苗圃土壤肥力评价及肥力系数与苗木生长的相关性

Evaluation of nursery soil fertility and relationship between fertility coefficients and seedling growth

以广东河源中心苗圃（共有5个不同地块，分别记为地块A，B，C，D，E）为研究对象，选用土壤质地、容重、pH、有机质、全氮、碱解氮、速效磷和速效钾等8项属性作为评价指标，运用修正的内梅罗（Nemoro）公式，对土壤肥力进行定量综合评价，并对肥力系数与苗木生长指标的相关性进行分析。结果表明，苗圃土壤肥力系数P平均为1．06～2．48，P最小、为0．03～0．97，综合肥力系数P为0．66～1．65，不同地块、同一地块不同土层同一系数差异很大。该苗圃仅有地块A，B和D的表层（0～20cm）土壤和地块A的表下层（20～40cm）土壤肥力达到一般水平，上述地块的其他土层和地块C和E的所有土层均属贫瘠。土壤氮素缺乏是导致P值低的主要原因。阔叶树苗高与P平。和P呈显著正相关关系；阔叶树单株苗木生物量与P平均，P最小、和P均呈显著正相关关系，表明P平均和P能较好反映苗圃土壤肥力水平，而单株苗木生物量是体现苗圃土壤肥力水平的适宜生物指标。

The soil fertility of Heyuan Central Nursery in Guangdong Province, which had 5 different sites coded A, B, C, D, E, was evaluated with modified Nemoro formula. The correlations between fertility coefficients and seedling growth were analyzed. Soil texture, bulk density, pH, organic matter, total N, available N, P and K were selected as main properties for the integrated quantitative evaluation of soil fertility. Results revealed that the soil fertility coefficient Pmean. of the 5 sites was between 1.06 and 2.48, the Pmin. was 0.03 -0.97 and the integrated coefficient p was between 0.66 and 1.65, with obvious differences existing in the 5 sites and different layers of each site. According to the evaluation result, the fertility of the surface layers （0 - 20 cm） of site A, B and D and the subsurface layer （20 - 40 cm） of site A was low and all other sites and layers was infertile. Significant positive correlations were found between height of broadleaved seedlings and soil fertility coefficients Pmean. and p. Single seedling biomass was observed to be significantly positively correlated to Pmean, Pmin. and p. Therefore, Pmean and p could be suitable coefficients of nursery soil fertility and seedling biomass could be a reasonable bio-index to evaluate soil fertility. [ Ch, 7 tab. 11 ref. ]