不同土地利用方式对济源石质山区土壤速效养分季节变化的影响

Effects of different land-use types on seasonal dynamics of soil available nutrients in rocky mountainous areas of Jiyuan

【目的】探讨不同土地利用方式对土壤速效养分的影响,为揭示华北石质山区土地合理利用策略提供理论依据。【方法】以华北石质山区5种土地利用方式农田(NT)、撂荒地(LHD)和人工林:侧柏(CB)、刺槐(CH)和栓皮栎(SPL)为研究对象,于3、6、9和12月分次采集0~10、10~20和20~30 cm土层土壤样品,测定分析土壤速效氮(available nitrogen,AN)、速效磷(available phosphorus,AP)和速效钾(available potassium,AK)含量等土壤指标。【结果】土地利用方式显著影响土壤速效养分含量变化(P<0.05),NT和CB在0~30 cm土层的年际均值显著高于其他土地利用方式,其中NT的AN、AP、AK含量分别比CH高56.32%、90.82%和57.4%,比SPL高62.04%、90.25%和70.34%。5种土地利用方式下土壤速效养分含量均呈明显的季节变化规律,除NT外,AN、AP含量均在6月达到最高,9月较低;AK含量在12月较高,3月较低。随土层深度的加深,5种土地利用方式下土壤速效养分呈表层(0~10 cm)富集现象。相关性分析表明,土壤AN、AP、AK含量均与β-葡糖苷酶、过氧化氢酶、蛋白酶和脲酶活性、DOC、SOC、pH值、含水率、黏粒、粉粒和砂粒体积分数均呈显著相关(P<0.05),但是三者的主要影响因子并不完全一致,土壤AN和AK含量主要受β-葡糖苷酶活性的影响;土壤AP含量主要受NO-3-N的影响。【结论】农田耕作和侧柏人工林的种植有利于增加土壤速效养分含量,提高土壤肥力,可推荐为华北石质山区合理的土地利用方式。

【Objective】This study was performed to explore the effects of different land-use types on soil available nutrients contents,and provide a theoretical basis for revealing the rational land-use strategy in rocky mountainous of North China.【Method】Five land-use types include farmland(NT),abandoned land(LHD)and artificial forests,i.e.Platycladus orientalis(CB),Robinia pseudoacacia(CH)and Quercus variabilis(SPL)in the rocky mountainous of North China were selected as research objects.Soil samples were collected from 0-10,10-20 and 20-30 cm soil layers in March,June,September and December,respectively.The contents of soil available nitrogen(AN),available phosphorus(AP),available potassium(AK)and other soil indexes were measured and analyzed.【Result】Land-use types significantly affected the changes of soil available nutrients content(P<0.05).The interannual mean values of NT and CB in 0-30 cm soil layer were significantly higher than those of other land-use types.The contents of AN,AP and AK of NT were 56.32%,90.82%and 57.4%higher than those of CH,62.04%,90.25%and 70.34%higher than those of SPL,respectively.The contents of soil available nutrients showed obvious seasonal dynamics under the five land-use types.Except NT,the contents of AN and AP reached the highest in June and lower in September;AK content was higher in December and lower in March.With the deepening of soil depth,the soil available nutrients were enriched in the surface layer(0-10 cm)under the five land-use types.Correlation analysis showed that the contents of soil AN,AP and AK were related to the activities ofβ-glucosidase,catalase,protease and urease,DOC,SOC,pH,moisture content,volume fraction of clay,silt and sand were significantly correlated(P<0.05),but the main influencing factors of the three types were not completely consistent.The contents of soil AN and AK were mainly affected byβ-glucosidase activity.The content of soil AP was mainly affected by NO_(3)^(-)-N.【Conclusion】Farmland tillage and platycladus orientalis plantation can increase the content of soil available nutrients and improve soil fertility,which can be recommended as a reasonable land-use types in rocky mountainous area of North China.