生态环境学报
生態環境學報
생태배경학보
ECOLOGY AND ENVIRONMENT
2014年
6期
932-937
,共6页
NO%N2O%N2%反硝化%亚热带土壤
NO%N2O%N2%反硝化%亞熱帶土壤
NO%N2O%N2%반초화%아열대토양
NO%N2O%N2%denitrification%subtropical soils
亚热带可变电荷土壤化学性质与温带地区恒电荷土壤有诸多不同特点，使得反硝化具有一些与温带土壤不同的特性，进一步深入研究亚热带土壤反硝化气体产物的组成比例、主要影响因素和机理，将有助于加深对亚热带环境条件下土壤 N循环的理解和认识，以及为正确评价亚热带土壤反硝化环境效应提高科学依据。因此，就亚热带土壤厌氧培养条件下反硝化的气态产物问题进行了探讨。土样采自江西典型亚热带红壤地区，在加入K15NO3(10 atom%15N，加入N量为200 mg·kg-1)条件下进行了7 d 30℃、密闭、淹水、充N2的严格厌氧培养试验。试验结果表明：随培养时间推移，15N回收率逐渐下降，土壤总残留的15NO3-质量分数和回收率之间存在显著正相关关系(p<0.001)，表明反硝化作用越弱的土样回收率越高。总气态氮损失率的估计值和实测值都随培养时间延长呈上升趋势，两者之间存在显著正相关性(p<0.001)。根据稳定性同位素15N示踪试验结果初步估计，厌氧培养7 d内反硝化作用产生的气态产物中N2O占总气态氮损失的17.1%，N2占8.7%，估计NO可能是主要的反硝化产物之一。以未能回收的氮计算，NO约占总气态氮损失的67.5%～78.6%，平均为74.1%。反硝化气态产物中NO和N2O总量占总气态氮损失的91.3%。NO、N2O和N2分别占总施入氮量的18.6%、4.4%、2.0%。因此，亚热带土壤氮素反硝化过程中主要气态产物可能为NO和N2O，而非对环境无害的N2。
亞熱帶可變電荷土壤化學性質與溫帶地區恆電荷土壤有諸多不同特點，使得反硝化具有一些與溫帶土壤不同的特性，進一步深入研究亞熱帶土壤反硝化氣體產物的組成比例、主要影響因素和機理，將有助于加深對亞熱帶環境條件下土壤 N循環的理解和認識，以及為正確評價亞熱帶土壤反硝化環境效應提高科學依據。因此，就亞熱帶土壤厭氧培養條件下反硝化的氣態產物問題進行瞭探討。土樣採自江西典型亞熱帶紅壤地區，在加入K15NO3(10 atom%15N，加入N量為200 mg·kg-1)條件下進行瞭7 d 30℃、密閉、淹水、充N2的嚴格厭氧培養試驗。試驗結果錶明：隨培養時間推移，15N迴收率逐漸下降，土壤總殘留的15NO3-質量分數和迴收率之間存在顯著正相關關繫(p<0.001)，錶明反硝化作用越弱的土樣迴收率越高。總氣態氮損失率的估計值和實測值都隨培養時間延長呈上升趨勢，兩者之間存在顯著正相關性(p<0.001)。根據穩定性同位素15N示蹤試驗結果初步估計，厭氧培養7 d內反硝化作用產生的氣態產物中N2O佔總氣態氮損失的17.1%，N2佔8.7%，估計NO可能是主要的反硝化產物之一。以未能迴收的氮計算，NO約佔總氣態氮損失的67.5%～78.6%，平均為74.1%。反硝化氣態產物中NO和N2O總量佔總氣態氮損失的91.3%。NO、N2O和N2分彆佔總施入氮量的18.6%、4.4%、2.0%。因此，亞熱帶土壤氮素反硝化過程中主要氣態產物可能為NO和N2O，而非對環境無害的N2。
아열대가변전하토양화학성질여온대지구항전하토양유제다불동특점，사득반초화구유일사여온대토양불동적특성，진일보심입연구아열대토양반초화기체산물적조성비례、주요영향인소화궤리，장유조우가심대아열대배경조건하토양 N순배적리해화인식，이급위정학평개아열대토양반초화배경효응제고과학의거。인차，취아열대토양염양배양조건하반초화적기태산물문제진행료탐토。토양채자강서전형아열대홍양지구，재가입K15NO3(10 atom%15N，가입N량위200 mg·kg-1)조건하진행료7 d 30℃、밀폐、엄수、충N2적엄격염양배양시험。시험결과표명：수배양시간추이，15N회수솔축점하강，토양총잔류적15NO3-질량분수화회수솔지간존재현저정상관관계(p<0.001)，표명반초화작용월약적토양회수솔월고。총기태담손실솔적고계치화실측치도수배양시간연장정상승추세，량자지간존재현저정상관성(p<0.001)。근거은정성동위소15N시종시험결과초보고계，염양배양7 d내반초화작용산생적기태산물중N2O점총기태담손실적17.1%，N2점8.7%，고계NO가능시주요적반초화산물지일。이미능회수적담계산，NO약점총기태담손실적67.5%～78.6%，평균위74.1%。반초화기태산물중NO화N2O총량점총기태담손실적91.3%。NO、N2O화N2분별점총시입담량적18.6%、4.4%、2.0%。인차，아열대토양담소반초화과정중주요기태산물가능위NO화N2O，이비대배경무해적N2。
Denitrification characteristics in subtropical variable charge soils may be different from other soils in temperate zone with constant charge due to their unique soil chemical properties. The identification of composition, ratios, influencing factors, and mechanism of nitrogenous gas products of denitrification in the area is crucial to understand soil nitrogen (N) cycle under subtropical conditions, and provide scientific basis for proper assessment of environmental effect of denitrification in subtropical soil. The objective was to study the gas products of denitrification in subtropical soils under anoxic incubation condition by applying stable isotope 15N tracer technique. Soil samples were collected from Jiangxi province, a typical subtropical red soil region in China. A 7-day anaerobic incubation was conducted under N2 gas in the headspace, at 30 ℃ after treatment with 200 mg 15NO3--N kg-1 soil (10 atom%15N). The results showed that the recovery rate of 15N was reduced with increased incubation time. The soil 15NO3--N content remained at the end of the incubation was significantly positively correlated with the 15N recovery rate (p<0.001), indicating that the weaker the soil denitrification the higher the 15N recovery rate. Both the estimated and measured ratios for the total gaseous nitrogen loss increased during the incubation, presenting a significant positive relationship between them (p<0.001). It was estimated preliminarily by the 15N tracer results that N2O and N2 accounted for proximately 17.1%and 8.7%of the total N gas produced during the 7 days anaerobic incubation, respectively. Nitric oxide (NO) would probably be the main N gas product of denitrification, accounting for about 67.5%-78.6% of the total N gas products with the mean value of 74.1%, by the estimation of the 15N unrecoverable. The ratio of NO and N2O to the total N gas loss produced by denitrification was 91.3%. The percentage of NO, N2O and N2 to the N added were 18.6%, 4.4%and 2.0%, respectively. The results indicated that the main composition of gas products of denitrification in subtropical soils might be NO and N2O, not be the environmentally benign N2.
