| Experimental data related to irrigation, nutrient management and cropping pattern of main crops carried out in Central Experimental Station (CES) of Water Management, Shanxi Province, North China, were analysed according to experiments from 1992 to 2004. Experimental results of Main crops as winter wheat, spring maize and sunflower about irrigation and nutrient management were analysed. Soil water dynamics under shallow water table were discussed. Irrigation management on different water table management (0.5 m, 1.0 m, 1.5 m, 2.0 m, 2.5 m, 3.0 m) was also discussed. After calibration for main crops WOFOST crop simulation model were used for simulation of potential under water-limited condition. A tile-based (1 km*l km) regional water balance model be built, and the results were analyzed directly linked with AricView GIS.The main results and conclusion from the study are:1. Water requirements of winter wheat and spring maize for whole growing season are 390~400 mm and 400-500 mm respectively, the relation between water requirement and WUE could be expressed by a negative logarithm curve, the relation between water requirement and gTain yield could be expressed by a positive logarithm curve, increasing in fertilizer application results higher grain yield and WUE. For the reason of growing in rainy season spring maize need one time of irrigation, sunflower need twice (105-110mm each) in dry years, but no need in rainy years.2. Soil water dynamics are influenced by capillary rise under shallow water table, mainly in the soil layer of 0-100 cm for both winter wheat and spring maize. Soil water content varies more obviously under shallower water table, and it lead to more ground water uptake and more water use. The start day of percolation after irrigation or rainfall lagged under deeper water table. Crop growth and yield were influenced by shallow water table, mainly by effect on individual seedlings, the amount of tillering, spikes, but little on grain weight . It has less influence under deeper groundwater table. The higher crop yield and WUE occurs when water table set at 1.0m and 1.5 m for spring maize and winter wheat, respectively. WUE decrease when water table increase or decreased from 1.0 m for winter wheat.3. After calibration of parameters, WOFOST model could simulate potential and water-limited crop production in Fen River Irrigation District. The results show an average total grain yield production under potential conditions of 10 500 kg·hm~-2 14 500 kg·hm~-2 and 5900 kg·hm~-2 for winter wheat, spring maize, and sunflower, respectively. Crop production under water-limited (rainfed) conditions is extremely low. The situation was still acceptable for spring maize and sunflower that grows in the rainy season. For sunflower, simulated water-limited grain yields are direct correlated with precipitation, and could be expressed by a logarithmic curve. Simulated potential leaf area index and harvest index are somewhat higher than the actual value. The relationships between simulated grain yield and precipitation plus irrigation could be expressed by logarithmic curve for winter wheat, spring maize and sunflower (correlation coefficiency is higher than 0.7). Simulated grain yield was overestimated 8.75%and 22.3% for spring maize and winter wheat, respectively, compared to measured yield under irrigated condition.4. Splash! model is not only a water balance model but also a database with enough spatial data. Simulated results could directly link with ArcView GIS and well expressed the water balance between surface system, unsaturated system and groundwater system. Compared to hilly region more irrigation water, infiltration and evapo-transpiration occurred in Fen River Irrigation District (FRID). Groundwater table is high in hilly region (or no ground water) and in FRID. Groundwater table within intermediate zone (between hilly region and FRID) changes between 85-120 m. Groundwater table in some areas of the north east part of the watershed is very deep (or no groundwater).5. Water...
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