5Humburg D S,Stange K W,Robert P C,et al.Spectral Properties of Sugsrbeets Related to Sugar Content and Quality [A].Proceedings of the Fourth International Conference on Precision Agriculture [C].St.Paul,Minnesota,USA,1998.19-22.Part A and Part B.,1999.159
6Blackmer T M,Schepers J S,Varvel G E,et al.Nitrogen Deficiency Detection Using Short-wave Radiation from Irrigated Corn Canopies[J].Agronomy Journal,1996,88:1-5.
7Daughtry C S T,Walthall C L,Kim M S,et al.Estimating Corn Foliar Chlorophyll Content from Leaf and Canopy Reflectance[J].Remote Sensing of Environment,2000,74:229-239.
8Penuelas J,Filella 1,Gamon J A.Assessment of Photosynthetic Radiation Use Efficiency with Spectral Reflectance[J].Mew Phytologist,1995,131:291- 296.
9Merzlyak M N,Gitelson A A,Chivkunova O B,et al.Nondestructive Optical Detection of Pigment Changes During Leaf Senescence and Fruit Ripening [J].Physiologia Plantarum,1999,106:135-141.
