Spatial and temporal characteristics of soil water dynamics and crop yield response from a 4-year of lucerne and winter wheat rotation system in the Loess Plateau Soil respiration and its responses to soil moisture and temperature under different tillage systems in dryland maize fields THE RAINWATER HARVESTING TECHNOLOGY APPROACH FOR DRYLAND AGRICULTURE IN SEMI ARID LOESS PLATEAU OF CHINA ENERGY FLOWING OF AGRICULTURAL ECOSYSTEM IN DRYLAND FARMING EXPERIMENTAL SITE BETWEEN EASTERN SHANXI AND WESTERN HENAN PROVINCE