多情景粮食安全底线约束下的中国耕地保护弹性空间

China’s resilience-space for cultivated land protection under the restraint of multi-scenario food security bottom line

科学解析中国耕地数量保多少与如何保等问题对保障国家粮食安全与资源环境可持续发展具有重要意义。面向共享社会经济路径(SSPs)的多情景粮食安全底线约束,本文试图利用耕地保有量、人口预测、粮食需求估算、单产提升潜力衰减等模型方法,依据产能特征—健康状态—耕作条件—利用水平的多维度耕地保护紧迫性评估框架,通过耦合时间序列的数量边界控制与空间尺度的区域规则约束刻画出中国的耕地保护弹性空间。在满足个人基本营养安全与作物单产条件干扰变量恒定的假设前提下,研究发现:(1)中国多情景耕地保有量在2020—2100年间呈下降态势,现有耕地数量足以维持长期的粮食安全,但短期内则仅勉强达到理论粮食安全的临界区间1.40×10^(8)~1.59×10^(8)hm^(2)。(2)不同维度耕地保护紧迫性在九大农业区划内呈现差异化分布特征,自然条件优越且适宜耕作的黄淮海平原区与长江中下游地区是综合紧迫性高值地块集聚区域。(3)可持续情景与区域冲突情景分别代表粮食安全底线约束下的最小与最大耕地保有量情景,在当前国际形势下,中国应保证短期(2035年内)可休耕量不高于9.29%。(4)基于时空耦合划定的耕地保护弹性空间可分为优先保护、严格管控、休养生息、战略储备、整治修复和特殊保护6类,不同空间的耕地保护弹性强度、目标与任务各有侧重。整体而言,耕地保护弹性空间的划定思路有助于农业结构调整、休耕政策完善等耕地空间规划体系构建,对中国耕地保护制度转型具有借鉴价值。

Under new international and domestic situations,scientific analysis of China’s cultivated land quantity and its protection ways is of great significance for ensuring national food security and sustainable resources and environment development.This paper analyzes the amount of cultivated land under the constraints of multi-scenario food security within shared social-economic paths(SSPs),using model methods such as cultivated land retention,population forecast,food demand estimation,and yield potential decay.According to the multidimensional urgency assessment framework based on productivity characteristics-health statusfarming,China’s resilience-space for cultivated land protection is delineated by coupling the quantitative boundary control of time series and the regional rules of spatial scale.On the premise of satisfying the assumption of individual basic nutrition security and the constant variables of crop yield conditions,we obtain the following findings.(1)China’s multi-scenario cultivated land retention will decline from 2020 to 2100.Existing cultivated land is sufficient to maintain long-term food security,but it barely reaches the critical range of theoretical food security(140 million-159 million hm^(2))in the short term.(2)The urgency of cultivated land protection in different dimensions presents different distribution characteristics within the nine agricultural zones.The North China Plain and the Middle-lower Yangtze River,which have superior natural conditions suitable for farming,are clusters of high-value plots of comprehensive urgency.(3)The sustainable scenario(SSP1)and the regional conflict scenario(SSP3)represent the minimum and maximum cultivated land retention scenarios under the constraints of food security bottom line.Given the current international situation,China should ensure that the short-term(before 2035)fallow land is not higher than 9.29%.(4)The resilience-space of cultivated land protection delineated based on time and space coupling can be divided into priority protection area,strict control area,rest area,strategic reserve area,comprehensive consolidation area,and special protection area.The flexibility,objectives and tasks of cultivated land protection in different divisions have their priorities.Overall,delineating resilience-space for cultivated land protection facilitates the establishment of spatial planning systems for cultivated land,such as agricultural structure adjustment and fallow policy improvement.This study provide a reference for research on the transformation of China’s cultivated land protection system.