退耕植茶地土壤团聚体及其无机磷组分分布特征

为了揭示土壤团聚体及其无机磷组分对退耕植茶的响应特征,以雅安市名山区中峰乡退耕植茶地(2～3年、9～10年、16～17年)为研究对象,选取邻近耕地为对照,采用野外调查与室内分析相结合的方法开展退耕植茶地土壤团聚体及其无机磷组分分布特征的研究.结果表明: 耕地及退耕植茶地土壤团聚体均以粒径>2 mm团聚体为主.随着退耕植茶年限的延长,各退耕植茶地粒径>5 mm的团聚体含量逐渐增加,粒径<5 mm的团聚体含量却逐渐降低.退耕植茶初期,退耕植茶地土壤团聚体平均质量直径(MWD)和几何平均直径(GMD)值与对照差异不明显,退耕植茶9～10年和退耕植茶16～17年显著高于对照,且随着退耕植茶年限的延长逐渐增大.退耕植茶地与耕地相比,其有效性较高的Al-P、Fe-P含量增加,有效性较低的O-P含量降低,随着退耕植茶年限的延长,各粒径团聚体中有效性较低的O-P逐渐降低,有效性较高的Al-P、Fe-P逐渐增加.耕地及退耕植茶地中Al-P、Ca-P含量随粒径的减小而增加,在<0.25 mm粒径中的含量最高;Fe-P在<0.25 mm粒径团聚体中的含量最多,其次是2～5 mm和0.25～0.5 mm粒径团聚体;退耕植茶后,O-P逐渐向较小粒径中富集,在<2 mm粒径中含量较高.

Characteristics of soil aggregates and inorganic phosphorus fractions in soils returned from cropland to tea

With soils returned from cropland to tea planting for different ages (2-3, 9-10 and 16-17 years old) as the object, and the nearby cropland soil as the control in Zhongfeng Township, Mingshan County, Ya’an, Sichuan Province, field investigation and laboratory analysis were combined to investigate the characteristics of soil aggregates and inorganic phosphorus fractions in response to the returning from cropland to tea. The particle size of >2 mm was the dominant aggregate size for the cropland and tea soils. With the increasing age, soil aggregate content of >5 mm particle size increased, while that of <5 mm particle size decreased gradually. In the earlier ages, for the mean mass diameter (MWD) and the geometry mass diameter (GWD), there was no significant difference between the cropland and tea soils. The MWD and GMD for the tea soils of 9-10 years and 16-17 years increased with the increasing age and were higher than those of the control. Compared with the cropland, the tea soils showed higher contents of Al-P and Fe-P, and lower content of O-P. The content of O-P in different particle size of aggregates reduced with the increasing age, while that of Al-P and Fe-P increased with the increasing age. The contents of Al-P and Ca-P in the cropland and tea soils increased with the decrease of the particle size and reached the maximum value in the particle size of <0.25 mm. The highest content of Fe-P was observed in the particle size of <0.25 mm, followed by 2-5 mm and 0.25-0.5 mm. Besides, with the returning fromcropland to tea planting, O-P gradually accumulated in smaller particle size and possessed higher content in the particle size of <2 mm.