In order to explore the eco-environment vulnerability in functional regions of soil and water conservation in Shanxi Province, the distribution characteristics of the eco-environment vulnerability in different primary function regions of soil and water conservation were analyzed, and the key areas and measures in carrying out the ecological constructions of soil and water conservation were discussed according to the regionalization and data of soil and water conservation, by using the method of combining principal factor analysis, the expert evaluation analysis, and the analytic hierarchy process. The results showed that: 1) There was significant differences in the eco-environment vulnerability among different regions, and the vulnerability degree from high to low followed the order of sand interception and reduction region (severe vulnerability), soil conservation region (medium and severe vulnerability),wind prevention and sand fixation region (medium vulnerability), water storage and holding region (mild and medium vulnerability) and water conservation region ( mild vulnerability); 2 ) In the eco-environment construction in different soil and water conservation areas, the comprehensive governing should be regarded as the first priority in soil conservation region (medium and severe vulnerability), sand interception and reduction region (severe vulnerability) and wind prevention and sand fixation region (medium vulnerability), and prevention, protection and supervision were also very important in water storage and holding region (mild and medium vulnerability) and water conservation region (mild vulnerability).

After model debugging, we designed a series of fertilizer andirrigation conditions as follows: N1, N2, N3, N4 and N5 mean the dose of pure nitrogen of 100, 200, 300, 400 and 500 kg/ hm², respectively; M0, M1, M2 and M3 represent the amount of organic fertilizer of 0, 7 500, 15 000 and 22 500 kg/ hm², respectively; I0represents no irrigation, Ib, Ik and Ig mean 50 mm water irrigated at the jointing stage, flowering period and grain-filling stage of Zea mays, respectively. Then the DSSAT model was used to simulate the growth situation of Z. mays with different water-fertilizer regimes under the conditions of light, temperature and rainfall in 2005. The results show that: 1) In the rain-fed conditions (no irrigation during the growth of Z. mays with the water depending on rainfall) with limited amount of N, the yield loss caused by the lack of N can be compensated by increasing the use of organic fertilizer; 2) Under the conditions of M1N4 treatment (the amounts of organic fertilizer and pure nitrogen were 7 500 and 400 kg/ hm², respectively) and M2N3 treatment (the amounts of organic fertilizer and pure nitrogen were 15 000 and 300 kg/ hm², respectively), no significant variations were observed in the yield of Z. mays: that of the former treatment was 14 313 kg/ hm² and that of the latter 14 711 kg/ hm², biomass of the former was 24 803 kg/ hm² and the latter 24 349 kg/ hm², yield productivities of N of the former was 40.8 kg/ kg and the latter 41.1 kg/ kg, and dry matter productivity of N of the former was 70.7 kg/ kg and the latter 70.4 kg/ kg. And all of them were at a high level. 3) Under the situation of simulated irrigation with a small amount of fertilizer, irrigation had little effect on Z. mays yield, indicating that the yield-limiting factor in this case may be fertilizer; when treated with a large amount of fertilizer, irrigation increased yield obviously, which is of important significance for productivity by ensuring water supply at the grain-filling stage.