四端子电极提高根系生物量电容法估测的有效性

发布时间：2018-02-14 08:49

本文关键词： 土壤含水率生物量根系电容二端子结构四端子结构电极接触效应　出处：《农业工程学报》2017年05期 　论文类型：期刊论文

【摘要】：二端子结构在测定根系电容时伴生的电极接触效应会影响根系电容的有效测量。分别采用二端子和四端子2种结构在土壤相对含水率为25%~30%、55%~60%和85%~90%下测定玉米根系电容,研究土壤含水率对电极接触效应的影响,并建立不同土壤水分条件和结构下根系电容与根系生物量的关系,探讨四端子结构在电容法估测根系生物量中的有效性。结果表明,二端子结构测定的根系电容较四端子结构小,随着土壤含水率减小,电极接触效应增大,在土壤相对含水率为25%~30%下最为明显。在土壤相对含水率为85%~90%时,2种结构下玉米根系电容表征根系生物量的有效性相近(二端子结构:R~2=0.63,P0.05;四端子结构:R~2=0.66,P0.05),但随土壤含水率减小,与四端子结构相比,二端子结构下玉米根系电容表征根系生物量的有效性急剧下降,在土壤相对含水率为25%~30%时最为明显,二端子结构R~2=0.37(P0.05)而四端子结构R~2=0.59(P0.05)。研究认为,土壤含水率越低,与二端子结构相比,四端子结构下根系电容表征根系生物量的有效性越好。
[Abstract]:The electrode contact effect associated with two-terminal structure in determining root capacitance will affect the effective measurement of root capacitance. Two and four terminal structures were used to measure the capacitance of maize root system at the relative moisture content of 255.55% and 850.90%, respectively. The effect of soil moisture content on electrode contact effect was studied, and the relationship between root capacitance and root biomass was established under different soil moisture conditions and structures. The validity of four-terminal structure in estimating root biomass was discussed. The capacitance of root system measured by two-terminal structure is smaller than that of four-terminal structure, and the electrode contact effect increases with the decrease of soil moisture content. Under the soil relative moisture content of 25% and 30%, the effectiveness of the capacitance of maize root system to characterize root biomass was similar under the soil relative moisture content of 85 ~ 90% (two-terminal structure: 0.63%, P 0.05; four-terminal structure: Ru 20.66%, P 0.05), but with the decrease of soil moisture content, Compared with the four-terminal structure, the validity of the capacitance of maize root system to characterize the root biomass decreased sharply under the two-terminal structure, which was most obvious when the soil relative moisture content was 25 ~ 30%, the two-terminal structure was 0.37 (P 0.05) and the four-terminal structure was R _ (2) (0.59 ~ (0.59) P _ (0.05)). The lower the soil moisture content, the better the effectiveness of root capacitance in characterizing root biomass under four-terminal structure compared with two-terminal structure.
【作者单位】：西北农林科技大学水土保持研究所;中国科学院水利部水土保持研究所;榆林学院生命科学学院;
【基金】：国家自然科学基金项目(41661101) 黄土高原土壤侵蚀与旱地农业国家重点实验室开放项目(A314021402-1604) 黄土高原水土流失综合治理技术及示范(2016YFC0501700)
【分类号】：S152.7

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