民勤青土湖区不同年限退耕地土壤颗粒组成和养分变化特征
柴成武1, 王理德1, 尉秋实1, 王方琳1, 吴 昊1, 郭春秀1, 陈思航1, 胥宝一1, 孟存宏2

(1.甘肃省治沙研究所, 甘肃省荒漠化与风沙灾害防治重点实验室, 甘肃 武威 733000; 2.甘肃省武威市石羊河林业总场,甘肃 民勤 733399)

青土湖区; 退耕地; 土壤颗粒; 土壤养分

Change Characteristics of Soil Particle Composition and Nutrient of Abandoned Farmland in Different Years in Qingtu Lake Area in Minqin
CHAI Chengwu1, WANG Lide1, YU Qiushi1, WANG Fanglin1, WU Hao1,GUO Chunxiu1, CHEN Sihang1, XU Baoyi1, MENG Cunhong2

(1.The State Key Laboratory of Desertification Combating Prevention and Sandstorm Disaster of Gansu Province & Gansu Desert Control Research Institute, Wuwei, Gansu 733000, China; 2.Shiyanghe Forestry Headquarters in Wuwei of Gansu Province, Minqin, Gansu 733399, China)

qingtu lake region; abandoned land; soil particle composition; soil nutrient

备注

以石羊河下游民勤青土湖区不同年限退耕地典型样地为研究对象,通过时空替代法分析该区不同年限退耕地土壤颗粒组成与养分变化特征。结果 表明:(1)不同年限退耕地上土壤颗粒组成含量总体砂粒>粉粒>黏粒>粗砂粒,其中,黏粒结构在CK及退耕后4 a间,0—20 cm,20—40 cm土层之间含量间存在显著差异,之后其在土壤中的含量随退耕年限增加而趋于稳定,且两土层间差异不显著; 粉粒和砂粒结构含量在CK及退耕后2 a变化较为剧烈,且同一年限内0—20 cm,20—40 cm两土层间存在显著差异,之后也随退耕年限的增加两土层及各退耕年限间均差异不显著,逐渐趋于稳定状态; 而粗砂粒仅在CK及退耕后2 a含量较为稳定,之后退耕4～40 a间含量变化较大,存在不稳定性,且同一年限两土层间存在显著差异。(2)三种土壤养分的总体变化趋势均表现为随退耕年限增加而减小并最终趋于稳定,在同一年限内均表现为0—20 cm土层中的含量大于20—40 cm,且同一年限内两层间的含量差异均随退耕年限增加而逐渐减小,以土壤有机质和速效磷表现较为明显; 其中土壤有机质含量在CK～退耕8 a间变化幅度较大,且在此期间退耕第4年时有一个剧烈上升的拐点,13～40 a间变化幅度较小; 全氮含量在三种土壤养分中变化最为稳定,且在整个退耕时间内变化幅度较小; 土壤速效磷含量CK含量最大,尤其在土壤表层0—20 cm最为明显,之后表现为随退耕年限增加而波动式下降的趋势,并趋于稳定。

Studied the characteristics of soil particle composition and nutrient of abandoned farmland as the research object of the typical district in different years in Qingtu Lake area in Minqin by the spatio-temporal substitution method. The results show that:(1)the total soil particle composition in different years was sand>silt>clay>coarse sand. And there were significant differences in the content of clay between CK and the soil layer of 0—20 cm and 20—40 cm. But the content of clay in the soil tended to be stable with the increase of the year, and there was no significant difference between the two soil layers. The structural content of silt and sand changed sharply in CK and 2 years later, and there were significant differences between 0—20 cm and 20—40 cm soil layers in the same year, and then the differences between the two soil layers and the years of conversion were not significant with the increase of the years of conversion, gradually becoming stable. The content of coarse sand is relatively stable only in CK and 2 years later, but which changes greatly in 4—40 years after conversion, there is instability in the same year, and significant differences shows among soil layers.(2)The overall change trend of the three soil nutrients decreased with the increase of the years of abandoned farmland, and finally became stable. In the same years, the content of soil nutrients in 0—20 cm soil layer was more than in 20—40 cm, and the content difference between the two layers decreased with the increase of the years of abandoned farmland, especially the content of soil organic matter and available phosphorus are obvious. The content of soil organic matter changed greatly in the period of CK～8 years, and there was a sharp turning point in the period of 4 years later, and the change range was small in the period of 13～40 years. The content of total nitrogen was the most stable in the three kinds of soil nutrients, and the change range was small in the whole time. The content of soil available phosphorus was the largest in CK, especially in the 0—20 cm of soil surface layer is the most obvious, and then it shows a trend of fluctuating decline with the increase of the years of abandoned land, and tends to be stable.