Wang Yuefeng, Wang Jigao, Wang Yini, Wang Xiaojing, Jin Baocheng, Chen Chao, Zhao Xuechun
College of Animal Science, Guizhou University, Guiyang 550025, China.
Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China.
Plants (Basel). 2024 Aug 21;13(16):2329. doi: 10.3390/plants13162329.
Litter and root decomposition is an important source of soil organic matter and nutrients. To ascertain the contribution of litter and root to natural grassland nutrients in rocky desertification areas, from March 2017 to January 2018, the continuous soil column method, collector method, and litter decomposition method were used to study the soil nutrients, litter and root biomass, decomposition, and nutrient release of potential, moderate, and severe rocky desertification grasslands, as well as their responses to rocky desertification. The results showed that the litter and root decomposition rate showed a trend of being first fast and then slow, and the decomposition rate of litter and root was greater than 50% after 300 days. The annual litter decomposition rates of potential, moderate, and severe rocky desertification grasslands were 69.98%, 62.14%, and 49.79%, respectively, and the annual decomposition rates of root were 73.64%, 67.61%, and 64.09%, respectively. With a deepening degree of rocky desertification, the litter and root decomposition rate decreased. The decomposition coefficients, , of litter in potential, moderate, and severe rocky desertification grasslands were 1.128, 0.896, and 0.668, respectively, and the decomposition coefficients, , of root were 1.152, 1.018, and 0.987, respectively. The nutrient release processes of litter and root were different, and the release mode ultimately manifests as "release". In rocky desertification grasslands, the organic carbon (OC), total nitrogen (TN), total phosphorus (TP), and total potassium (TK) released by litter and root decomposition were 18.93-263.03 g·m·yr, 1.79-5.59 g·m·yr, 0.18-0.47 g·m·yr, and 0.66-3.70 g·m·yr, respectively. The contribution of root to soil nutrients was greater than that of litter. The degree of rocky desertification was negatively correlated with the biomass, decomposition rate, and nutrient return amount of litter and root. The results of this study provide direct field evidence and illustrate the contribution of litter and root decomposition in rocky desertification grasslands to soil nutrients.
凋落物和根系分解是土壤有机质和养分的重要来源。为了确定凋落物和根系对石漠化地区天然草地养分的贡献，于2017年3月至2018年1月，采用连续土柱法、收集器法和凋落物分解法，研究了潜在、中度和重度石漠化草地的土壤养分、凋落物和根系生物量、分解及养分释放情况，以及它们对石漠化的响应。结果表明，凋落物和根系分解速率呈先快后慢的趋势，300天后凋落物和根系的分解率均大于50%。潜在、中度和重度石漠化草地的年凋落物分解率分别为69.98%、62.14%和49.79%，年根系分解率分别为73.64%、67.61%和64.09%。随着石漠化程度的加深，凋落物和根系分解速率降低。潜在、中度和重度石漠化草地凋落物的分解系数分别为1.128、0.896和0.668，根系的分解系数分别为1.152、1.018和0.987。凋落物和根系的养分释放过程不同，释放模式最终表现为“释放”。在石漠化草地中，凋落物和根系分解释放的有机碳（OC）、全氮（TN）、全磷（TP）和全钾（TK）分别为18.93 - 263.03 g·m·yr、1.79 - 5.59 g·m·yr、0.18 - 0.47 g·m·yr和0.66 - 3.70 g·m·yr。根系对土壤养分的贡献大于凋落物。石漠化程度与凋落物和根系的生物量、分解速率及养分归还量呈负相关。本研究结果提供了直接的田间证据，阐明了石漠化草地中凋落物和根系分解对土壤养分的贡献。
