Ammonia Volatilization from Soil-Applied Organic Fertilizers

ABSTRACT: A reliable quantification of nitrogen (N) losses by ammonia (NH3) volatilization can contribute to identifying optimized strategies of fertilizer management. The objective of this study was to quantify ammonia volatilization from several organic N sources incorporated into or applied onto the soil surface. Two cultivation areas, under snap bean and corn, were evaluated at Embrapa Agrobiology, Seropédica, Rio de Janeiro (RJ). Both experiments used a randomized complete block design in split-plots, with four replications. The main plots consisted of four organic fertilizers (castor bean cake, bokashi, legume fertilizers, cattle manure), at rates of 200 kg ha-1 N, and a control treatment (without fertilization), and the subplots corresponded to the management forms (incorporated or surface-applied) of the fertilizers. In the first experiment, snap bean cv. Novirex was grown in winter/spring and in the second, corn cv. Catingueiro in summer/autumn. In each subplot, static semi-open NH3 collectors were installed. We conclude that surface-applied castor cake was the organic fertilizer with highest N loss by NH3 volatilization. A comparison of the management systems (incorporated or surface-applied) showed that volatilization from organic fertilizers incorporated into the soil was significantly lower, with a reduction of 80 % for castor cake, of 78 % for bokashi and 67 % for legume fertilizer. Nitrogen loss through ammonia volatilization varied, from rates of 3 to 25 % in winter/spring and from 2 to 38 % in summer/autumn, according to the organic fertilizer applied. The period required to recover 95 % of the N lost by NH3-N volatilization was between 13 to 18 days for castor cake; 14 to 43 days for bokashi; 17 to 49 days for legume fertilizer and more than 43 days for cattle manure.

摘要：可靠量化氨（NH₃）挥发导致的氮（N）损失，有助于筛选优化的肥料管理策略。本研究旨在量化施入土壤或表施于土壤表面的多种有机氮源的氨挥发损失。试验在里约热内卢州塞罗佩迪卡市的巴西农牧业研究公司农业生物研究所（Embrapa Agrobiology）开展，分别设置菜豆和玉米两个种植区。两项试验均采用裂区随机完全区组设计，设置4次重复：主区包含4种有机肥料（蓖麻饼肥、bokashi有机肥、豆科肥料、牛粪肥），施氮量为200 kg·ha⁻¹，另设不施肥对照处理；副区为肥料施用方式（翻入土壤或表施）。第一项试验种植冬春茬菜豆品种Novirex，第二项试验种植夏秋茬玉米品种Catingueiro。每个副区均安装静态半开放式氨（NH₃）收集器。研究结果表明，表施蓖麻饼肥的有机肥料氨挥发氮损失最高。对比两种施用方式发现，翻入土壤的有机肥料氨挥发损失显著更低：蓖麻饼肥挥发损失降低80%，bokashi有机肥降低78%，豆科肥料降低67%。不同有机肥料的氨挥发氮损失率因肥料种类而异，冬春季节为3%~25%，夏秋季节为2%~38%。氨挥发损失的氮中95%被收集所需的时间分别为：蓖麻饼肥13~18天，bokashi有机肥14~43天，豆科肥料17~49天，牛粪肥则超过43天。