumulation per plant was less than that under the condition of low density planting.The harvest index of dense-resistant varieties was greater than that of dense-resistant varieties.The harvest index of dense-resistant cultivars reached the maximum value under the treatment of increasing density and decreasing fertilizer application to 112.5 kg/hm2,and was greater than that under the constant fertilization treatment under the low-density condition,while the harvest index of dense-resistant cultivars was opposite.The yield of dense-resistant cultivars was significantly higher than that of dense-resistant cultivars under different density planting and fertilizer application.And the yield under high density planting condition was significantly higher than that under low density planting condition.Under the condition of high density planting,the yield of dense-resistant varieties reached the maximum value in the treatment of weight loss to 112.5kg/hm2,and was greater than that of the low-density constant fertilization treatment.Under the condition of densification,Amsoy,an impermeable variety,also reached the maximum yield under the treatment of weight loss to 112.5 kg/hm2,but the yield was smaller than that under the treatment of low-densification constant fertilization,while the yield of impermeable variety,Liaodou 11,reached the maximum yield under the treatment of constant densification fertilization,but was also smaller than that under the treatment of low-densification constant fertilization.With the increase of planting density,the protein content increased significantly and the fat content decreased significantly.Under the condition of densification,the protein content of densifier varieties reached the maximum under the condition of weight loss to 112.5 kg/hm2,while that of densifier varieties reached the maximum under the condition of constant fertilization.The fat contents of Dennison and Shennong 28 reached the maximum under the treatment of weight loss to 112.5 kg/hm2,and the fat contents of Amsoy,Liaodou 11 and Liaodou 14 reached the maximum under the treatment of weight loss to 75 kg/hm2.