The role of grazing management for the net biome productivity and greenhouse gas budget (CO2, N2O and CH4) of semi-natural grassland
The role of grazing management for the net biome productivity and greenhouse gas budget (CO2, N2O and CH4) of semi-natural grassland
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DOI：
10.1016/j.agee.2006.12.004
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发表时间：
2007-06-01
影响因子：
6.6
通讯作者：
Pinares-Patino, C.
中科院分区：
文献类型：
--
作者：
Allard, V.;Soussana, J-F.;Pinares-Patino, C.
在3年的时间内，与大气交换的CO2，N2 O和CH 4通量进行了研究，在一个高地半天然草地网站，这是在实验开始时划分在两个大围场连续放牧牛。现场土壤为有机质含量高的冻土。集中管理的围场提供了矿物N肥，并在目标草地高度为6厘米放牧。广泛管理的围场没有收到N施肥和放养密度的集约围场的一半。利用涡度相关技术，在每个围场连续测量了CO的净生态系统交换。一氧化二氮的排放量进行了测量，每两周在两个围场使用静态室。甲烷排放量的放牧牛测量四次，每年在每个围场使用SF6示踪法。按3年平均值计算，这两个围场是大气CO2的净汇（集约和集约处理分别为97和75 CO2-C m（-2）年（-1））。考虑到牛的LW增益和通过甲烷排放的C损失，在集约和粗放处理中，净C储存分别估计为87和69 g C m（-2）年（-1）。一氧化二氮和甲烷的排放量减少了89%和55%的大气汇活动的密集和广泛的治疗，分别。3年的平均温室气体（GHG）平衡分别为-10和-31克CO2-C当量的集约和粗放处理。然而，净生物群落生产力（NBP）和温室气体汇活动随着时间的推移而增加，在密集放牧处理，而他们在1年后下降，在广泛的治疗，可能是由于减少氮的植被状况。它的结论是，抑制肥料氮供应结合放牧压力的强烈减少可能无法在短期内增加单位土地面积的温室气体汇管理草原。(c)2006 Elsevier B. V.保留所有权利。
Over a 3-years period, the CO2, N2O and CH4 fluxes exchanged with the atmosphere were studied in an upland semi-natural grassland site which was divided at the start of the experiment in two large paddocks continuously grazed by cattle. The soil at the site is an Andosol with high organic matter content. The intensively managed paddock was supplied with mineral N fertilizer and was grazed at a target sward height of 6 cm. The extensively managed paddock received no N fertilization and was stocked at half the stocking density of the intensive paddock. The net ecosystem exchange of CO, was continuously measured in each paddock using the eddy covariance technique. Nitrous oxide emissions were measured fortnightly in both paddocks using static chambers. Methane emissions by the grazing cattle were measured four times per year in each paddock using the SF6 tracer method. Averaged across the 3 years, the two paddocks were net sinks of atmospheric CO2 (97 and 75 CO2-C m(-2) year(-1) in the intensive and extensive treatments, respectively). Taking into account the LW gain of the cattle and the C loss through methane emissions, the net C storage was estimated at 87 and 69 g C m(-2) year(-1) in the intensive and extensive treatments, respectively. Emissions of nitrous oxide and methane reduced by 89 and 55% the atmospheric sink activity of the intensive and extensive treatments, respectively. The average greenhouse gas (GHG) balance across the 3 years was -10 and -31 g CO2-C equivalents in the intensive and extensive treatments, respectively. However, the net biome productivity (NBP) and GHG sink activities increased over time in the intensive grazing treatment, whereas they declined after 1 year in the extensive treatment, possibly as a result of a reduced nitrogen status of the vegetation. It is concluded that the suppression of fertilizer N supply combined with a strong reduction in grazing pressure may not be able to increase in the short term the GHG sink per unit land area of managed grasslands. (c) 2006 Elsevier B.V. All rights reserved.