摘要
为了克服LED作为主动光源的土壤全氮含量检测仪波段单一、光强信号较弱、仪器信噪比难以提高的不足,基于卤钨灯光源和特制多路光纤设计了一款便携式土壤全氮含量检测仪。检测仪选用1108、1248、1336、1450、1537、1696 nm作为土壤全氮敏感波长,选用高功率卤钨灯作为光源以提高信号强度,采用“一分六”特制光纤实现1路入射光通道和6路反射光通道。性能试验表明,调理电路和卤钨灯光源工作稳定,并且卤钨灯作为主动光源测量精度更高,“一分六”石英光纤测量精度高于其他类型光纤。根据检测仪吸光度和土壤全氮含量标准值建立了不同预测模型,结果表明,采用PLS建模精度最高,建模RC^2为0.8613,验证RV^2为0.8042,可以用于检测仪模型嵌入。田间试验结果表明,检测仪测量值和标准值的相关系数达到0.8280。设计的检测仪测量精度较高,可以满足田间快速准确检测的目的。
Soil total nitrogen content is an important soil fertility parameter.However,the existed portable detector of soil total nitrogen content had several deficiencies,such as weak light intensity and low signal-to-noise ratio.Hence,a new portable soil total nitrogen content detector was designed based on high intensity light source and special optical fiber.Six sensitive wavelengths were used,which were 1108 nm,1248 nm,1336 nm,1450 nm,1537 nm and 1696 nm.A high-power tungsten halogen lamp was used as the light source to improve the signal intensity,and one-way incident optical channel and six-way reflected optical channel were realized by using a“one-six”special optical fiber.The performance test of the detector showed that the conditioning circuit and the tungsten halogen lamp source worked stably,and the tungsten halogen lamp had higher measurement accuracy than the LED as the active light source.The prediction model was established by the absorbance values of the detector and the soil total nitrogen standard value.The highest model accuracy was obtained from a PLS model.The calibration RC^2 of the model was 0.8613 and the verification RV^2 of the model was 0.8042,which showed that the model had high precision and could be used for detector model embedding.A field experiment was conducted and the correlation coefficient between the real-time measurement result of the detector and the soil total nitrogen standard value reached 0.8280.The detector had high measurement accuracy and can meet the purpose of fast and accurate detection of the soil total nitrogen content in the field.
作者
李民赞
姚向前
杨玮
周鹏
郝子源
郑立华
LI Minzan;YAO Xiangqian;YANG Wei;ZHOU Peng;HAO Ziyuan;ZHENG Lihua(Key Laboratory on Modern Precision Agriculture System Integration Research,Ministry of Education,China Agricultural University,Beijing 100083,China)
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2019年第11期169-174,共6页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家重点研发计划项目(2017YFD0201500-2017YFD0201501、2016YFD0700300-2016YFD0700304)
关键词
土壤全氮
近红外光谱
卤钨灯光源
检测仪
一分六光纤
soil total nitrogen
near infrared spectroscopy
halogen tungsten light source
detector
one-six optical fiber
