农业工程学报
農業工程學報
농업공정학보
2015年
4期
240-247
,共8页
张恒恒%严昌荣%张燕卿%王健波%何文清%陈保青%刘恩科
張恆恆%嚴昌榮%張燕卿%王健波%何文清%陳保青%劉恩科
장항항%엄창영%장연경%왕건파%하문청%진보청%류은과
土壤%农业%生态系统%传统耕作%免耕%土壤有机碳%碳平衡
土壤%農業%生態繫統%傳統耕作%免耕%土壤有機碳%碳平衡
토양%농업%생태계통%전통경작%면경%토양유궤탄%탄평형
soils%agriculture%ecosystem%conventional tillage%no-tillage%soil organic carbon SOC%carbon balance
农田系统对大气CO2库呈碳汇还是碳源效应取决于土壤有机碳的固定和温室气体释放之间的平衡，而耕作措施会改变土壤有机碳含量和储量，影响农田系统的碳循环与碳平衡。该研究以北方旱区山西临汾20 a长期保护性耕作定位试验为基础，田间原位测定土壤呼吸和土壤有机碳含量，确定各类农业投入碳排放参数，利用碳足迹方法综合分析不同耕作措施（传统耕作CT和免耕NT）下农田生态系统碳平衡。结果表明：在化肥、机械等农业投入产生的间接碳排放量方面，化肥投入碳排放量约占系统农业总投入碳排放量的73.5%～77.4%，是农业投入中主要的碳源。由于免耕减少了翻耕、旋耕和秸秆移除3道程序，NT比CT少排放约5.1%，NT产量显著提高28.9%，且碳生产力大于CT。0～60 cm土壤有机碳储量NT（50.86 Mg/hm2）比CT（46.00 Mg/hm2）高10.5%。与CT相比，在小麦休闲期和生育期NT土壤呼吸CO2释放总量高于 CT。但根据农田系统碳平衡公式分析得出，NT 更有利于农田生态系统固碳，呈碳汇效应，而 CT 表现为碳源。因此，长期免耕耕作能够提高农田土壤固碳量，减少大气温室气体排放，对于改善北方旱区土壤碳库和减排效果是一个良好的选择。
農田繫統對大氣CO2庫呈碳彙還是碳源效應取決于土壤有機碳的固定和溫室氣體釋放之間的平衡，而耕作措施會改變土壤有機碳含量和儲量，影響農田繫統的碳循環與碳平衡。該研究以北方旱區山西臨汾20 a長期保護性耕作定位試驗為基礎，田間原位測定土壤呼吸和土壤有機碳含量，確定各類農業投入碳排放參數，利用碳足跡方法綜閤分析不同耕作措施（傳統耕作CT和免耕NT）下農田生態繫統碳平衡。結果錶明：在化肥、機械等農業投入產生的間接碳排放量方麵，化肥投入碳排放量約佔繫統農業總投入碳排放量的73.5%～77.4%，是農業投入中主要的碳源。由于免耕減少瞭翻耕、鏇耕和秸稈移除3道程序，NT比CT少排放約5.1%，NT產量顯著提高28.9%，且碳生產力大于CT。0～60 cm土壤有機碳儲量NT（50.86 Mg/hm2）比CT（46.00 Mg/hm2）高10.5%。與CT相比，在小麥休閒期和生育期NT土壤呼吸CO2釋放總量高于 CT。但根據農田繫統碳平衡公式分析得齣，NT 更有利于農田生態繫統固碳，呈碳彙效應，而 CT 錶現為碳源。因此，長期免耕耕作能夠提高農田土壤固碳量，減少大氣溫室氣體排放，對于改善北方旱區土壤碳庫和減排效果是一箇良好的選擇。
농전계통대대기CO2고정탄회환시탄원효응취결우토양유궤탄적고정화온실기체석방지간적평형，이경작조시회개변토양유궤탄함량화저량，영향농전계통적탄순배여탄평형。해연구이북방한구산서림분20 a장기보호성경작정위시험위기출，전간원위측정토양호흡화토양유궤탄함량，학정각류농업투입탄배방삼수，이용탄족적방법종합분석불동경작조시（전통경작CT화면경NT）하농전생태계통탄평형。결과표명：재화비、궤계등농업투입산생적간접탄배방량방면，화비투입탄배방량약점계통농업총투입탄배방량적73.5%～77.4%，시농업투입중주요적탄원。유우면경감소료번경、선경화갈간이제3도정서，NT비CT소배방약5.1%，NT산량현저제고28.9%，차탄생산력대우CT。0～60 cm토양유궤탄저량NT（50.86 Mg/hm2）비CT（46.00 Mg/hm2）고10.5%。여CT상비，재소맥휴한기화생육기NT토양호흡CO2석방총량고우 CT。단근거농전계통탄평형공식분석득출，NT 경유리우농전생태계통고탄，정탄회효응，이 CT 표현위탄원。인차，장기면경경작능구제고농전토양고탄량，감소대기온실기체배방，대우개선북방한구토양탄고화감배효과시일개량호적선택。
Soil conservation tillage practices such as no-tillage and straw mulching are of great significance for saving energy input in farmland,mitigating greenhouse gas emission to the atmosphere,and increasing carbon sequestration potential in soils.Despite of great interest in the effect of no-tillage (NT) management practice on carbon sequestration and GHG emissions in northern China, long-term effects of different tillage practices in that region on farmland system carbon footprints remain unclear. Based on a 20-year conservation tillage experiment in a winter wheat system at Linfen City in Shanxi province, we evaluated long-term (20-year) effects of NT and conventional tillage (CT) practices on the carbon balance. During the experiment, we measured soil respiration and soil