[Crown interception of apple trees in loess hilly and gully region, Northwest China]

Taking the apple trees at their full-fruit stage in the loess hilly and gully region of Shaanxi as test objects, a three-year consecutive monitoring was conducted on the precipitation outside the tree crown, the through fall of the crown, and the stem flow from 2008 to 2010, with the effects of different precipitation factors on the crown interception analyzed. In the study region, the stem flow rate and crown interception rate of the trees accounted for 0. 8% and 8.9% of the precipitation, respectively, the inter-plant interception was higher than the inter-row interception, and the interception increased with the decreasing distance to the stem. In rainy season, the crown interception was greater while the interception rate was smaller; in drought season, it was in adverse. The crown interception increased with increasing precipitation amount, precipitation intensity, precipitation duration, and precipitation interval, and the relationships followed power function or logarithmic function. The interception rate was negatively correlated with precipitation amount, precipitation intensity, and precipitation duration, but positively correlated with precipitation interval, and the relationships were in power function. Among the precipitation factors, precipitation amount had the greatest effects on the crown interception capability of the apple trees.