Portable Computer Fertilization Practice 丑Help Ru。h Canopy color information Soil-plant investigation information 100-500m A:soil Nmin testing SPAD,biomass,N% sap nitrate concentration grain yield,field image, aerialimage and so on b,c,d,e: soil Nmin testing,SPAD, sap nitrate concentration, 300-500m A: soil Nmin testing SPAD, biomass, N% sap nitrate concentration grain yield, field image, aerial image and so on b, c, d, e: soil Nmin testing, SPAD, sap nitrate concentration, 100-500m 300~500m A b c e d Canopy color information Soil-plant investigation information Portable Computer Fertilization Practice