玉米秸秆和化肥配施对团聚体中胡敏酸数量和红外光谱的影响

Effects of Chemical Fertilizer Combined Corn Stalk Application on the Quantity and Infrared Spectra of Humic Acids in Soil Aggregates

利用湿筛法进行土壤团聚体分组,并对团聚体(2～0.25,0.25～0.053,<0.053 mm粒级)中胡敏酸(HA)进行分离和纯化,研究了玉米秸秆和化肥配施对团聚体中HA数量、光学性质和红外光谱的影响.结果表明:团聚体的含量随着粒级的减小呈先增加后降低的趋势.2～0.25 mm和0.25～0.053 mm为优势粒级.不同粒级红外光谱相比,2～0.25 mm粒级HA在2 920 cm-1处的吸收最强,2 920/1 720值最大,脂族性最强.玉米秸秆和化肥配施使各粒级的全碳含量增加,HA含量减少.玉米秸秆和化肥配施后2～0.25 mm粒级HA的△lgK值提高,RF值下降,2 920/1 720值增加,分子脂族性增强,结构变简单.

Soil aggregates were separated by wet sieve analysis.The humic acid(HA) fraction was extracted from 2—0.25,0.25—0.053 and <0.053 mm aggregates and then purified.Effects of chemical fertilizer combined corn straw(NPKM) application on the quality and optical properties and infrared spectra of HA in soil aggregates were studied.The results showed that the aggregate contents firstly increased and then decreased with the increase of aggregate size.2—0.25 mm and 0.25—0.053 mm aggregates were dominant.With NPKM application,the total carbon contents increased in all aggregates,but the content of HA decreased.Comparing IR of HA in different soil aggregates,the absorb intensity and aliphatic property of HA in 2—0.25 mm aggregates were the highest.The ΔlgK value and 2 920/1 720 ratio of HA increased in 2—0.25 mm aggregate,but the RF value decreased,which indicated aliphatic property increased after NPKM application,and the structure of HA became simpler.