Grain quality of winter wheat in a cropping system without synthetic plant protection products and with reduced nitrogen fertilization

Synthetic plant protection products (SPs) can be important for high yields and qualities but also face criticism. A novel mineral-ecological cropping system (MECS) without SPs but with mineral fertilization aims to maintain high yields and quality while reducing pesticide use. This study investigated winter wheat (Triticum aestivum L.) quality in two locations over three seasons, comparing MECS with a conventional cropping system (ConvCS) with SPs and mineral fertilization, and an organic cropping system (OrgCS) without nitrogen fertilization. To account for a projected yield loss of 30% from omitting SPs, nitrogen fertilization was reduced in the MECS, but yield was only 16% lower. Nitrogen use efficiency was similar for ConvCS and MECS but higher in OrgCS compared to these systems. Thousand grain weight was increased or reduced for OrgCS and MECS compared to ConvCS, depending on the location. The concentration of Fusarium mycotoxins in the grains was low in all systems. Compared to the ConvCS, grain protein concentration, gluten concentration, and baking volume were markedly reduced (by 17%–28%) in the OrgCS and moderately (by 7%–13%) in the MECS. Grain iron and calcium concentrations were also reduced in the OrgCS (by 24% and 7%) and MECS (by 8% and 7%); iron concentration correlated positively with grain protein concentration. Overall, nitrogen-dependent quality traits were decreased in the MECS relative to ConvCS, indicating the need for increased nitrogen fertilization. Given the global importance of wheat, the results suggest that the MECS achieved good yields with similar quality compared to ConvCS, while considerably reducing the use of SPs and nitrogen fertilizer.