IMPROVING NUTRIENT UTILIZATION IN WESTERN IRRIGATED CROP PRODUCTION SYSTEMS
Location: Northwest Irrigation and Soils Research
Title: Nitrogen availability and uptake by sugarbeet in years following manure application
Submitted to: International Journal of Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 20, 2012
Publication Date: June 4, 2012
Citation: Lentz, R.D., Lehrsch, G.A. 2012. Nitrogen availability and uptake by sugarbeet in years following manure application. International Journal of Agronomy. DOI:10.1155/2012/120429.
Interpretive Summary: An estimated 22 million tons of manure is produced annually by the 9-million-cow, US dairy herd. The manure is commonly applied to crop land to supply nutrients to crops. However, the use of solid dairy manure for sugarbeet production is problematic because beet yield and quality are sensitive to both deficiencies and excesses in soil N; and soil N availability from manure may vary substantially depending on the age (year) of application. This study determined how N availability from a one-time manure application changes in the three years following application and evaluated their effects on sugarbeet yield, quality, and profitability relative to conventional fertilizer. With appropriate manure application rates and attention to residual N and timing of sugarbeet planting, growers can best exploit the N mineralized from manure, while simultaneously increasing profits 1.5 fold above those obtained using inorganic fertilizer. This research can help producers maximize manure-use efficiency and beet production, and minimize losses of nitrogen (N) to the environment.
The use of solid dairy manure for sugarbeet production is problematic because beet yield and quality are sensitive to deficiencies or excesses in soil N, and soil N availability from manure varies substantially depending on the year of application. Experimental treatments included combinations of two manure rates (0.33 and 0.97 Mg total N ha-1) and three application times, and no manure treatments (control and urea fertilizer). We measured soil net N mineralization and biomass, N uptake, and yields for
sprinkler-irrigated sugarbeet. On average, the 1-year-old, low-rate manure, and 1- and 2-year-old, high-rate manure treatments produced 1.2-fold greater yields, 1.1-fold greater estimated recoverable sugar, and 1.5-fold greater gross margins than that of
fertilizer alone. As a group the 1-year-old, low-rate manure, and 2- and 3-year-old, high-rate-manure treatments produced similar cumulative net N mineralization as urea fertilizer; whereas the 1-year-old, high-rate manure treatment provided nearly 1.5-fold
more N than either group. With appropriate manure application rates and attention to residual N and timing of sugarbeet planting, growers can best exploit the N mineralized from manure, while simultaneously maximizing sugar yields and profits.