7Balasubramanian V,Morales A C,Cruz R T,et al.Adaptation of the chlorophyll meter (SPAD) technology for real-time N management in rice:a review.IRRN,2000,25(1):4～8
8Yang W H,Peng S B,Huang J L,et al.Using leaf color charts to estimate leaf nitrogen status of rice.Agron J,2003,95:212～217
9Dobermann A,Witt C,Dawe D.Site-specific nutrient management for in intensive rice cropping systems in Asia.Field Crops Res,2002,74:37～66
10Singh B,Singh Y,Ladha J K,et al.Chlorophyll meter-and leaf color chart-Based nitrogen management for rice and wheat in Northwestem India.Agron J,2002,94:821～829
