Microbial biomass C, N and P in two arctic soils and responses to addition of NPK fertilizer and sugar: Implications for plant nutrient uptake
Microbial biomass C, N and P in two arctic soils and responses to addition of NPK fertilizer and sugar: Implications for plant nutrient uptake
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DOI：
10.1007/bf00329709
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发表时间：
1996-06-01
期刊：
影响因子：
2.7
通讯作者：
Callaghan, TV
中科院分区：
文献类型：
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作者：
Jonasson, S;Michelsen, A;Callaghan, TV
在逐级添加糖、NPK 肥料和杀菌剂苯菌灵之前和之后，采用熏蒸提取法对北极/高山低海拔荒地和高海拔荒地土壤的有机层中的土壤微生物碳 (C)、氮 (N) 和磷 (P) 库进行了定量。在未改良土壤中，微生物C、N和P分别占土壤C、N和P总含量的3.3-3.6%、6.1-7.3%和34.7%。无机可提取氮库含量低于土壤库总规模的0.1%，无机可提取磷含量略低于1%。春季和夏季添加苯菌灵不会影响秋季分析的微生物 C 或养分含量。糖改良剂使两种土壤中的微生物碳分别增加了15%和37%，但没有影响微生物养分含量，而无机氮和磷则显着下降或呈下降趋势。微生物碳的增加表明微生物生物量也增加了，但氮和磷的吸收没有成比例的增加。添加 NPK 不会影响微生物 C 的量，但几乎使微生物 N 库增加一倍，使 P 库增加一倍以上。一项单独的研究表明，在土壤中进行糖改良后，二氧化碳排放量增加了 50% 以上，而在土壤中添加 NPK 和 NK 后，二氧化碳排放量增加了约 30%。因此，微生物生物量并没有随着 NPK 的添加而增加，但微生物固定了大量添加的营养物质，并且从 CO2 释放增加来看，它们的活性增加了。我们得出的结论是：（1）这些土壤中微生物生物量的产生受到不稳定碳的刺激，并且微生物活性受到不稳定碳和养分（N）的刺激； (2) 微生物生物质是一个强大的养分库，并且微生物群落可能可以从无机的、植物可利用的库中提取大量的养分，至少定期地； (3) 微生物种群的暂时减少可能会向土壤释放大量无机养分，特别是微生物生物量占土壤库总量三分之一以上的磷； (4) 养分的动员-固定循环与土壤生物的种群动态相结合，可能是初级生产者养分供应的一个重要调节因素，而在北极生态系统中，初级生产者的养分通常受到严重限制。
The soil microbial carbon (C), nitrogen (N) and phosphorus (P) pools were quantified in the organic horizon of soils from an arctic/alpine low-altitude heath and a high-altitude fellfield by the fumigation-extraction method before and after factorial addition of sugar, NPK fertilizer and benomyl, a fungicide. In unamended soil, microbial C, N and P made up 3.3-3.6%, 6.1-7.3% and 34.7% of the total soil C, N and P content, respectively. The inorganic extractable N pool was below 0.1% and the inorganic extractable P content slightly less than 1% of the total soil pool sizes. Benomyl addition in spring and summer did not affect microbial C or nutrient content analysed in the autumn. Sugar amendments increased microbial C by 15 and 37% in the two soils, respectively, but did not affect the microbial nutrient content, whereas inorganic N and P either declined significantly or tended to decline. The increased microbial C indicates that the microbial biomass also increased but without a proportional enhancement of N and P uptake. NPK addition did not affect the amount of microbial C but almost doubled the microbial N pool and more than doubled the P pool. A separate study has shown that CO2 evolution increased by more than 50% after sugar amendment and by about 30% after NPK and NK additions to one of the soils. Hence, the microbial biomass did not increase in response to NPK addition, but the microbes immobilized large amounts of the added nutrients and, judging by the increased CO2 evolution, their activity increased. We conclude: (1) that microbial biomass production in these soils is stimulated by labile carbon and that the microbial activity is stimulated by both la bile C and by nutrients (N); (2) that the microbial biomass is a strong sink for nutrients and that the microbial community probably can withdraw substantial amounts of nutrients from the inorganic, plant-available pool, at least periodically; (3) that temporary declines in microbial populations are likely to release a flush of inorganic nutrients to the soil, particularly P of which the microbial biomass contained more than one third of the total soil pool; and (4) that the mobilization-immobilization cycles of nutrients coupled to the population dynamics of soil organisms can be a significant regulating factor for the nutrient supply to the primary producers, which are usually strongly nutrient-limited in arctic ecosystems.