Multi-factors Fertilization Trial of Tectona grandis in Seedling Stage Spectral Monitoring of Winter Wheat Above-ground Dry Biomass in Various Sowing Dates Effect of Soil Drying-Wetting Alternation on Dry Biomass Accumulation and Reallocation at Maize Flowering Stage Effects and Mechanisms of Alternate Water and Nitrogen Supply to Partial Root Zone of Maize A Tentative Study on Utilization of Canopy Hyperspectral Reflectance to Esti-mate Canopy Growth and Seed Yield in Soybean