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就０～５０ｃｍ 土层中，利用中子仪和土钻两种方法测定土壤含水量的偏差问题进行了探讨，得出：不同植被的下垫面，因土壤中有机物质的含量不同，对中子仪测定结果产生的干扰也不同。农田０～５０ｃｍ 土层中有机物含量普遍偏高，相对偏差较大；当土壤湿度较大时，同一土壤有机物中的Ｈ＋ 对测定结果的影响变小。中子外溢主要表现在０～１０ｃｍ 耕层，２０ｃｍ 以下外溢现象不明显；采用对中子吸收截面小的材料做屏障，可以有效防止中子外溢。防护效果与防护屏障的厚度和直径有关，与土壤湿度也有一定关系，在干燥土壤上，可使表层相对偏差减少９２％ 。
In the 0 ~ 50cm soil layer, the deviations of soil water content by neutron meter and soil drilling were studied. The results showed that the underlying surface of different vegetation was affected by the content of organic matter in soil, Sub-meter measurement results produce interference is also different. The content of organic matter in 0-50 cm soil layer of farmland is generally high and the relative deviation is relatively large. When the soil moisture is relatively large, the effect of H + in the same soil organic matter on the determination result becomes smaller. The neutron spillover is mainly manifested in the 0-10 cm layer, but the phenomenon of spilling below 20 cm is not obvious. The use of materials with small neutron absorption cross section can effectively prevent neutron spillover. The protective effect is related to the thickness and diameter of the protective barrier and to soil moisture. In dry soil, the relative deviation of the surface layer can be reduced by 92%.