Grabau Zane J, Zar Maung Zin Thu, Noyes D Corey, Baas Dean G, Werling Benjamin P, Brainard Daniel C, Melakeberhan Haddish
Department of Horticulture, Michigan State University, East Lansing, MI 48824.
Entomology and Nematology Department, University of Florida, Gainesville, FL 32611.
J Nematol. 2017 Mar;49(1):114-123. doi: 10.21307/jofnem-2017-051.
Cover cropping is a common practice in U.S. Midwest carrot production for soil conservation, and may affect soil ecology and plant-parasitic nematodes-to which carrots are very susceptible. This study assessed the impact of cover crops-oats (), radish () cv. Defender, rape () cv. Dwarf Essex, and a mixture of oats and radish-on plant-parasitic nematodes and soil ecology based on the nematode community in Michigan carrot production systems. Research was conducted at two field sites where cover crops were grown in Fall 2014 preceding Summer 2015 carrot production. At Site 1, root-lesion () and stunt ( sp.) nematodes were present at low population densities (less than 25 nematodes/100 cm soil), but were not significantly affected ( > 0.05) by cover crops. At Site 2, population densities were increased ( ≤ 0.05) by 'Defender' radish compared to other cover crops or fallow control during cover crop growth and midseason carrot production. At both sites, there were few short-term impacts of cover cropping on soil ecology based on the nematode community. At Site 1, only at carrot harvest, radish-oats mixture and 'Dwarf Essex' rape alone enriched the soil food web based on the enrichment index ( ≤ 0.05) while rape and radish increased structure index values. At Site 2, bacterivore abundance was increased by oats or radish cover crops compared to control, but only during carrot production. In general, cover crops did not affect the nematode community until nearly a year after cover crop growth suggesting that changes in the soil community following cover cropping may be gradual.
在美国中西部的胡萝卜生产中，覆盖作物种植是一种常见的土壤保护措施，可能会影响土壤生态和植物寄生线虫，而胡萝卜对植物寄生线虫非常敏感。本研究基于密歇根州胡萝卜生产系统中的线虫群落，评估了覆盖作物（燕麦、萝卜品种Defender、油菜品种Dwarf Essex以及燕麦和萝卜的混合物）对植物寄生线虫和土壤生态的影响。研究在两个田间地点进行，2014年秋季种植覆盖作物，随后于2015年夏季种植胡萝卜。在地点1，根腐线虫和矮化线虫的种群密度较低（每100立方厘米土壤中少于25条线虫），但覆盖作物对其没有显著影响（P>0.05）。在地点2，与其他覆盖作物或休耕对照相比，在覆盖作物生长和胡萝卜生产中期，“Defender”萝卜使线虫种群密度增加（P≤0.05）。基于线虫群落，在两个地点，覆盖作物种植对土壤生态的短期影响都很小。在地点1，仅在胡萝卜收获时，萝卜-燕麦混合物和单独的“Dwarf Essex”油菜根据富集指数使土壤食物网得到富集（P≤0.05），而油菜和萝卜增加了结构指数值。在地点2，与对照相比，燕麦或萝卜覆盖作物增加了食细菌线虫的丰度，但仅在胡萝卜生产期间。总体而言，覆盖作物在生长近一年后才对线虫群落产生影响，这表明覆盖作物种植后土壤群落的变化可能是渐进的。
