Cropping system design can improve nitrogen use efficiency in intensively managed agriculture

• Published in: Environmental pollution (1987) 2021-07, Vol.280, p.116967-116967, Article 116967
• Main Authors: Zhang, Chong, Rees, Robert M., Ju, Xiaotang
• Format: Article
• Language: English
• Subjects: 15N labelling; Cropping system design; Fate of fertilizer N; Fertilizer nitrogen use efficiency (FNUE); Groundwater use efficiency; Intensive agriculture
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2021.116967

New agronomic and management approaches are urgently required to meet the challenges of improving resource use efficiency and crop yields in intensive agricultural systems. Here we report the fertilizer N use efficiency (FNUE), fate of fertilizer N and N budgets in newly designed cropping systems as compared with conventional winter wheat-summer maize double cropping (Con. W/M) in the North China Plain. A15N labelling approach was used to quantify FNUE by these new cropping systems which included optimized winter wheat-summer maize (Opt. W/M) with two harvests in one year; winter wheat/summer maize-spring maize (W/M-M) and winter wheat/summer soybean-spring maize (W/S-M) with three harvests in two years, and spring maize (M) with one harvest in one year. The results showed that only 18–20% of fertilizer N was recovered by crops in Con. W/M. Although Opt. W/M significantly increased FNUE to 33%–35% with increased crop yields, it consumed as much groundwater as Con. W/M. The W/M-M, W/S-M and M significantly increased FNUE to 27%–44% and reduced groundwater use and fertilizer N losses when compared to Con. W/M. The W/M-M achieved a comparable grain yield, but W/S-M and M had significantly lower grain yields when compared to Con. W/M. However, grain N harvest in W/S-M was comparable with Con. W/M due to higher grain N content in soybean. Post-anthesis fertilizer N uptake provided little contribution to total N uptake, and accounted for 5%, 12%, 7% and 2% of the average N uptake for winter wheat, spring maize, summer maize and summer soybean, respectively. When taking the second crop into account, Con. W/M recovered 27% of fertilizer N, while it increased to 36%–50% under the new cropping systems. We conclude that W/M-M and W/S-M will deliver significant improvements in the environmental footprints and sustainability of intensively managed cropping systems in the North China Plain. [Display omitted] •Conventional winter wheat-summer maize had a low N and water use efficiency and high fertilizer N losses.•Optimized winter wheat-summer maize increased grain yield and fertilizer N use efficiency but consumed large groundwater.•Post-anthesis fertilizer N uptake made little contribution to total crop N, even fertilizer was applied in later growth stage.•Winter wheat/summer maize (or soybean)-spring maize are alternative cropping systems for sustainable crop production.