Greenhouse Gas Global Warming Potential Research Articles

Effect of Straw Residues in Combination with Reduced Fertilization Rate on Greenhouse Gas Emissions from a Vegetable Field

Greenhouse gases mainly come from farmland soils. Re-spreading chaff (straw returning) is an effective ecological management in China. Quantitative analysis of straw residues together with reduced fertilization rates can provide a scientific basis for reducing greenhouse gas emissions. A field experiment with six different fertilizer amounts combined with straw residues was carried out in a vegetable field (lettuce-cabbage-chili rotation), including the control (CK), conventional fertilizing (F), straw returning with 100% conventional fertilizing (100FS), straw returning with 70% conventional fertilizing (70FS), straw returning with 60% conventional fertilizing (60FS),and straw returning with 50% conventional fertilizing (50FS). The dynamic characteristics and emission factors of CO2, CH4 and N2O in the soil were analyzed using an in-situ, closed chamber, gas chromatography-based system, from November 2016 to September 2017. The results showed that the emission of CO2, CH4 and N2O has seasonal variation characteristics. The peak value mainly occurred in April to August, and the gas emission peak would appear after fertilizing and irrigating. Compared with F treatment, straw returning with fertilizing treatments reduced the N2O emission fluxes, cumulative emission and emission factor, especially in the 100FS treatment. The N2O cumulative emission and emission factor was 60.76 kg·hm-2, 0.138 kg·kg-1 (N2O-N/N) respectively in 100FS treatment during planting chili was more than that during planting lettuce and cabbage. Moreover, straw returning with reducing conventional fertilizing could reduce the N2O emission factor compared with 100FS treatment. The CO2 emission fluxes 55.28-1831.62[mg·(m2·h)-1] and cumulative emission (7502.13-25988.55 kg·hm-2) in 70FS treatment were lower than that in CK and F treatments, while other treatments increased the CO2 emission fluxes and cumulative emission, especially in 60FS and 50FS treatments. During planting lettuce and cabbage, the CH4 cumulative emission mainly showed negative values in treatments except for CK, indicating that soil could adsorb CH4. Moreover, straw returning with 30%-50% conventional fertilizing treatment could reduce CH4 emission fluxes and cumulative emission during planting chili, but increased in 100FS. Compared with CK and F treatment, generally, straw retuning with conventional fertilizing could significantly increase the global warming potential (GWP) in the study, except for 70FS treatment. 70FS could reduce the CO2, CH4 emission and the GWP of greenhouse gases, but could not significantly affect N2O emission reduction.

中国主要农作物种植农药施用温室气体排放估算

PDF HTML阅读 XML下载 导出引用 引用提醒 中国主要农作物种植农药施用温室气体排放估算 DOI: 10.5846/stxb201405271084 作者: 作者单位: 中国科学院生态环境研究中心,中国科学院生态环境研究中心,中国科学院生态环境研究中心 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金青年基金项目(71003092);科技部973专题(2010CB833504-2);中国科学院战略性先导科技专项子课题(XDA05050602,XDA05060102) Estimate of greenhouse gases emission from pesticides usage in China's major crops Author: Affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences,Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:过去30年来我国农作物的播种面积并未产生太大变化,但病虫害的发生和防治次数却不断增加。根据6种中国主要农作物的病虫害发生情况,收集了相应的农药用量及其制造的温室气体排放量数据,估算了中国主要农作物在种植过程中,因对病虫害使用杀虫剂和杀菌剂而产生的温室气体排放量现状。结果表明,我国主要农作物小麦、水稻、玉米、马铃薯、油菜和棉花的每公顷病虫害防治时使用农药所产生的温室气体排放量分别是9.19(1.86-23.24)、20.54(2.03-50.95)、10.38(3.45-19.32)、5.91(2.15-18.34)、10.84(8.10-13.62)、19.51(5.11-49.01)kg CE hm-2 a-1,即水稻和棉花最高;但论单产农药温室气体排放量,则油菜和棉花远高于其余4种粮食作物。每年小麦、水稻、玉米、马铃薯、油菜和棉花的病虫害防治使用农药所产生的总温室气体排放量分别是220.8(44.7-558.4)、606.7(60.0-1505.1)、336.4(112.0-606.3)、30.9(11.2-96.0)、79.5(59.4-99.8)、96.4(25.2-242.2)Gg CE,总计1.37(0.31-3.13)Tg CE。将以上6种作物的病虫害防治情况外推到全国农作物,则我国一年因为农作物病虫害防治而产生的温室气体排放量为2.13(0.48-4.85)Tg CE。另外由于缺乏草害面次数据而没有包括除草剂本分,所以以上数字仍是低估。病虫害防治由于作物本身、防治对象、防治方法以及药剂用量的固有差异,导致农作物病虫害防治的温室气体排放量计算结果存在着较大的不确定性,目前基于自下而上农户调查的估算方法无法克服这些问题,更精确的估算需要自上而下的企业级调查数据。 Abstract:Over the past 30 years, China's total area sown with crops did not change significantly. Meanwhile, the occurrences of crop pests and diseases as well as the control (treatment) areas have increased drastically. China has become the world's largest pesticide manufacturer and consumer since 2005 and the up-trend is expected to continue. Correspondingly, the greenhouse gases (GHGs) emission resulting from pesticide usage may also increase fast and become an important part of indirect GHGs emission in agriculture. However, domestic GHGs emission parameters from pesticide usage were rarely reported in analysis of China's agricultural life-cycle, which leads to considerable uncertainty in studies related to agricultural indirect GHGs emission. In this study, GHGs emission from pesticides manufacture was estimated by summing up the global warming potential of GHGs emitted from four processes including manufacture of active ingredients, formulation of emulsifiable oils/wettable powders/granules, packaging, and transport. According to the occurrence of pests and diseases in six major crops (wheat, rice, maize, potato, oilseed rape, and cotton) in China, the amount of current GHGs emissions induced by usage of insecticides and fungicides specific for these crops was assessed based on the integration of available information on the use of relevant pesticides and GHGs emissions from their manufacturing. Our estimation indicated that the GHGs emission pertaining to pests and diseases control was the highest for rice and cotton (20.54 [2.03-50.95] and 19.51 [5.11-49.01], respectively) followed by oilseed rape (10.84 [8.10-13.62]), maize (10.38 [3.45-19.32]), wheat (9.19 [1.86-23.24]), and potato (5.91 [2.15-18.34] kg carbon equivalent [CE] per hectare each year). Different crop pests and diseases contributed differently to crop's GHGs emission from pesticides usage: for maize and cotton, pests were the main contributors (especially maize borer, maize earworm, and cotton plant-bug); for oilseed rape and potato, diseases were the main contributors (especially potato late blight and rape sclerotinia rot); and for wheat and rice, pests and diseases both contributed equally to the total emission (especially wheat aphid, wheat midge, wheat red spider, wheat powdery mildew, wheat scab, rice plant hopper, rice leaf roller, rice striped stem borer, rice blast, and rice sheath blight). Meanwhile, as to the pesticide GHGs emission per unit yield, all four grain crops contributed far less than cotton and oilseed rape. Correspondingly, the overall emission due to the insect pests and diseases control measures for each of the analyzed crops in China was: 220.8 (44.7-558.4), 606.7 (60.0-1505.1), 336.4 (112.0-606.3), 30.9 (11.2-96.0), 79.5 (59.4-99.8), and 96.4 (25.2-242.2) Gg CE/a for wheat, rice, maize, potato, oilseed rape, and cotton, respectively, with a total amount of 1.37 (0.31-3.13) Tg CE/a. It should be noted that these results are underestimation of China's actual pesticide GHGs emission since the herbicides were not considered because of the unavailability of weed treatment data. Owing to the variation in the characteristics of crop pests and diseases control measures (including various conditions of crops, pests, and diseases, wide range of pesticide and fungicide choices and their legal dosage), non-negligible uncertainties still exist in our current bottom-up estimates based on farmer surveys. More accurate estimation requires implementation of top-down methods and data based on enterprise-level surveys. 参考文献 相似文献 引证文献

