Nitrogen-rich fertilizers are an essential component of modern agriculture, helping to feed the growing human population and fuel the four-fold expansion of the population over the last century. However, the intensive use of these fertilizers has come at a high cost, with more than half of the nitrogen in fertilizers seeping into the air and water, leading to pollution, soil acidification, climate change, ozone depletion, and loss of biodiversity.
In a recent study published in the journal Nature, a group of international researchers outlined a dozen urgently-needed reforms for reducing nitrogen pollution from global croplands. The researchers, led by Baojing Gu, a professor at Zhejiang University, analyzed over 1,500 field observations from croplands around the world and identified 11 key measures to decrease nitrogen losses while still enhancing crop yields.
One such measure is crop rotation, where a variety of crops are planted on the same plot of land to optimize the flow of nutrients in the soil. Other measures include optimizing the use of fertilizers, implementing precision agriculture techniques, and increasing the use of nitrogen-fixing crops and legumes.
The benefits of reducing agricultural nitrogen pollution are estimated to be 25 times higher than the implementation costs, which are around $34 billion globally. However, the proposed measures may have a negative impact on the fight against climate change, as the reduction of carbon sequestration in ecosystems can slightly damage the climate.
To address this issue, the researchers suggest the implementation of a nitrogen-credit system, which would subsidize farmers who adopt advanced nitrogen management techniques. This system could be funded by taxing food consumers or enterprises that use farming for commercial food production, or by taxing polluting activities and products.
Overall, the researchers conclude that better management of nitrogen-rich fertilizers through a variety of measures can yield significant environmental and health benefits, but must also boost food production at the same time. While the upfront costs of these measures may be a challenge for small-holder farmers, the long-term benefits far outweigh the costs and are crucial for addressing the “grand challenge” of reducing nitrogen pollution from croplands.