caa a22 4500 445864737 CHVBK 20180317145454.0 cr unu---uuuuu 170323e20111001xx s 000 0 eng 10.1007/s11119-010-9213-2 doi (NATIONALLICENCE)springer-10.1007/s11119-010-9213-2 Spectral characterization and prediction of nutrient content in winter leaves of litchi during flower bud differentiation in southern China [Elektronische Daten] [Shuisen Chen, Dan Li, Yingfang Wang, Zhiping Peng, Weiqi Chen] Nutrient availability can affect the cracking rate of the litchi fruit tree, and the nutrient content of the canopy can be used to monitor availability and fertilizer needs of the litchi orchard. In this study, we analyzed the correlation between calcium (Ca), magnesium (Mg) and potassium (K) in canopy leaves and four indices of in situ spectral data of litchi canopy. These were reflectance (R), reciprocal-logarithm-transformed reflectance (log(1/R)), the first-order derivative of reflectance (dR) and the first-order derivative of reciprocal-logarithm-transformed reflectance (dlog(1/R)). The results showed that the spectra of the litchi canopy have common spectral characteristics. The correlation between the selected nutrients of the litchi canopy and R or log(1/R) was weak, that between the nutrients and dR was significant and with dlog(1/R) it was the most significant. The 1262nm wavelength for dR and 1018nm one for dlog(1/R) had the most significant correlation with Ca. The 1293nm wavelength for dR and 1601nm one for dlog(1/R) had the most significant correlation with Mg. The 1686nm wavelength for dR and 1337nm one for dlog(1/R) had the most significant correlation with K. Therefore, those wavelengths were chosen to create the regression equations for prediction. The linear regression equations performed the best when predicting canopy nutrient content of litchi for Ca at 1018nm, Mg at 1601nm and K at 1337nm. Further, the formulated application of K2O played an important role in reducing the amount of K2O applied (50.6g/plant on average) and in increasing the yield of the litchi tree by 4.4kg/plant on average. These results are relevant for implementing a precision agriculture approach for litchi production and for environmental protection in South China or in other litchi production areas of the world. Other nutrients that affect litchi growth need to be studied in the future. Springer Science+Business Media, LLC, 2010 Litchi ( Litchi chinensis Soon. ) nationallicence Winter canopy nationallicence Nutrient content nationallicence Calcium (Ca) nationallicence Magnesium (Mg) nationallicence Potassium (K) nationallicence Spectral model nationallicence Fertilizer application nationallicence Chen Shuisen Guangzhou Institute of Geography, 510070, Guangzhou, China aut Li Dan Guangzhou Institute of Geography, 510070, Guangzhou, China aut Wang Yingfang Guangzhou Institute of Geography, 510070, Guangzhou, China aut Peng Zhiping Soil & Fertilizer Institute, Guangdong Academy of Agricultural Sciences, 510640, Guangzhou, China aut Chen Weiqi Department of Geography, Florida State University, 32306-2190, Tallahassee, FL, USA aut Precision Agriculture Springer US; http://www.springer-ny.com 12/5(2011-10-01), 682-698 1385-2256 12:5<682 2011 12 11119 https://doi.org/10.1007/s11119-010-9213-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11119-010-9213-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chen Shuisen Guangzhou Institute of Geography, 510070, Guangzhou, China aut NATIONALLICENCE 700 1- Li Dan Guangzhou Institute of Geography, 510070, Guangzhou, China aut NATIONALLICENCE 700 1- Wang Yingfang Guangzhou Institute of Geography, 510070, Guangzhou, China aut NATIONALLICENCE 700 1- Peng Zhiping Soil & Fertilizer Institute, Guangdong Academy of Agricultural Sciences, 510640, Guangzhou, China aut NATIONALLICENCE 700 1- Chen Weiqi Department of Geography, Florida State University, 32306-2190, Tallahassee, FL, USA aut NATIONALLICENCE 773 0- Precision Agriculture Springer US; http://www.springer-ny.com 12/5(2011-10-01), 682-698 1385-2256 12:5<682 2011 12 11119 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer