王帅 张永发 任常琦 罗雪华 薛欣欣 赵春梅 马钧耀 耿建梅 王文斌

摘  要：橡胶园土壤中无机氮形态和含量呈现季节性的动态变化，本研究通过设置不同氮肥用量进行田间试验，分析早期施肥后橡胶园土壤中氮素运移规律。结果表明：不同施氮量土壤中矿质氮素的运移特点有所不同，但均以垂直运移为主;土壤中的铵态氮和硝态氮在不同层次的水平迁移主要在30 cm以内;各施肥处理土壤中铵态氮、硝态氮均存在明显的向下迁移，铵态氮主要迁移至40～60 cm深度，常规施肥、减量20%处理铵态氮含量分别达到209.43 mg/kg、133.32 mg/kg;硝态氮主要迁移至20～40 cm深度，常规施肥和减量20%硝态氮含量分别为127.21 mg/kg和114.29 mg/kg;不同施肥处理无机氮向下的迁移量也存在明显差异，减量40%施肥的无机氮在深层土壤中低于常规施肥和减量20%施肥处理，进一步减少了无机氮的向下淋溶损失;不同施肥处理土壤矿质氮的主要形式为铵态氮，施肥增加了硝态氮的占比，这可能与氮肥输入以及土壤pH有关。

关键词：橡胶林;施肥配比;铵态氮;硝态氮;水平方向;垂直方向

中图分类号：S794.1      文献标识码：A

Abstract： The form and content of inorganic nitrogen in rubber plantation showed seasonal dynamic changes. In this study， field experiments with different nitrogen application rates were conducted to study the transportation of nitrogen in rubber plantation after fertilization at the early stage. The transportation characteristics of mineral nitrogen were different with different nitrogen application rates， but vertical transportation was the main pathway. The horizontal transportation of ammonium nitrogen and nitrate nitrogen in soil at different levels was mainly within 30 cm. There was obvious downward transportation of ammonium and nitrate nitrogen in the soil under different fertilization treatments. Ammonium nitrogen was mainly transported to the depth of 40–60 cm， and the content of ammonium nitrogen reached 209.43 mg/kg in conventional fertilization and 133.32 mg/kg in 20% reduced fertilization， respectively. Nitrate nitrogen was mainly transported to 20–40 cm depth， and the nitrate nitrogen content of conventional and 20% reduced fertilization was 127.21 mg/kg and 114.29 mg/kg， respectively. There were also significant differences in the downward transportation of inorganic nitrogen under different fertilization treatments. The inorganic nitrogen under 40% reduced fertilization was lower in the deep soil than that under traditional fertilization and 20% reduced fertilization， which indicated further reducing of N leaching loss. The main form of soil mineral nitrogen under different fertilization treatments was ammonium nitrogen. Fertilization increased the proportion of nitrate nitrogen， which may be related to nitrogen fertilizer input and soil pH.

Keywords： rubber plantation; fertilization ratio; ammonium nitrogen; nitrate nitrogen; horizontal direction; vertical direction

DOI： 10.3969/j.issn.1000-2561.2021.12.018

橡膠树（Hevea brasiliensis）是一种重要的经济树种，是天然橡胶的主要来源。天然橡胶的种植对于国家工业发展、国防不可或缺。海南是我国主要的橡胶种植地区，橡胶种植总面积由20世纪50年代的1万hm2增加到目前的52.7万hm2，约占海南人工林面积的84%[1]。海南属于高温多雨的热带季风气候，土壤呈酸性，铁铝氧化物含量高，土壤高度风化，导致土壤肥力下降[2]。……