滇中高原农田生产力脆弱性时空格局及对气候因子的响应

Spatiotemporal patterns of farmland productivity vulnerability and its response to climate factors in the Central Yunnan Plateau

关键词:  农田生产力  脆弱性  时空变化  滇中高原

Key words:  farmland NPP  vulnerability  spatiotemporal variation  Central Yunnan Plateau

摘要:

了解农田生态系统脆弱性特征及其气候响应机制，对农业可持续发展具有重要指导意义。基于CASA（Carnegie-Ames-Stanford approach）模型估算1989—2019年滇中高原农田生产力，分析农田生产力时空演变格局及产能空间分布情况，探讨近30 a来农田生产力脆弱性变化特征；利用地理探测器方法探究农田生产力分布的气候驱动机制。结果表明：受气候变化和人类活动影响，近年来滇中高原农田生产力水平有所提升；脆弱性呈微度、轻度脆弱态势，水热条件的差异使脆弱性表现出四周高、中间低的空间分布；太阳辐射是影响农田生产力分布的主要因素，受自然条件、种植结构和干旱的影响，降水正逐步转变为影响农业生产的重要贡献因子。研究结果可为区域制定有效措施应对气候变化提供科学参考。

Abstract:

Background, aim, and scope Farmland ecosystems are crucial components of terrestrial ecosystems. Understanding the vulnerability characteristics of farmland ecosystems and their responses to climate change is vital for sustainable development of agriculture. The Central Yunnan Plateau, a traditional agricultural base in Yunnan Province, plays a significant role in the region’s agricultural economy. However, it is also an ecologically fragile area with low resistance to natural disasters. This study aims to investigate the spatiotemporal changes in the vulnerability of farmland productivity in the Central Yunnan Plateau and explore the underlying climate response mechanism. The findings have important implications for food security and the sustainable development of agriculture in the province. Materials and methods The CASA (Carnegie-Ames-Stanford approach) model was employed to estimate the farmland productivity in the Central Yunnan Plateau from 1989 to 2019. Then the spatiotemporal evolution pattern and spatial distribution of farmland productivity were analyzed, and the changes in vulnerability over the past three decades were examined. Additionally, the geographic detector methods were utilized to explore the climate-driven mechanism of farmland productivity distribution. Results From 1989 to 2019, the NPP value of farmland in the Central Yunnan Plateau fluctuated between 425.30 and 824.86 g·m−2·a−1 (calculated as C, the same below), with a multi-year average of 671.71 g·m⁻²·a⁻¹. Over 90% of farmland NPP exhibited a significant upward trend. The farmland production capacity in Yuxi City and Kunming City was relatively high, while that in the dry and hot valley areas of Chuxiong Prefecture and Qujing City was relatively low. The fragility of farmland productivity was mainly characterized by mild fragility, and the degree of fragility increased from 2010 to 2019 compared to the previous decade. The vulnerability of farmland in Yuxi City was the lowest, while that in Qujing City was the highest. The vulnerability of farmland in the southern part of Qujing City has intensified, while the vulnerability of farmland in the central part of Kunming City has eased. Discussion Due to favorable hydrothermal conditions and a conducive planting environment, the productivity level of farmland in the Central Yunnan Plateau was relatively high, with over 70% of the area categorized as medium to high productivity. Nearly 90% of farmland’s NPP shows a significant upward trend, and low-productivity farmland was mainly concentrated in the dry and hot valley areas due to terrain and climate conditions. Climate changes and human activities have further improved the productivity level of farmland in recent years. The vulnerability of farmland in the Central Yunnan Plateau weakened from the southern part of Kunming to the center in 1989—1999 and then intensified from the center to the surrounding areas in 2010—2019. Overall, there was a negligible and mild vulnerability trend, indicating the system’s ability to resist external risks. The spatial distribution of farmland NPP on the Central Yunnan Plateau from 1989 to 2010 was primarily influenced by solar radiation, followed by annual precipitation and minimum temperature. From 2010 to 2019, precipitation became the main explanatory factor, followed by solar radiation and maximum temperature. The interaction between meteorological elements enhances the nonlinear explanatory power of individual factors on farmland NPP, with the greatest impact observed between solar radiation and other factors, followed by the combination of precipitation and other factors. Solar radiation was the primary influencing factor for agricultural production, followed by precipitation. Due to natural conditions, planting structure, and an increasing trend of drought in the Central Yunnan Plateau, agricultural activities have become more dependent on water resources, making precipitation an increasingly important factor affecting agricultural production. Conclusions Climate change and human activities have improved the productivity level of farmland in the Central Yunnan Plateau. The vulnerability showed a negligible and mild trend, with high vulnerability concentrated around the four sides and low vulnerability in the middle due to differences in water and thermal conditions. Solar radiation was the main factor influencing the distribution of agricultural productivity. Influenced by natural conditions, planting structures, and drought, precipitation was gradually becoming an important contributing factor affecting agricultural production. Recommendations and perspectives To mitigate the negative impact of drought and water scarcity on agriculture in the Central Yunnan Plateau, it is essential to develop appropriate irrigation areas, promote water-saving agricultural cultivation models, respond scientifically to climate change, actively promote agricultural modernization, and transform traditional agricultural systems into climate-adaptive agricultural systems.