摘要
为了解不同土地利用方式下土壤团聚体的分布特征,选取海南定安县菜地、林地、农田和不同年限撂荒地撂荒地A(撂荒年限<3年)、撂荒地B(3年<撂荒年限<8年)、撂荒地C(8年<撂荒年限<10年)0~30 cm土层土壤团聚体及其有机碳的分布进行研究。结果表明:同一种土地利用方式农田团聚体含量随着粒径的减小而增加,<0.25 mm粒径时,其含量最大;不同年限撂荒地团聚体粒径组成呈双峰趋势,菜地团聚体粒径在1~2 mm时含量最大;林地团聚体含量随着粒径的减小而减少。在不同土层,农田>5 mm粒径团聚体含量在表层最少,撂荒地>5 mm粒径团聚体含量在表层最多,菜地团聚体含量随着土层的增加而减少;林地土壤团聚体变化较为复杂,说明人为活动(如施肥、踩踏、除草等)对较大粒径团聚体影响明显。不同土地利用方式下各粒径团聚体有机碳的含量也各有差异,总体上表现出随着团聚体粒径的减少团聚体有机碳含量呈增加的趋势。另外,农田、撂荒地A、撂荒地B、撂荒地C、菜地和林地粒径为<0.25 mm的团聚体有机碳含量分别是粒径为>5 mm的团聚体有机碳含量的2.78、2.45、3.71、3.73、4.08、2.92倍,其含量差异最大,由此可以说明在土地利用方式的变化过程中,最先影响的是粒径为>5 mm团聚体中的有机碳累积和分布,是土地利用方式变化过程中较为敏感的部分。不同土地利用方式下团聚体有机碳中菜地>农田>林地>撂荒地A>撂荒地B>撂荒地C,说明撂荒地10年内不利于团聚体有机碳的累积。
The results indicated that under the same use mode of land, the content of agglomerate in farmland increased with the decrease of particle size. When the particle size was less than 0.25mm, the content was the largest. The particle size composition of agglomerate in land for different years was bimodal. When the particle size of the vegetable agglomerate is 1~2mm, the content of agglomerate is the largest. The aggregate content of the forestland decreased with the decrease of the particle size. In different soil layers, he aggregate content of particle size which is more than 5mm in farmland was the least in the surface layer, and the aggregate content of particle size which is more than 5mm in the wasteland was the most in the surface layer, and the content of vegetable agglomerates decreased with the increase of soil layer. The change of soil aggregates in forest land is more complicated. All of them indicate that human activities such as fertilization, trampling, weeding, etc.have obvious effects on larger particle size aggregates. The content of organic carbon in aggregates of different particle sizes was also different under different land use patterns. Generally, the organic carbon content of aggregates increased with the decrease of aggregate size. In addition, The organic carbon content of aggregates with a particle size less than 0.25 mm in farmland, abandoned land A, abandoned land B, abandoned land C, vegetable land and forest land is 2.78, 2.45, 3.71, 3.73, 4.08 and 2.92 times as much as the content with particle size of 5 mm, respectively. The difference of content is the largest, which indicates that in the changing process of land use, the accumulation and distribution , which is a sensitive part of the change in land use patterns, of organic carbon is the first part that can be impacted in aggregates with a particle size more than 5 mm. Under different land use modes, the organic carbon in the aggregates decreased in the following order, that is, vegetable land, farmland, woodland, abandoned land A, abandoned land B, and abandoned land C, indicating that the wasteland within 10 years is not conducive to the accumulation of organic carbon in aggregates.
作者
邢瑶丽
赵志忠
李燕
赵泽阳
李沁枚
XING Yao-li;ZHAO Zhi-zhong;LI Yan;ZHAO Ze-yang;LI Qin-mei(College of C.eography and Environmental Science,Hainan Normal University,Haikou 571158,China)
出处
《广东农业科学》
CAS
2018年第10期74-81,共8页
Guangdong Agricultural Sciences
基金
海南省自然科学基金(2017CXTD006)
海南省研究生科研创新项目(Hys2017-142)
关键词
土地利用方式
农田
撂荒地
有机碳
土壤团聚体
land use type
abandonment land
farmland
soil organic carbon
soil aggregate