1. College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China 2. State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
Abstract：Soil organic matter (SOM) is an essential indicator for the fertility assessment of farmland. and An efficient and stable prediction model is in need to rapidly estimate SOM in larger scale. Spectroscopic technology has been proved as a powerful tool to access SOM in the last decade. The aims of this paper were: to compare different selection method of calibration set for modeling SOM in paddy soil by using visible-near infrared (VNIR), mid-infrared (MIR) and VNIR-MIR spectra and to assess the prediction ability of the results. All spectra were transformed from reflectance to absorbance, and preprocessed by Savitzky-Golay smoothing algorithm. The prediction models of SOM were built by using partial least squares regression (PLSR) coupled with three selection methods of calibration set in VNIR, MIR and VNIR-MIR regions. The selection method of calibration Rank-KS performed better than Rank method and KS method, meanwhile the models in MIR region showed stronger prediction ability than VNIR and VNIR-MIR regions. The best prediction model was obtained with the MIR model combined with Rank-KS, and the root mean square error of prediction (RMSEP) and ratio of performance to deviation (RPD) were 3.25 g·kg-1 and 4.24. According to variable in the projection (VIP) score, important bands for SOM prediction in paddy soil were identified in VNIR and MIR region. Our results show that MIR spectroscopy could make quantitative prediction of SOM in paddy soil and Rank-KS is an effective method for selection of calibration sets, so as to provide some scientific basis for fertility assessment of farmland and rational fertilization.
Key words：Paddy soil;Prediction of SOM;Visible-near infrared spectra;Mid-infrared spectra
[1] Ji W, Viscarra Rossel R A, Shi Z. European Journal of Soil Science, 2015, 66: 555. [2] Shi Z, Ji W, Viscarra Rossel R A. European Journal of Soil Science, 2015, 66: 679. [3] Condit H R. Applied Optics, 1972, 11(1): 74. [4] Al-Abbas A H, Swain P H, Baumgardner M F. Soil Scinece, 1972, 114(6): 477. [5] PENG Jie, ZHOU Qing, ZHANG Yang-zhu, et al(彭 杰, 周 清, 张杨珠, 等). Acta Pedologica Sinica(土壤学报), 2013, 50 (3): 517. [6] Li S, Shi Z, Chen S C, et al. Environmental Science and Technology, 2015, 49: 4980. [7] XU Ming-xing, ZHOU Sheng-lu, DING Wei, et al(徐明星, 周生路, 丁 卫，等). Transactions of the Chinese Society of Agricultural Engineering(农业工程学报), 2011, 27 (2): 219. [8] JI Wen-jun, SHI Zhou, ZHOU Qing, et al(纪文君, 史 舟, 周 清, 等). Journal of Infrared and Millimeter Waves(红外与毫米波学报), 2012, 31(3): 277. [9] Vohland M, Ludwig M, Thiele-Bruhn S, et al. Geoderma, 2014, 223-225: 94. [10] Nguyen T T, Janik L J, Raupach M. Australian Journal of Soil Research, 1991, 29(1): 49. [11] Reeves J B, McCarty G W, Reeves V B. Journal of Agricultural and Food Chemistry, 2001, 49: 766. [12] McCarty G W, Reeves J B, Reeves V B, et al. Soil Science Society of America Journal, 2002, 66: 640. [13] JIANG Lu-lu, ZHANG Yu, WANG Yan-yan, et al(蒋璐璐, 张 瑜, 王艳艳, 等). Journal of Zhejiang University·Agriculture & Life Science(浙江大学学报·农业与生命科学版), 2010, 36(4): 445. [14] Wold S, Sjstrm M, Eriksson L, et al. Chemometrics and Intelligent Laboratory Systems, 2001, 58: 109. [15] Madari B E, Reeves III J B, Machado P L O A, et al. Geoderma, 2006, 136: 251. [16] Viscarra Rossel R A, Behrens T. Geoderma, 2010, 158: 52. [17] Bornemann L, Welp G, Amelung W. Soil Science Society of America Journal, 2010, 74: 1150. [18] SHI Zhou, WANG Qian-long, PENG Jie, et al(史 舟, 王乾龙, 彭 杰, 等). Science China: Earth Sciences(中国科学: 地球科学), 2014, 57(7): 1671. [19] Movasaghi Z, Rehman S, Rehman D I. Applied Spectroscopy Reviews, 2008, 43(2): 137. [20] Janik L J, Skjemstad J, Shepherd K, et al. Austrian Journal of Soil Research, 2007, 45: 77. [21] Baes A U, Bloom P R. Soil Science Society of America Journal, 1989, 53: 698. [22] Janik L J, Skjemstad J O, Shepherd K D, et al. Austrian Journal of Soil Research, 2007, 45: 77.
