柴达木盆地东部浅层土壤水分增量对降水的响应

分析浅层土壤水分增量变化对降水量的响应,以期为干旱区藜麦推广种植提供气象科学依据。利用2018—2021年4—10月柴达木盆地东部2个自动土壤水分监测站数据,包括降水量、降水前土壤含水量、降水期间平均气温以及降水历时等资料,利用Excel和SPSS进行统计分析。结果表明：（1）在生长季,与德令哈相比,乌兰小降水事件偏少4%,大降水事件偏多6%,两地土壤水分增加对降水的响应均有滞后性,根据土层深度和降水强度的不同,单次滞后时间在1~63 h之间。（2）同量级降水条件下土层水分增量随深度增加响应逐渐减小,随着降水量级的增大,同深土层含水量响应增大。（3）当累计降水< 5 mm时,0~10 cm土层水分增加有响应;当累计降水为5~10 mm时,0~40 cm土壤含水量以降水前地表含水量的不同而不同程度地响应;当降水量>10 mm时,0~40 cm各层土壤平均含水量增加响应明显。（4）0~10 cm土层含水量对降水的响应与降水期间气温呈不显著的负相关;与降水前该层含水量呈正相关,乌兰显著、德令哈不明显;与降水历时相关性表现显著(P<0.01)。结果可为藜麦各生长期需水量、雨后吸水量及灌溉作参考。

Response of Shallow Soil Moisture Increment to Precipitation in Eastern Qaidam Basin

The response of shallow soil moisture increment to precipitation was analyzed to provide a meteorological basis for promoting quinoa planting in arid areas. The data of two automatic soil moisture monitoring stations in eastern Qaidam Basin from April to October in 2018-2021 were used for the study, including precipitation, shallow soil water content before precipitation, average temperature during precipitation and precipitation duration. Statistical analysis was performed by Excel and SPSS. The results are as follows. (1) In quinoa growing season, compared with those in Delingha, the small precipitation events were 4% less and the large precipitation events were 6% more in Ulan; the response of soil moisture increment to precipitation in both places showed a lag, and depending on soil depth and precipitation intensity, the single lag time ranged from 1 h to 63 h. (2) Under the same magnitude of precipitation, the soil moisture increment gradually decreased with the increase of soil depth; with the increase of precipitation level, the water content of the same depth layer increased gradually. (3) When the cumulative precipitation was less than 5 mm, the moisture in 0-10 cm soil layer changed, but the moisture in 10-40 cm soil layer did not change; when the precipitation was 5-10 mm, the soil water content of 0-40 cm increased by different amounts according to the surface water content before precipitation; when the precipitation was more than 10 mm, the average soil water content in each layer of 0-40 cm increased significantly. (4) The response of water content in 0-10 cm soil layer to precipitation was insignificantly and negatively correlated with temperature during precipitation, and it was positively correlated with the water content before precipitation, which was significant in Wulan and not obvious in Delingha. The correlation between the response and the precipitation duration was significant (P<0.01). The results could be used as reference for studying water demand of quinoa in each growing period, quinoa water absorption after rain and irrigation.