carbon concentration in the field. A random block design with three replications was used to assess both the tillage and its effects on soil carbon sequestration and yield of winter wheat (Triticum aestivum L.). Production, formulation, storage, and distribution of these inputs such as seed, chemical fertilizer and application with tractor equipment cause the combustion of fossil fuel and use of energy from other sources, which also emits CO2and other GHGs into the atmosphere. Thus, it is essential to understand emissions in kilograms carbon equivalent (kg CE) of various tillage operations, fertilizers, pesticides, harvesting and residue management. The index of carbon emission of different agricultural inputs were taken from literatures. In our study, carbon emission produced by chemical fertilizer with NT and CT practices accounted for 73.3%-77.1% of total carbon emission from agricultural inputs, and has become the main carbon source. Compared with other countries, fertilizer input in China accounts for a greater portion within agricultural production, and fertilizer costs made up about 50% of total costs in china. Reducing fertilizer use is an effective means to decrease indirect carbon emission. Because NT reduced moldboard ploughing, chisel ploughing and stover removal, carbon emission from agricultural inputs under NT was 5.1% less than that under CT. Moreover,T. aestivum L. yield with NT treatment increased by 28.9% over CT treatment. Carbon productivity in the NT system was greater than that in CT. After 20 years, SOC concentration in NT soil was greater than that in the CT soil, but only in the layer between 0 and 10 cm. There was significant SOC accumulation (0-60 cm) in the NT soil (50.86 Mg/hm2) compared with that in the CT soil (46.00 Mg/hm2). The total CO2 flux of soil respiration under NT was greater than that under CT. However, according to a carbon balance analysis, NT acted as a carbon sink compared to CT as a carbon source. This favored carbon sequestration in the farmland system. Therefore, long-term NT practice can increase soil carbon sequestration and reduce GHG emissions. The carbon emission coefficients are from literatures and N2O emission is not considered in the study. These may affect the results, but the trend among the different tillage system remains unchanged. With the improvement of the parameters, the accuracy of the assessment can be further improved. NT can be a significant innovation for carbon-friendly agricultural production technology in Northern China, because of its savings of energy/labor/time, reduction of GHG emissions, and benefits of SOC sequestration.
