As president of the Howard G. Buffett Foundation, I am disappointed with the suggestion by Ken Giller, our partner in the nitrogen-fixation research programme N2 Africa, that the teaching of conservation agriculture in sub-Saharan Africa is “wholly misplaced” (Nature 483, 525–527; 2012).

Millions of growers, large and small, are reaping the benefits of no-tillage farming. It is one of the most cost-effective ways to protect and improve soil — a farmer's most precious asset. It builds soil fertility by increasing biological activity, reducing the need for fertilizers and minimizing their effects on the environment. It also reduces soil erosion, improves water quality, increases crop yields, helps to sequester carbon and reduces labour.

No-tillage farmers are growing crops on roughly 111 million hectares worldwide, including 70% of farmland in Brazil and Argentina. At Brazil's agricultural-research organization Embrapa, no-tillage farming is helping to unlock the agricultural potential of the vast Cerrado savannah, fuelling economic growth.

There are challenges in teaching new practices to smallholder farmers, and much work is needed to adapt no-tillage farming to Africa's diverse agroecological and socioeconomic environments. But with the proper research, training and capacity, it will be one of many tools African farmers need to increase productivity sustainably.