|Karlen, Douglas - Doug|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2007
Publication Date: 6/29/2007
Citation: Nance, C.D., Gibson, L.R., Karlen, D.L. 2007. Soil Profile Nitrate Response to Nitrogen Fertilization of Winter Triticale. Soil Science Society of America Journal. 71:1343-1351. Interpretive Summary: Incorporating a winter hardy small grain into a soybean-corn rotation could reduce nitrate nitrogen (NO3-N) leaching by capturing residual NO3-N in the plant biomass during the late fall and early spring. This research was conducted to determine the changes in NO3-N concentrations within the soil profile when triticale (a cross between rye and wheat) was grown following either soybean or corn crops at two locations in Iowa. We found that following either crop, growing winter triticale reduced profile NO3-N by an average of 33 to 53 kg/ha (30 to 50 lb/acre). Our results are important for farmers, conservation planners, crop consultants, and policy makers interested in creating more sustainable agricultural production enterprises throughout the Midwest.
Technical Abstract: Growing triticale (XTriticosecale Wittmack) as a winter crop has the potential to utilize residual nitrate-nitrogen (NO3-N) from previous crops, thus reducing its availability for leaching. Our objectives were to quantify nitrogen (N) capture and changes in soil NO3-N levels in response to N fertilization of triticale grown following either silage corn (Zea mays L.) or soybean [Glycine max (L.) Merr.]. Field studies were conducted in 2003-2004 and 2004-2005 near Ames and Lewis, IA. Soil samples to a depth of 120 cm were collected after the corn and soybean were harvested and again after growing triticale with four rates of N fertilizer (0, 33, 66, and 99 kg N ha-1). Partial N budgets were computed using profile NO3-N before triticale planting, N fertilizer applications, plant uptake, and profile NO3-N after triticale harvest. Nitrogen capture by triticale at physiological maturity was 44 to 93 kg N ha-1 when no N was applied and was as high as 164 kg N ha-1 with addition of 99 kg N ha-1. Growing winter triticale reduced profile NO3-N by an average of 33 to 53 kg ha-1 at Ames and 46 to 53 kg ha-1 at Lewis. Winter triticale dry matter and grain yields were maximized while simultaneously capturing and efficiently utilizing soil N left from previous silage corn and soybean crops.