We conducted two case studies testing effectiveness of a soil-borne bacteria, Pseudomonas fluorescens strain D7, in controlling Bromus tectorum (cheatgrass) when mixed with native seeds sown after a fire and when sprayed on a native community with high abundances of B. tectorum. Each case study area (162 ha) compared treatments with D7 present and absent and was replicated four times (20.3 ha each) in a completely randomized design. Response variables (foliar cover, aboveground biomass, and density of B. tectorum; density of sown native plants) were measured pretreatment for the sprayed area and each year for 3 yr after treatment at both study areas and were evaluated as a repeated measures analysis. Foliar cover, biomass, and density of B. tectorum with sprayed or seed mixture applications did not differ between D7-treated and untreated areas at any time within the study (F_1,6 ≤ 1.42; P ≥ 0.28). D7 as a seed mixture did not significantly impact densities of native seedlings (F_1,6 = 1.27; P = 0.30) at any time during the study. Results contrasted with previous D7 studies that showed effective control of B. tectorum within 3 yr of treatment. Since bioherbicidal methods are being commonly applied, we believe that reporting negative results is important for future meta-analytical studies that provide managers with information on the likelihood for weed-suppressive bacteria to effectively control weeds.

我们进行了两个案例研究，测试了土壤传播细菌荧光假单胞菌D7菌株在与火后播种的本地种子混合以及喷洒于富含丰富的扇形芽孢杆菌的本地社区时，在控制Bromus tectorum（草）中的有效性。每个案例研究区域（162公顷）比较了存在和不存在D7的治疗情况，并在完全随机的设计中重复了四次（每次20.3公顷）。响应变量（叶面覆盖，地上生物量和鹤望兰的密度；在两个研究区域对喷洒区域进行预处理，并在处理后的3年中每年测量已播种天然植物的密度），并作为重复测量分析进行评估。叶面盖，生物质和密度B. tectorum用喷雾或种子混合物应用没有D7处理的和未处理的区域之间在任何时间内研究不同（F _1,6 ≤1.42; P ≥0.28）。 在研究过程中的任何时候，D7作为种子混合物都不会显着影响天然幼苗的密度（F _1,6  = 1.27；P = 0.30）。结果与先前的D7研究相反，后者显示了有效控制胸腺治疗3年内。由于生物除草方法是普遍使用的方法，因此我们认为报告阴性结果对于未来的荟萃分析研究非常重要，该研究为管理人员提供了抑制杂草的细菌有效控制杂草的可能性的信息。