The Effects Of N And Density Interaction On K, Ca And Mg Uptake In Soybean Plants

In order to study the effects of N and density interaction on K, Ca and Mg accumulation in different soybean organs and yield, a field experiment was conducted with soybean cultivar Dongnong52, using a split-plot design with two N application patterns (a single application of N60kg·ha-1as basal fertilizer; N18kg·ha-1as basal fertilizer followed by N42kg·ha-1as topdressing at stage R4) and three densities (200thousand plants·ha-1,250thousand plants·ha-1and300thousand plants·ha-1). K, Ca and Mg contents during R2-R6stage in various soybean organs were determined, K, Ca and Mg accumulation in various soybean organs were calculated as well. The main results are shown as following:K contents in various soybean organs has basically the same trends with growth stages, each treatment were manifested as decreased. K accumulation at stage R6in each organ on per unit area: in leaves D2N2and D3N2were higher than D1N1by39.8%and48.5%(p<0.05), in petioles D2N2and D3N2were higher than D1N1by11.7%and19.0%, in stems D2N2and D3N2were higher than D1N1by20.1%and27.9%(p<0.05), in s pods D2N2and D3N2were higher than D1N1by28.8%and29.9%(p<0.05). At harvest, K accumulation of D2N2and D3N2were higher than that of D1N1by24.9%and23.5%(p<0.05) in soybean seeds.Ca contents in various soybean organs has basically the same trends with growth stages, each treatment in leaves and petioles first decreased and then increased, in stems and pods decreased gradually. Ca accumulation at stage R6in each organ on per unit area:in leaves D2N2and D3N2were higher than D1N1by30.0%and31.3%(p<0.05), in petioles D2N2and D3N2were higher than D1N1by28.0%and28.9%(p<0.05), in stems D2N2and D3N2were higher than D1N1by30.1%and31.3%(p<0.05), in pods D2N2and D3N2were higher than D1N1by18.7%and12.7%(p<0.05). At harvest, Ca accumulation of D2N2and D3N2were higher than that of D1N1by33.9%and31.1%(p<0.05) in soybean seeds.Mg content in various soybean organs has basically the same trends with growth stages, each treatment in leaves and petioles first decreased and then increased, in stems and pods decreased gradually. Mg accumulation at stage R6in each organ on per unit area:in leaves D2N2and D3N2were higher than D1N1by25.4%and26.5%(p<0.05), in petioles D2N2and D3N2were higher than D1N1by30.3%and32.3%(p<0.05), in stems D2N2and D3N2were higher than D1N1by34.1%and33.6%(p<0.05), in pods D2N2and D3N2were higher than D1N1by23.9%and15.0% (p<0.05). At harvest, Mg accumulation of D2N2and D3N2were higher than that of D1N1by28.7%and29.5%(p<0.05) soybean seeds.Soybean yield of D2N2and D3N2were higher than D1N1by36.6%and23.4%(p<0.05). D2N2had the highest yield,3.96t·ha-1, increased by10.6%-36.6%compared with other treatments (p<0.05). K, Ca and Mg accumulation during R4-R6stage in soybean plant and yield were significant positively correlated.