摘要：Water storage pit irrigation (WSPI) is a new method suitable for orchard irrigation in gully areas in northern China. Research on the fine root distribution of apple trees in WSPI was conducted. The results were as follows. The root length density (RLD) under WSPI and surface irrigation (SI) increased initially before decreasing with depth. The RLD under SI was mainly distributed 0-110 cm below the ground. The RLD under WSPI was mainly distributed 0-150 cm below the ground. The RLD under WSPI in the middle-depth soil was 60-150 cm, which is 1.91 times higher than that of SI. The fine root distribution of apple trees changed with varying pit depths. The RLD was mainly distributed 0-150 cm below the ground when the water storage pit was 60 cm deep. A depth of 40 cm resulted in the RLD distribution of 0-130 cm underground. The RLD also changed with different tree canopy areas. A large tree canopy meant a large RLD. The root distribution of fruit trees accords with the two-dimensional negative exponential function (RLD(r,z)= Ae~(-B|r-r~*|-C|z-z~*|) under WSPI. The correlation coefficient of the formula fitting is above 0.9. Therefore, WSPI benefits deep root growth of fruit tree.
关键词：Water storage pit irrigation;fine roots;root length density;root distribution function
