农业环境科学学报
農業環境科學學報
농업배경과학학보
Journal of Agro-Environment Science
2015年
7期
1398-1406
,共9页
柯韵%杨红薇%王小国%胡廷旭%刘韵%朱波
柯韻%楊紅薇%王小國%鬍廷旭%劉韻%硃波
가운%양홍미%왕소국%호정욱%류운%주파
紫色土%桤柏混交林地%坡耕地%退耕还林%N2O
紫色土%榿柏混交林地%坡耕地%退耕還林%N2O
자색토%기백혼교임지%파경지%퇴경환림%N2O
purple soil%alder and cypress mixed forest land%sloping cropland%returning cropland to forestland%N2O
采用静态暗箱-气相色谱法对紫色土坡耕地常规施肥处理(CL)、坡耕地不施肥处理(CL-CK)和退耕15、30年的桤柏混交林地(FL15、FL30)的土壤N2O排放通量进行为期1年的观测,同时测定土壤温度、土壤湿度、土壤无机氮含量等。结果表明,观测期内CL、CL-CK、FL15与FL30的N2O平均释放速率分别是25.6、6.60、1.20、4.35μg N2O-N·m-2·h-1,CL小麦季N2O平均释放速率是18.0μg N2O-N·m-2·h-1,玉米季35.2μg N2O-N·m-2·h-1,CL土壤N2O排放速率显著高于CL-CK、FL15和FL30(P<0.01),且CL-CK高于FL15、FL30(P<0.01),FL30高于FL15(P<0.01)。CL、CL-CK、FL15和FL30全年的N2O排放量分别为1.01、0.400、0.050、0.310 kg N2O-N· hm-2。比较CL以及CL-CK的N2O排放总量,停止施氮的措施对土壤N2O排放的减排潜力达到0.610 kg N2O-N·hm-2。与CL-CK相比,FL15、FL30土壤N2O释放量分别减少0.350、0.090 kg N2O-N·hm-2,主要原因是退耕后土壤碳氮比升高,土壤无机养分、温度以及湿度等发生变化。
採用靜態暗箱-氣相色譜法對紫色土坡耕地常規施肥處理(CL)、坡耕地不施肥處理(CL-CK)和退耕15、30年的榿柏混交林地(FL15、FL30)的土壤N2O排放通量進行為期1年的觀測,同時測定土壤溫度、土壤濕度、土壤無機氮含量等。結果錶明,觀測期內CL、CL-CK、FL15與FL30的N2O平均釋放速率分彆是25.6、6.60、1.20、4.35μg N2O-N·m-2·h-1,CL小麥季N2O平均釋放速率是18.0μg N2O-N·m-2·h-1,玉米季35.2μg N2O-N·m-2·h-1,CL土壤N2O排放速率顯著高于CL-CK、FL15和FL30(P<0.01),且CL-CK高于FL15、FL30(P<0.01),FL30高于FL15(P<0.01)。CL、CL-CK、FL15和FL30全年的N2O排放量分彆為1.01、0.400、0.050、0.310 kg N2O-N· hm-2。比較CL以及CL-CK的N2O排放總量,停止施氮的措施對土壤N2O排放的減排潛力達到0.610 kg N2O-N·hm-2。與CL-CK相比,FL15、FL30土壤N2O釋放量分彆減少0.350、0.090 kg N2O-N·hm-2,主要原因是退耕後土壤碳氮比升高,土壤無機養分、溫度以及濕度等髮生變化。
채용정태암상-기상색보법대자색토파경지상규시비처리(CL)、파경지불시비처리(CL-CK)화퇴경15、30년적기백혼교임지(FL15、FL30)적토양N2O배방통량진행위기1년적관측,동시측정토양온도、토양습도、토양무궤담함량등。결과표명,관측기내CL、CL-CK、FL15여FL30적N2O평균석방속솔분별시25.6、6.60、1.20、4.35μg N2O-N·m-2·h-1,CL소맥계N2O평균석방속솔시18.0μg N2O-N·m-2·h-1,옥미계35.2μg N2O-N·m-2·h-1,CL토양N2O배방속솔현저고우CL-CK、FL15화FL30(P<0.01),차CL-CK고우FL15、FL30(P<0.01),FL30고우FL15(P<0.01)。CL、CL-CK、FL15화FL30전년적N2O배방량분별위1.01、0.400、0.050、0.310 kg N2O-N· hm-2。비교CL이급CL-CK적N2O배방총량,정지시담적조시대토양N2O배방적감배잠력체도0.610 kg N2O-N·hm-2。여CL-CK상비,FL15、FL30토양N2O석방량분별감소0.350、0.090 kg N2O-N·hm-2,주요원인시퇴경후토양탄담비승고,토양무궤양분、온도이급습도등발생변화。
Cropland is a large source of global N2O emissions, while forestland emits much less N2O. Thus, returning cropland to forestland would help reduce global N2O emissions. Here static chamber-GC technique was used to compare soil N2O emission fluxes from sloping cropland(CL)and forestland returned from cropland for 15 and 30 years. Soil temperature, moisture, nitrate(NO-3- N)and ammonia (NH+4-N)nitrogen content in the soils were also recorded for one year. Results showed that average fluxes of soil N2O from CL, CL-CK (CL-Check test), FL15 and FL30(15 and 30 years old forest)were 25.6, 6.60, 1.20, and 4.35μg N2O-N·m-2·h-1, respectively, with signifi-cantly higher N2O emissions from CL than from CL-CK, FL15 and FL30(P<0.01). The N2O emissions from FL30 were also significantly higher than that from FL15(P<0.01). Annual cumulative N2O emissions from CL, CL-CK, FL15 and FL30 were respectively 1.01, 0.400, 0.050, and 0.310 kg N2O-N·hm-2. The potential of N2O mitigation by nitrogen fertilizer reduction was as high as 0.620 kg N2O-N·hm-2. Compared with CL-CK, FL15 and FL30 reduced N2O emissions by 0.350 and 0.090 kg N2O-N·hm-2, respectively, may due to increases in soil carbon to nitrogen ratios and changes in soil properties.