ABSTRACT In organic production systems, composted manure and a short-term grass/legume sod rotation component may improve soil health. However, little is known about the lasting benefits of these two management practices for the duration of the several crop components of an organic rotation. This study was designed to determine whether 3 years of grass sod and composted manure application affected soil properties and crop biomass yield at the beginning and end of 4 years of organic crop production. The effects of the sod rotation component and composted manure on bulk density (BD), dry (dryGMD [dry aggregate geometric mean diameter]) and wet (wetGMD [wet aggregate geometric mean diameter]) aggregation, soil organic matter, bioavailable nutrient concentrations, and crop biomass were determined in two long-term rotations at the West Virginia University Certified Organic Research Farm in Morgantown, West Virginia. The rotations were a 4-year continuous rotation of corn (Zea mays L.), soybean (Glycine max L. Merr.), wheat (Triticum aestivum L.), and kale/cowpea (Brassica oleracea)/Vigna unguiculata L. Walp.), and a 7-year rotation of the same crop sequence followed by 3 years of grass/legume (orchardgrass/red clover, Dactylis glomerata L./Trifolium pretense L.) sod. Two composted manure levels, 0 (nonmanured [n-M]) and 2.25 (manured [M]) Mg ha−1, were imposed only to the corn and wheat rotation components. Results for 2013 and 2014 showed that manure application significantly improved soil physical and chemical properties for corn and kale/cowpea regardless of the sod component. In the corn component, BD was lower (P < 0.0001) in M soils (1.13 Mg m−3) than in n-M soils (1.24 Mg m−3). A significant (P = 0.0060) decrease in BD due to the sod component was observed when corn was not manured, 1.27 and 1.21 Mg m−3 in the 4- and 7-year rotations, respectively. Soil organic matter was significantly (P < 0.0001) higher in M than n-M soils and was also higher for the rotation with the sod component, regardless of manure application (P < 0.0001). The sod component resulted in significantly (P = 0.012) increased pH in n-M soils (5.61 and 5.89 for the 4- and 7-year rotations, respectively). Soil health and corn biomass were found to be most improved in soils receiving manure and subject to sod insertion in the rotation. The soil organic matter, dryGMD, wetGMD, and bioavailable soil P and Mg were found to be higher in M soils under corn in the 7-year rotation. Although differences in soil health indicators were measured in kale/cowpea soils, no differences (P = 0.510) in the biomass indicator were observed. This research supports the use of manure, in conjunction with insertion of a short-term grass/legume sod component, to improve soil health in organic crop rotations.

中文翻译：

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在长期有机作物轮作中施用堆肥和插入草皮成分对土壤健康的益处

摘要在有机生产系统中，堆肥和短期草/豆类草皮轮作成分可以改善土壤健康。然而，在有机轮作的几种作物组成部分期间，这两种管理做法的持久益处知之甚少。本研究旨在确定 3 年的草皮和堆肥施用是否会影响 4 年有机作物生产开始和结束时的土壤特性和作物生物量产量。草皮旋转成分和堆肥对堆积密度 (BD)、干 (dryGMD [干骨料几何平均直径]) 和湿 (wetGMD [湿骨料几何平均直径]) 聚集、土壤有机质、生物可利用养分浓度的影响，和作物生物量是在西弗吉尼亚州摩根敦的西弗吉尼亚大学认证有机研究农场的两次长期轮作中确定的。轮作是玉米 (Zea mays L.)、大豆 (Glycine max L. Merr.)、小麦 (Triticum aestivum L.) 和羽衣甘蓝/豇豆 (Brassica oleracea)/Vigna unguiculata L. Walp 的 4 年连续轮作.)，以及相同作物序列的 7 年轮作，然后是 3 年的草/豆科植物（果园草/红三叶草，Dactylis glomerata L./Trifolium pretense L.）草皮。两种堆肥水平，0（未施肥 [nM]）和 2.25（施肥 [M]）Mg ha-1，仅用于玉米和小麦轮作成分。2013 年和 2014 年的结果表明，无论草皮成分如何，施肥都能显着改善玉米和羽衣甘蓝/豇豆的土壤物理和化学性质。在玉米成分中，M 土壤 (1.13 Mg m-3) 中的 BD 比 nM 土壤 (1.24 Mg m-3) 中的 BD 低 (P < 0.0001)。当玉米未施肥时，观察到由于草皮成分导致的 BD 显着（P = 0.0060）下降，在 4 年和 7 年轮作中分别下降 1.27 和 1.21 Mg m-3。土壤有机质在 M 中显着（P < 0.0001）高于 nM 土壤，并且与草皮成分轮作也更高，无论施肥量如何（P < 0.0001）。草皮成分导致 nM 土壤中 pH 值显着增加（P = 0.012）（4 年和 7 年轮换分别为 5.61 和 5.89）。发现土壤健康和玉米生物量在接受粪便并在轮作中插入草皮的土壤中得到最大改善。土壤有机质，dryGMD，wetGMD，在 7 年轮作中，玉米下 M 土壤中的生物可利用土壤 P 和 Mg 较高。尽管在羽衣甘蓝/豇豆土壤中测量了土壤健康指标的差异，但未观察到生物量指标的差异（P = 0.510）。这项研究支持使用粪肥，结合短期草/豆科植物的草皮成分，以改善有机作物轮作中的土壤健康。