湖南会同不同年龄杉木人工林土壤磷素特征

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 湖南会同不同年龄杉木人工林土壤磷素特征 DOI: 10.5846/stxb201404060655 作者: 作者单位: 中南林业科技大学,中南林业科技大学,中南林业科技大学,中南林业科技大学,中南林业科技大学,湖南会同县林业局 作者简介: 通讯作者: 中图分类号: 基金项目: 国家林业公益性行业科研专项(201404316);湖南省自然科学基金创新群体项目(湘基金委字[2013]7号);城市森林生态湖南省重点实验室运行项目资助;湖南省优势重点学科项目资助;湖南省"百人计划"项目(0842);中南林业科技大学研究生科技创新基金项目(CX2014A04) Characteristics of soil phosphorus in different aged stands of Chinese fir plantations in Huitong, Hunan Province Author: Affiliation: Central South University of Forestry Technology,Changsha,Central South University of Forestry Technology,Changsha,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:对湖南会同不同年龄(7年生、17年生、25年生)杉木人工林土壤全磷、有效磷、无机磷组分和有机磷进行了研究,结果表明:3种不同林龄杉木林土壤全磷和有效磷的含量分别在 317.06-398.56 mg/kg和 0.82-1.38 mg/kg 之间,土壤全磷和速效磷含量均属低水平;杉木林土壤全磷含量从7年生幼龄林到25a近熟林出现先升高后降低的规律,并且17 年生和25年生林分比7 年生林分分别增加了19.68%、15.75%,土壤有效磷含量17 年生和25 年生林分比7 年生林分提高了45.55%左右;土壤磷素活化系数均小于2.0%,这表明本研究区土壤全磷向速效磷转化较难,土壤中磷素的有效性较低,但该值随着林分年龄的增加而出现增大的现象;无机磷含量分别为:7年生 169.50 mg/kg、17年生 182.03 mg/kg、25年生 175.94 mg/kg,从幼龄林到中龄林增高, 中龄林以后降低;土壤中无机磷组分以O-P含量最高,其次是Fe-P,Ca-P,Al-P最少;杉木不同生长发育阶段对无机磷形态的吸收是有选择性的,幼龄林到中龄林阶段林木以吸收Al-P为主,近熟林阶段林木以吸收Fe-P和Ca-P为主;有机磷含量在全磷所占比例随林龄的变化来看,杉木生长过程中有部分的有机磷矿化为无机磷.土壤不同形态磷的相关性分析结果显示,土壤有效磷与有机磷相关系数为0.667,呈极显著相关性,是研究区杉木人工林土壤有效磷的主要来源. Abstract:Phosphorus (P) is an essential element for growth and development of plants. At cellular and sub-cellular levels, P plays a vital role in various important metabolic processes, such as protein synthesis, cell division, newborn tissues development and energy transformations. In terrestrial ecosystems, P is often the most limiting nutrient. This is particularly the case for some regions where nitrogen (N) in the soils is likely saturated due to high N deposition, extensive N fertilizer application and fossil fuel combustion. In this study, changes in P formations (total P, available P, inorganic P and organic P) in soils were investigated in three aged stands of Chinese fir plantations (7-, 17- and 25-year-old stands) in Huitong County, Hunan Province, China. The fractions of inorganic P in soils were also determined in the studied plantations. The purpose of this project is to examine the alterations of soil P in different aged Chinese fir forests. The results showed that the total P content ranged from 317.06 to 398.56 mg/kg and available P content from 0.82 to 1.38 mg/kg, in the three examined aged stands. The total P and available P contents were in a relative low level when compared with the corresponding values derived from the national soil survey. But the total P and available P contents in soils significantly increased with the aged stands. The average total P content in soils was about 19.68% and 15.75% higher in 17-year-old stands and 25-year-old stands than in 7-year-old stands. Available P content was about 45.55% higher in the 17- and 25-year-old stands than in the 7-year-old stands. P activation coefficient in the soils was low (< 2.0%) in the three aged stands of Chinese fir forests, which suggested that the transformation of organic P to available P was restricted, even certain mineralization indeed occurred in the studied site. The concentration of inorganic phosphorus was 169.50, 182.03 and 175.94 mg/kg in the 7-, 17- and 25-year-old stands, respectively. On average, the amount of inorganic P fractions in the studied soils was in an order: occluded bound P (O-P) > iron bound P (Fe-P) > calcium bound P (Ca-P) > aluminum bound P (Al-P). Significant changes in the patterns of absorption of inorganic phosphorus fraction occurred in different growth and developmental stages of Chinese fir forests. Typically, the Al-P fraction was the major component of the inorganic P absorbed by the tree in the 7- and 17-year-old plantations. But the Fe-P and Ca-P fractions became the most assimilated inorganic P in 25-year-old Chinese fir stands. It was found that there was a close relationship between the available P and organic P in soils with a correlation coefficient of 0.667 in the studied stands, which implied that the organic P was the main source of soil available P in Chinese fir plantations in the study region. The results suggested that it was likely an important management practice to increase the transform rate of inorganic P to available P in the younger stands in order to improve soil fertility and promote forest productivity. Our study provided a scientific basis and reference for better understanding of P storage and cycling in Chinese fir forests. 参考文献 相似文献 引证文献