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United States Department of Agriculture

Agricultural Research Service

Title: Fertilizer Phosphorus Management Options for No-Till Dryland Winter Wheat

Authors
item Halvorson, Ardell
item Havlin, John - NCSU, RALEIGH, NC
item Reule, Curtis

Submitted to: Better Crops
Publication Type: Popular Publication
Publication Acceptance Date: October 22, 2002
Publication Date: December 1, 2002
Citation: Halvorson, A.D., Havlin, J.L., Reule, C.A. 2002. Fertilizer phosphorus management options for no-till dryland winter wheat. Better Crops. 86(4):4-7.

Interpretive Summary: Adoption of no-till (NT) farming systems raises the question of how to best manage fertilizer phosphorus (P)to optimize crop yields. We evaluated fertilizer P placement method and P rate effects on wheat yields in a dryland, NT winter wheat-fallow cropping system near Peetz, CO on a loam soil with a soil test P level of 10 ppm. Fertilizer P placement methods examined were broadcast incorporated (BCI), broadcast without incorporation (BC), deep band (DB), and seed placed (SP). Fertilizer P rates (0, 69, 137, 206, and 275 lb P2O5/A) were applied as a one time application in each of the BCI, BC, and DB treatments. The SP fertilizer P rates were 0, 17, 34, 52, and 69 lb P2O5/A placed directly with the seed at planting for each of four crop years. The N subplots were with and without fertilizer N applied. Grain yields did not vary significantly between P placement methods when averaged over N and P rates. Wheat yields with or without N applied increased significantly with increasing P rate. Yields were maximized with the application of 275 lb P2O5/A. Wheat responded to fertilizer P rate similarly for each N rate and P placement treatment. As P rate increased, cumulative wheat yields were slightly higher for the DB, BCI, and BC treatments than for the SP treatment. Soil test P levels seven years after P application were high enough to increase wheat yields of several more crops. This study shows the need for higher rates of fertilizer P application to optimize winter wheat yields in the Central Great Plains. If soil P is deficient in a NT system, applying fertilizer P on the soil surface will help alleviate P deficiency even without incorporation. A high level of available P is needed to optimize wheat yields in the Central Great Plains regardless of P application method.

Technical Abstract: Adoption of no-till (NT) farming systems raises the question of how to best manage fertilizer phosphorus (P)to optimize crop yields. We evaluated fertilizer P placement method and P rate effects on wheat yields in a dryland, NT winter wheat-fallow cropping system near Peetz, CO on a loam soil with a soil test P level of 10 ppm. Fertilizer P placement methods examined were broadcast incorporated (BCI), broadcast without incorporation (BC), deep band (DB), and seed placed (SP). Fertilizer P rates (0, 69, 137, 206, and 275 lb P2O5/A) were applied as a one time application in each of the BCI, BC, and DB treatments. The SP fertilizer P rates were 0, 17, 34, 52, and 69 lb P2O5/A placed directly with the seed at planting for each of four crop years. The N subplots were with and without fertilizer N applied. Grain yields did not vary significantly between P placement methods when averaged over N and P rates. Wheat yields with or without N applied increased significantly with increasing P rate. Yields were maximized with the application of 275 lb P2O5/A. Wheat responded to fertilizer P rate similarly for each N rate and P placement treatment. As P rate increased, cumulative wheat yields were slightly higher for the DB, BCI, and BC treatments than for the SP treatment. Soil test P levels seven years after P application were high enough to increase wheat yields of several more crops. This study shows the need for higher rates of fertilizer P application to optimize winter wheat yields in the Central Great Plains. If soil P is deficient in a NT system, applying fertilizer P on the soil surface will help alleviate P deficiency even without incorporation. A high level of available P is needed to optimize wheat yields in the Central Great Plains regardless of P application method.

Last Modified: 7/12/2014
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