摘要
为了解连栽杉木人工林不同代际土壤氮的季节变化特征,以中亚热带不同连栽代数杉木人工林(一代、二代、三代)及格氏栲天然林为研究对象,测定不同形态氮(全氮、可溶性有机氮、铵态氮、硝态氮、微生物量氮)含量及其季节动态变化,探究连栽和季节变化对土壤氮素有效性的影响。结果表明:(1)杉木人工林土壤全氮和可溶性有机氮有明显的季节变化,其中全氮含量由大到小表现为6月、12月、3月、9月,可溶性有机氮含量由大到小表现为6月、9月、3月、12月。(2)杉木人工林土壤铵态氮含量随着栽植代数的增加而增加,而硝态氮则呈现出相反的趋势,且土壤硝态氮和铵态氮含量具有明显的季节变化特征,在3月时土壤铵态氮含量达到最大,而土壤硝态氮含量在6月达到最大。(3)不同连栽代数和采样季节及其交互作用均对土壤微生物量氮含量有显著影响。(4)杉木人工林土壤全氮、铵态氮和硝态氮之间均存在极显著的相关关系,土壤微生物量氮、可溶性有机氮和铵态氮之间也存在极显著相关关系(p<0.01);且土壤含水量与土壤微生物量氮、可溶性有机氮和铵态氮含量呈显著相关关系,表明土壤水分是影响该地区土壤氮含量变化的关键因子。尽管连栽对于土壤全氮和可溶性有机氮无显著影响,但是随着连栽代数的增加,杉木人工林土壤NH^(+)_(4)-N总体呈现出增加的趋势,而NO^(-)_(3)-N则呈现出下降的趋势,这可能反映了土壤系统在氮匮乏条件下采取了一种保氮策略,其微生物学机理还有待进一步探究。
This study aims to investigate the seasonal dynamics of the contents of different fractions of soil nitrogen(total nitrogen, TN;dissolved organic nitrogen, DON;ammonium nitrogen, NH^(+)_(4)-N;nitrate nitrogen, NO^(-)_(3)-N;microbial biomass nitrogen, MBN) in different successive rotations(first-rotation plantation, FRP;second-rotation plantation, SRP;third-rotation plantation, TRP) of subtropical Chinese fir(Cunninghamia lanceolate) plantation and Castanopsis Kawakamii dominated natural forest(NF) from December 2017 to September 2018 in Sanming, Fujian, China. The results showed that:(1) the contents of soil TN and DON exhibited significant seasonal variations in Chinese fir plantation;TN content decreased in the order: June>December>March>September, DON content decreased in the order: June>September>March>December;(2) the contents of soil NH^(+)_(4)-N in soils increased with the increment of successive rotations of Chinese fir, while the contents of NO^(-)_(3)-N presented the opposite trend;the contents of soil NH^(+)_(4)-N and NO^(-)_(3)-N exhibited significant seasonal variations in Chinese fir plantations, and the soil NH^(+)_(4)-N content reached the maximum in March, while the soil NO^(-)_(3)-N content reached the maximum in June;(3) the soil MBN content was significantly affected by different generations of Chinese fir plantation, sampling seasons and their interactions;(4) there was significant correlation among soil TN, NH^(+)_(4)-N and NO^(-)_(3)-N contents in Chinese fir plantations, and there was also significant correlation among soil MBN, DON and NH^(+)_(4)-N(p< 0.01), and there was significant relationship among soil moisture, MBN, DON and NH^(+)_(4)-N, indicating that soil moisture was the key factor regulating the seasonal dynamics of soil N in Chinese fir plantations. Successive rotation had no significant impact on contents of soil TN and DON, but led to the reduction in the nitrate content and enhancement of ammonium content. These results indicate the N-conservation strategy of successive rotations in Chinese fir plantation, and the underlying microbial mechanism on the dynamics of soil nitrogen needs to be further studied.
作者
任丽红
索沛蘅
唐楚珺
刘雨晖
陈辉
王玉哲
刘先
REN Lihong;SUO Peiheng;TANG Chujun;LIU Yuhui;CHEN Hui i;WANG Yuzhe;LIU Xian(Forestry College,Fujian Agriculture and Forestry University,Fuzhou 350002,China;Xinkou Forest Station,Fujian Agriculture and Forestry University,Sanming,Fujian 365002,China)
出处
《水土保持研究》
CSCD
北大核心
2021年第5期22-28,34,共8页
Research of Soil and Water Conservation
基金
国家自然科学基金(41603081)
福建省科技厅自然科学基金青年创新项目(2018J05046)。
关键词
杉木人工林
连栽
土壤氮素
季节变化
Chinese fir plantation
consecutive rotation
soil nitrogen
seasonal variation
