摘要
以广西环江(石灰土)、湖南桃源(红壤)两个亚热带典型农田(旱地)长期定位试验为平台,采用碱性氧化铜-固相萃取-气相色谱法,分析两种长期施肥制度[化肥(NPK)、秸秆还田配施化肥(NPKS)]下土壤中木质素V、S、C等3类单体含量及组成的变化,并阐明影响旱地土壤中木质素积累的主要因子.结果表明:长期施用化肥(NPK)对石灰土木质素总量(SumVSC)无显著影响,而红壤木质素总量显著增加(55±1)%;秸秆还田配施化肥(NPKS)均显著增加了两种土壤木质素总含量(P<0.01),增加比例分别为(328±4)%、(456±9)%.长期施肥处理增加了红壤木质素单体C的比例,石灰土则表现为单体V的比例增加,表明农田土壤中木质素的转化具有单体特异性;长期施肥后木质素单体的酸醛比(Ac/Al)V和(Ac/Al)S均有所降低,其中石灰土高于红壤,说明石灰土的木质素分解矿化程度较红壤高.有机质、全氮与木质素单体含量无显著相关,而对木质素单体V、S、C组成有显著影响;木质素V、S和C类单体含量及组成均与土壤速效养分(碱解氮、速效磷、速效钾)显著相关(P<0.05),由此认为土壤速效养分是木质素积累特性的关键影响因子.
To investigate the effect of long-term fertilization on lignin accumulation and clarify its influencing factors in subtropical agricultural upland soils, alkaline CuO oxidation and gas chroma- tography was performed to quantify the amount of lignin and its monomers components （V, S and C）. The soil samples were collected from the fertilization treatments of NPK and NPKS （ NPK com- bined with straw） in Huanjiang County, Guangxi Province （limestone soil） and Taoyuan County, Hunan Province （red soil）. The results showed that NPK had no significant effect on the lignin con- tent （SUmvsc ） of limestone soil, whereas the content in red soil significantly increased by （55±1 ）%. For the NPKS treatment, the lignin content in limestone and red soil increased by （328±4） % and （456±9 ）%, respectively. After the same fertilization treatment, the proportion of cin- namyl （C）-type significantly increased in red soil, while a significant increase of vanillyl （V）-type monomers occurred in limestone soil, indicating that lignin degradation in agricultural soils was monomer specific. Furthermore, the acid-to-aldehyde ratios of syringyl-type [ （Ac/A1） s] or va- nillyl-type [ （Ac/A1）v ] monomers tended to decrease after long-term fertilization with the highervalue for limestone soil, suggesting the degree of lignin degradation in limestone was higher than that in red soil. Soil organic matter and total nitrogen were not correlated with lignin content, but were significantly correlated with the composition of VSC monomers. Meanwhile, the available nutri- ent content in the soil （available nitrogen, phosphorus, and potassium） was closely related to the contents and components of V, S, and C-type monomers （P〈0.05）. It indicated that the availabili- ty of soil nutrition should be considered as a key factor for the accumulation of lignin.
出处
《应用生态学报》
CAS
CSCD
北大核心
2015年第1期93-100,共8页
Chinese Journal of Applied Ecology
基金
国家自然科学基金青年科学基金项目(41301273)
国家自然科学基金重点项目(41430860)
国家科技支撑计划项目(2012BAD05B03-6)
中国科学院"西部之光"人才培养计划"西部博士项目"资助
关键词
长期施肥
秸秆还田
木质素
积累特性
土壤酶活性
long-term fertilization
returning straw to field
lignin
accumulation characteristics
soil enzyme activity.
