绿肥对华北潮土土壤可溶性有机物的影响

在华北潮土上种植不同绿肥，于绿肥翻压前原位采集其地上部及土壤样品，进行56d的绿肥翻压模拟试验。设毛叶苕子(Vicia villosa Roth.)、二月兰(Orychophragmus Violaceus L.)、黑麦(Secale cereale L.)三个绿肥处理和无绿肥对照处理，分析培养过程中土壤可溶性有机物(DOM)组分及其紫外-可见光谱参数的变化，以探究绿肥对土壤DOM的影响。种植和翻压绿肥增加土壤可溶性有机碳(DOC)、总有机酸碳(TOAs)和总碳水化合物碳(TCs)含量，三者的变化趋势一致，各处理均在培养第1 d上升至峰值后迅速下降。毛叶苕子提高DOC和TOAs的效果最好，最高比对照增加114.01%(培养第1d)和109.10%(培养第14 d)。黑麦提高TCs的效果最好，最高比对照增加323.18%(培养第42 d)。种植和翻压绿肥增加土壤可溶性有机氮(DON)含量，与DOC变化趋势不同，各处理在培养第1 d上升后迅速下降一段时间后又迅速上升。毛叶苕子提高DON的效果最好，最高比对照增加305.83%(培养第42d)。绿肥增加了SUVA₂₅₄，SUVA₂₆₀，SUVA₂₇₂，SUVA₂₈₀，SAUC_240-400，降低了A₂₅₀/A₃₆₅和A₂₄₀/A₄₂₀。紫外-可见光谱参数的主成分分析显示SUVA₂₅₄，SUVA₂₆₀，SUVA₂₇₂，SUVA₂₈₀间有很高正相关性，A₂₅₀/A₃₆₅和A₂₄₀/A₄₂₀间亦有很高正相关性，SAUC_240-400是这些参数中表征DOM性质的关键因子。综上结果表明，种植翻压绿肥增加了土壤DOM含量，提高了土壤DOM的芳香性、疏水性、腐殖化程度、平均分子量，增加了土壤DOM的稳定性。

Effects of Green Manures on Soil Dissolved Organic Matter in Moisture Soil in North China

Soil dissolved organic matter (DOM)plays an important role in the biogeochemistry of carbon,nitrogen,and phos-phorus and in the transport of heavy metals and pesticides in soil.In moisture soil,green manures and soils were sampled in situ at the ploughed stage of green manures.A 5 6-day laboratory incubation experiment was conducted to simulate the dynamic chan-ges of soil DOM influenced by the decomposition of green manures,the green manures were Hairy vetch (Vicia villosa Roth.), February orchid (OrychophragmusViolaceus L.),Rye (Secalecereale L.),the soil without green manure was used as a control (CK).The composition and ultraviolet-visible spectrum parameters of soil DOM were investigated at different incubation stages. Results showed that green manures could increase the dissolved organic carbon (DOC),the total organic acids (TOAs)and total carbohydrate (TCs)contents,and all treatments were reached a peak on the 1st day and decreased later.Hairy vetch affected DOC and TOAs most and were increased by 114.01% and 109.10% higher than CK respectively at the 1st and 14th day.Rye influenced the total carbohydrate (TCs)most and was maximumly 323.18% higher than CK at the 42nd day.Green manures could increase the dissolved organic nitrogen (DON)content,DON in all green manure treatments increased on the 1 st day,de-creased several days later and increased again after 20~30 d.Hairy vetch effected DON best and was 305.83% higher than CK at the 42nd day.All green manures increased in SUVA254 ,SUVA260 ,SUVA272 ,SUVA280 and SAUC240-400 ,while decreasing in A250/A365 and A240/A420 .The PCA analysis of ultraviolet-visible spectrum parameters showed that SUVA254 ,SUVA260 ,SU-VA272 ,SUVA280 had a high positive correlation between each other,and the same situation was found between A250/A365 and A240/A420 .Among them,SAUC240-400 was a key factor parameter featuring the characteristics of DOM.The results suggested that green manures could increase the contents of DOM and its aromaticity,hydrophobic percentage,humification degree and av-erage molecular weight,and could be increased and the stability of DOM could be enhanced accordingly.The ultraviolet-visible spectrum parameters could indicate the changes of characteristics of DOM in this study.