Invasive winter annual grasses have degraded ecosystems around the world, forming large monocultures. However, common management methods, such as tillage, herbicide, and prescribed burning, also reduce native plant diversity and harm the soil microbial community. Early-season, short-term nutrient reduction applied to intact vegetation to manage invasive winter annual grasses could potentially decrease their abundance, while not impacting later season species. Low rates of sucrose, a labile carbon, were applied in a Pacific Northwest semiarid grassland in early spring to stimulate microbial growth and reduce nutrient availability to the invasive grass Ventenata dubia. Inorganic nitrogen was tracked throughout the experiment and plant and soil microbial community changes were determined at the end of the growing season. Sucrose application reduced nitrogen at the beginning of the season, but effects did not persist to mid-May when most plants were still active and soil moisture was not limiting. Treatments reduced V. dubia cover, per area seed production, and seed mass with no corresponding impact on perennial or other annual plants, except at the highest application rate when annual cover was reduced by 2%. The soil microbial community, determined via phospholipid fatty acid and neutral lipid fatty acid analysis, and the soil nematode community were largely unchanged at the end of the growing season with no reduction in the abundance of arbuscular mycorrhizal fungi. This short-term nutrient reduction method has the potential to not only target invasive winter annual grasses, but any plants that are active earlier or later than the rest of the community.

中文翻译：

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短期养分减少减少了侵入性冬季一年生草的覆盖率，而不会对土壤微生物群落产生负面影响

入侵的冬季一年生草已经使世界各地的生态系统退化，形成了大型单一栽培。然而，常见的管理方法，如耕作、除草剂和规定的燃烧，也会减少本地植物的多样性并损害土壤微生物群落。对完整的植被进行早期、短期的营养减少以管理入侵的冬季一年生草可能会降低它们的丰度，同时不会影响后期的物种。早春在太平洋西北半干旱草原上施用低比例的蔗糖，一种不稳定的碳，以刺激微生物生长并减少入侵草Ventenata dubia 的养分供应. 在整个实验过程中跟踪无机氮，并在生长季节结束时确定植物和土壤微生物群落的变化。蔗糖施用在季节开始时减少了氮，但效果并没有持续到 5 月中旬，当时大多数植物仍然活跃，土壤水分不受限制。治疗减少了V. dubia覆盖、单位面积种子产量和种子质量，对多年生或其他一年生植物没有相应影响，除非年覆盖减少 2% 时的最高施用量。通过磷脂脂肪酸和中性脂肪酸分析确定的土壤微生物群落和土壤线虫群落在生长季节结束时基本没有变化，而丛枝菌根真菌的丰度没有减少。这种短期的营养减少方法不仅可以针对入侵的冬季一年生草，还可以针对任何比社区其他植物更早或更晚活跃的植物。