引用本文:何晓丽,吴艳宏,周 俊,邴海健,孙宏洋.贡嘎山东坡亚高山土壤生物有效磷的时空分异[J].土壤学报,2018,55(6):1502-1512.
HE Xiaoli,WU Yanhong,ZHOU Jun,BING Haijian,SUN Hongyang.Spatial and Temporal Distribution of Bioavailable Phosphorus in the Subalpine Soil on the Eastern Slope of Gongga Mountain[J].Acta Pedologica Sinica,2018,55(6):1502-1512
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贡嘎山东坡亚高山土壤生物有效磷的时空分异
何晓丽,吴艳宏,周俊,邴海健,孙宏洋
中国科学院水利部成都山地灾害与环境研究所,中国科学院水利部成都山地灾害与环境研究所,中国科学院水利部成都山地灾害与环境研究所,中国科学院水利部成都山地灾害与环境研究所,中国科学院水利部成都山地灾害与环境研究所
摘要:
采用湿化学浸提法测定了贡嘎山东坡亚高山带不同海拔(2 628 m、2 781 m、3 044 m和3 210 m)峨眉冷杉林的土壤生物有效磷(Bio-PL)含量,并利用原位树脂袋包埋法测定了土壤生物有效磷(Bio-PS)供给量,以阐明土壤生物有效磷的垂直分异和季节变化特征及其主要影响因素。研究发现:(1)土壤Bio-PL库及Bio-PS均随海拔升高呈增大趋势,低海拔地区生物有效磷因淋溶大量流失是形成这种梯度变化的主要原因。(2)随土层深度增加,Bio-PL库及Bio-PS显著降低,有机质层(O层)Bio-PL库约占土壤剖面的75%且该层的Bio-PS全年均为正值。O层中较高的有机磷含量和较强的磷酸酶活性是O层生物有效磷富集的重要原因。(3)2 781 m样点O层Bio-PS在9月最高,而3 044 m和3 210 m样点的Bio-PS在6月和9月出现两个高值。各样点矿质土层的Bio-PS全年多低于0,在8月时最低。Bio-PS的季节变化主要受生物吸收及径流流失控制。
关键词:  生物有效磷  树脂袋  垂直分异  季节变化  贡嘎山
DOI:10.11766/trxb201803290567
分类号:
基金项目:国家自然科学基金项目(41630751和41877011)
Spatial and Temporal Distribution of Bioavailable Phosphorus in the Subalpine Soil on the Eastern Slope of Gongga Mountain
He Xiaoli,Wu Yanhong,Zhou Jun,Bing Haijian and Sun Hongyang
Institute of Mountain Hazards and Environment Chinese Academy of Sciences,Institute of Mountain Hazards and Environment Chinese Academy of Sciences,Institute of Mountain Hazards and Environment Chinese Academy of Sciences,Institute of Mountain Hazards and Environment Chinese Academy of Sciences,Institute of Mountain Hazards and Environment Chinese Academy of Sciences
Abstract:
【Objective】 Phosphorus (P) is an important nutrient for plants. Enough supply of bioavailable P is essential for maintaining the stability of montane ecosystems. Many previous studies have focused on distribution and main driving factors of soil bioavailable P. However, there still are disputes about the synergistic effects of soil parent material, soil age, climate, biological activity, and soil properties on the bioavailable P distribution. The large altitudinal difference of high mountains provides an opportunity for determining the dominant factors and their interactions on the bioavailable P distribution in natural ecosystems. Therefore, the objectives of this study were to investigate the distribution of bioavailable P in profiles along the altitudinal gradient and to clarify the factors impacting the spatial and temporal distribution of bioavailable P in subalpine soils. 【Method】 Four altitudes (2 628 m, 2 781 m, 3 044 m and 3 210 m a.s.l.) were selected for sampling in May 2016. Six soil profiles were randomly set up for each site with a distance larger than 10 m between them. Soil profiles were divided into the four horizons O, A, B and C. One- to two-kilogram soil samples were collected hierarchically from the C to the O horizon. After soil samples were collected, mixed-bed ion-exchange resins bags were inserted into the four horizons (profiles 1~4) at each site. Soil samples were assayed to estimate the content of bioavailable P (Bio-PL). Bio-PL was defined as the inorganic P extracted using 0.5 mol•L-1 NaHCO3 (pH = 8.5) followed by colorimetric analysis with a UV2450 (Shimadzu, Japan). Resin bags were recovered to analyze the soil supply of bioavailable P (Bio-PS). Bio-PS was estimated by PO43--P concentrations using an Autoanalyzer 3 (Seal Analytical, Germany). 【Result】 The concentrations and stocks of Bio-PL as well as Bio-PS increased with altitude. The leaching process was more intensified in lower altitudes. This altitudinal pattern of bioavailable P was likely related to a lager loss of bioavailable P in lower altitudes (especially at the 2 781 m site) as shown by increasing soil moisture downward. The concentrations and stocks of Bio-PL decreased with soil depth. The stock of Bio-PL in the O horizon accounted for the largest proportion of the total Bio-PL stock, with an average of 75%. The Bio-PS in the O horizon was larger than 0 mg•kg-1•d-1 in the whole year. Thus, most soil bioavailable P was stored in the O horizon. The higher organic P content and phosphatase activity in the O horizon were the most important factors for this vertical distribution of bioavailable P in soil profiles. Bio-PS in the O horizon at the 2 781 m site was higher in September. For both of the 3 044 m and 3 210 m site, Bio-PS in the O horizon were higher in June and September. Bio-PS in the mineral horizons at the four sites was smaller than 0 mg•kg-1•d-1 in most months. The minimum Bio-PS for both A and B horizon were in August at the 2 781 m site, which were -1.143 and -0.943 mg•kg-1•d-1, respectively. Biological assimilation and loss with runoff were the main factors controlling the seasonal changes of soil bioavailable P. 【Conclusion】 Bioavailable P in the subalpine soil on the eastern slope of Gongga Mountain showed obvious spatial and temporal variations. The content of bioavailable P increased with altitude, and this altitudinal pattern was likely caused by a larger amount of loss in lower altitudes. Soil P bioavailability was highest in September for the O horizon and lowest in August for the mineral horizons. The seasonal change of soil bioavailable P was mainly controlled by the biological assimilation and loss with runoff.
Key words:  Bioavailable phosphorus  Ion-exchange resin bags  Altitudinal distribution  Seasonal variation  Gongga Mountain