| 摘要: |
| 【目的】分析不同施肥处理对土壤理化性质、N2O的排放特征及小麦产量的影响，以期为旱作雨养农田化肥合理施用以及降低温室气体排放提供科学依据。【方法】2016-2018年，以始于1990年的陕西杨凌“国家黄土肥力与肥料效益监测基地”冬小麦/夏休闲体系长期肥料定位试验为基础，对其中6个处理（（1）不施肥（CK）、（2）单施氮肥（N）、（3）氮肥与钾肥配施（NK）、（4）磷肥与钾肥配施（PK）、（5）氮肥与磷肥配施（NP）、6）氮肥、磷肥与钾肥配施（NPK））进行研究，测定不同处理土壤样品理化性质、N2O排放特征以及小麦产量，并就N2O排放总量与土壤理化性质的关系进行了冗余（RDA）分析。【结果】不同处理对土壤理化性质影响有差异，其中NP和NPK处理土壤有机碳(SOC)、全氮(TN)、无机氮（铵态氮(NH4+-N)和硝态氮(NO3--N)）、微生物量碳（MBC）、微生物量氮（MBN）含量均明显高于其他处理，而土壤pH显著下降。2016-2017和 2017-2018年不同处理的土壤N2O排放总量分别为0.48~1.31和0.41~1.18 kg/hm2，其中施氮处理（NK、NP和NPK）的土壤N2O排放总量均显著高于 CK；土壤N2O排放总量平均值表现为NPK＞NP＞NK＞N＞PK>CK。所有施氮处理中，NPK处理的N2O排放系数平均值最高，达0.59%，显著高于其他处理。2016-2017和2017-2018年，所有施肥处理小麦产量均显著高于CK，其中NP和NPK处理的小麦产量均较高。6个处理中，N处理的土壤N2O排放强度平均值最高，显著高于其他处理；CK、NK和NPK处理次之，且三者之间差异不显著；NP和PK处理均较低，且两者之间差异不显著。RDA分析结果表明，土壤N2O排放总量与土壤理化性质的相关性由大到小表现为TN>NO3--N>SOC>NH4+-N>MBN>MBC。【结论】对于土娄土区雨养农田而言，长期氮、磷肥配施（NP）或者氮、磷、钾肥配施（NPK）可显著提高土壤肥力和小麦产量以及N2O排放总量，是研究区较好的施肥方式。 |
| 关键词: 长期施肥 冬小麦/夏休闲体系 N2O排放系数 |
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| 基金项目:国家高技术研究发展计划项目（2013AA102904）；陕西省科技统筹创新工程计划项目（2016KTZDNY03-06）；陕西省自然科学基础研究计划项目(2018JM4007)；高等学校学科创新引智计划资助项目（B12007） |
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| Effects of long-term chemical fertilization on N2O emission from rain-fed dry farmland |
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XIAO Jie,LIU Pingjing,SUN Benhua,et al
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| Abstract: |
| 【Objective】The effects of long-term different fertilizations on soil physical and chemical characteristics,wheat yield and N2O emission were investigated to provide basis for reducing emission from farmland soil by reasonable fertilization.【Method】From 2016 to 2018,based on the long-term fertilizer experiment of winter wheat/summer fallow system started in 1990 as “National Monitoring Base of Soil Fertility and Fertilizer Efficiency on Loess Soil” in Yangling,Shaanxi,different treatments including farmland without fertilization (CK),N fertilizer (N),N and K fertilizer (NK),P and K fertilizer (PK),N and P fertilizer (NP),as well as N,P and K fertilizer (NPK) were selected.The physicochemical properties of soil samples,N2O emission characteristics and wheat yield of different treatments were measured,and the relationship between total N2O emission and soil physicochemical properties was analyzed by redundancy analysis (RDA).【Result】 The effects of different treatments on soil physical and chemical properties were different.Soil organic carbon,total nitrogen,inorganic nitrogen (ammonium nitrogen and nitrate nitrogen),microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) contents in NP and NPK treatments were significantly higher than that in other treatments.Soil pH in treatments decreased significantly.Total N2O emissions from different treatments during 2016-2017 and 2017-2018 were 0.48-1.31 and 0.41-1.18 kg/hm2,respectively.The total N2O emissions of nitrogen fertilization treatments (NK,NP and NPK) were significantly higher than that of CK.The average soil N2O emissions were in the order of NPK>NPK>NK>N>PK>CK.Among all nitrogen fertilization treatments,the NPK treatment had the highest average N2O emission factor of 0.59%,and it was significantly higher than that of other treatments.In 2016-2017 and 2017-2018,the wheat yields of all fertilization treatments were significantly higher than that of CK with the highest in NP and NPK treatments.N treatment had the highest yiled scaled N2O emission and it was significantly higher than other treatments.CK,NK and NPK were lower without significant difference.NP and PK treatments were the lowest without significant difference.RDA analysis showed that the correlation coefficient between soil N2O emission and soil physical and chemical properties was in the order of TN>NO3--N>SOC>NH4+-N>MBN>MBC.【Conclusion】For rain-fed farmland in Lou soil area,long-term combined application of nitrogen and phosphorus (NP) or combined application of nitrogen,phosphorus and potassium (NPK) can significantly increase soil fertility,wheat yield and cumulative emission of N2O.The two treatments are suggested fertilizer application methods in the study aera. |
| Key words: long-term fertilization winter wheat-summer fallow cropping system N2O emission factor |
