Abstract: Water and fertilizer are the keys in improving dry land productivity,and the main factors limiting the agricultural development in dry land regions.For our food security and agricultural sus-tainable development, it’s of significance to bring the effect of water and fertilizer on increasing yield into full play. This paper introduced the design principles of several commonly used methods in researching the effect of water and fertilizer, e . g . , irrigation experiment, rainproof-shed exp-eriment and long-term experiment, compared their advantages and disadvantages, and discussed the mechanisms and models of water-fertilizer interaction on dry land farmland, based on the sum-up of the achievements of related qualitative and quantitative researches. It was indicated that under appropriate conditions, there was a positive interaction between water and fertilizer on grain yield, but the effect differed with research method and natural condition. The development trend of the researches on the water-fertilizer effect on dry land farmland in light of the characteristics of agro-ecosystem was also prospected.

Key words: Forest health, Risk assessment, Forest resource management