Sucrose fatty acid esters enhance efficiency of foliar-applied urea-nitrogen to soybeans

Abstract

A greenhouse study is described showing the effect of sucrose fatty acid esters (SFE) applied to soybeans (Glycine max (L.) Merrill cv Fukuyutaka) during the flowering and/or pod-filling periods on the efficiency of foliar-applied urea-nitrogen. SFE applied in combination with urea delayed senescence and when applied during both the flowering and pod-filling periods increased seed yields by 103% and nitrogen accumulation by 132% as compared to urea alone. Average total recovery of15N-urea in the above ground portions of the plant was 20.6%. SFE combined with urea increased the average recovery to 34.8%. Recovered15N-urea was only a small portion of the total nitrogen content of the plant. The yield increase resulting from a foliar application of urea may have been due to the leaves continuing to export photosynthates to the nodules hence maintaining the nodules' nitrogen fixing activity for a longer period of time. The addition of SFE to the urea solution increased the retention and/or absorption of urea and increased translocation of urea-nitrogen to the seeds.