Litter mass loss and nutrient release are key links in the material cycling and energy flowing in ecosystems and of special ecological significance in maintaining ecosystem stability, improving soil structure, and promoting vegetation restoration in the arid and semi-arid regions. Furthermore, litter mass loss could be affected by the change in precipitation patterns. However, currently, most studies on the response of litter mass loss to precipitation pattern change focus on the precipitation amount much more than the precipitation frequency. Therefore, we conducted a 3-year manipulative research in a desert steppe to assess the effects of decreasing precipitation amount and increasing precipitation interval on the litter mass loss of Stipa klemenzii and their relationships with litter chemical traits [contents of carbon (C), nitrogen (N), phosphorus (P), potassium (K), lignin and ash, C/N ratio, and lignin/N ratio] and abiotic factors (light intensity and temperature and humidity of soil and air). The results showed that (1) both treatments have negative effects on litter mass loss; (2) for abiotic factors, both treatments affected only soil moisture; for biotic factors, both treatments decreased the litter lignin contents; the increased precipitation interval treatment decreased the litter N and K contents, but increased the litter C/N ratio and lignin/N ratio; (3) the main control of litter mass loss was due to our manipulation of drought regime and its effects on the soil decomposition environment, rather than to other factors such as litter quality or light intensity; (4) compared to decreased precipitation amount, increased precipitation interval has more impact on litter mass loss, and this was caused by the increased litter C/N ratio in increased precipitation interval treatment. We speculated that increased precipitation interval was a harsher abiotic factor for the decomposer, and more research on this should be conducted in the future.

中文翻译：

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沙漠草原增加降水间隔对凋落物质量损失的影响大于减少降水量

凋落物质量损失和养分释放是生态系统物质循环和能量流动的关键环节，对干旱半干旱地区维持生态系统稳定、改善土壤结构、促进植被恢复具有特殊的生态意义。此外，凋落物质量损失可能会受到降水模式变化的影响。然而，目前关于凋落物质量损失对降水模式变化响应的研究大多集中在降水量而非降水频率上。因此，我们在沙漠草原进行了为期 3 年的人工研究，以评估减少降水量和增加降水间隔对针茅枯枝落叶质量损失的影响及其与枯枝落叶化学性状 [碳 (C)、氮含量(N), 磷（P）、钾（K）、木质素和灰分、C/N 比和木质素/N 比]和非生物因素（光照强度和土壤和空气的温度和湿度）。结果表明：（1）两种处理对凋落物质量损失都有负面影响；(2) 对于非生物因素，两种处理都只影响土壤水分；对于生物因素，两种处理均降低凋落物木质素含量；增加降水间隔处理降低了凋落物N和K含量，但增加了凋落物C/N比和木质素/N比；(3) 凋落物质量损失的主要控制是由于我们对干旱状况的操纵及其对土壤分解环境的影响，而不是其他因素，如凋落物质量或光照强度；(4) 与减少的降水量相比，增加降水间隔对凋落物质量损失的影响更大，这是由于增加降水间隔处理中凋落物C/N比增加造成的。我们推测降水间隔的增加对分解者来说是一个更严厉的非生物因素，未来应该对此进行更多的研究。