Many agricultural and environmental technologies require large upfront investments in exchange for longer-term benefits. This time profile of costs and benefits makes adoption particularly sensitive to liquidity and credit constraints, which are prevalent in low-income settings. We test the importance of these barriers to the adoption of an agricultural technique that helps reduce land degradation and restore soil fertility in Niger. We find little evidence that liquidity or credit constraints deter adoption. Instead, providing farmers with training increases the share of adopters by over 90 percentage points, while adding conditional or unconditional cash transfers has no additional effect. Adoption increases agricultural output, reduces land turnover and leads to adoption spillovers up to three years after treatment. These results imply that training can be a cost-effective and scalable means of promoting the adoption of profitable technologies.