在砖红壤中施用不同氮肥后的氮素淋溶动态与特性研究

摘要

为探讨不同氮肥在砖红壤中的养分释放特性,本研究采用土柱淋溶试验,研究了普通尿素、腐植酸脲及缓释氮肥(自制)在分别由花岗岩、砂页岩、浅海沉积物、玄武岩母质发育的4种砖红壤中的淋溶特性及动态,采用一级动力学方程Nt=No(1-e-kt)、Elovich方程qt=a+blnt、抛物线方程qt=a+bt0.5对肥料在不同砖红壤中的氮素累积释放动态变化进行描述.结果表明,一级动力学方程拟合程度最高(0.936 0**～0.995 0**),抛物线方程次之(0.923 8**～0.986 4**).氮素最大释放率(No值)与氮素累积释放率变化趋势一致,均为尿素＞腐脲＞缓释氮肥.淋溶曲线表明,缓释氮肥和腐植酸脲均能减小氮素淋出率,降低氮素淋出量,减少氮素的淋溶损失,且缓释氮肥效果更显著.与尿素相比,在4种砖红壤中缓释氮肥的氮素淋出量减少了41.47 ％～48.62％,腐植酸脲的氮素淋出量减少了6.21％～9.32％.尿素、腐植酸脲、缓释氮肥在砂页岩砖红壤中的首次氮素淋出率均为最大;尿素、腐植酸脲在浅海沉积物砖红壤中累积氮素淋出率最小,而缓释氮肥在玄武岩砖红壤中累积氮素淋出率最小.本研究可为热区土壤的合理施肥提供理论依据.%In order to investigate the nutrient release characteristics of different nitrogen fertilizers in four types of laterite,soil column leaching methods were used to study the leaching characteristics in granite latosol,sandy shale laterite,shallow sediments latosol,basalt latosol four types latosol of urea,humic acid urea and slow-release nitrogen fertilizer (homemade).The dynamic changes of the cumulative release of nitrogen fertilizer in different laterite was described with the first-order kinetics equation Nt=No(1-e-kt),Elovich equation qt=a+blnt and parabolic equation qt=a+bt0.5.The first-order kinetic equation had the highest fitting degree (0.936 0**～0.995 0**),The parabolic equation was in the second position (0.923 8**～0.986 4**).The maximum nitrogen release rate (No) of different fertilizers was the same as that of nitrogen accumulation in the order urea＞humic acid urea＞slow-release nitrogen fertilizer SRFs and humic acid urea could reduce the rate and amount of nitrogen leaching.In the three kinds of fertilizers,the slow release nitrogen fertilizer (SRFs) had better performance.Compared with urea,the nitrogen leaching amount of SRFs decreased by 41.47％-48.62％ in the four kinds of latosols,and the humic acid urea decreased by 6.21％-9.32％.The nitrogen leaching rate of urea,humic acid urea,SRFs was the largest in sandy shale laterite.The accumulated N leaching rate of urea and humic acid urea was the minimum in shallow sediments latosol,and SRFs was the smallest in basalt latosol.This study could provide a theoretical basis for rational fertilization of soils in tropical areas.