General Distribution and Composition and Collocation Pattern of Plant Species of Urban Forests in Zhuhai City Research progress on collocation planting of crops for decreasing the loss of soil nitrate nitrogen through leaching Solid Collocation of Water Collected Shrub Grass and Water Regulation in Semi Arid Region of Loess Plateau Soil water dynamic of Hippophae rhamnoides in Loess Hilly Region The novel methods of quantitative classification of plant life cycle forms and weight collocation: taking classification of life cycle forms of Psophocarpus tetragonolobus as an example