Nitrogen Availability and Uptake by Sugarbeet in Years Following a Manure Application

Abstract EN

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 non-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.