CAJ | 학술논문

为了提高基于土壤光谱特征预测土壤盐渍化程度的准确性，需要研究土壤光谱特征的因素影响。该文通过对野外、室内预处理、不同含水率、粒径和粗糙度条件下龟裂碱土表层土壤光谱的测定，系统研究了不同因素对龟裂碱土光谱特征的影响。结果表明：土壤碱化程度越强表层土壤光谱反射率越高，在450～925 nm范围内，碱土表层野外光谱反射率比重度、中度、轻度碱化土壤和非碱化土壤野外光谱反射率高7.36%、23.18%、32.10%和39.97%；765、945和974 nm附近是龟裂碱土盐渍化信息的敏感波段；相同土壤经过室内预处理后反射率明显低于野外土壤，且预处理后不同碱化程度土壤间光谱反射率差异也小于野外光谱。土壤含水率较低时，随着土壤含水率的增加土壤光谱反射率逐渐降低，但当含水率高于田间持水率时土壤反射率随土壤含水率的增加而增加，在整个研究波段含水率为26.45%时土壤反射率较含水率为22.33%和25.39%的反射率平均分别升高39.68%和19.79%。土壤粒径越小反射率越高，较大粒径土壤在760～768 nm形成独特的“双峰”现象。土壤粒径越大反射率受表面粗糙度的影响越小，且土壤表面越粗糙光谱吸收率越大。整体来讲，在450～1000 nm波段范围内，不同碱化程度的龟裂碱土野外表层土壤光谱特征差异显著；室内经过预处理后的龟裂碱土土壤光谱特征差异主要取决于土壤含水率，而碱化程度和土壤表面粗糙度的变化对其影响较小。该研究可以为龟裂碱土盐渍化信息的准确预测提供科学依据。
위료제고기우토양광보특정예측토양염지화정도적준학성，수요연구토양광보특정적인소영향。해문통과대야외、실내예처리、불동함수솔、립경화조조도조건하구렬감토표층토양광보적측정，계통연구료불동인소대구렬감토광보특정적영향。결과표명：토양감화정도월강표층토양광보반사솔월고，재450～925 nm범위내，감토표층야외광보반사솔비중도、중도、경도감화토양화비감화토양야외광보반사솔고7.36%、23.18%、32.10%화39.97%；765、945화974 nm부근시구렬감토염지화신식적민감파단；상동토양경과실내예처리후반사솔명현저우야외토양，차예처리후불동감화정도토양간광보반사솔차이야소우야외광보。토양함수솔교저시，수착토양함수솔적증가토양광보반사솔축점강저，단당함수솔고우전간지수솔시토양반사솔수토양함수솔적증가이증가，재정개연구파단함수솔위26.45%시토양반사솔교함수솔위22.33%화25.39%적반사솔평균분별승고39.68%화19.79%。토양립경월소반사솔월고，교대립경토양재760～768 nm형성독특적“쌍봉”현상。토양립경월대반사솔수표면조조도적영향월소，차토양표면월조조광보흡수솔월대。정체래강，재450～1000 nm파단범위내，불동감화정도적구렬감토야외표층토양광보특정차이현저；실내경과예처리후적구렬감토토양광보특정차이주요취결우토양함수솔，이감화정도화토양표면조조도적변화대기영향교소。해연구가이위구렬감토염지화신식적준학예측제공과학의거。
Spectral reflectance of soil can be used to accurately predict the degree of soil salinization, however, it has not been widely used in the Typical Takyr Solonetzs of northern Yinchuan city, Ningxia Province. Although it has been reported that soil spectral reflectance can be affected by multiple factors, it is still lack of enough evidences to test which factor plays main role in soil spectral reflectance. Therefore, we conducted an experiment using several treatments in Typical Takyr Solonetzs of northern Yinchuan city, including alkalinity degree (extremely alkaline soil, strongly alkaline soil, moderately alkaline soil, slightly alkaline soil, and non-alkaline soil), water content (3.93%, 11.71%, 19.24%, 22.33%, 25.39%and 26.45%), particle size (3 mm, 2 mm, 1 mm, 0.25 mm and 0.1 mm) and roughness (coarse and smooth). We measured soil spectral reflectance both in field and in laboratory under different treatments. By analyzing these variables, we wanted to systematically determine how these factors affect spectral reflectance of Takyr Solonetzs. The results showed that reflectance in the top soil (0-20 cm) observed in the field had a positive relationship with the degree of soil alkalinity, indicating that the soil with the most serious alkalinity had the highest reflectance. In the wavelength range of 450-925 nm, the reflectance of extremely alkaline soil was 7.36%、23.18%、32.10%and 39.97%respectively higher than those of strongly alkaline soil, moderately alkaline soil, slightly soil and non-alkaline soil. Reflectance at 765 nm, 945 nm and 974 nm was sensitive to diagnose the alkalinity of Takyr Solonetzs. Soil reflectance can be significantly decreased by pretreatment (including air dried, ground and sifted before spectral measurement) in laboratory. The reflectance of extremely alkaline soil, strongly alkaline soil, moderately alkaline soil and slightly alkaline soil measured in the field were 0.1645, 0.1312, 0.0575 and 0.0246 higher than that with pretreatment. Spectral reflectance showed a decreasing trend with the increase of soil water content. However, it increased gradually when soil water content was over 22.85%(field capacity). Spectral reflectance in the soil with 26.45%of water content increased by 39.68%and 19.79%than those with 22.33%and 25.39%of water content, respectively. We also observed that particle size of soil sample had obvious impact on soil reflectance. When the particle size was smaller than 0.25 mm, the difference of reflectance between 0.25mm and 0.1mm were smaller than the particle size with 3 mm, 2 mm and 1 mm. The reflectance of soil particle size below 0.10 mm were 30.39%, 28.62%, 23.87%and 8.10%higher than 3 mm, 2 mm, 1 mm and 0.25 mm of particle size, and the bigger particle size had a special twin-peak phenomenon. Surface roughness had a negative effect on soil reflectance. We concluded that salinity degree can significantly influenced the field spectral reflectance of Takyr Solonetzs;the soil water content was the major factor that influenced the spectral reflectance of strongly alkaline soil by pretreatment, and there were little influences of the salinity degree and surface roughness on the soil spectral reflectance. Our results will be helpful for in situ prediction of the degree of soil alkalinity of Takyr Solonetzs.