[Nitrogen status diagnosis of rice by using a digital camera].
In the present research, a field experiment with different N application rate was conducted to study the possibility of using visible band color analysis methods to monitor the N status of rice canopy. The Correlations of visible spectrum band color intensity between rice canopy image acquired from a digital camera and conventional nitrogen status diagnosis parameters of leaf SPAD chlorophyll meter readings, total N content, upland biomass and N uptake were studied. The results showed that the red color intensity (R), green color intensity (G) and normalized redness intensity (NRI) have significant inverse linear correlations with the conventional N diagnosis parameters of SPAD readings, total N content, upland biomass and total N uptake. The correlation coefficient values (r) were from -0.561 to -0.714 for red band (R), from -0.452 to -0.505 for green band (G), and from -0.541 to 0.817 for normalized redness intensity (NRI). But the normalized greenness intensity (NGI) showed a significant positive correlation with conventional N parameters and the correlation coefficient values (r) were from 0.505 to 0.559. Compared with SPAD readings, the normalized redness intensity (NRI), with a high r value of 0.541-0.780 with conventional N parameters, could better express the N status of rice. The digital image color analysis method showed the potential of being used in rice N status diagnosis in the future.
College of Resources and Environment Sciences, China Agricultural University, Beijing 100193, China.
Liang-Liang
LL
Jia
Ming-Sheng
MS
Fan
Fu-Suo
FS
Zhang
Xin-Ping
XP
Chen
Shi-Hua
SH
Lü
Yan-Ming
YM
Sun
D002734:Chlorophyll / Q000737:chemistry; D003116:Color; D009584:Nitrogen / Q000737:chemistry*; D012275:Oryza / Q000737:chemistry*; D010781:Photography / Q000295:instrumentation*; D018515:Plant Leaves / Q000737:chemistry
D002734:Chlorophyll; D009584:Nitrogen