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United States Department of Agriculture

Agricultural Research Service

Title: Starter Fertilizer Effects on Soybean Yield and Quality in the Northern Great Plains

Authors
item Osborne, Shannon
item Riedell, Walter
item Pikul Jr, Joseph

Submitted to: Soil/Water Research, Progress Report
Publication Type: Experiment Station
Publication Acceptance Date: February 26, 2001
Publication Date: May 21, 2001
Citation: Osborne, S.L., Riedell, W.E., Pikul Jr, J.L. 2001. Starter fertilizer effects on soybean yield and quality in the northern great plains. Soil/Water Research, Progress Report.

Interpretive Summary: Fertilizing soybeans is not a new concept to try to increase production. For many years scientists have evaluated the effect of nitrogen (N) fertilizer on yield and quality of soybeans resulting in mixed conclusions. The objectives of this experiment were to determine the effect of two different starter N fertilizer sources (ammonium nitrate or urea) and four N rates on soybean yield, protein, and oil content, and to determine the effect of applied N on N fixation in the cool, moist soils of the Northern Great Plains. A field experiment was established within a two-year corn- soybean rotation. The experiment was conducted under conventional and no-tillage conditions. All biomass samplings and grain yield sampling for the 7 lb N ac-1 ammonium nitrate treatment resulted in decreased production. This could be due to a decrease in nodulation in the early growth stages and subsequent decrease in N fixation. Perhaps the higher N treatments may have provided enough soil N to overcome a delay in nodulation. Although yield differences and biomass production are small, it is important to know that yield increased when N was applied at planting. Effect on soybean quality such as protein and oil content will be needed to determine if starter fertilizer is economical.

Technical Abstract: The concept of fertilizing soybeans (Glycine max (L.) Merrill) is not new. For a number of years scientists have investigated the effect of nitrogen (N) fertilizer on yield and quality of soybeans resulting in mixed conclusions. The objectives of this experiment were to determine the effect of starter fertilizer N sources and rates on soybean yield, protein, ,and oil content, and to determine the effect of applied N on N fixation in the cool, moist soil of the Northern Great Plains. A field experiment was established within a two-year corn (Zea mays L.) soybean rotation. The experimental design was a split-plot design with four replications. Whole plots were no-till and conventional tillage and the split plots were fertilizer (two sources x four rates) treatments. In all biomass samplings and grain yield sampling the 7 lb N ac-1 resulted in decreased production. This could be due to a decrease in nodulation in the early growth stages and subsequent decrease in N fixation. Perhaps the 14 and 21 lb treatment may have provided enough soil N to overcome a delay in nodulation. Although yield differences in yield and biomass production are small, it is important to know that yield increased when N was applied at planting. Effect on soybean quality such as protein and oil content will be needed to determine if starter fertilizer is economical.

Last Modified: 4/25/2014