Researchers of the Chinese Academy of Sciences (CAS) have found a promising approach to reducing fertilizer nitrogen loss in China’s black soil region. The study, published in the journal Agriculture, Ecosystems & Environment, investigated the effects of no-tillage farming combined with straw mulching.

Chemical fertilizers are crucial for boosting crop yields, but their overuse can lead to environmental problems. Nitrogen, a key component of these fertilizers, can leach into groundwater, causing pollution.

The researchers, from the Chinese Academy of Sciences' Institute of Applied Ecology, used a technique called nitrogen (15N) isotope tracing to track nitrogen movement in a three-year field experiment. Their findings revealed a critical depth for nitrate leaching loss in the black soil. While 99% of crop roots stay within the top 120 cm soil layer, a significant portion (up to 7%) of fertilizer nitrogen leaches deeper as nitrate, becoming unavailable to plants and contributing to losses.

The study showed that no-tillage with straw mulching offers a potential solution. This technique significantly improves nitrogen use efficiency and crop yields. Compared to traditional ridge tilling, it reduces the conversion of fertilizer nitrogen into mineral nitrogen, a readily leachable form of nitrogen, by an average of 36%. Additionally, it slows down the downward movement of fertilizer nitrogen, leading to up to 43% less leaching loss.

The research suggests that no-tillage with 33% or 100% straw mulching is most effective in Northeast China's black soil region. This approach not only maximizes fertilizer nitrogen use but also boosts crop yields and minimizes nitrate leaching losses compared to both 67% mulching and no-tillage without straw mulching.

These findings offer valuable insights for promoting sustainable agricultural practices in China's black soil region.

YUE Qian

Institute of Applied Ecology, Chinese Academy of Sciences

Tel: 86-24-83970317

E-mail: yueqian@iae.ac.cn

Web: http://english.iae.cas.cn