【作者】 张琪；

【导师】 蔡崇法；

【作者基本信息】 华中农业大学 ， 土壤学， 2003， 硕士

【摘要】 土壤团聚体是影响土壤抗蚀性的重要指标之一，研究它对侵蚀过程的影响对于减小水蚀危害、保护土壤资源、维持和提高生产率、维护土壤生态系统平衡具有重要意义。本研究根据红壤丘陵区成土母质及其发育的土壤结构的差异，选用通城(T1、T2、T3)、贺胜桥(H1、H2、H3)三种母质发育的六种典型红壤，采用盖纱网、不盖纱网两种处理，通过人工模拟降雨试验，从团聚体特征与物理化学性质入手，研究了红壤的侵蚀敏感性、泥沙的颗粒分布及团聚体稳定性与物理化学性质间的关系，得到如下结果： 侵蚀过程中，团聚体稳定性强的土壤(H2、T1)较团聚体稳定性差的土壤，产流和径流稳定时间都较迟，径流量也较少，且盖纱网处理径流量分别比不盖纱网少3.3L／6min、2.6L／6min，而其它四种团聚体稳定性较差的土壤，两种降雨处理中径流量的差异不大。比较不同处理，六种土壤盖纱网处理的产流和径流稳定时间比不盖纱网的迟。侵蚀过程中产沙率的波动较大，H2、T1产沙率随时间的延长而增大；H1、H3先增大，后降低；T2、T3产沙率有随时间延长而下降的趋势。盖网处理的平均产沙率较无网处理小2.18-14.29g／l。 对侵蚀泥沙来说，粘粒含量高的土壤由于含有较多稳定的团聚体，其泥沙团粒分布较粗，而砂粒、粉粒含量高的土壤，侵蚀泥沙中单粒较多。泥沙中0.002-0.02mm颗粒最多，占泥沙总量的26.68％-60.33％，这由于径流优先选择该粒径颗粒。在覆盖纱网处理中，薄层水流对土壤的侵蚀力下降，携沙能力下降，对不同土壤颗粒的选择性趋于一致。 抗蚀性指标中DR与三种形态铁铝氧化物、Si_d、Si_o、OM、HA、FA、胡敏素负相关，与焦磷酸钠提取硅(Si_p)、C／N正相关。ASC、CFI、clay％多与无机、有机胶结物正相关，与Si_p、C／N负相关。其中无机胶结物(Fe_d、Al_d、Al_o、Si_o)，有机胶结物(OM、C／N、FA、胡敏素)与DR、ASC、clay％的相关性较好，相关系数大多能达到显著(p＜0.05)、极显著(p＜0.01)水平。 DR、Si_p、C／N与侵蚀率、平均产沙率正相关，与泥沙MWD(分散前)／MWD(分散后)负相关；ASC、CFI、clay％、三种形态铁铝氧化物、Si_d、Si_o、OM、HA、FA、胡敏素与侵蚀率、平均产沙率负相关，与泥沙MWD(分散前)／MWD(分散后)正相关。其中抗蚀性指标(DR、ASC、CFI、clay％)，无机胶结物(Fe_d、Al_d、Al_o、Si_o)，有机胶结物(有机质、C／N、富里酸、胡敏素)与侵蚀率、平均产沙率、泥沙MWD(分散前)／MWD(分散后)的相关性较好，相关系数大多能达到显著、极显著水平。 Fe_d、Al_d、Si_o、Al_o在通城三个土样的泥沙中有随泥沙粒径增大而降低的趋势，它们在大粒径中的低含量使其团聚作用下降，因而大粒径泥沙稳定性较差。Fe_d、Al_d、Al。，在贺胜桥土样的泥沙中，随粒径增大而增大，它们在大粒径中的高含虽，使大粒径泥沙具有较强的稳定性。 对贺胜桥土壤，泥沙对有机质有明显的富集作用，泥沙中大颗粒团聚体的官集作用强于小颗粒。对通城土壤泥沙，这种富集作用较弱，但其有机质含量与POM的分布有关，盖网处理中，POM集中在0.05一0.25二粒径，无网处理集中在<0.05二，粒径。有机质C/N的数据说明，侵蚀过程中维持土粒稳定的不足新鲜的POM，而是与矿质土粒结合紧密的有机一无机复合体。干筛团聚休中，大粒级C/N小于<0 .05ITirn颗粒，含有更多新鲜的有机质。泥沙和干筛团聚体中粒径越大，胡敏素含量越高，HA、FA的含量变化无明显规律。更多还原

