**Acknowledgements**

rainfall event while the coefficient was only 1.6% to the small rainfall event); the antecedent soil moisture content also significantly affected the runoff coefficient in the vadose zone [20]. In artificially field slope rainfall-runoff experiment, Ding found that under the same rainfall intensity, the share of interflow in the total precipitation increased with rise of runoff plot's slope, while the percentage of the subsurface flow occupying the total precipitation increased with the decrease of rainfall intensity under the same slope gradient [29]. Wang et al. [2017] investigated the effects of tillage practices and slope on runoff and erosion under simulated rainfall in laboratory plots and found that AD (Artificial Digging), AH (Contour Plow) and CP (Contour Plow) can be adopted as a beneficial summer tillage practice for controlling erosion during summer fallow period because it delayed the time to runoff, decreased runoff and sediment, increased infiltration, which in turn promoted rainfall water

This study gave a summary of controlled hydrological experiments using rainfall simulator in China, especially in the red soil-covered region of Jiangxi province, including the design and construction of artificial hydrological experiments, studies and outcomes related to the impacts of slope, land use, tillage, rainfall patterns and antecedent soil moisture on runoff generation and sediment export. Results showed that grass covered slope arable land had lower surface runoff and sediment fluxes, higher subsurface runoff, peak flow, and tailing time relative to bare land; the response of subsurface flow was faster to rainfall and surface runoff from lower to upper layer and lag time increased with increasing soil depth; subsurface runoff had close relationship with rainfall amount, rainfall intensity affected peak subsurface runoff substantially, but did not impact starting time and runoff of subsurface flow; rainfall pattern affected subsurface runoff generation considerably including hydrographs and runoff; precedent soil water content had direct influences on runoff generation and runoff of subsurface flow, characterized by decrease of lag time, increase of runoff and peak flow with increase of precedent soil water content. Runoff plot test is a principal method for research of soil and water conservation and also the main approach of runoff sedimentation measurement. The design of runoff plot should obey the principles of improving the accuracy and decreasing the error of tests, saving construction materials and cutting down project costs, reducing the difficulty of construction and enhancing construction quality, as well as being conducive to post observations and lessening operating costs [31]. Although many studies have been conducted worldwide on soil water movement and transformation on field slopes, most of the former researches were focused on surficial soil water movement in indoor artificial rainfall condition with homogeneous initial soil water content and field slope. Some similar studies have been conducted in the field, however, the studies on infiltration of soil water during rainfall period and its redistribution after the infiltration are not sufficient; most studies do not relate rainfall-infiltration, runoff generation at field slopes, and soil water dynamics; spatial heterogeneity of soil property, hysteresis, surface crust, plant interception, and water uptake by roots were not comprehensively considered. In particular, studies on redistribution and export of surface runoff, interflow and groundwater flow are

and soil conservation [30, 31].

192 Hydrology of Artificial and Controlled Experiments

lacking [32].

**4. Conclusions and outlooks**

This work is also supported by the National Natural Science Foundation of China (41501531), the Natural Science Foundation of Jiangsu Province (BK20151062), the Open Research Fund of State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin (China Institute of Water Resources and Hydropower Research, Grant No: IWHR-SKL-201710) and the Science Foundation of Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences (NIGLAS2014QD07).
