記者日前從中科院成都山地所獲悉,，該所博士蔡延江采用靜態(tài)箱—氣相色譜法，在河南省封丘縣對(duì)不同施肥制度下玉米—小麥輪作體系的氧化亞氮排放進(jìn)行了觀測(cè)研究,。結(jié)果顯示,，將一半有機(jī)肥與一半無(wú)機(jī)肥氮配施，能有效降低我國(guó)華北平原農(nóng)田土壤氧化亞氮的排放,。相關(guān)成果發(fā)表在《大氣環(huán)境》雜志上,。
據(jù)了解，氧化亞氮是排在二氧化碳,、甲烷之后的第三大溫室氣體,，其單分子增溫潛勢(shì)是二氧化碳的298倍，其中農(nóng)業(yè)生產(chǎn)及氮肥施用是氧化亞氮重要的排放源,。過(guò)量施用氮肥導(dǎo)致的溫室氣體排放,，已成為我國(guó)乃至全球農(nóng)業(yè)可持續(xù)發(fā)展的嚴(yán)重威脅。
此次研究人員通過(guò)對(duì)比長(zhǎng)期定位試驗(yàn)地內(nèi)不施肥（CK）與有機(jī)肥（OM）,、有機(jī)肥氮和化肥氮各半（HOM）以及化肥氮磷鉀（NPK）處理的3年氧化亞氮通量發(fā)現(xiàn),，小麥HOM和NPK處理氧化亞氮累積排放量存在顯著的年際變化。玉米季和全年氧化亞氮累積排放量雖然在統(tǒng)計(jì)學(xué)上無(wú)明顯的年際差異,，但其年際變化仍較為明顯,。
科研人員還發(fā)現(xiàn)，不同年份間氧化亞氮排放的差異主要?dú)w因于基肥施用后土壤水分含量的差異,，基肥施用后立即灌水或降水比翻耕前灌水更能誘導(dǎo)土壤排放氧化亞氮,。HOM與OM,、NPK相比具有更高的氮肥利用效率，且其單位產(chǎn)量上的氧化亞氮排放量更低,。（生物谷Bioon.com）
生物谷推薦的英文摘要
Atmospheric Environment doi.org/10.1016/j.atmosenv.2012.10.038
Nitrous oxide emissions from Chinese maize–wheat rotation systems： A 3-year field measurement
Yanjiang Caia,，Weixin Dinga，Jiafa Luob
Nitrous oxide (N2O) fluxes were measured over a 3-year period (2004–2007) in a long-term experimental field. The objectives of the study were to evaluate the interannual variation of N2O emissions from a maize–wheat rotation,， under different fertilizer regimes and to determine the key controlling factors. The study involved four treatments： compost (OM),， half compost N plus half inorganic fertilizer-N (HOM)， inorganic fertilizer-N (NPK),， and control (CK) where no N application. The mean annual N2O emission over a 3-year period was 0.30 ± 0.11 kg N2O–N ha1 in the CK treatment,， but increased to 1.61 ± 0.10 kg N2O–N ha1 in the HOM treatment， 2.13 ± 0.15 kg N2O–N ha1 in the OM treatment,， and 2.76 ± 0.19 kg N2O–N ha1 in the NPK treatment. Differences were significant among treatments. The N2O emission factors of the applied OM,， NPK and HOM were 0.61 ± 0.02， 0.82 ± 0.10 and 0.44 ± 0.04%,， respectively,， at a rate of 300 kg N ha1 year1， indicating that the combined application of compost with inorganic fertilizer significantly reduced N2O emission. Over a maize–wheat rotation year,， more than 65% of the annual N2O emission occurred during the maize growing season. There was a large interannual variation in N2O emission in all treatments,， albeit not significant either during the maize growing season or at an inter-year scale. This interannual variation was mainly attributable to differences in soil moisture after basal fertilizer application， and irrigation and/or heavy rainfall events immediately following basal fertilization could induce more N2O production than pre-irrigation before plowing. The HOM treatment had higher N fertilizer use efficiency and lowest yield-scaled N2O emissions compared with the OM and NPK treatments. We therefore argue that the combined application of half compost N plus half fertilizer-N will mitigate N2O emissions from soils in the North China plain.
