Prolonged benefits following a single application of compost in organic dryland wheat (Triticum aestivum L.) in the western United States have been documented, including the long-term bioavailability of phosphorus (P). Information on the bioavailability and forms of P following a one-time compost application in marginal organic agroecosystems with low and infrequent use of fertilizers is required to promote sustainability. The goal of this study was to evaluate changes in Hedley P pools following a one-time application of manure compost and its potential influence on short-term (3-yr) P bioavailability. Steer manure compost at 0, 25, and 50 Mg dry weight ha^–1 was applied to two organic dryland sites, Snowville and Blue Creek, with contrasting soil characteristics in northern Utah in a randomized complete block design. Potential phosphatase assays, a laboratory aerobic incubation study, and soil P fractionations were carried out to assess the transformation of P 1 and 3 yr after a one-time compost application. At 0–10 cm, compost application resulted in increased acid phosphatase at Snowville (67.3 vs. 42.7 μg p-nitrophenol g^–1 soil, p = .003), while alkaline phosphatase increased at Blue Creek (124 vs. 49 μg p-nitrophenol g^–1 soil, p = .0185). The path coefficient between compost P and Hedley labile inorganic P was significant at Snowville, but not at Blue Creek, suggesting that the pathways of P differed between the sites. The Hedley stable P pool was a sink of compost P at Snowville but a source at Blue Creek. In conclusion, our work shows that a one-time compost application had a differential effect on the variation in P dynamics in organic dryland winter wheat–fallow soils. The potential long-term benefits may be greater in semiarid soils with lower available P levels, higher carbonate levels and pH, and drier conditions.

中文翻译：

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一次性施用后堆肥对有机旱地土壤磷动态的可变影响

在美国西部的有机旱地小麦 ( Triticum aestivum L.) 中单次施用堆肥后的长期效益已被记录在案，包括磷 (P) 的长期生物利用度。需要关于在边缘有机农业生态系统中一次性堆肥施用后磷的生物利用度和形式的信息，肥料使用率低且不经常使用，以促进可持续性。本研究的目的是评估一次性施用粪肥后 Hedley P 池的变化及其对短期（3 年）P 生物利用度的潜在影响。以 0、25 和 50 毫克干重 ha ^{–1 控制}粪便堆肥以随机完整区组设计应用于犹他州北部具有对比土壤特征的两个有机旱地场地，Snowville 和 Blue Creek。进行了潜在的磷酸酶测定、实验室有氧培养研究和土壤 P 分馏，以评估一次性堆肥施用后 1 年和 3 年 P 的转化。在 0–10 cm 处，堆肥施用导致 Snowville 酸性磷酸酶增加（67.3 对 42.7 μg p-硝基苯酚 g ^–1土壤，p  = .003），而 Blue Creek 碱性磷酸酶增加（124 对 49 μg p-硝基苯酚 g ^–1土壤，p = .0185）。堆肥 P 和 Hedley 不稳定无机 P 之间的路径系数在 Snowville 显着，但在 Blue Creek 不显着，表明 P 的途径在不同地点之间存在差异。Hedley 马厩 P 池是 Snowville 的堆肥 P 池，但 Blue Creek 的源。总之，我们的工作表明，一次性堆肥对有机旱地冬小麦-休耕土壤中磷动态的变化有不同的影响。在有效磷含量较低、碳酸盐含量和 pH 值较高以及条件较干燥的半干旱土壤中，潜在的长期效益可能更大。