主要的约束包括农业基础设施差，产品市场低效，信贷不足，土地贫瘠，劳动力市场不景气等。

Key constraints include poor physical infrastructure, inefficient product markets, lack of credit, and weak land and labor markets.

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但是这些农户们时刻面临着全球人口不断增加、土地过度耕种贫瘠、气候变化导致的严重干旱或洪涝灾害等巨大挑战。

They face challenges from an increasing population; land that's overfarmed and worn out; and climate change, bringing with it worsening drought or increased rainfall.

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