Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster, OH 44691.
Department of Horticulture and Crop Science, The Ohio State University, Columbus, OH 43210.
Plant Dis. 2017 Dec;101(12):1998-2011. doi: 10.1094/PDIS-03-17-0414-RE. Epub 2017 Oct 26.
In Ohio, changes in nitrogen (N) fertilizer application rates and row spacing in combination with fungicide applications have been proposed as possible strategies for increasing wheat productivity and profitability. Field experiments were conducted in 2013, 2014, and 2015 to evaluate the benefits of increasing row spacing and N rates in soft red winter wheat as influenced by diseases. Combinations of narrow (19 cm) and wide (38 cm) row spacings, N rates ranging from 34 to 180 kg ha, and the fungicide prothioconazole + tebuconazole applied at flag leaf emergence, boot, or early anthesis represented different management programs. Linear mixed model analyses were performed to evaluate the effects of N, row spacing, and fungicide timing on leaf rust, Fusarium head blight (FHB), and deoxynivalenol (DON), and to quantify relationships among leaf rust, N, grain yield (YLD), and test weight (TW). YLD, TW, grain prices and price discounts, as well as input costs were used to estimate net cash income (NCI) for each management program. Wide row wheat had statistically higher mean FHB and DON, and lower mean yield and test weight than narrow row wheat in 2014 and 2015 but not in 2013. There were significant positive linear relationships between leaf rust and N as well as YLD and TW with N. Differences in FHB and DON among N rates were not statistically significant. Leaf rust severity was consistently lower in treated plots, with efficacy influenced by N rate and application timing. Programs with narrow row spacing and treated with the fungicide generally resulted in the highest mean YLD and TW across N rates. Price discounts due to high FDK and DON, and low TW were higher, and consequently, NCIs were lower in 2014 and 2015 than in 2013. The highest NCIs were obtained for programs with the highest YLD and lowest price discounts, consequently programs with wide row spacing, a fungicide treatment, and high N rates were only economically beneficial when FHB levels were low and grain prices were high.
在俄亥俄州，改变氮肥（N）施肥率和行间距，同时结合杀菌剂的应用，被认为是提高小麦生产力和盈利能力的可能策略。2013 年、2014 年和 2015 年进行了田间试验，以评估在病害影响下增加软红冬小麦行间距和 N 率的好处。窄行（19 厘米）和宽行（38 厘米）、N 肥用量（34-180 公斤/公顷）以及在旗叶期、孕穗期或初花期施用的杀菌剂丙硫菌唑+戊唑醇的组合，代表了不同的管理方案。采用线性混合模型分析，评估 N、行间距和杀菌剂施药时间对叶锈病、赤霉病（FHB）和脱氧雪腐镰刀菌烯醇（DON）的影响，并量化叶锈病、N、籽粒产量（YLD）和千粒重（TW）之间的关系。每个管理方案的净现金收入（NCI）使用籽粒产量、千粒重、籽粒价格和价格折扣以及投入成本进行估算。2014 年和 2015 年，宽行小麦的平均赤霉病和 DON 显著高于窄行小麦，平均产量和千粒重低于窄行小麦，但 2013 年并非如此。叶锈病与 N 以及 YLD 和 TW 与 N 之间存在显著的正线性关系。不同 N 肥用量之间的赤霉病和 DON 差异不显著。在处理过的地块中，叶锈病的严重程度始终较低，且其防治效果受 N 肥用量和施药时间的影响。窄行和施用过杀菌剂的方案通常在所有 N 肥用量下都能获得最高的平均 YLD 和 TW。由于高 FDK 和 DON 以及低 TW 导致的价格折扣更高，因此 2014 年和 2015 年的 NCI 低于 2013 年。最高的 NCI 是在 YLD 最高和价格折扣最低的方案中获得的，因此，只有在赤霉病水平较低且谷物价格较高时，宽行间距、杀菌剂处理和高 N 肥用量的方案才具有经济效益。
