【摘要】：為闡明大孔隙豐富且孔徑呈兩極分化的紫色土坡耕地土壤大孔隙流的運(yùn)移規(guī)律,通過室內(nèi)土柱試驗(yàn)獲取耕作層0~20 cm、非耕作層20~40 cm原狀土柱和填裝土柱的穿透曲線,分析飽和條件下土壤大孔隙流發(fā)生規(guī)律,并采用解析法CXTFIT軟件擬合了水分優(yōu)先運(yùn)移參數(shù),PFSP指標(biāo)(大孔隙流引起的穿透曲線延展量與水動(dòng)力彌散作用及兩區(qū)作用引起的延展量的比值)定量評(píng)價(jià)土壤大孔隙流的貢獻(xiàn)率。研究結(jié)果表明:1)以填裝土柱水流為平衡基質(zhì)流計(jì)算,耕作層0~20 cm原狀土柱中大孔隙流的導(dǎo)水貢獻(xiàn)率為66.2%~68.5%,而Br-累積淋出量占總淋出量的62.3%~66.1%。對(duì)于非耕作層20~40 cm,土壤大孔隙流導(dǎo)水貢獻(xiàn)率為0.2%~1.7%,而Br-隨大孔隙流運(yùn)移的比例卻達(dá)14.5%~20.5%。說明耕作層土壤中大孔隙流現(xiàn)象遠(yuǎn)比在非耕作層土壤中更為顯著;2)PFSP值結(jié)果表明大孔隙流作用對(duì)穿透曲線延展量的貢獻(xiàn)率最大,兩區(qū)交換運(yùn)移作用次之,水動(dòng)力彌散作用的最小。即PFSP值越大,大孔隙流對(duì)總水流通量的貢獻(xiàn)率越大。
[Abstract]:In order to elucidate the migration law of macropore flow in purple sloping farmland with rich macropores and polarizing pore size, the penetrating curves of undisturbed soil column and filled soil column in uncultivated layer of 0 ~ 20 cm, uncultivated layer for 20 cm, were obtained by laboratory soil column test. The occurrence law of soil macroporous flow under saturated condition was analyzed, and the moisture preferential migration parameters were fitted by analytic method CXTFIT software. The PFSP index (the ratio of penetration curve extension caused by macropore flow to hydrodynamic dispersion and the extension caused by two-zone interaction) was used to quantitatively evaluate the contribution rate of soil macroporous flow. The results show that: 1) the contribution rate of macroporous flow in undisturbed soil column is 66.2% and 68.5%, which is calculated by using filled soil column flow as balance matrix flow, and the contribution rate of macropore flow in undisturbed soil column of 0 ~ 20 cm is 66.2%. The cumulative leaching amount of Br- accounted for 62.3% of the total leaching amount. For 20 ~ 40 cm, of non-tilling layer, the contribution rate of macroporous flow water conductivity is 0.22 ~ 1.7, while the proportion of Br- migration with macroporous flow is 14.5and 20.5. The results show that the phenomenon of macropore flow in tilling layer soil is much more significant than that in non-cultivated layer soil. 2) the results of PFSP show that the contribution of macroporous flow to the extension of the penetrating curve is the largest, the exchange migration between the two regions is the second, and the hydrodynamic dispersion is the least. That is, the larger the PFSP value, the greater the contribution of macroporous flow to the total water flux.
【作者單位】： 中國科學(xué)院成都山地災(zāi)害與環(huán)境研究所;四川省中醫(yī)藥科學(xué)院;
【基金】：國家重點(diǎn)研發(fā)計(jì)劃課題(2016YFD0800203) 國家自然科學(xué)基金項(xiàng)目(41501237,41471268)
【分類號(hào)】：S152.7

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本文編號(hào)：2404494