Liu Jia-Qi, Liang Yan, Xiao Fan, Han Yi-Qing, Hu Chuan-Xing, Wei Liu-Hong, Duan Min
Ministry of Education Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Guangxi Normal University, Guilin 541006, Guangxi, China.
Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilization in Lijiang River Basin, Guilin 541006, Guangxi, China.
Ying Yong Sheng Tai Xue Bao. 2023 Dec;34(12):3313-3321. doi: 10.13287/j.1001-9332.202312.016.
Investigating the main sources of soil phosphorus and their seasonal variations across different vegetation restoration stages in karst region of southwest China can deepen our understanding of soil phosphorus cycling during vegetation restoration, and provide scientific reference for the controlling of rocky desertification. Taking the typical karst ecosystems at different vegetation restoration stages in Guilin, Guangxi as the research objects, we conducted a one-year field experiment with three treatments: vegetation restoration for about 10 years (R10), 30 years (R30) and 50 years (R50). We collected rainfall based on precipitation frequency, as well as soil, fresh litter and root samples in each season to measure the concentrations of total phosphorus (TP) in rainfall, the contents of TP and available phosphorus (AP) in soil, and the contents of TP in fresh litter and roots. In combination with litter phosphorus storage and soil microbial biomass phosphorus (MBP), we analyzed the contributions of phosphorus input to soil from different phosphorus sources. The results showed that soil TP content increased initially and then decreased with vegetation restoration, with a seasonal pattern of autumn > summer > spring > winter. Soil AP content was low in all treatments, with higher levels in summer and winter than in spring and autumn. Soil MBP content increased with vegetation restoration, with a seasonal variation pattern of spring >autumn > summer > winter. The annual phosphorus input from rainfall was 0.78 kg·hm with the highest value in spring. The annual phosphorus input from fresh litter in the R10, R30, and R50 treatments was 2.42, 10.64 and 5.03 kg·hm. Phosphorus storage in litter was 1.23, 5.32 and 3.45 kg·hm. The annual phosphorus input from plant roots was 5.18, 12.65, and 5.96 kg·hm, respectively. The highest levels of the above parameters always occurred in the R30 treatment. There was a significant positive correlation between soil TP content and plant root phosphorus input, and a significant negative correlation between soil AP content and rainfall phosphorus input. In summary, the contribution of phosphorus input from different sources to soil phosphorus pool varied across different vegetation restoration stages in the karst region of southwest China. Roots are the main source of soil phosphorus, followed by litters. Phosphorus entering the soil through wet deposition is very limited. Soil microorganisms also contribute to soil phosphorus reserve.
研究中国西南喀斯特地区不同植被恢复阶段土壤磷素的主要来源及其季节变化，有助于深化我们对植被恢复过程中土壤磷循环的理解，并为石漠化治理提供科学参考。以广西桂林不同植被恢复阶段的典型喀斯特生态系统为研究对象，我们进行了为期一年的田间试验，设置了三个处理：植被恢复约10年（R10）、30年（R30）和50年（R50）。我们根据降雨频率收集降雨，以及在每个季节采集土壤、新鲜凋落物和根系样本，以测量降雨中总磷（TP）的浓度、土壤中TP和有效磷（AP）的含量，以及新鲜凋落物和根系中TP的含量。结合凋落物磷储量和土壤微生物生物量磷（MBP），我们分析了不同磷源对土壤磷输入的贡献。结果表明，土壤TP含量随植被恢复先增加后降低，季节变化规律为秋季>夏季>春季>冬季。所有处理的土壤AP含量均较低，夏季和冬季的含量高于春季和秋季。土壤MBP含量随植被恢复而增加，季节变化规律为春季>秋季>夏季>冬季。降雨的年磷输入量为0.78 kg·hm，春季最高。R10、R30和R50处理中新鲜凋落物的年磷输入量分别为2.42、10.64和5.03 kg·hm。凋落物中的磷储量分别为1.23、5.32和3.45 kg·hm。植物根系的年磷输入量分别为5.18、12.65和5.96 kg·hm。上述参数的最高值均出现在R30处理中。土壤TP含量与植物根系磷输入之间存在显著正相关，土壤AP含量与降雨磷输入之间存在显著负相关。综上所述，中国西南喀斯特地区不同植被恢复阶段，不同来源的磷输入对土壤磷库的贡献各不相同。根系是土壤磷的主要来源，其次是凋落物。通过湿沉降进入土壤的磷非常有限。土壤微生物也对土壤磷储备有贡献。
