Vincelli Paul, Lee Chad
Department of Plant Pathology, University of Kentucky.
Department of Plant and Soil Sciences, University of Kentucky.
Plant Dis. 2015 Feb;99(2):263-266. doi: 10.1094/PDIS-04-14-0415-RE.
Including open alleys at ends of plots is a common practice when field-testing foliar fungicides used in corn production. Open alleys facilitate movement of workers and equipment between plots during spray application. Open alleys affect crop yield estimates in small plots typically used in replicated, randomized experimental designs, because of reduced interplant competition. However, no published research has tested whether the alley effect interacts with fungicide to bias the assessment of the agronomic effects of the latter. We tested this hypothesis over 2 years by evaluating yield with and without application of Headline AMP (containing pyraclostrobin and metconazole) plus nonionic surfactant applied once at VT/R1 in 7.6-m plots separated on their ends by 1.5-m alleys free of aboveground vegetation. In each plot, data were collected from seven subplots, each measuring 1.09 m of row-length and running parallel to the long axis of the plot. Consistent with previous reports, yields of subplots were substantially higher toward plot ends than in the central areas of plots. Surprisingly, a significant (P < 0.10) fungicide × subplot interaction was observed in both experiments, indicating that the yield response from fungicide depended on subplot position within the plot. However, yield differences due to fungicide were trivial when comparing regression-based yield estimates from all seven subplot positions to those obtained from only the centermost three subplot positions. Our study does not lend support to the hypothesis that the open-alley design creates a meaningful bias in assessment of treatment effects due to foliar fungicides in corn. However, additional research on this question is warranted, given the complexities of comparing results in large-scale plots vs. small plots, the limitations of our study, and the widespread use of fungicides on field corn in the United States.
在对玉米生产中使用的叶面杀菌剂进行田间试验时，在试验小区两端设置开放式通道是一种常见做法。开放式通道便于在喷雾施药期间工人和设备在各试验小区之间移动。由于种植株间竞争减少，开放式通道会影响通常用于重复随机试验设计的小试验小区的作物产量估计。然而，尚无已发表的研究测试通道效应是否会与杀菌剂相互作用，从而使对后者农艺效应的评估产生偏差。我们在两年时间里进行了此项验证，在7.6米长的试验小区中，于VT/R1期一次性施用含有唑菌酯和丙环唑的Headline AMP加非离子表面活性剂，并在试验小区两端设置1.5米宽且无地上植被的开放式通道，分别评估施药和未施药情况下的产量。在每个试验小区中，从七个子小区收集数据，每个子小区行长1.09米，且与试验小区的长轴平行。与之前的报告一致，子小区的产量在试验小区两端显著高于小区中部区域。令人惊讶的是，在两个试验中均观察到显著的（P < 0.10）杀菌剂×子小区交互作用，这表明杀菌剂的产量响应取决于子小区在试验小区内的位置。然而，将基于回归的所有七个子小区位置的产量估计值与仅从最中间三个子小区位置获得的估计值进行比较时，杀菌剂导致的产量差异微不足道。我们的研究不支持开放式通道设计会在评估玉米叶面杀菌剂的处理效果时产生显著偏差这一假设。然而，鉴于大规模试验小区与小试验小区结果比较的复杂性、我们研究的局限性以及美国田间玉米上杀菌剂的广泛使用情况，有必要对此问题进行更多研究。
