Effects of Land Use on Nitrous Oxide and Nitric Oxide Emission from Soils of a Tropical Rainforest Region

该项目是为完成和扩大目前的N2O和热带牧场和森林的无通量所做的额外努力。该项目的目标是：1)。在一个年度周期内，衡量哥斯达黎加低地热带地区常见土地利用类型的N2O和NO通量，这些土地利用类型代表典型的土地利用周期：原生林、由这些森林形成的活跃牧场、废弃牧场和来自废弃牧场的次生林；将实地试验与目标1中的实地测量相结合，以确定控制这些通量速率的因素的重要性。对于额外的研究期，项目团队将1)。完成土地利用地块的年度循环，2)。对该地区其他土壤和土地利用类型的通量进行探索性测量，以扩大推广结果的能力；3)进行实验室和野外实验，这些实验都受到了我们之前的发现的启发。这些实验包括森林地点的暴雨模拟，以确定这些系统气体通量短期时间动态的原因，以及牧场地点的施肥实验，以确定这些系统与森林相比氮氧化物排放量较低的原因。

This project represents additional effort for completion and extension of current N2O and NO flux from tropical pastures and forests. The objectives of the project are: 1). to measure, over an annual cycle, N2O and NO flux from common land use types in lowland tropical Costa Rica representing a typical cycle of land usage: primary forests, active pastures created from these forests, abandoned pastures and secondary forests derived from abandoned pastures, and 2). to combine field experiments with the field measurements in objective 1 for determination of the importance of factors controlling the rates of these fluxes. For the additional period of research the project team will 1). complete the annual cycle on the land use plots, 2). make exploratory measurements of flux rates from other soil and land use types in the area to extend the ability to generalize results, and 3). carry out laboratory and field experiments that have been stimulated by earlier our findings. These experiments include rain storm simulations in forest sites to determination the causes for short-term time dynamics in gas flux from these systems, and fertilization experiments in pasture sites to determine the causes for lower rates of nitrogen oxide emissions in those systems compared with the forests.