本文選題：沉降管法 + 沉降速度�。� 參考：《土壤學(xué)報(bào)》2017年05期

【摘要】：了解不同粒徑泥沙遷移運(yùn)動(dòng)規(guī)律,有助于深入理解侵蝕條件下碳、氮、磷等元素的生物地球化學(xué)過程。土壤營(yíng)養(yǎng)元素的遷移轉(zhuǎn)化與泥沙顆粒的運(yùn)動(dòng)規(guī)律密切相關(guān),而泥沙的運(yùn)動(dòng)規(guī)律由顆粒大小、性狀、孔隙度和密度等因素共同決定。依據(jù)泥沙顆粒沉降速度分選的原理,針對(duì)中國(guó)兩種典型侵蝕土壤(紅壤和黃綿土),分別進(jìn)行了土壤機(jī)械組成(礦質(zhì)土粒分選)和沉降速度分選測(cè)定。結(jié)果表明,土壤顆粒的沉降粒級(jí)可有效區(qū)分紅壤和黃綿土中不同粒徑團(tuán)聚體的沉降速度,能夠更加準(zhǔn)確地反映出同一粒徑顆粒因性狀、密度和孔隙度的差異而形成的不同沉降速度。相對(duì)于質(zhì)地疏松的黃綿土,紅壤的機(jī)械組成顯示,有86.9%的有機(jī)碳與≤32μm的礦物顆粒相結(jié)合,很有可能隨懸移過程匯入下游水體。但土壤顆粒沉降速度分布表明,約有90.5%的紅壤有機(jī)碳與等效石英粒徑≥63μm的團(tuán)聚體相結(jié)合,易在經(jīng)歷較短的遷移過程后,快速沉積于下坡面。這表明,現(xiàn)有的土壤侵蝕模型大多利用土壤機(jī)械組成(即礦質(zhì)粒徑大小)在反映泥沙運(yùn)動(dòng)或元素遷移規(guī)律方面存在片面性。土壤的團(tuán)聚過程可有效縮減有機(jī)碳和無機(jī)碳的遷移距離,從而使其更易沉積于陸生環(huán)境。土壤顆粒的沉降速度分級(jí)對(duì)認(rèn)識(shí)泥沙顆粒和養(yǎng)分元素在侵蝕—遷移—沉積過程中的生物地球化學(xué)過程提供了新的途徑和視角。
[Abstract]:It is helpful to understand the biogeochemical processes of carbon, nitrogen, phosphorus and other elements under erosion conditions. The transport and transformation of soil nutrient elements are closely related to the movement of sediment particles, while the movement of sediment is determined by the particle size, characteristics, porosity and density. According to the principle of sedimentation velocity separation of sediment particles, two typical eroded soils (red soil and yellow spongy soil) in China were determined by soil mechanical composition (mineral soil particle sorting) and settling velocity separation respectively. The results show that the sedimentation particle size of soil particles can effectively distinguish the settling velocity of different aggregates in red soil and yellow cavernous soil, and can more accurately reflect the characteristics of particle size of the same size. The difference in density and porosity resulted in different settlement rates. Compared with the loose yellow spongy soil, the mechanical composition of red soil shows that 86.9% of the organic carbon is combined with mineral particles 鈮，

本文編號(hào)：1882048