模擬降雨下土壤前期含水量對土壤可蝕性的影響-全文預覽
【正文】 399405.[19] 于東升, 史學正, 梁音等. 應用不同人工摸擬降雨方式對土壤可蝕性K值的研究[J]. 土壤侵蝕與水土保持學報, 1997, 3(2): 5357. Yu Dongsheng, Shi Xuezheng, Liang Yin et al. Study on Soil Erodibility Factor K with Deferent Simuluation Rainfall Methods[J]. Journal of Soil Erosion and Soil and Water Conservatiion. 1997, 3(2): 5357.Effect of antecedent soil moisture on soil erodibility using simulation rainfallLiu Zhenbo, Shi Xuezheng, Yu Dongsheng, Wang Hongjie, Zhang XiangyanState Key Laboratory of Soil and Sustainable Agriculture//Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, ChinaAbstract: Antecedent soil moisture content is a very important factor leading to soil erodibility dynamic change. 42 artificial simulated rainfall experiments were conducted in 14 soil erodibility plots with different soil types in South China, and the impact of three antecedent soil moisture levels (dry, dampish, wet) on soil erodibility K value were studied as well. The results showed that soil erodibility K value was affected by antecedent soil moisture content. Also, the change pattern of soil erodibility K value varied with different soil types. For the same soil type, the highest value was 16 times greater than the lowest value within the range of antecedent soil moisture content. For the different soil types, different pattern of soil erodibility K value was found with the change of antecedent soil moisture content. The change trend of soil erodibility K value was sorted into three types: Firstly, the soil erodibility factor K values for nine soil types would be going up with the increase of the antecedent soil moisture content。 antecedent soil moisture。 Thirdly, the soil erodibility factor K values for one kind of soil would be going down with the decrease of the antecedent soil moisture content.Key words: soil erodibility。hhm2)R/(17 MJ其中有10種土壤類型在干態(tài)下徑流系數(shù)最低，在濕態(tài)下徑流系數(shù)最高，只有3種土壤在稍濕態(tài)下徑流系數(shù)最高；同樣，9種類型土壤最高土壤流失速率出現(xiàn)在土壤前期含水量濕態(tài)下，最低土壤流失速率在干態(tài)下，另外有4種土壤類型土壤流失速率最高在稍濕態(tài)下。hm2計算得到14種土壤不同土壤前期含水量下的K值（表6），紫紅色砂頁巖發(fā)育的耕作的紫色濕潤雛形土（22小區(qū)）在濕態(tài)下土壤可蝕性K值高過了理論值，因此在分析中不予考慮。mm1，R值單位為17 MJac1）為土壤流失量，R為降雨侵蝕力，根據(jù)R值的“經(jīng)典”方法計算得到，LS為地形因子，經(jīng)測算得到（表5）。P所規(guī)定的條件，在本實驗中，植被覆蓋與管理因子C=1，水土保持工程措施因子P＝1，所以通用流失方程可簡化為：A=R 人工模擬降雨的土壤可蝕性K值本研究采用通用土壤流失方程（USLE）的經(jīng)典方法來估算土壤可蝕性K值[1]，根據(jù)通用土壤流失方程A=Rhm2hm2 人工模擬降雨試驗下的產(chǎn)沙由于降雨歷時不盡相同，我們用單位時間內(nèi)的土壤流失量——土壤流失速率（t由圖表3可知，大多數(shù)土壤類型3次人工模擬降雨徑流系數(shù)隨著土壤前期含水量的增加而增高，、。同一土壤的濕態(tài)土壤水分質(zhì)量分數(shù)比干態(tài)差別最大的為花崗片麻巖發(fā)育的簡育濕潤富鐵土（16小區(qū)），％；差距最小的為未破壞土壤表面結殼的第四紀紅色粘土發(fā)育的粘淀濕潤富鐵土（18小區(qū)）。實驗數(shù)據(jù)均采用Microsoft Excel統(tǒng)計分析軟件完成統(tǒng)計分析。該旱地土壤處在坡的中部，坡度約為7186。21第四紀紅色粘土簡育濕潤富鐵土荒地土壤，詳情同11號小區(qū)。20千枚巖鋁質(zhì)濕潤淋溶土旱耕地土壤，土壤土層深厚，厚度可達3 m以上。19千枚巖鋁質(zhì)濕潤淋溶土荒地土壤，土壤土層深厚，厚度可達3米以上，荒地上有少量的薪炭林木。種植花生、紅薯、西瓜等，種植年限已有15～20 a。13紅砂巖鋁質(zhì)濕潤淋溶土約40多年前由原始林地開墾成的耕地，主要種植油菜和花生。 采樣與分析方法表1 試驗小區(qū)中不同土壤類型的基本情況[18]Table 1 Status of di
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