The response of microbial biomass and hydrolytic enzymes to a decade of nitrogen, phosphorus, and potassium addition in a lowland tropical rain forest
The response of microbial biomass and hydrolytic enzymes to a decade of nitrogen, phosphorus, and potassium addition in a lowland tropical rain forest
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DOI：
10.1007/s10533-013-9848-y
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发表时间：
2013
期刊：
影响因子：
4
通讯作者：
Benjamin L Turner;S. Joseph Wright
中科院分区：
文献类型：
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作者：
Benjamin L Turner;S. Joseph Wright
养分的可利用性被广泛认为是制约低地热带森林初级生产力的重要因素，但土壤微生物生物量的可比较信息却很少。在巴拿马中部的低地热带雨林中，我们通过长期的养分添加实验，通过量化土壤微生物生物量和水解酶活性来评估微生物养分限制。在一个年度周期内，在接受了十年的氮，磷，钾和微量营养素添加的地块进行了多次测量。施磷使土壤微生物碳、氮和磷含量分别增加13%、21%和49%，磷酸酶活性降低65%，N-乙酰β-氨基葡萄糖苷酶活性降低24%，但对β-葡萄糖苷酶活性没有影响。相比之下，添加氮，钾，或微量营养素没有显着影响微生物生物量或任何酶的活性。微生物营养盐和水解酶活性在旱季均显著下降，微生物生物量的变化相当于或大于细凋落物年养分通量。虽然多种营养物质限制树的生产力在这个网站上，我们得出结论，磷限制在这个强风化的低地热带森林土壤中的微生物生物量。这一发现表明，努力包括酶在土壤地球化学模型必须考虑到不成比例的微生物投资在强风化土壤中的磷收购。
Nutrient availability is widely considered to constrain primary productivity in lowland tropical forests, yet there is little comparable information for the soil microbial biomass. We assessed microbial nutrient limitation by quantifying soil microbial biomass and hydrolytic enzyme activities in a long-term nutrient addition experiment in lowland tropical rain forest in central Panama. Multiple measurements were made over an annual cycle in plots that had received a decade of nitrogen, phosphorus, potassium, and micronutrient addition. Phosphorus addition increased soil microbial carbon (13 %), nitrogen (21 %), and phosphorus (49 %), decreased phosphatase activity by ~65 % andN-acetyl β-glucosaminidase activity by 24 %, but did not affect β-glucosidase activity. In contrast, addition of nitrogen, potassium, or micronutrients did not significantly affect microbial biomass or the activity of any enzyme. Microbial nutrients and hydrolytic enzyme activities all declined markedly in the dry season, with the change in microbial biomass equivalent to or greater than the annual nutrient flux in fine litter fall. Although multiple nutrients limit tree productivity at this site, we conclude that phosphorus limits microbial biomass in this strongly-weathered lowland tropical forest soil. This finding indicates that efforts to include enzymes in biogeochemical models must account for the disproportionate microbial investment in phosphorus acquisition in strongly-weathered soils.