【Abstract】 Soil aggregate is one of the important factors to determine soil anti-eredibility. The study of its’ responses during erosion processes have great importance in reducing water erosion danger, stabilizing and improving agricultural production, preserving soil resources and balancing soil ecological system. Six typical red soils, which developed from three parent materials at Heshengqiao(Hl,H2,H3) and Tongcheng(T1,T2,T3), arc used in this paper. From the aspects of aggregate characteristics and physic-chemical properties, the susceptivity of red soil to water erosion, size characteristics of sediment and the physic-chemical mechanism of aggregates stability are studied using covered and uncovered net under simulated rainfall conditions. The main results are summarized as follows:During erosion process, soils (H2, T1) having more stability aggregates put off the time of emergence flow, and the time of steadying flow and their runoff volume is more less than other soils. In the covered net treatment the runoff volume of H2 and Tl is less 3.3L/6min and 2.6L/6min than uncovered, but other soils have similar runoff volume in two treatment. The time of emergence flow and steadying flow is delayed in the treatment of covered net. The sediment concentration changes greatly during erosion process, H2 and Tl increase with time, H1 and H3 increase at beginning and decrease subsequently, T2 and T3 decrease with time. In covered treatment the average sediment concentration is less 2.18-14.29g/l than uncovered.The sediment from high-clay soils has more stability aggregates and less primary particles than high -sand and high-silt soils, therefore it was much coarser. The runoff electively transport 0.002-0.02mm particle, and contains 26.68-60.33% of this class particle in sediment. The transportability of thin-flow and its selection to sediment particle decrease when splash is eliminated.DR, Sip and C/N are positively correlated with erosion rates, average sediment concentration and MWD (undispersed)/MWD(dispersed) of sediment; ASC ,CFI, clay%, iron and aluminum oxides, Sid , Si0 ,OM, HA, FA, humin are negatively correlated with them. DR, ASC ,CFI, clay%, Fed, Ald, Al0, Si0, OM, C/N, FA, humin are mostly significant or highly correlated with erosion rates ,average sediment concentration and MWD(undispersed)/MWD(dispersed) of sediment.Among erosion indexes, DR is negatively correlated with iron and aluminum oxides, Sid, Si0 ,OM, HA, FA, humin and positively correlated with Sip, C/N. ASC, CFI, clay% negatively correlated with Sip, C/N and positively correlate with others. Fed, Ald, A10,Si0, OM, C/N, FA, humin are mostly significant or highly correlated with DR, ASC, clay%.Fed, Ald, A10 and Si0 decrease with the increase of sediments size of Tongcheng soils. The low concentration in bigger particles make them less stable than small ones. Fea, Ald and A10 increase with the increase of sediments size of Heshengqiao soils. Their relative enrichment in bigger particles make big particles more stable.OM is enriched in sediment and more significant in the soils of Heshengqiao. OM and C/N indicated more POM is depleted from bigger particles and it can’t stable aggregates. Organo-mineral complex can stable aggregates. POM is concentrated in 0.05-0.25mm particle in covered sediment of Tongcheng and <0.05mm particle in uncovered sediment of Tongcheng. Humus increases with the increase of particle size in sediment and aggregates. It may stable particles. HA changes differently in different soils and HA/FA changes with HA. The function that HA and FA stable particles is uncertain and worth studying further.更多还原