State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University/College of Environmental and Resource Sciences, Zhejiang A&F University, Hangzhou 311300, China.
College of Ecology and Environment, Chengdu University of Technology, Chengdu 610059, China.
Ying Yong Sheng Tai Xue Bao. 2023 Jan;34(1):58-66. doi: 10.13287/j.1001-9332.202301.008.
Plant residues can affect C:N:P of soil, microbial biomass, and extracellular enzyme, but the effects are still unclear. We conducted a field experiment in an alpine meadow on the eastern part of the Qinghai-Tibetan Plateau to explore the effects of removing aboveground plant or roots and adding plant residues on the C:N:P of soil, microbial biomass, and extracellular enzyme. The results showed that removing aboveground plant biomass significantly decreased soil C:N (the change was -23.7%, the same below) and C:P (-14.7%), microbial biomass C:P and N:P, while significantly increased microbial biomass C:N, and enzyme C:N:P compared with meadow without human disturbance. Removing all plant biomass (aboveground and roots) significantly reduced soil C:N (-11.6%), C:P (-24.0%), N:P (-23.3%) and microbial biomass C:N in comparison to removing aboveground plant, while significantly improved microbial biomass N:P and enzyme N:P. Adding plant residues after removing aboveground plant significantly increased microbial biomass C:N and C:P, enzyme C:N compared with removing aboveground plant, while significantly decreased enzyme N:P. Compared with removing all the plant, adding plant residues after removing whole plant significantly reduced soil C:N (-16.4%), microbial biomass C:P, N:P and enzyme N:P, while significantly increased enzyme C:N. Our results suggest that removal of plants could have a strong effect on C:N:P of soil, microbial biomass, and extracellular enzyme, and C:N:P of microbial biomass and that extracellular enzyme woule be more sensitive to plant residues. Roots could play a key role in stabilizing C:N:P of soil, microbial biomass, and extracellular enzyme under plant residues addition. Adding plant residues could be a suitable solution for restoring alpine meadows under the circumstance of intact roots, which was conducive to soil C storage, but might not be suitable for alpine meadows with serious root damage, which would increase soil CO emission.
植物残体可以影响土壤的 C:N:P、微生物生物量和胞外酶，但影响仍不明确。我们在青藏高原东部的高寒草甸进行了田间实验，以探讨去除地上植物或根系并添加植物残体对土壤 C:N:P、微生物生物量和胞外酶的影响。结果表明，去除地上植物生物量显著降低了土壤 C:N（变化为-23.7%，下同）和 C:P（-14.7%）、微生物生物量 C:P 和 N:P，而与无人为干扰的草地相比，显著增加了微生物生物量 C:N 和酶 C:N:P。与去除地上植物相比，去除所有植物生物量（地上和根系）显著降低了土壤 C:N（-11.6%）、C:P（-24.0%）、N:P（-23.3%）和微生物生物量 C:N，而显著改善了微生物生物量 N:P 和酶 N:P。去除地上植物后添加植物残体，与去除地上植物相比，显著增加了微生物生物量 C:N 和 C:P，以及酶 C:N，但显著降低了酶 N:P。与去除所有植物相比，去除整株植物后添加植物残体，显著降低了土壤 C:N（-16.4%）、微生物生物量 C:P、N:P 和酶 N:P，而显著增加了酶 C:N。我们的结果表明，去除植物对土壤 C:N:P、微生物生物量和胞外酶以及微生物生物量的 C:N:P 具有很强的影响，胞外酶对植物残体更为敏感。在添加植物残体的情况下，根系可能在稳定土壤 C:N:P、微生物生物量和胞外酶方面发挥关键作用。在根系完整的情况下添加植物残体可能是恢复高寒草地的一种合适方法，这有利于土壤碳储存，但可能不适合根系严重受损的高寒草地，这会增加土壤 CO 排放。
