准确评估草地生态系统固碳速率、提升其碳汇能力对于深入认识国家尺度陆地生态系统碳源汇特征及其固碳潜力具有重要意义。通过梳理文献,本文总结了我国草地碳汇大小、空间格局及其未来趋势,并提出了提升草地碳汇的可能途径。结果发现,...准确评估草地生态系统固碳速率、提升其碳汇能力对于深入认识国家尺度陆地生态系统碳源汇特征及其固碳潜力具有重要意义。通过梳理文献,本文总结了我国草地碳汇大小、空间格局及其未来趋势,并提出了提升草地碳汇的可能途径。结果发现,不同研究对我国草地碳源汇特征的估算差异较大,大小介于-3.4~17.6 Tg C year^(-1)(1 Tg=10^(12)g),中值为13.0 Tg C year^(-1)。模型预测未来全球变化背景下我国草地碳汇呈增加趋势,由1970s—2010s的12.8 Tg C year^(-1)(不同研究结果的范围:-3.6~18.0 Tg C year^(-1))增加至2050s的29.0 Tg C year^(-1)(10.3~50.0 Tg C year^(-1))。通过构建退化草地恢复技术体系、加强重大生态工程、自然保护区和人工草地建设、利用碳汇植物提升荒漠化草地碳汇、以及实施有效的生态奖补政策等手段,有望进一步提升草地固碳能力。未来亟需在草地碳通量长期联网观测、碳循环关键过程对全球变化响应和反馈机制、数据—模型融合等方面加强研究,以降低草地碳汇估算中的不确定性。此外,还需加强草地退化和恢复过程中碳循环观测和模拟研究,从而针对性地恢复退化草地碳汇功能,为我国实现“碳中和”国家战略目标提供科技支撑。展开更多
Drought is one of the main factors limiting the agricultural planting and production;gravel mulching is an effective inhibiting evaporation and water-saving planting pattern in the arid regions. In this study, experim...Drought is one of the main factors limiting the agricultural planting and production;gravel mulching is an effective inhibiting evaporation and water-saving planting pattern in the arid regions. In this study, experiments were conducted to study soil moisture effect and regression model with different gravel mulching, the soil moisture content and evaporation were compared that gravel mulched with different particle sizes, different thickness layer and different mulched years. The results showed that: 1) The cumulative soil evaporation of gravel mulched was only 29.3% of that bare fields. Mulching gravel could significantly reduce soil moisture evaporation. 2) The effects of inhibiting soil moisture evaporation are the best when mulch gravel thickness is 10 - 15 cm. 3) The particle size of gravel mulched is smaller, the evaporation inhibition effect will be better. Considering the water holding capacity and material economy, it is the most suitable to mulch gravel with the particle size of 3 - 5 cm. 4) Mulching gravel on the soil surface for 1 - 3 years can improve the soil moisture content. However, the gravel was mulched for more than five years, the soil moisture content decreased significantly. 5) The quadratic polynomial regression fitting model can better simulate and predict the cumulative evaporation on different gravel mulched, and the regression fitting degree R<sup>2</sup> is more than 0.98.展开更多
文摘草地是不可或缺的自然资源,但关于我国草地面积到底有多大存在很大争议.本文主要利用植被分布与降水之间的相关关系来探讨我国草地的分布和面积.归一化植被指数(NDVI)数据能够很好地反映植被的覆盖状况,与降水之间也存在良好的相关关系,因此可以通过建立已知草原地区的降水与NDVI的关系来反演草地的分布和面积.利用此方法及与遥感数据相匹配的过去30年(1982~2011年)的平均降水量数据,估算得到我国的草地总面积约为293×104 km2.将研究期间的降水数据每5年求其平均,估算得到我国草地面积的年际变化并不显著,变动于290×104~295×104 km2.
文摘准确评估草地生态系统固碳速率、提升其碳汇能力对于深入认识国家尺度陆地生态系统碳源汇特征及其固碳潜力具有重要意义。通过梳理文献,本文总结了我国草地碳汇大小、空间格局及其未来趋势,并提出了提升草地碳汇的可能途径。结果发现,不同研究对我国草地碳源汇特征的估算差异较大,大小介于-3.4~17.6 Tg C year^(-1)(1 Tg=10^(12)g),中值为13.0 Tg C year^(-1)。模型预测未来全球变化背景下我国草地碳汇呈增加趋势,由1970s—2010s的12.8 Tg C year^(-1)(不同研究结果的范围:-3.6~18.0 Tg C year^(-1))增加至2050s的29.0 Tg C year^(-1)(10.3~50.0 Tg C year^(-1))。通过构建退化草地恢复技术体系、加强重大生态工程、自然保护区和人工草地建设、利用碳汇植物提升荒漠化草地碳汇、以及实施有效的生态奖补政策等手段,有望进一步提升草地固碳能力。未来亟需在草地碳通量长期联网观测、碳循环关键过程对全球变化响应和反馈机制、数据—模型融合等方面加强研究,以降低草地碳汇估算中的不确定性。此外,还需加强草地退化和恢复过程中碳循环观测和模拟研究,从而针对性地恢复退化草地碳汇功能,为我国实现“碳中和”国家战略目标提供科技支撑。
文摘Drought is one of the main factors limiting the agricultural planting and production;gravel mulching is an effective inhibiting evaporation and water-saving planting pattern in the arid regions. In this study, experiments were conducted to study soil moisture effect and regression model with different gravel mulching, the soil moisture content and evaporation were compared that gravel mulched with different particle sizes, different thickness layer and different mulched years. The results showed that: 1) The cumulative soil evaporation of gravel mulched was only 29.3% of that bare fields. Mulching gravel could significantly reduce soil moisture evaporation. 2) The effects of inhibiting soil moisture evaporation are the best when mulch gravel thickness is 10 - 15 cm. 3) The particle size of gravel mulched is smaller, the evaporation inhibition effect will be better. Considering the water holding capacity and material economy, it is the most suitable to mulch gravel with the particle size of 3 - 5 cm. 4) Mulching gravel on the soil surface for 1 - 3 years can improve the soil moisture content. However, the gravel was mulched for more than five years, the soil moisture content decreased significantly. 5) The quadratic polynomial regression fitting model can better simulate and predict the cumulative evaporation on different gravel mulched, and the regression fitting degree R<sup>2</sup> is more than 0.98.
