Estimation of Solar Energy Use Efficiency and Spatiotemporal Pattern in Guangdong Based on Multitemporal NOAA-AVHRR NDVI and GIS Methods Studies on the Energy and Material Use Efficiency of Cultivated Grassland and Farmland Ecosystem in the Hilly Regions of Southern China Photosynthetic Responses of Sch im a supe rba Grown in D ifferentL ight Reg imes of Subtropica l Evergreen Broadleaf Forest Application of GIS and integrated mathematic models on estimating forest land wood productiveness and solar energy use efficiency