摘要
以广西平果喀斯特生态系统国家野外科学观测研究站及周边地块的三种土地利用方式(退耕林地、退耕草地、耕地(甘蔗地和玉米地))为研究对象,通过采集0~15 cm表层土壤,分析土壤的理化性质和土壤碳、氮、磷全量与易利用组分及其关系,以期能更加准确地理解和把握退耕还林还草、土地利用方式转变对喀斯特地区土壤碳、氮、磷全量及易利用组分的影响。结果表明:(1)与耕地相比,退耕后林地和草地土壤pH值显著升高,大团聚体、速效氮显著增加,微团聚体、速效磷显著减少。(2)退耕后林地和草地土壤有机碳较耕地显著增加,林地和草地分别是甘蔗地的1.98和1.88倍,分别是玉米地的2.15和2.04倍。林地和草地土壤微生物生物量碳、全氮、微生物生物量氮较耕地也明显提高。对于磷,草地全磷(1.04 g·kg^(-1))最高,其次玉米地(0.81 g·kg^(-1)),且甘蔗地和玉米地的可溶性磷均显著高于林地和草地。在土壤碳氮磷生态化学计量比方面,林地的OC/TP、TN/TP显著高于草地和耕地,而草地和耕地没有显著差异。(3)土壤容重、团聚体结构、pH、速效氮、速效磷都与土壤碳、氮、磷全量与易利用组分有着显著的相关关系。上述结果表明,退耕还林还草、土地利用方式转变显著提高了喀斯特土壤碳、氮水平,提升了土壤质量,退耕还林还草、转变土地利用方式是喀斯特地区石漠化治理、生态环境保护的重要、有效途径。
Soil carbon,nitrogen and phosphorus are important factors of soil quality,which play important roles in increasing soil nutrient storage,improving soil fertility and promoting plant growth.A large number of studies have shown that returning cultivated land back to forest and grassland and converting land use patterns will lead to changes in soil nutrient status and stoichiometry.However,systematic studies on total and easy-to-use components of soil carbon,nitrogen,and phosphorus are relatively few in Pingguo karst area of Youjiang River Valley in central Guangxi.In this study,plots of three types of land use(the restored forest and grassland from cultivated land and cultivated land for sugarcane and maize)inside and near Pingguo National Field Observation and Research Station of Karst Ecosystem,Guangxi were taken as research objects,and 0-15 cm surface soil was sampled in March,2021.The physical and chemical properties of soil,total and easy-to-use components of carbon,nitrogen and phosphorus and their relationships were analysed in order to better understand the effects of returning cultivated land back to forest and grassland and converting land utilization patterns on total and easy-to-use components of carbon,nitrogen and phosphorus of soil in karst areas.The results showed as follows:1)Compared to cultivated land,the soil pH values of the restored forest and grassland from cultivated land increased significantly.The macro-aggregates of restored forest and grassland(42.82%,57.11%respectively)were significantly higher than those of cultivated land for sugarcane(16.94%)and maize(5.49%),and their micro-aggregates(4.58%,1.76%respectivey)were significantly lower than those of cultivated land for sugarcane(12.42%)and maize(16.34%).Meanwhile,compared to cultivated land for sugarcane(103.39 mg·kg^(−1),3.22 mg·kg^(−1))and that for maize(105.02 mg·kg^(−1),3.07 mg·kg^(−1)),available nitrogen of restored forest and grassland significantly increased to 156.55 and 166.49 mg·kg^(−1),repectively,while available phosphorus significantly decreased to 0.41 and 0.30 mg·kg^(−1),respectively.2)Compared to cultivated land,the organic carbon,microbial biomass carbon and total nitrogen of soil in restored forest and grassland increased significantly.The values of soil organic carbon of restored forest and grassland(34.12 g·kg^(−1),32.45 g·kg^(−1)respectively)were 1.98 and 1.88 times of cultivated land for sugarcane(17.26 g·kg^(−1)),and 2.15 and 2.04 times of cultivated land for maize(15.89 g·kg^(−1)),respectively.The values of microbial biomass carbon of soil in restored forest and grassland(985.35 mg·kg^(−1),1,110.04 mg·kg^(−1)repectively)were 2.71 and 3.05 times of cultivated land for sugarcane(364.07 mg·kg^(−1)),and 3.14 and 3.54 times of cultivated land for maize(313.92 mg·kg^(−1)),respectively.The values of total nitrogen of soil in restored forest and grassland(4.14 g·kg^(−1),4.10 g·kg^(−1)respectively)were 2.48 and 2.46 times of cultivated land for sugarcane(1.67 g·kg^(−1)),and 2.19 and 2.16 times of cultivated land for maize(1.89 g·kg^(−1)),respectively.The total value of phosphorus in restored grassland was the highest(1.04 g·kg^(−1)),followed by that of cultivated land for maize(0.81 g·kg^(−1)),and the values of dissolved phosphorus of cultivated land for sugarcane and maize were significantly higher than those of restored forest and grassland.The values of stoichiometry of carbon,nitrogen,and phosphorus,OC/TP,TN/TP of soil in restored forest were significantly higher than those of restored grassland and cultivated land,and the values of restored grassland and cultivated land did not show significant difference.3)Soil bulk density,aggregate structure,pH value,available nitrogen and available phosphorus were significantly correlated with total and easy-touse components of carbon,nitrogen and phosphorus of soil.Properly speaking,soil pH value,large macro-aggregates,and available nitrogen showed a significantly positive correlation with organic carbon,microbial biomass carbon,total nitrogen and microbial biomass nitrogen of soil,and a significantly negative correlation with dissolved phosphorus.Meanwhile,bulk density,micro-aggregates,and available phosphorus of soil showed a significantly negative correlation with organic carbon,microbial biomass carbon,total nitrogen and microbial biomass nitrogen of soil,and a significantly positive correlation with dissolved phosphorus.The results indicated that the measures of returning cultivated land back to forest and grassland and converting land use patterns significantly improved soil carbon,nitrogen and soil quality in karst areas.These two measures are important and effective ways to control rocky desertification and protect ecological environment in karst areas.
作者
苏同庆
崔婷婷
张建兵
罗为群
胡宝清
SU Tongqing;CUI Tingting;ZHANG Jianbing;LUO Weiqun;HU Baoqing(Key Laboratory of Beibu Gulf Environment Change and Resources Utilization of Ministry of Education,Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation,Nanning Normal University,Nanning,Guangxi 530001,China;Key Laboratory of Karst Dynamic,MNR&GZAR,Institute of Karst Geology,CAGS,Guilin,Guangxi 541004,China;Pingguo National Field Observation and Research Station of Karst Ecosystem in Guangxi,Pingguo,Guangxi 531400,China)
出处
《中国岩溶》
CAS
CSCD
北大核心
2023年第2期311-320,共10页
Carsologica Sinica
基金
国家自然科学基金(31960238,42071135)
广西科技基地和人才专项(桂科AD19245103,桂科AD19110142)
广西高校中青年教师科研基础能力提升项目(2019KY0421)
北部湾环境演变与资源利用教育部重点实验室(南宁师范大学)
广西地表过程与智能模拟重点实验室(南宁师范大学)系统基金项目(GTEU-KLOP-X1813)。
关键词
土地利用方式
广西平果
喀斯特
碳
氮
磷
land utilization patterns
Guangxi Pingguo
karst
carbon
nitrogen
phosphorus
