锡林郭勒盟典型草原区草地开垦及退耕造林对土壤粒径分布和养分的影响  

Effects of Cultivation and Cropland Afforestation on Soil ParticleSize Distribution and Soil Nutrients in the Typical Steppe of Xilingol League

作　　者：罗玉红 黄予姝 珠娜 李乐 程延彬 刘嘉慧 张敬敏 包雨凡 徐诺 闫玉春[1] LUO YuHong;HUANG YuShu;ZHU Na;LI Le;CHENG YanBin;LIU JiaHui;ZHANG JingMin;BAO YuFan;XU Nuo;YAN YuChun(State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China/Institute of Agricultural Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081;School of Grassland,Beijing Forestry University,Beijing 100083;Hulun Buir Agricultural Reclamation Xieertala Farm Co.,Ltd.,Hulun Buir 021012,Inner Mongolia)

机构地区：[1]北方干旱半干旱耕地高效利用全国重点实验室/中国农业科学院农业资源与农业区划研究所,北京100081 [2]北京林业大学草业与草原学院,北京100083 [3]内蒙古呼伦贝尔农垦谢尔塔拉农牧场有限公司,内蒙古呼伦贝尔021012

出　　处：《中国农业科学》2024年第24期4919-4932,共14页Scientia Agricultura Sinica

基　　金：国家自然科学基金项目(32230065,42071070);重点研发计划课题(2023YFF1304102);中国农业科学院中央级公益性科研院所基本科研业务费专项资金(CAAS-ZDRW202417,G2024-01-02)。

摘　　要：【目的】深入探讨锡林郭勒盟典型草原区天然草地在历经60年农业耕作后其土壤质地和养分的动态变化,以及评估实施退耕造林18年是否能有效消减长期开垦耕作对土壤粒径分布及养分造成的负面影响,旨在加深对该地区生态恢复进程中土壤质量演变规律的认识,为科学评估生态恢复措施的实际效果提供科学依据。【方法】选取研究区60 km2范围内的5个样点作为重复,调查4种土地利用类型,即天然草地(GL)、农田(CL)以及种植灌木柠条锦鸡儿(Caragana korshinskii),行距分别为2 m(AL-2)和5 m(AL-5)的退耕造林地,0—30 cm土层中的粒径分布、容重和养分特征。【结果】(1)各用地类型土壤颗粒组成砂粒61%—82%、粉粒16%—35%、黏粒低于4%。农田和林地土壤粉粒(2—50μm)含量显著低于草地,砂粒(>50μm)含量则明显高于草地。相较于天然草地,开垦耕作导致≤120μm颗粒组分减少,>120μm颗粒组分增加,而退耕造林18年没有减轻因开垦导致细颗粒组分(≤120μm)减少的情况。(2)在0—30 cm的土层中,各土地利用类型的粒径分布垂直变化不显著,分选性较差,呈现出负偏至极负偏的粒径分布特征,且峰态尖窄。其中草地的平均粒径最小,分形维数最高。(3)土壤容重随土层深度的增加而增加。养分的变化主要集中在0—10 cm的浅层土壤,其中开垦活动显著降低了土壤有机碳、全氮、全磷含量。退耕造林后形成的灌木林地没有显著改变有机碳、全氮含量,但全磷含量却显著降低。(4)≤120μm的颗粒组分与土壤有机碳、全氮、全磷之间存在极显著的正相关关系,这表明土壤养分的衰减与土壤细颗粒的流失密切相关。【结论】草地开垦为农田后,长期耕作破坏了土壤物理结构,细颗粒组分及土壤养分显著下降,而退耕造林18年在改善土壤质地和恢复养分水平方面的效果不显著。【Objective】This study aimed to explore the dynamic change of soil texture and nutrients resulting from 60 years of agricultural cultivation subsequent to the conversion of grassland to cropland in the typical steppe of Xilingol County.It also evaluated whether the 18 years cropland afforestation had effectively mitigated the negative impacts of long-term cultivation on soil particle size distribution and soil nutrients.The research sought to enhance understanding of soil quality evolution during ecological restoration processes in this region and provided a scientific basis for assessing the actual effectiveness of ecological restoration measures.【Method】Five sites within 60 km~2 of the study area as replicates were chosen to investigate the particle size distribution,bulk density,and nutrient characteristics within the 0-30 cm soil layer across four land use types,including grassland(GL),cropland (CL) and afforestation land with row spacing of 2 m (AL-2) and 5 m (AL-5).【Result】(1) The soil particle composition across various land use types included sand (61%-82%),silt (16%-35%) and clay (less than 4%).Notably,the content of silt (2-50μm) in cropland and afforestation land was significantly lower than that in grassland,whereas the proportion of sand (>50μm) was markedly higher in comparison to grassland.Further,compared with natural grassland,the cultivation has resulted in a reduction of soil particles smaller than 120μm and an increase in soil particles larger than 120μm.However,the afforestation for 18 years has not alleviated the decrease in fine particles (≤120μm) caused by cultivation.(2) In 0-30 cm soil layer,the composition of soil particle size in each land use type showed uniformity along the soil depth,which reflected poor sorting characteristics and a negative to extremely negative particle size distribution pattern and sharp kurtosis.Among them,the grassland had the smallest mean particle size and the highest fractal dimension.(3) The soil bulk density gradually increased with the

关 键 词：天然草地 开垦 退耕造林 土壤粒径分布 粒度参数 土壤养分 锡林郭勒盟典型?原 

分 类 号：S812.2[农业科学—草业科学]