摘要
以东北典型黑土区耕地土壤为研究对象，采用室内模拟冻融以及CT（Computerizedtomo—graphy）扫描相结合的方法，通过大孔隙数目、平均面积、Feret直径以及成圆率4个指标的量化与分析，研究了冻融循环对不同深度范围土层（0～40em、40～80em、120～160em）土壤大孔隙特征的影响规律。结果表明：冻融循环没有对表层土壤大孔隙结构产生影响，却能够显著降低40～80em土层范围内平均大孔隙面积以及Feret直径，降幅分别为46．72％和17．32％（P〈0．05），且以1～2mm和≥5mm的孔隙对冻融循环响应最为强烈，冻融循环后分别降低9．58％和42．19％（P〈0．05）。研究结果不仅证明了黏化层滞水效应的可能，同时探明了黏化层孔隙结构对冻融循环的敏感性，由此印证了季节性冻融循环对黏化层抗蚀性的削弱以及黏化层的滞水效应是导致黑土区地表侵蚀与沟蚀的主要原因。
Taking cropland soil in the Mollisol region of Northeast China as object,an indoor experiment was carried out to have the soil subjected to simulated freezing-thawing alternation for investigation of effects of the alternation on mac- ro-pores in the soil profile using CT （ Computerized tomography） thorough quantifying and analyzing variation of the num- ber, average area,Feret diameter and roundness of macro-pores with soil depth （0 -40 cm,40 -80 em, 120 ~ 160 cm）. Results show that the alternation did not change the characterization of macro pores in 0 - 40 em but significantly reduced the average area and Feret diameter of pores in 40 - 80 em by 46.72% and 17.32% , respectively （p 〈 0.05 ）. Pores, 1 2 mm and /〉5 mm in diameter were found most vulnerable to the alternation,decreasing by 9.58% and 42. 19% （p 〈 0.05 ） , respectively. The findings confirmed the possible effect of argillic horizon stagnating water, and susceptibility of the pore structure in argillie horizon to the alternation,thus demonstrating that seasonal freezing-thawing alternation is the ma- jor cause of surface soil erosion and gully erosion of the Mollisol region through weakening erosion resistance of its argillic horizon and enhancing the effect of the argillie horizon stagnating water.
出处
《土壤学报》
CAS
CSCD
北大核心
2014年第3期490-496,共7页
Acta Pedologica Sinica
基金
国家自然科学基金项目(41271293)
国家自然科学青年科学基金项目(41302222)资助
关键词
黑土
冻融循环
CT
大孔隙
黏化层
Mollisol
Freezing-thawing alternation
CT
Macro-pore
Argillic horizon
