Water‐holding soil amendments such as super‐absorbent polymer (SAP) may improve native species establishment in restoration but may also interact with precipitation or invasive species such as Bromus tectorum L. (cheatgrass or downy brome) to influence revegetation outcomes. We implemented an experiment at two sites in Colorado, U.S.A., in which we investigated the interactions of drought (66% reduction of ambient rainfall), B. tectorum seed addition (BRTE, 465 seeds/m²), and SAP soil amendment (25 g/m²) on initial plant establishment and 3‐year aboveground and belowground biomass and allocation. At one site, SAP resulted in higher native seeded species establishment but only with ambient precipitation. However, by the third year, we detected no SAP effects on native seeded species biomass. Treatments interacted to influence aboveground and belowground biomass and allocation differently. At one site, a SAP × precipitation interaction resulted in lower belowground biomass in plots with SAP and drought (61.7 ± 7.3 g/m²) than plots with drought alone (91.6 ± 18.1 g/m²). At the other site, a SAP × BRTE interaction resulted in higher belowground biomass in plots with SAP and BRTE (56.6 ± 11.2 g/m²) than BRTE alone (35.0 ± 3.7 g/m²). These patterns were not reflected in aboveground biomass. SAP should be used with caution in aridland restoration because initial positive effects may not translate to long‐term benefits, SAP may uniquely influence aboveground versus belowground biomass, and SAP can interact with environmental variables to impact developing plant communities in positive and negative ways.

中文翻译：

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土壤改良剂与侵入性草皮和干旱相互作用，对干旱恢复中的地上生物量和地下生物量产生独特影响

保水土壤改良剂（例如超吸收性聚合物（SAP））可以改善恢复过程中的原生物种建立，但也可能与降水或入侵物种（如Bromus tectorum L.（草木或霜霉病））相互作用，从而影响植被恢复结果。我们在美国科罗拉多州两个位点，在此我们研究了干旱（环境降雨减少66％），的相互作用实现的实验B. tectorum种子加成（BRTE，465粒/米²），和SAP土壤改良剂（25克/米²）建立初始工厂以及3年以上的地上和地下生物量和分配。在一个站点上，SAP导致建立了更高的本地种子物种，但仅在环境降水的情况下。但是，到第三年，我们没有发现SAP对原生种子物种生物量的影响。处理相互作用影响地上和地下生物量和分配的方式不同。在一个地点，SAP和降水的相互作用导致SAP和干旱地块的地下生物量（61.7±7.3 g / m ²）比仅干旱地块的地下生物量（91.6±18.1 g / m ²）低。在另一个站点上，SAP×BRTE相互作用导致使用SAP和BRTE的地块中的地下生物量（56.6±11.2 g / m ²）比单独使用BRTE（35.0±3.7 g / m ^2）高）。这些模式没有反映在地上生物量中。在干旱地区恢复过程中应谨慎使用SAP，因为最初的积极影响可能不会转化为长期利益，SAP可能会唯一影响地上生物量与地下生物量，并且SAP可以与环境变量相互作用，以正向和负向方式影响发展中的植物群落。