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目前全球性的氮沉降和施磷肥不断增加对森林土壤产生重要影响。藜蒴(Castanopsis fissa)是我国南方重要的用材树种之一,研究外源性氮和磷对藜蒴林土壤养分和生化特性的影响,可以为藜蒴人工林的可持续经营提供理论指导。针对广东省云勇林场一片立地条件相似的14年生黎蒴人工林进行为期2年的模拟氮和磷沉降,设置不施肥(对照)、施N肥、施P肥、施N+P肥4种处理,对应的氮和磷施用量分别为0,200 kg N,80 kg P and200 kg N+80 kg P(hm-2·a-1),每种处理有8个重复。结果表明,加N减少了土壤全P、全K和速效K含量,增加了土壤碱解N含量;加P提高了土壤有机质、全N、全P、速效P和速效K含量,减少了土壤全K含量;加N+P提高了土壤有机质、全N、全P、碱解N和速效P含量,减少了土壤全K含量。加N、加P和加N+P处理增加了土壤细菌、真菌数量及磷酸酶和过氧化氢酶活性。加P处理还增加了土壤放线菌数量及土壤脲酶活性,加N+P处理也提高了脲酶活性。
At present, the global nitrogen deposition and phosphorus application have an important impact on forest soils. Castanopsis fissa (Castanopsis fissa) is one of the important timber species in southern China. Studying the effects of exogenous nitrogen and phosphorus on the soil nutrient and biochemical characteristics of Castanopsis fargesii forest can provide theoretical guidance for the sustainable management of the plantation. A 14-year-old Li bolt plantation with similar site conditions in Yunyong Forest Farm of Guangdong Province was used to simulate nitrogen and phosphorus deposition for two years. Four non-fertilizer and control N fertilizers and four N + P fertilizers were applied. The corresponding nitrogen and phosphorus application rates were 0,200 kg N, 80 kg P and 200 kg N + 80 kg P (hm-2 · a-1) with 8 replicates for each treatment. The results showed that addition of N reduced soil total P, total K and available K content and increased soil alkaline N content; addition of P increased soil organic matter, total N, total P, available P and available K, and reduced total soil K content. Adding N + P increased soil organic matter, total N, total P, available N and available P, and decreased soil total K content. Adding N, P and N + P treatments increased soil bacteria, fungi and phosphatase and catalase activities. Adding P also increased the amount of soil actinomycetes and soil urease activity, plus N + P treatment also increased urease activity.