Fusarium species are important cereal pathogens that cause severe production losses to major cereal crops such as maize, rice, and wheat. However, the causal agents of Fusarium diseases on cereals have not been well documented because of the difficulty in species identification and the debates surrounding generic and species concepts. In this study, we used a citizen science initiative to investigate diseased cereal crops (maize, rice, wheat) from 250 locations, covering the major cereal-growing regions in China. A total of 2 020 Fusarium strains were isolated from 315 diseased samples. Employing multi-locus phylogeny and morphological features, the above strains were identified to 43 species, including eight novel species that are described in this paper. A world checklist of cereal-associated Fusarium species is provided, with 39 and 52 new records updated for the world and China, respectively. Notably, 56 % of samples collected in this study were observed to have co-infections of more than one Fusarium species, and the detailed associations are discussed. Following Koch’s postulates, 18 species were first confirmed as pathogens of maize stalk rot in this study. Furthermore, a high-confidence species tree was constructed in this study based on 1 001 homologous loci of 228 assembled genomes (40 genomes were sequenced and provided in this study), which supported the “narrow” generic concept of Fusarium (= Gibberella). This study represents one of the most comprehensive surveys of cereal Fusarium diseases to date. It significantly improves our understanding of the global diversity and distribution of cereal-associated Fusarium species, as well as largely clarifies the phylogenetic relationships within the genus.

Reactive nitrogen (Nr) emissions aggravate air and water pollution across the world.The factors influencing Nr emissions have not been clearly uncovered, especially for regions under rapid economic growth. Here we modeled total Nr emissions in mainland China and analyzed factors driving their growth during the decade (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) of fastest socioeconomic development. Results show that total Nr emissions increased from 24.9 terrogram (Tg) to 35.2 Tg, a 41.7% increase with an average annual growth rate of 3.5%. Agricultural activities, including crop planting and livestock and poultry breeding, together took a substantial but decreasing share, from 75.2% in 2000 to 61.4% in 2010. Industrial wastewater discharge, energy use, and crop production are the three largest sources contributing to the Nr emissions growth. Factors related to scale (e.g., the amount of industrial energy use) led to a growth in Nr emissions, and factors related to efficiency (e.g., industrial energy use per unit of economic output) contributed to reduction. The decreasing effect of efficiency gains, however, was still unable to overcome the increasing effect of the activity scale. More indepth research studies on mitigation strategies are required, to inform the decoupling between socioeconomic development and Nr emissions.

The continuous improvement of the Chinese people’s lifestyle and consumption level and the promotion of healthful and reasonable diets have created a greater demand for fruit production. There is an urgent to determine how to meet the increasing demand for fruit, with lower inputs and environmental costs, because the Chinese fruit production has excessive agricultural input and relatively high environmental burden of greenhouse gas (GHG) emissions. This study conducted a meta-analysis of the experimental results of 307 conventional management measures and 333 optimized management measures. We found that by taking appropriate optimization measures such as N reduction, coupling of water and fertilizer and increasing organic carbon, has not only the fruit yield increased by 16.1% (5 Mg ha −1 year −1 ) but also the GHG emissions of the entire orchard system have also been drastically reduced by 65.4%. Net GHG balance has decreased from 11.3 ± 0.3 to 3.9 ± 0.3 Mg of CO 2 equivalent (CO 2 e) ha −1 year −1 , and GHG intensity per unit product has decreased from 3.6 ± 0.1 to 1.1 ± 0.1 kg of CO 2 e kg −1 . The main sources of total GHG emissions are from upstream production and transportation, due to N fertilizer application, mechanical irrigation energy, and N-fertilizer-induced soil N 2 O emissions. Our results highlight that the Chinese fruit production system has a large room to reduce GHG emissions by applying the mentioned optimization measures in above, and our findings will provide some guidance for agricultural carbon peak.