摘要
为探讨杨梅(Morella rubra L.)林中生草模式和降雨强度对氮、磷淋溶特性以及土壤养分的影响,本试验采用室内淋溶柱法模拟不同林下生草模式[紫花苜蓿(Medicago sativa cv.WL525HQ)单作、鸭茅(Dactylis glomerata cv.Amba)单作和紫花苜蓿-鸭茅混作],研究暴雨和大暴雨强度对淋溶过程(20、40、60 cm)中氮、磷流失以及土壤氮、磷养分的影响。结果表明:生草模式的差异对淋溶氮流失通量有显著影响,紫花苜蓿单作氮流失严重,60 cm处淋溶液中全氮和可溶性氮流失浓度较40 cm处孔隙水增加27%和29%,鸭茅单作能有效降低0~40 cm孔隙水和60 cm淋溶液中全氮和可溶性氮的浓度,60 cm较40 cm处均降低60%左右。生草模式和降雨强度能显著影响磷流失通量,大暴雨强度下紫花苜蓿-鸭茅混作较紫花苜蓿单作、鸭茅单作分别减少70%和60%。相关性分析表明,淋溶液中总氮、可溶性氮、全磷含量与土壤速效氮相关,并且随着降雨强度的增加,生草模式对速效氮的影响增大,大暴雨强度下紫花苜蓿-鸭茅混作后0~40 cm土壤速效氮含量最高为32.6 mg·kg^(-1),到60 cm处3种生草模式无显著差异。研究表明,暴雨强度下,鸭茅单作对减少氮流失通量有显著作用,大暴雨强度下紫花苜蓿-鸭茅混作根平均直径和总根体积的增加,能提高土壤速效氮在20~40 cm处的截留,减少土壤中速效氮成分向深处的迁移,因此,推荐紫花苜蓿-鸭茅混作模式以减少极端降雨下氮、磷流失通量。
In order to explore the effects of different planting patterns and rainfall intensities on the rate of N and P leaching as well as soil N and P content in Morella rubra L.forests,an indoor column experiment was performed to simulate the effects of different understory planting patterns(Medicago sativa cv.WL525HQ monocropping,Dactylis glomerata cv.Amba monocropping and mixed cropping).The effects of heavy rainfall on N and P loss through leaching was simulated in soil at 20,40,and 60 cm.The results showed that the differences in planting patterns had a significant effect on the fluxes of N loss from leaching,and considerable N loss occurred under M.sativa monocropping.The concentrations of total nitrogen(TN)and dissolved nitrogen(DN)from leaching at 60 cm increased by 27%and 29%compared with that from pore water at 40 cm.However,the D.glomerata monocropping effectively reduced the concentrations of TN and DN from leaching in pore water between 0-40 cm and 60 cm,and both the concentrations of TN and DN in the leachate were reduced by approximately 60%at 60 cm compared with that at 40 cm.The flux of P losses was significantly affected by planting pattern and rainfall intensity in the M.sativa-D.glomerata mixed cropping and was reduced 70%and 60%compared with the values obtained from the M.sativa monocropping and D.glomerata monocropping,respectively.The correlation analyses showed that TN,DN and TP contents in leachate were correlated with soil available nitrogen,and that the grassing pattern had a greater effect on quick-acting nitrogen as rainfall intensity increased.The results showed that AN content was highest(32.6 mg·kg^(-1))in the at 0-40 cm soil layer under M.sativa-D.glomerata mixed cropping under heavy rainfall,and there was no obvious difference among the three planting patterns at 60 cm.In conclusion,under heavy rainfall,D.glomerata monocropping had a significant effect on reducing N loss fluxes.In the mixed cropping pattern,the increase in the average diameter and total root volume of D.glomerata under heavy rainfall may be the reason for improved retention of soil AN at 20-40 cm and impeded migration of AN constituents from the topsoil to deeper depths.Based on these results,the M.sativa-D.glomerata mixed cropping pattern was determined to be an effective measure in reducing the N and P loss fluxes in conditions of extreme rainfall intensity.
作者
徐翠
刀承娇
赵鹏程
邢赟
陈建军
李元
祖艳群
XU Cui;DAO Chengjiao;ZHAO Pengcheng;XING Yun;CHEN Jianjun;LI Yuan;ZU Yanqun(College of Resources and Environment,Yunnan Agriculture University,Kunming 650201,China;Faculty of Animal Science and Technology,Yunnan Agriculture University,Kunming 650201,China;Shiping County Forestry and Grassland Survey Planning Team,Honghe 662200,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2024年第7期1568-1579,共12页
Journal of Agro-Environment Science
基金
云南省科技计划项目(202203AC100002)。
关键词
林下生草模式
降雨强度
淋溶
氮磷流失
planting pattern
rainfall intensity
leaching
nitrogen and phosphorus loss
