Departamento de Viticultura, Instituto de Ciencias de la Vid y del Vino (CSIC, Universidad de La Rioja, Gobierno de La Rioja), Finca La Grajera, Ctra. de Burgos Km. 6 (LO-20 - salida 13), 26007 Logroño, Spain.
Departamento de Agricultura y Alimentación, Universidad de La Rioja, C/ Madre de Dios 53, 26006 Logroño, Spain.
J Invertebr Pathol. 2022 Jul;192:107781. doi: 10.1016/j.jip.2022.107781. Epub 2022 May 29.
The entomopathogenic nematodes (EPNs) are biological control agents that are widespread in crop soils. However, traditional agricultural management practices such as cultivation and agrochemical usage can alter the soil balance that enables their occurrence and activity. Alternative strategies like mulching are commonly employed to prevent weed growth, enhance below-ground biodiversity by improving soil, organic matter content, fertility, and moisture. We hypothesized that organic mulches would favor biotic conditions for nematofauna development in crop soil, including EPNs, compared to herbicide application or tillage. Traditional (insect baits) and molecular (qPCR analysis) tools were used in this study to assess the abundance and activity of native EPNs, and the abundance of potential natural enemies, such as free-living nematode (FLN) competitors, nematophagous fungi (NF), and ectoparasitic bacteria, in soils managed with different organic mulches or traditional practices. As a model agroecosystem, we selected the vineyard, one of the most intensively managed crop systems. We compared mulches of grape pruning debris (GPD-M), straw (Str-M), and spent mushroom compost (SMC-M) in two commercial vineyards, which employed either integrated or organic pest and disease management. Following a completely randomized design, we retrieved two composite samples per plot (n = 3 per treatment in each vineyard) in April, June, and October 2020. Numbers of EPNs and selected members of their soil food web were higher in the organic than the integrated managed vineyard. Supporting our hypothesis, organic mulching overall favored nematode occurrence in both vineyards. We found higher NF abundance for Str-M, and GPD-M in the organic vineyard, which plausibly explained the lower EPN activity and occurrence compared to SMC-M in both vineyards. We conclude that the organic mulches can provide appropriate conditions for increasing nematofauna numbers but, depending on the mulch type, may also adversely affect EPNs by increasing their natural enemies. Our findings highlight the need to explore alternative farming practices to unravel complex biotic interactions that affect beneficial soil organisms in agroecosystems.
昆虫病原线虫（EPNs）是广泛存在于作物土壤中的生物防治剂。然而，传统的农业管理措施，如耕作和农药使用，会改变土壤平衡，从而影响它们的发生和活动。替代策略，如覆盖，通常被用来防止杂草生长，通过改善土壤、有机质含量、肥力和水分来提高地下生物多样性。我们假设，与使用除草剂或耕作相比，有机覆盖物会有利于线虫类动物在作物土壤中的生物条件的发展，包括 EPNs。在这项研究中，我们使用了传统的（昆虫诱饵）和分子（qPCR 分析）工具来评估土壤中本地 EPNs 的丰度和活性，以及潜在的自然天敌（如自由生活线虫（FLN）竞争者、食线虫真菌（NF）和外寄生细菌）的丰度，这些土壤采用了不同的有机覆盖物或传统管理措施进行管理。作为一个典型的农业生态系统，我们选择了葡萄园，这是最集约化管理的作物系统之一。我们比较了在两个商业化葡萄园使用的葡萄修剪碎片（GPD-M）、稻草（Str-M）和蘑菇废料（SMC-M）的覆盖物，这些葡萄园采用了综合或有机的病虫害管理。按照完全随机设计，我们在 2020 年 4 月、6 月和 10 月从每个地块中取回了两个混合样本（每个葡萄园的每个处理 3 个样本）。与综合管理的葡萄园相比，有机管理的葡萄园中的 EPNs 和其土壤食物网的选定成员数量更高。支持我们的假设，有机覆盖物总体上有利于两个葡萄园中的线虫发生。我们发现 Str-M 和 GPD-M 在有机葡萄园中的 NF 丰度更高，这可能解释了与 SMC-M 相比，两个葡萄园中的 EPN 活性和发生都较低。我们得出结论，有机覆盖物可以为增加线虫类动物数量提供适当的条件，但根据覆盖物的类型，也可能通过增加其天敌而对 EPNs 产生不利影响。我们的研究结果强调了需要探索替代农业实践，以揭示影响农业生态系统中有益土壤生物的复杂生物相互作用。
