摘要
本文针对我国北方干旱、半干旱地区草地植物生长的主要限制因子,即水分问题,提出草地植物生物量和土壤水分的常微分方程模型。模拟的目标是一个生长期中植被生物量和土壤水分的变化。在此基础上,推导出了以维持系统平衡为前提,使总收获量达到可能的最大值的最优收获理论方程。最后求取模型在特定的情形下的解并讨论其表征和特点。具体模型求解的结果表明:(1)给定退化草地,围栏保护完全不加利用不一定是最佳恢复途径;(2)存在着最优的收获力投入,使草地植物的收获量达到极大值。
Water is a common limiting factor for plant growth in the vast grassland in the arid and semi-arid northern China.A differential equation model for the plant-water system was constructed in this research which stresses the interaction and coupling effect between vegetation and water circulation.Two quantities,soil water content and plant biomass,were selected as state variables.The objective of the model is to describe the variation of the two quantities in a ty- pical grouth period(one year).Theory of optimal control was then applied to the differetial equation system to obtain the possible ma- ximum harvest with the system stability as the main constraint.
基金
本文为国家自然科学基金
中国科学院植被数量生态学开放实验室共同资助项目
关键词
草地植被
优化利用
数学模型
grassland
Vegetation
Optimal management
Mathematical model
Restoration ecology
