Moss-biocrusts (BCs) play an essential role in soil stabilization, but it reduces soil hydraulic conductivity, hindering precipitation convert to soil water. Freeze-thaw cycles (FTCs) is a natural phenomenon, which can alter soil properties, causing widespread concern. However, few studies have focused on the effects of FTCs on hydraulic conductivity in BCs, which may alter the negative effects of BCs on hydraulic conductivity. We conducted an in-situ FTCs simulated experiment in BCs and bare sand (BS), to analyze the response of particle-size composition, water-stable aggregates and water repellency (WR) to FTCs, and their effects on saturated hydraulic conductivity (K_s). The results showed that the existence of BCs had affected water-stable aggregates, particle-size composition, WR and K_s. Compared with BS, the percentage of clay-size particle content increased by 44% and 60% in BCs layer and its underlying soil, respectively. The stability of water-stable aggregates was 19% higher in BCs than the measured stability in BS. K_s of BS was 2.4 times higher than that of BCs, and the increasing percentage of water-stable aggregates larger than 5 mm would reduce K_s in sandy land. FTCs had the significant effects on water-stable aggregates, WR and K_s. WR and K_s of BCs were decreased 57% and 25% after FTCs, respectively. Moreover, after FTCs, the percentage of soil water-stable aggregates > 5 mm reduced 19%, while 1–5 mm increased 18%. WR and sand content were significantly and negatively correlated with K_s, while clay content and the percentage of soil water-stable aggregates > 5 mm were significantly and positively correlated with K_s in BCs. Our results indicated that BCs and FTCs had a significant and negative effects on K_s. FTCs further decreased the hydraulic conductivity, which was not conductive to the supply of meltwater to soil water reservoir in the period of winter and early spring.

苔藓-生物结壳（BCs）在土壤稳定中发挥着重要作用，但它会降低土壤导水率，阻碍降水转化为土壤水。冻融循环 (FTC) 是一种自然现象，可以改变土壤性质，引起广泛关注。然而，很少有研究关注 FTCs 对 BCs 水力传导率的影响，这可能会改变 BCs 对水力传导率的负面影响。我们在 BCs 和裸砂 (BS) 中进行了原位FTCs 模拟实验，以分析粒径组成、水稳性骨料和防水性 (WR) 对 FTCs 的响应，以及它们对饱和导水率 ( K_秒）。结果表明，BCs的存在影响了水稳性团聚体、粒径组成、WR和K _s。与 BS 相比，BCs 层及其下伏土壤中粘土大小颗粒含量的百分比分别增加了 44% 和 60%。BC 中水稳定聚集体的稳定性比 BS 中测得的稳定性高 19%。BS 的K _s比 BC 高 2.4 倍，大于 5 mm 的水稳性团聚体的增加百分比会降低沙地的K _s。FTCs对水稳性骨料WR和K _s有显着影响。WR 和K _s在 FTC 之后，BCs 的数量分别下降了 57% 和 25%。此外，在 FTCs 之后，> 5 mm 的土壤水稳性团聚体的百分比减少了 19%，而 1-5 mm 增加了 18%。WR和沙子含量与K _s显着负相关，而粘土含量和土壤水稳性团聚体> 5 mm的百分比与BCs中的K _s显着正相关。我们的结果表明 BCs 和 FTCs 对K _s有显着的负面影响。FTCs进一步降低了导水率，不利于冬季和早春时期融水向土壤水库的供给。