WTO是允许有一定的农业补贴的，美国也是符合规范的。这是我的research结果：

资料来源：

WTO Disciplines on U.S. Domestic Support for Agriculture

https://fas.org/sgp/crs/misc/IF10983.pdf

我将文章的核心内容摘录于下，并试着加上中文翻译。我不是学经济的，有些词句的翻译可能不太准确，请原谅。

WTO Classification of Domestic Support

（WTO对境内补贴的分类）

The WTO uses a traffic light analogy to group programs.

（WTO以交通灯为类比给补贴措施分类）

** Green box programs are minimally or non-trade distorting and are not subject to any spending limits.

（绿盒措施：不造成对贸易的扭曲或产生的影响极小，该类补贴没有限制。）

** Blue box programs are described as market-distorting but production-limiting. Payments are based on either a fixed area or yield or a fixed number of livestock and are made on less than 85% of base production. As such, blue box programs are not subject to spending limits.

（蓝盒措施：可能会造成市场扭曲但产量有限。补贴是基于固定的地区、产量或固定的牲畜数量，补贴额不超过基本产量的85%。基于此，该类补贴没有限制。）

** Amber box programs are the most market-distorting programs and are subject to strict aggregate annual spending limits. They are cumulatively measured by the aggregate measure of support (AMS).

（琥珀盒措施：这是最为扭曲市场的补贴类别，有严格的累计年度花费限额，由综合补贴量AMS的累加而得。）

** Prohibited programs include certain types of export and import subsidies and non-tariff trade barriers that are not explicitly included in a country’s WTO schedule or identified and accepted in the WTO legal texts.

（禁止措施：某些特定类型的进出口补贴和非关税贸易壁垒。这些补贴措施没有明确地包括在一国的WTO进程表中，亦未被WTO的合法文书所鉴别和接受。）

** De minimis exemptions are spending that is sufficiently small (less than 5% of the value of production)—relative to either the value of a specific product or total production— to be deemed benign. 

（微量免除措施：相对于特定产品或总产品的价值而言，补贴额足够小 -- 对于发达国家是低于年产量价值的5%，对于发展中国家是低于年产量价值的10%。这类补贴被认为无害。）

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美国的农产品补贴，属于Amber box programs类别，其AMS额度被限定为每年不超过191亿美元。相比于美国的年度总农产品价值，这个额度是落在De minimis exemptions的比例范围内的（即低于年产量价值的5%）。