Field tests were conducted to determine if differences in response to nematicide application (i.e., root-knot nematode (RKN) populations, cotton yield, and profitability) occurred among RKN management zones (MZ). The MZ were delineated using fuzzy clustering of five terrain (TR) and edaphic (ED) field features related to soil texture: apparent soil electrical conductivity shallow (ECa-shallow) and deep (ECa-deep), elevation (EL), slope (SL), and changes in bare soil reflectance. Zones with lowest mean values of ECa- shallow, ECa- deep, NDVI, and SL were designated as at greater risk for high RKN levels. Nematicide-treated plots (4 rows wide and 30 m long) were established in a randomized complete block design within each zone, but the number of replications in each zone varied from four to six depending on the size of the zone.The nematicides aldicarb (Temik 15 G) and 1,3-dichloropropene (1,3-D,Telone II) were applied at two rates (0.51 and 1.0 kg a.i./ha for aldicarb, and 33.1 and 66.2 kg a.i./ha for 1,3-D) to RKN MZ in commercial fields between 2007 and 2009. A consolidated analysis over the entire season showed that regardless of the zone, there were not differences between aldicarb rates and 1,3-D rates. The result across zones showed that 1,3-D provided better RKN control than did aldicarb in zones with low ECa values (high RKN risk zones exhibiting more coarse-textured sandy soils). In contrast, in low risk zones with relatively higher ECa values (heavier textured soil), the effects of 1,3-D and aldicarb were equal and application of any of the treatments provided sufficient control. In low RKN risk zones, a farmer would often have lost money if a high rate of 1,3-D was applied. This study showed that the effect of nematicide type and rate on RKN control and cotton yield varied across management zones (MZ) with the most expensive treatment likely to provide economic benefit only in zones with coarser soil texture. This study demonstrates the value of site specific application of nematicides based on management zones, although this approach might not be economically beneficial in fields with little variability in soil texture.
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机译：进行现场试验以确定RKN管理区（MZ）中发生对杀线虫应用的响应（即根结线虫（RKN），棉花产量和盈利能力）的差异。使用与土壤纹理相关的五个地形（TR）和仿生（ED）田间特征的模糊聚类划定MZ：表观土壤导电性浅（ECA浅）和深（ECA-Deep），海拔（EL），斜坡（ SL），并改变裸土反射率。 eCA浅，ECA-深，NDVI和SL的最低平均值的区域被指定为高RKN水平的更大风险。在每个区域内的随机完整块设计中建立了界面处理的图（4排和30米长），但根据区域的尺寸，每个区域的复制数量从四到六个变化。尼癌素醛癌（ Temik 15g）和1,3-二氯丙烯（1,3-D，Telone II）以两个速率（0.51和1.0kg Ai / Ha为Aldicarb，33.1和66.2 kg Ai / Ha为1,3-d ）在2007年至2009年期间的商业领域进行RKN MZ。整个季节的综合分析表明，无论区域如何，AldicarB率和1,3-D率之间没有差异。跨区域的结果表明，1,3-D提供比具有低ECA值的区域（高RKN风险区）的aldicarb提供更好的RKN控制（表现出更粗糙的砂土）。相反，在具有相对较高的ECA值的低风险区域（较重的纹理土壤），1,3-D和Aldicarb的效果是相同的，并且任何处理的施用提供了足够的控制。在低RKN风险区，如果应用高速率为1,3-D，农民通常会丢失金钱。该研究表明，境内典型型和速率对RKN控制和棉花产量的影响与管理区（MZ）变化，最昂贵的处理仅在具有较粗糙的土壤质地的区域中提供经济效益。本研究表明了基于管理区的网站网站目的特定应用的价值，尽管这种方法可能在土壤质地变异几乎没有变异的领域中可能没有经济有益。
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