Li Baozhen, Ge Tida, Xiao Heai, Zhu Zhenke, Li Yong, Shibistova Olga, Liu Shoulong, Wu Jinshui, Inubushi Kazuyuki, Guggenberger Georg
Changsha Research Station for Agricultural & Environmental Monitoring and Key Laboratory of Agro-ecology Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, 410125, China.
Institute of Soil Science, Leibniz Universität Hannover, 30419, Hannover, Germany.
Environ Sci Pollut Res Int. 2016 Apr;23(8):7494-503. doi: 10.1007/s11356-015-5977-2. Epub 2016 Jan 4.
Red soils are the major land resource in subtropical and tropical areas and are characterized by low phosphorus (P) availability. To assess the availability of P for plants and the potential stability of P in soil, two pairs of subtropical red soil samples from a paddy field and an adjacent uncultivated upland were collected from Hunan Province, China. Analysis of total P and Olsen P and sequential extraction was used to determine the inorganic and organic P fractions in different aggregate size classes. Our results showed that the soil under paddy cultivation had lower proportions of small aggregates and higher proportions of large aggregates than those from the uncultivated upland soil. The portion of >2-mm-sized aggregates increased by 31 and 20 % at Taoyuan and Guiyang, respectively. The total P and Olsen P contents were 50-150 and 50-300 % higher, respectively, in the paddy soil than those in the upland soil. Higher inorganic and organic P fractions tended to be enriched in both the smallest and largest aggregate size classes compared to the middle size class (0.02-0.2 mm). Furthermore, the proportion of P fractions was higher in smaller aggregate sizes (<2 mm) than in the higher aggregate sizes (>2 mm). In conclusion, soils under paddy cultivation displayed improved soil aggregate structure, altered distribution patterns of P fractions in different aggregate size classes, and to some extent had enhanced labile P pools.
红壤是亚热带和热带地区的主要土地资源，其特点是有效磷含量低。为了评估植物对磷的有效性以及土壤中磷的潜在稳定性，从中国湖南省采集了两对来自稻田和相邻未开垦旱地的亚热带红壤样本。通过分析总磷、有效磷以及连续提取法来确定不同粒径级别中无机磷和有机磷的组分。我们的结果表明，与未开垦旱地土壤相比，稻田土壤中小团聚体比例较低，大团聚体比例较高。在桃源和桂阳，粒径大于2毫米的团聚体比例分别增加了31%和20%。稻田土壤中的总磷和有效磷含量分别比旱地土壤高50 - 150%和50 - 300%。与中等粒径级别（0.02 - 0.2毫米）相比，最小和最大粒径级别的无机磷和有机磷组分往往更富集。此外，较小粒径团聚体（<2毫米）中磷组分的比例高于较大粒径团聚体（>2毫米）。总之，稻田土壤显示出改善的土壤团聚体结构，不同粒径级别中磷组分的分布模式发生了改变，并且在一定程度上增加了活性磷库。
