摘要
采用碱性氧化铜-固相萃取-气相色谱法将木质素氧化分解为V类(即香草基酚类,包括香草醛、香草酮和香草酸)、S类(即紫丁香基酚类,包括丁香醛、丁香酮和丁香酸)和C类(即肉桂基酚类,包括对香豆酸和阿魏酸)单体,以VSC的总和表征土壤中木质素的含量及其在土壤中的积累特性。基于红壤丘陵区的湖南盘塘中低产田改良长期定位试验平台,研究不同土地利用方式下(旱地、水旱轮作地),两种典型长期施肥方式[单施化肥(NPK)、秸秆还田配施化肥(S+NP)]对土壤中木质素各单体含量及组成的影响,同时测定p H、有机质、全量养分、速效养分及多酚氧化酶、过氧化物酶等指标探索影响红壤农田土壤木质素积累的关键因子。结果表明:与试验前本底相比,NPK和S+NP两种长期施肥处理均显著增加红壤农田中木质素VSC三类单体总量,其积累速率表现为水旱轮作地显著高于旱地,在旱地中分别为(8.15±1.39)μg·g-1·a-1和(119.85±3.10)μg·g-1·a-1、水旱轮作地分别为(17.67±0.87)μg·g-1·a-1和(126.48±0.03)μg·g-1·a-1;长期施肥显著增加了红壤中木质素组分中C类单体的比例,其中水旱轮作地中C类单体含量及其占总木质素总量的比例均低于旱地。双因素方差分析表明,土地利用方式、施肥处理均在不同程度上影响土壤养分和酶活性,并对土壤中木质素单体含量产生影响,其中V类与C类单体含量受土地利用方式及施肥处理交互作用的影响显著(P<0.01);相关性分析及冗余分析表明,有机质、氮素(全氮和速效氮,P<0.05)、速效钾(P<0.01)可能是红壤农田木质素积累的关键因子。因此,研究农田培肥管理对贫瘠红壤有机碳截获与转化影响时,应考虑土壤氮素及速效钾对木质素积累的作用。
Lignin is an important component in soil carbon cycle, and plays a particular role in the carbon storage. Lignin phenol content was calculated as the sum of vanillyl(V), syringyl(S), and cinnamyl(C)type phenols. To investigate the effect of long-term fertilization on lignin accumulation in agricultural soils, lignin content and its monomer composition were determined in upland and upland-paddy rotation fields under different fertilization practices[chemical fertilizer(NPK), combined straw and NP(S+NP)] in a subtropical red soil region. Soil p H, soil organic matter, and total nutrient content, and key enzymes were also determined. Results showed that both NPK and S+NP fertilization increased lignin content(VSC). The average accumulation rate of lignin in the upland was(17.67±0.87)μg·g-1·a-1and(126.48±0.03)μg·g-1·a-1for NPK and S+NP, respectively, while it was correspondingly(8.15±1.39)μg·g-1·a-1and(119.85±3.10)μg·g-1·a-1in uplandpaddy rotation field. Long-term fertilization significantly increased the proportion of relative unstable cinnamyl(C)type monomer(P<0.05),with lower values in the rotation field than that in upland, suggesting that the composition of lignin monomers in the rotation field was more stable than in upland. Land use and fertilization significantly influenced soil nutrient, enzyme activity and lignin monomer content. Land use and fertilization interaction had significant effect on the content of V and C type monomers(P<0.01). Both correlation and RDA analysis showed that soil organic matter, nitrogen(total nitrogen and available nitrogen, P <0.05), and available potassium(P <0.01) were the key factors determining the lignin accumulation. Therefore, the influences of nitrogen and available potassium on lignin accumulation should be considered when studying the sequestration and turnover of organic carbon in red soil.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2015年第9期1761-1768,共8页
Journal of Agro-Environment Science
基金
国家科技支撑计划项目(2012BAD05B06)
国家自然科学基金青年基金(41301273)
国家自然科学基金重点项目(41430860)
中国科学院西部之光人才培养计划"西部博士资助项目"
关键词
长期施肥
土地利用方式
红壤
木质素
单体
积累特性
long-term fertilization
land use
red soil
lignin
monomer
accumulation characteristics
