秸秆混掺对石漠化地区土壤水氮分布的影响_沈秉涛.pdf

节水灌溉Water Saving I秸秆混掺对石漠化地区土壤水氮分布的影响沈秉涛1，王妍1，2，刘云根1，2，张水琳1（1.西南林业大学生态与环境学院，昆明 650224；2.云南省山地农村生态环境演变与污染治理重点实验室，昆明 650224）摘 要：氮素流失已成为石漠化地区修复治理过程中亟待解决的重要问题，以小麦秸秆为添加物，典型石漠化地区土壤为供试土壤进行水肥入渗试验，探究灌溉施肥下石漠化地区土壤水、氮的运移规律和分布特征。结果表明：一维积水入渗试验中，秸秆混掺对石漠化地区土壤水分下渗具有阻碍作用，处理组相较于对照组累积入渗量降低5.07%59.32%，其中累积入渗量及湿润锋运移距离与秸秆施加量成反比，而秸秆长度水平间变化并不规律。入渗过程符合Philip入渗模型，拟合系数均在0.99以上，吸渗率S对施加量响应为在施加量0.7%水平下较CK提升，后随施加量增长，吸渗率降低，其中对比对照组最低减少31.11%，最高减少48.92%，秸秆长度对吸渗率的影响在3 cm长度水平下更显著，对比对照组降低47.21%，为所有处理中最低值。各土层硝态氮含量在05 cm范围内高，后随湿润锋运移逐渐降低，而秸秆施加量的增长提高了1 cm、2 cm、3 cm长度水平下硝态氮在湿润土体下部的含量，对比对照组最高上升44.7%，不同于上述规律，秸秆粉末水平下，硝态氮含量随施加量增长而降低，A3对比A1最高降低47.55 mg/kg，秸秆长度对硝态氮分布同施加量水平下，2 cm、3 cm长度处理均高于1 cm处理。综上所述，对于石漠化浅薄的土层而言，秸秆混掺减缓了硝态氮随水分下渗的趋势，使得肥液在运移过程中，硝态氮得以在湿润锋上部累积，对于石漠化地区的浅薄土层修复治理有积极作用。关键词：秸秆混掺；石漠化地区；一维入渗；土壤改良；水氮分布；氮素流失；秸秆长度；秸秆施加量；湿润锋；土壤硝态氮中图分类号：S154.2；S27 文献标识码：A DOI：10.12396/jsgg.2022399沈秉涛，王 妍，刘云根，等.秸秆混掺对石漠化地区土壤水氮分布的影响 J.节水灌溉，2023（6）：66-75，82.DOI：10.12396/jsgg.2022399.SHEN B T，WANG Y，LIU Y G，et al.Effect of straw blending on the distribution of water and nitrogen in soils of rocky desertification areasJ.Water Saving Irrigation，2023（6）：66-75，82.DOI：10.12396/jsgg.2022399.Effect of Straw Blending on the Distribution of Water and Nitrogen in Soils of Rocky Desertification AreasSHEN Bing-tao1，WANG Yan1，2，LIU Yun-gen1，2，ZHANG Shui-lin1（1.College of Ecology and Environment，Southwest Forestry University，Kunming 650224，China；2.Yunnan Provincial Key Laboratory of Mountain Rural Ecological Environment Evolution and Pollution Control，Kunming 650224，China）Abstract：Nitrogen loss has become an important problem to be solved in the restoration and treatment of rocky desertification areas.Taking wheat straw as additive and soil in typical rocky desertification area as test soil,the infiltration test of water and fertilizer was carried out to explore the migration law and distribution characteristics of soil water and nitrogen in rocky desertification area under irrigation and fertilization.The results showed that:In one-dimensional water infiltration test,straw mixing hindered the infiltration of soil water in rocky desertification area.Compared with the control group,the cumulative infiltration of the treatment group was reduced by 5.07%to 59.32%.The cumulative infiltration and the migration distance of the wetting front were inversely proportional to the amount of straw applied,and the straw length varied irregularity between levels.The infiltration process was in line with Philips infiltration model,and the fitting coefficients were all above 0.99.The response of the imbibition rate S to the applied dose was that it was higher than CK at the applied dose 文章编号：1007-4929（2023）06-0066-10收稿日期：2022-12-07基金项目：国家自然科学基金项目（32260420）；云南省教育厅科学研究基金项目（2022Y599）。作者简介：沈秉涛（1997-），男，硕士研究生，研究方向为石漠化修复治理。E-mail:。通讯作者：王妍（1980-），女，副教授，博士，研究方向为脆弱生态系统恢复研究。E-mail:。66秸秆混掺对石漠化地区土壤水氮分布的影响 沈秉涛 王妍 刘云根 等level of 0.7%,and then with the increase of the applied dose,the imbibition rate decreased,among which the lowest decreased by 31.11%and the highest decreased by 48.92%compared with the control group.The influence of straw length on imbibition rate was more significant at the level of 3cm length,which was reduced by 47.21%compared with the control group,which was the lowest value among all treatments.The nitrate nitrogen content in each soil layer was high in the range of 05cm,and then decreased gradually with the migration of the wet front.However,the increase of straw application increased the nitrate nitrogen content in the lower part of the wet soil at the length of 1cm,2cm and 3cm,and the maximum increase was 44.7%compared with the control group.Different from the above law,under the straw powder level,the nitrate nitrogen content decreased with the increase of the applied amount,and the maximum reduction of A3 was 47.55mg/kg compared with A1.Under the same applied amount level,the nitrate nitrogen distribution under the straw length treatment of 2cm and 3cm was higher than that under the treatment of 1cm.In summary,for the shallow soil layer of rocky desertification,straw mixing slows down the trend of nitrate nitrogen infiltration with water,so that nitrate nitrogen can accumulate in the upper part of the wet front during the migration of fertilizer liquid,which has a positive effect on the restoration and treatment of shallow soil layer in rocky desertification area.Key words：straw mixing；rocky desertification area；one-dimensional infiltration；soil improvement；water and nitrogen distribution；nitrogen loss；straw length；straw application amount；wetting front；soil nitrate nitrogen0引 言石漠化被喻为“地球癌症”1，是发生在我国西南岩溶地区最严重的生态环境问题2-4。由于岩溶环境的地带二元结构特性，石漠化地区常存在地表、地下的双层空间发育结构。加之石漠化地区土层浅薄，在水流机械作用下，地表水易沿岩溶裂隙等通道携带泥沙下渗5,6，这一过程中存在的养分流失不仅加剧了土地退化，更为地下水安全带来了新的隐患。相关研究表明，岩溶石漠化地区地表水硝态氮含量逐年上升，地下水硝态氮含量大体呈增长趋势且远超天然背景浓度值（2 mg/L）7-9，而水体中硝态氮主要来源于农业生产过程中的含氮化肥，因此在石漠化修复治理过程中应注意施肥处理对土壤水、氮分布的影响8,9。为解决石漠化地区水氮漏失这一问题，学术界提出了大量的修复技术和成熟的治理模式，通过工程措施整改土地结合筛选适宜植被修复土地是主要手段，但工程量大，也有通过简单的外源添加物来改善土壤理化性质的技术手段，如绿肥改良、食用菌糠改良、糖厂滤泥及酒精厂废弃物改良技术等等10-14，上述技术