Greenhouse gases, radiative forcing, global warming potential and waste management — an introduction

Management of post-consumer solid waste contributes to emission of greenhouse gases (GHGs) representing about 3% of global anthropogenic GHG emissions. Most GHG reporting initiatives around the world utilize two metrics proposed by the Intergovernmental Panel on Climate Change (IPCC): radiative forcing (RF) and global warming potential (GWP). This paper provides a general introduction of the factors that define a GHG and explains the scientific background for estimating RF and GWP, thereby exposing the lay reader to a brief overview of the methods for calculating the effects of GHGs on climate change. An objective of this paper is to increase awareness that the GWP of GHGs has been re-adjusted as the concentration and relative proportion of these GHGs has changed with time (e.g., the GWP of methane has changed from 21 to 25 CO(2)-eq). Improved understanding of the indirect effects of GHGs has also led to a modification in the methodology for calculating GWP. Following a presentation of theory behind GHG, RF and GWP concepts, the paper briefly describes the most important GHG sources and sinks in the context of the waste management industry. The paper serves as a primer for more detailed research publications presented in this special issue of Waste Management & Research providing a technology-based assessment of quantitative GHG emissions from different waste management technologies.

N2O emissions and carbon sequestration in a nitrogen‐fertilized Douglas fir stand

This study investigated how nitrogen (N) fertilization with 200 kg N ha−1 of a 58‐year‐old West Coast Douglas fir stand influenced its net greenhouse gas (GHG) global warming potential (GWP) in the first year after fertilization. Effects of fertilization on GHG GWP were calculated considering changes in soil N2O emissions, measured using the static chamber technique and the soil N2O gradient technique; eddy covariance (EC) measured net ecosystem productivity (NEP); and energy requirements of fertilizer production, transport, and its aerial spreading. We found significant N2O losses in fertilized plots compared to a small uptake in nonfertilized plots. Chamber‐measured N loss in the fertilized plots was about 16 kg N2O ha−1 in the first year, which is equivalent to 10 kg N ha−1 or 5% of the applied fertilizer N. Soil N2O emissions measured using the gradient technique, however, exceeded the chamber measurements by about 50%. We also compared a polymer‐coated slow‐release urea with regular urea and found that the former delayed N2O emissions but the year‐end total loss was about the same as that from regular urea. Change in NEP due to fertilization was determined by relating annual NEP for the nonfertilized stand to environmental controls using an empirical and a process‐based model. Annual NEP increased by 64%, from 326 g C m−2, calculated assuming that the stand was not fertilized, to the measured value of 535 g C m−2 with fertilization. At the end of the year, net change in GHG GWP was −2.28 t CO2 ha−1 compared to what it would have been without fertilization, thereby indicating favorable effect of fertilization even in the first year after fertilization with significant emissions of N2O.