基于Agro-IBIS模型的新疆农田生态系统净初级生产力时空动态及其对气候变化的响应模拟研究

为了系统地了解干旱区农田生态系统碳动态及其对气候变化的响应，笔者利用基于过程的新型全球动态植被模型(Agro-IBIS)模拟了1979—2009年间新疆农田生态系统净初级生产力(NPP)的时空变化，并通过相关性分析揭示农田NPP对不同气候因子和CO2浓度变化的响应。结果表明，在1979—2009年间，新疆农田NPP平均值为723.78 g C/(m2·a)，总碳储量约为237.15 Tg C，净农田生态系统碳交换量(NEE)年平均值为-63.36 g C/(m2·a)，并总体上呈碳汇特征。对新疆农田NPP的空间变化而言，除了在天山地区绿洲农田NPP出现较小幅度的减少外，总体变化呈逐步增加趋势。31年来，新疆农田年度NPP总量与年均气温的相关性比与降水量的相关性较高。说明以灌溉对新疆干旱区绿洲田生产力的影响远大于自然降水。经验证，Agro-IBIS模型对于新疆农田生态系统碳收支的模拟结果合理，可以为中国西北干旱区农田生态系统的固碳潜力的模拟预测和科学制定区域碳管理政策提供科学依据。

Net Primary Productivity of Farmland Ecosystem in Xinjiang: The Spatio-temporal Dynamics and Its Response to Climate Change Based on Agro-IBIS Model

To systematically understand the carbon dynamics of farmland ecosystem in arid area and its response to climate change, the authors simulated the spatio-temporal changes of net primary productivity (NPP) of farmland ecosystem in Xinjiang during 1979-2009 by using a new process-based dynamic global vegetation model (Agro-IBIS), and revealed the response of farmland NPP to the changes of different climatic factors and CO2 concentration through the correlation analysis. The results showed that: the average NPP of farmland in Xinjiang was 723.78 g C/(m2·a), while the average total carbon storage was 237.15 Tg C, the average annual net exchange of carbon in agroecosystem (NEE) was -63.36 g C/(m2·a), overall playing as carbon sink during 1979-2009. In terms of the spatial variation of farmland NPP in Xinjiang, the overall change showed a gradual increasing trend except for a slight decrease of NPP in oasis farmland of the Tianshan Mountains. In past 31 years, the correlation between total annual NPP and the average annual temperature was higher than that between it and the average annual precipitation in Xinjiang farmland, indicating that irrigation had much more effects than natural precipitation on oasis agricultural productivity in arid areas of Xinjiang. It was verified that the results of Agro-IBIS model were reasonable in simulation of the carbon budget of farmland ecosystem in Xinjiang, which could provide scientific basis for the simulation and prediction of potential carbon sequestration of farmland ecosystem in the arid area of northwestern China and the scientific formulation of regional carbon management policies.