WTO是允許有一定的農業補貼的，美國也是符合規範的。這是我的research結果：

資料來源：

WTO Disciplines on U.S. Domestic Support for Agriculture

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

我將文章的核心內容摘錄於下，並試著加上中文翻譯。我不是學經濟的，有些詞句的翻譯可能不太準確，請原諒。

WTO Classification of Domestic Support

（WTO對境內補貼的分類）

The WTO uses a traffic light analogy to group programs.

（WTO以交通燈為類比給補貼措施分類）

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

（綠盒措施：不造成對貿易的扭曲或產生的影響極小，該類補貼沒有限製。）

** 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.

（藍盒措施：可能會造成市場扭曲但產量有限。補貼是基於固定的地區、產量或固定的牲畜數量，補貼額不超過基本產量的85%。基於此，該類補貼沒有限製。）

** 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：這是最為扭曲市場的補貼類別，有嚴格的累計年度花費限額，由綜合補貼量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：某些特定類型的進出口補貼和非關稅貿易壁壘。這些補貼措施沒有明確地包括在一國的WTO進程表中，亦未被WTO的合法文書所鑒別和接受。）

** 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：相對於特定產品或總產品的價值而言，補貼額足夠小 -- 對於發達國家是低於年產量價值的5%，對於發展中國家是低於年產量價值的10%。這類補貼被認為無害。）

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美國的農產品補貼，屬於Amber box programs類別，其AMS額度被限定為每年不超過191億美元。相比於美國的年度總農產品價值，這個額度是落在De minimis exemptions的比例範圍內的（即低於年產量價值的5%）。