用地理知识解说：18亿亩耕地红线为什么是“生命线”
18亿亩≈1.2亿公顷，这不是简单数字，而是用中国地理格局、人口承载力、粮食安全算出来的底线。
从地形地貌看：我们能种地的地方本来就极少
中国山地+高原+丘陵占2/3，平原仅占12%，宜耕土地稀缺。
西北干旱、青藏高寒、南方多山，真正连片优质耕地集中在东北平原、华北平原、长江中下游平原。
18亿亩是能稳定养活中国人的最小耕地规模。
从人口与承载力看：人多地少的刚性矛盾
用世界7%耕地养活近20%人口，人均耕地远低于世界平均。
人口基数大、饮食结构升级（肉蛋奶），粮食需求刚性增长，耕地不能再少。
从气候与农业生产看：耕地是稳产的基础
季风气候雨热同期但水旱灾害频繁，必须靠连片、肥沃、有灌溉条件的耕地保产量。
18亿亩包含大量高标准农田，是对抗气候波动的“压舱石”。
从区域差异与粮食格局看：守住耕地就是守住供给
东北：商品粮核心区
华北：小麦主产区
长江流域：水稻主产区
任何区域耕地被侵占，都会打破全国粮食供需平衡。
从生态与国土安全看：耕地是不可替代的国土功能
耕地兼具生产、生态、防灾功能，过度侵占会加剧城市热岛、水土流失、地面沉降。
守住18亿亩，就是守住国土空间最优结构。
一句话地理总结
18亿亩耕地红线，是中国地理禀赋决定的“生存底线”——地不能再少，粮必须自给。
Using Geography to Explain Why the 1.8 Billion Mu Arable Land Red Line Is a "Life Line"
1.8 billion mu ≈ 120 million hectares. This is not just a number, but the bottom line calculated from China’s geographical structure, population carrying capacity, and food security.
From the perspective of topography: Land suitable for farming is extremely scarce.
Mountains, plateaus and hills account for two-thirds of China, while plains only make up 12%.
The northwest is arid, the Qinghai-Tibet region is frigid, and the south is mountainous. Truly contiguous high-quality arable land is concentrated in the Northeast Plain, North China Plain, and Middle-Lower Yangtze Plain.
1.8 billion mu is the minimum scale of arable land to stably feed the Chinese people.
From the perspective of population and carrying capacity: The rigid contradiction of more people and less land.
China feeds nearly 20% of the world’s population with only 7% of global arable land, and per capita arable land is far below the world average.
With a large population and upgraded diet (meat, eggs, milk), food demand grows rigidly, so arable land cannot be reduced further.
From the perspective of climate and agricultural production: Arable land is the foundation of stable yields.
The monsoon climate provides synchronous rain and heat but frequent floods and droughts. Stable yields rely on contiguous, fertile, irrigated arable land.
1.8 billion mu includes a large number of high-standard farmlands, which serve as a "stabilizer" against climate fluctuations.
From the perspective of regional differences and food patterns: Protecting arable land means protecting supply.
Northeast: core commercial grain base
North China: main wheat production area
Yangtze River Basin: main rice production area
Occupation of arable land in any region will break the national balance between food supply and demand.
From the perspective of ecology and territorial security: Arable land provides irreplaceable territorial functions.
Arable land has functions of production, ecology and disaster prevention. Excessive occupation will worsen urban heat island, soil erosion and land subsidence.
Protecting 1.8 billion mu means maintaining the optimal structure of territorial space.
Geographical Summary in One Sentence
The 1.8 billion mu arable land red line is the "survival bottom line" determined by China’s geographical endowment — no more loss of land, and food self-sufficiency is a must.
Key Terms
arable land 耕地
red line 红线
topography 地形地貌
monsoon climate 季风气候
high-standard farmland 高标准农田
geographical endowment 地理禀赋
food security 粮食安全
