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首页> 外文学位 >Modeling organic matter and nitrogen dynamics in integrated aquaculture/agriculture systems: Effects of cycling pathways on nitrogen retention and system productivity.
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Modeling organic matter and nitrogen dynamics in integrated aquaculture/agriculture systems: Effects of cycling pathways on nitrogen retention and system productivity.

机译：在水产养殖/农业综合系统中对有机物和氮动力学进行建模：循环路径对氮保留和系统生产力的影响。

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摘要

A computer model was developed to investigate the effects of organic matter and nitrogen cycling pathways on nitrogen retention and productivity in integrated aquaculture/agriculture systems and to identify the processes responsible for increased nitrogen retention in integrated systems. The model, developed using StellaTM modeling software, consists of a series of mass balance calculations for fish growth, phytoplankton biomass, dissolved oxygen, pond and terrestrial soil organic matter and nitrogen, and crop biomass growth. Solar radiation, temperature and wind speed are included in the model as driving variables. The model allowed for the simulation of sporadic water inflow and outflow that occur during harvest, irrigation and seepage. The model was calibrated using literature and measured data from the Pond Dynamics/Aquaculture Collaborative Research Support Program (PD/A CRSP) database. The model performance was evaluated using sensitivity analysis and model verification procedures that compared model simulations to measured data from three sites. Sensitivity analysis results suggest that priority areas for future research in integrated aquaculture/agriculture systems are stocking density effects, sediment processes and water management. Model verification results showed that the model performance was satisfactory with respect to fish growth, crop growth, nitrogen and organic matter simulations. However, the modeling of phytoplankton biomass was less satisfactory and the results suggested the need for more site-specific calibration of exogenous factors. A modeling study designed to investigate the effects of different cycling pathways on nitrogen retention and productivity showed that the recycling of plant wastes to aquaculture ponds had a major effect in reducing system nitrogen losses and increasing system productivity. Sediment organic matter processes were identified as the major determinants of system nitrogen retention as measured by the nitrogen retention index. Results of the modeling study suggested that the system nitrogen status may be more important in determining the number and type of cycling pathways that should be incorporated in integrated aquaculture/agriculture systems. The long term behavior of the nitrogen retention index was similar to that observed in natural systems suggesting that the index could be a useful measure of system nitrogen retention and cycling in managed agroecosystems.
机译：开发了一个计算机模型，以研究有机物和氮循环路径对水产养殖/农业综合系统中氮保留和生产力的影响，并确定导致综合系统中氮保留增加的过程。使用StellaTM建模软件开发的模型包括一系列质量平衡计算，包括鱼类生长，浮游植物生物量，溶解氧，池塘和陆生土壤有机质和氮以及作物生物量的增长。模型中包括太阳辐射，温度和风速作为驱动变量。该模型可以模拟在收获，灌溉和渗漏过程中发生的零星水流入和流出。使用文献和池塘动态/水产养殖合作研究支持计划（PD / A CRSP）数据库中的测量数据对模型进行了校准。使用敏感性分析和模型验证程序评估模型性能，该程序将模型仿真与来自三个站点的测量数据进行比较。敏感性分析结果表明，未来水产养殖/农业综合系统研究的重点领域是种群密度影响，沉积过程和水管理。模型验证结果表明，在鱼类生长，作物生长，氮和有机质模拟方面，模型性能令人满意。然而，浮游植物生物量的建模并不令人满意，结果表明需要对外源性因子进行更多的位点特异性校准。旨在研究不同循环路径对氮保留和生产力影响的模型研究表明，将植物废物回收到水产养殖池中对减少系统氮损失和提高系统生产力具有重大影响。沉积物有机物过程被确定为通过氮保留指数测量的系统氮保留的主要决定因素。建模研究的结果表明，系统氮含量在确定应纳入水产养殖/农业综合系统的循环途径的数量和类型时可能更为重要。氮保留指数的长期行为与在自然系统中观察到的相似，这表明该指数可能是管理型农业生态系统中系统氮保留和循环的有用度量。

著录项

  • 作者

    Jamu, Daniel Matthews.;

  • 作者单位

    University of California, Davis.;

  • 授予单位 University of California, Davis.;
  • 学科 Biology Ecology.; Agriculture Fisheries and Aquaculture.
  • 学位 Ph.D.
  • 年度 1998
  • 页码 297 p.
  • 总页数 297
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 生态学（生物生态学）;水产、渔业;
  • 关键词

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