S. R. Olsen, C. V. Cole, F. S. Watatanabe, and L. A. Dean...

来自 : www.oalib.com/references/13461 发布时间：2021-03-26

ABSTRACT: 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. 1. Introduction An estimated 20 million Mg manure is produced annually by the 9-million-cow US dairy herd. The regional dairy center in southern Idaho comprises 5.6% of the US total dairy herd and produces approximately 1.11 million Mg manure annually. In Idaho, much of the dairy manure is soil applied to supply crop nutrients and as a means of rebuilding soil organic carbon. The latter is particularly important for eroded soils, which are common in this historically furrow irrigated region [1]. To maximize their use of manure and minimize losses of nitrogen (N) to the environment, growers need to know how much N becomes available to crops from manure applications [2]. In addition, as competition increases for cropland in the region, farmers who rent acreage can expand the pool of land available to them if they are willing to utilize manured ground. This is particularly important for sugarbeet (Beta vulgaris L.) growers because yield and beet quality parameters, sugar, and brei nitrate concentration are sensitive to both insufficient N [3, 4] and excess soil N [5, 6]. In addition, sugarbeet tends to incorporate soil residual N preferentially over fertilizer N, that is, sugarbeet will utilize more soil residual N and less applied fertilizer N than corn or tomato crops [7]. Applying excess N fertilizer early in