Research Progress of Precipitation Interception by Plants

Precipitation resource is the main water source for plant growth and development and yield formation. Plants maintain normal growth and development by absorbing water from soil. Precipitation is not only related to species distribution of natural plants, but also closely related to plant productivity. However, the role of precipitation is often overestimated in water resources assessment and farmland water balance research because the interception of precipitation by plant canopy is not considered. Therefore, the study of precipitation interception is of great significance in hydro-ecology and agrometeorology. Indirect and direct methods of estimating precipitation interception are introduced. Indirect measurement method is known as water balance method, and measurement methods of each component and the calculation method of precipitation interception are introduced. Direct measurement method is also known as the weighing method, the detailed operation process of various direct measurement methods, as well as the relevant problems that should be paid attention to in various methods are introduced. There are many researches on the precipitation interception by forest at home and abroad, involving interception storage, interception rate, interception model and other aspects, almost of these research results are obtained based on the indirect measurement method under natural precipitation. Many researches on precipitation interception of the crop focus on corn and wheat, but few on other crops, most of them are based on artificial sprinkling irrigation or simulated precipitation, and few of them are carried out under natural precipitation. The main problems existing in estimating precipitation interception by plants are discussed. First, different understanding of the concept of precipitation interception leads to significant differences in results of interception measurement. Second, there is no perfect method at present, which leads to the insufficient accuracy of results. Third, different planting density of plants leads to different throughfall, which makes significant difference in interception. Fourth, different precipitation intensity can lead to different interception. Finally, other factors, such as wind speed, plant morphology and structure, leaf surface characteristics, can also impact the interception. Although the simulated precipitation experiment can obtain necessary observations in a short period of time, it does not fully represent the canopy interception process and characteristics of the actual precipitation in nature. Therefore, in natural environment, how to perfertly simulate the canopy interception needs extensive exploration and in-depth study. The evaporation of plant leaves, the interception of snowfall, the impact of wind, the scale of research, measurement methods, and the comprehensive simulation model will be the emphases and difficulties in future.