Soil nitrogen oxide fluxes from lowland forests converted to smallholder rubber and oil palm plantations in Sumatra, Indonesia
Soil nitrogen oxide fluxes from lowland forests converted to smallholder rubber and oil palm plantations in Sumatra, Indonesia
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DOI：
10.5194/bg-14-2781-2017
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发表时间：
2017-06-07
期刊：
影响因子：
4.9
通讯作者：
Veldkamp, Edzo
中科院分区：
文献类型：
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作者：
Hassler, Evelyn;Corre, Marife D.;Veldkamp, Edzo
油棕（Elaeis guineensis）和橡胶（Hevea brasiliensis）种植园覆盖了印度尼西亚苏门答腊岛大面积的前热带雨林，供应了全球对这些作物的需求。虽然森林转换是已知的影响土壤一氧化二氮（N2 O）和一氧化氮（NO）通量，测量油棕榈和橡胶种植园是稀缺的（N2 O）或不存在（NO）。我们的研究目的是（1）量化的变化，土壤-大气的N氧化物与森林转化为橡胶和油棕种植园和（2）确定其控制因素。在苏门答腊的詹比，我们选择了两个景观，主要是不同的质地，但都在严重风化的土壤：壤土和粘土Acrisol土壤。在每一个景观，我们调查了低地森林，橡胶树穿插在次生林（称为“丛林橡胶”），无论是作为参考土地利用和小农橡胶和油棕榈种植园转换的土地利用。在壤土Acrisol景观，我们进行了后续的研究，在一个大规模的油棕种植园（称为PTPN VI）的土壤N2 O通量与小农油棕种植园的比较。土地利用转换为小农种植园没有影响土壤氮氧化物通量（P = 0.58至0.76），由于土壤氮的可用性普遍较低的参考土地利用，进一步减少与土地利用转换。从大规模的油棕种植园的土壤N2 O通量没有差异，从小农种植园（P = 0.15）。在1年的观测中，土壤氮氧化物通量的时间格局受土壤矿质氮和水分含量的影响。在景观，每年的土壤N2 O排放量控制总硝化和砂含量，这也表明土壤氮和水的有效性的影响。土壤N2 O通量（μ g Nm（-2）h（-1））为7 +/- 2至14 +/- 7（参考土地利用）、6 +/- 3至9 +/- 2（橡胶）、12 +/- 3至12 +/- 6（小农油棕）和42 +/- 24（大规模油棕）。土壤NO通量（μ g Nm（-2）h（-1）/）为0.6 +/- 0.7至5.7 +/- 5.8（参考土地利用）、1.2 +/- 0.5至1.0 +/- 0.2（橡胶）和0.2 +/- 1.2至0.7 +/- 0.7（小农油棕）。为了提高该地区油棕种植园土壤氮氧化物通量的估计，研究应集中在大规模的种植园（通常有2至4倍高的氮肥施用率比小农）与施肥后频繁测量。
Oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) plantations cover large areas of former rainforest in Sumatra, Indonesia, supplying the global demand for these crops. Although forest conversion is known to influence soil nitrous oxide (N2O) and nitric oxide (NO) fluxes, measurements from oil palm and rubber plantations are scarce (for N2O) or nonexistent (for NO). Our study aimed to (1) quantify changes in soil-atmosphere fluxes of N oxides with forest conversion to rubber and oil palm plantations and (2) determine their controlling factors. In Jambi, Sumatra, we selected two landscapes that mainly differed in texture but were both on heavily weathered soils: loam and clay Acrisol soils. Within each landscape, we investigated lowland forests, rubber trees interspersed in secondary forest (termed as "jungle rubber"), both as reference land uses and smallholder rubber and oil palm plantations as converted land uses. In the loam Acrisol landscape, we conducted a follow-on study in a large-scale oil palm plantation (called PTPN VI) for comparison of soil N2O fluxes with smallholder oil palm plantations. Land-use conversion to smallholder plantations had no effect on soil N-oxide fluxes (P = 0.58 to 0.76) due to the generally low soil N availability in the reference land uses that further decreased with land-use conversion. Soil N2O fluxes from the large-scale oil palm plantation did not differ with those from smallholder plantations (P = 0.15). Over 1-year measurements, the temporal patterns of soil N-oxide fluxes were influenced by soil mineral N and water contents. Across landscapes, annual soil N2O emissions were controlled by gross nitrification and sand content, which also suggest the influence of soil N and water availability. Soil N2O fluxes (mu g Nm(-2) h(-1)) were 7 +/- 2 to 14 +/- 7 (reference land uses), 6 +/- 3 to 9 +/- 2 (rubber), 12 +/- 3 to 12 +/- 6 (smallholder oil palm) and 42 +/- 24 (large-scale oil palm). Soil NO fluxes (mu g Nm(-2) h(-1) / were 0.6 +/- 0.7 to 5.7 +/- 5.8 (reference land uses), 1.2 +/- 0.5 to 1.0 +/- 0.2 (rubber) and 0.2 +/- 1.2 to 0.7 +/- 0.7 (smallholder oil palm). To improve the estimate of soil N-oxide fluxes from oil palm plantations in this region, studies should focus on large-scale plantations (which usually have 2 to 4 times higher N fertilization rates than smallholders) with frequent measurements following fertilizer application.