免耕与常规耕作下黑土腐殖酸含量与结构的差异

以东北农业科学院长期耕作定位实验为研究对象,结合元素分析和红外光谱来研究免耕与翻耕两种耕作方式对黑土腐殖酸含量与胡敏酸结构的影响。结果表明：免耕处理的腐殖酸含量高于常规耕作处理18.28%,两种耕作处理间HA/FA值差异很小;免耕处理的碳、氮和氢元素含量分别高于翻耕处理5.48%、36.49%和27.65%,N/C和H/C值也高于翻耕处理,而翻耕处理的O/C值高于免耕处理;不同耕作处理的红外光谱吸收带表现相似趋势,其中2920、2580、1620、1420和1220σ·cm-1处吸光度免耕信号高于翻耕,而1026、721σ·cm-1处吸光度相反。免耕增加了腐殖酸、胡敏酸及富里酸含量;免耕增加了黑土胡敏酸的芳香度、脂肪化程度和聚合程度,而翻耕作增加了黑土胡敏酸的氧化程度,这说明经过长达26年的免耕处理使黑土腐殖质结构趋于稳定,而翻耕处理使黑土腐殖质结构趋于简单。

The difference of black soil humus content and structure in no-tillage and plowing tillage

Based on the long-term tillage experiment of Jilin academy of agricultural sciences,the effect of no-tillage and plowing tillage on soil humus content and humic acid structure was analyzed by elemental analyzer and infrared-spectrum analyzer.The results showed that the humus content under no-tillage treatment is higher 18.28%than plowing tillage,the HA/FA values under two tillage treatments had no significant difference;the carbon,nitrogen and hydrogen content of no-tillage treatment is higher 5.48%, 36.49%and 27.65%than plowing tillage treatment,respectively,and the value of N/C and H/C under no-tillage is also higher than plowing tillage treatment,while the O/C of plowing tillage treatment is higher than no-tillage treatment;the absorb band of infrared-spectrum in different tillage treatments show the similar trend,the absorb band of 2 920σ·cm-1,2 580σ·cm-1,1 620σ·cm-1,1 420 σ·cm-1and 1 220σ·cm-1under no-tillage treatment is higher than plowing tillage treatment,while the 1 026 cm and 721 cm showed the reverse trend.No-tillage increase the humus,include humic acid and fulvic acid content;no-tillage increase the aromatic,ali-phatic degree and polymerization degree of humic acid in black soils;plowing tillage increase the oxidation degree of humic acid in black soils,that indicated no-tillage treatment made the hunus structure stable,while plowing tillage made the humus structure simplify after 26 years.