Optimum three-point linkage set up for improving the quality of soil spectra and the accuracy of soil phosphorus measured using an on-line visible and near infrared sensor
Optimum three-point linkage set up for improving the quality of soil spectra and the accuracy of soil phosphorus measured using an on-line visible and near infrared sensor
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DOI：
10.1016/j.still.2008.10.006
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发表时间：
2009-04-01
影响因子：
6.5
通讯作者：
Ramon, H.
中科院分区：
文献类型：
--
作者：
Mouazen, A. M.;Maleki, M. R.;Ramon, H.
利用可见光（维斯）和近红外（NIR）光谱法在线测量土壤性质对土壤到传感器的距离（D）和角度（α）变化敏感，这阻碍了迄今为止在线土壤传感器的成功开发。本研究通过优化拖拉机的三点联动装置来最大限度地减少这些变化，以提高土壤光谱的质量和用在线土壤传感器测量的植物有效磷（P-avl）的准确性。该传感器由一个尖齿组成，在尖齿的背面连接一个光学探头，以漫反射模式从尖齿打开的沟槽底部获取土壤光谱。使用测量范围为306.5-1710.9 nm的移动的光纤型可见-NIR分光光度计（Zeiss Corona 45 visnir fiber，德国）。选择545、550、555、560和565 mm的拖拉机第三点链接（L）的五个长度来评估在0.15 m齿深处在线收集的光谱的质量。对在线测量的光谱进行了校正，以消除D和a的影响。结果表明，当L为555 mm时，在线测量的光谱质量最好，此时D和α均消失。这一发现得到了75.7%的平均最大反射率（AMR）的最大值和100%成功收集的光谱的支持。在545 mm的L处获得最差质量的光谱，最大D为6 mm，最大α为0.6度。560和565 mm的L值导致AMR降低（分别为43.3和33.2%），同时记录100%成功的光谱。在线测量光谱的校正导致在线测量的P-avl的准确性的明显改善。与未校正的光谱相比，校正光谱的均方根误差（RMSE）为1.07 mg 100 g（-1），预测偏差比（RPD）为1.42（RMSE = 1.15，RPD = 1.39）。此外，光谱的校正导致实验室和在线测量的P-avl图之间的相似度增加了29.6%。这些结果表明，需要优化拖拉机液压三点联动装置，并进行光谱校正，以提高在线测量土壤性质的准确性。(C)2008 Elsevier B. V.保留所有权利。
On-line measurement of soil properties using the visible (Vis) and near infrared (NIR) spectroscopy is sensitive to soil-to-sensor distance (D) and angle (alpha) variations, which have prevented the successful development of on-line soil sensors so far. This study was undertaken to minimise these variations through optimising the three-point linkage of the tractor to improve the quality of soil spectra and the accuracy of plant available phosphorus (P-avl) measured with an on-line soil sensor. The sensor consisted of a tine, to the back of which an optical probe was attached to acquire soil spectra in diffuse reflectance mode from the bottom of the trench opened by the tine. A mobile, fibre-type, Vis-NIR spectrophotometer (Zeiss Corona 45 visnir fibre, Germany), with a measurement range of 306.5-1710.9 nm was used. Five lengths of the third point link (L) of the tractor of 545, 550, 555, 560 and 565 mm were selected to evaluate the quality of spectra collected on-line at 0.15 m tine depth. The on-line measured spectra were corrected to remove the effect of D and a. The correction was evaluated by estimating the accuracy of predicting P-avl using on-line measured spectra and a previously developed P-avl calibration model.Results showed that the best quality of spectra measured on-line was obtained for L of 555 mm, at which D and alpha vanished. This finding was supported by the maximum value of average maximum reflectance (AMR) of 75.7% obtained and by 100% successfully collected spectra. The worst quality of spectra was obtained at L of 545 mm, with the largest D of 6 mm and the largest alpha of 0.6 degrees. Values of L of 560 and 565 mm led to a decrease in the AMR (43.3 and 33.2%, respectively), while recording 100% successful spectra. Correction of on-line measured spectra led to clear improvements in the accuracy of on-line measured P-avl. A lower root mean square error (RMSE) of 1.07 mg 100 g(-1) and higher ratio of prediction deviations (RPD) of 1.42 were obtained with corrected spectra as compared to uncorrected spectra (RMSE = 1.15 and RPD = 1.39). In addition, the correction of spectra resulted in an increase in the degree of similarity between laboratory and on-line measured P-avl maps by 29.6%. These results suggest the need for optimising the tractor hydraulic three-point linkage set up, and for spectra correction in order to improve the accuracy of on-line measured soil properties. (C) 2008 Elsevier B.V. All rights reserved.