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Introducing smart and sustainable tools for climate change adaptation and mitigation is a major need to support agriculture’s productivity potential. We assessed the effects of the processed gypsum seed dressing SOP® COCUS MAIZE+ (SCM), combined with a gradient of N fertilization rates (i.e. 0 %, 70 % equal to 160 kg N ha-1, and 100 % equal to 230 kg N ha-1) in maize (Zea mays L.), on: (i) grain yield, (ii) root length density (RLD) and diameter class length (DCL), (iii) biodiversity of soil bacteria and fungi, and (iv) Greenhouse Gases (GHGs, i.e. N2O, CO2, and CH4) emission. Grain yield increased with SCM by 1 Mg ha-1 (+8 %). The same occurred for overall RLD (+12 %) and DCL of very fine, fine, and medium root classes. At anthesis, soil microbial biodiversity was not affected by treatments, suggesting earlier plant-rhizosphere interactions. Soil GHGs showed that (i) the main driver of N losses as N2O is the N-fertilization level, and (ii) decreasing N-fertilization in maize from 100 % to 70 % decreased N2O emissions by 509 mg N-N2O m-2 y-1. Since maize grain yield under SCM with 70 % N-fertilization was similar to that under Control with 100 % N-fertilization, we concluded that under our experimental conditions SCM may be used for reducing N input (-30 %) and N2O emissions (-23 %), while contemporarily maintaining maize yield. Hence, SCM can be considered an available tool to improve agriculture’s alignment to the United Nation Sustainable Development Goals (UN SDGs) and to comply with Europe’s Farm to Fork strategy for reducing N-fertilizer inputs.

Organic and mineral fertilizers are important sources of ammonia (NH3) emissions from agricultural fields. The objectives of this study were (a) to evaluate how different cover crop (CC) residues (i.e., rye [Secale cereale L.], white mustard [Sinapis alba L.], and bare soil as control) in combination with different application methods of digestate (surface broadcast vs. shallow injection) affect NH3 volatilization before planting maize (Zea mays L.) and (b) to assess the residual effect of previous CCs on NH3 volatilization after urea top‐dress application at the V5‐V6 phonological stage of maize. Ammonia volatilization was measured using semi‐static chambers for 14 d (335 h) after planting and for 6 d (150 h) at the V5‐V6 stage. Overall, NH3 emissions decreased by 67–77% with digestate injection compared with surface broadcasting. However, the reduction in NH3 volatilization using the injection method was significantly lower with mustard residue (6.72 kg NH3–N ha–1) than with rye residue (14.15 kg NH3–N ha–1), which allowed for more volatilization by increasing the exposure of digestate to the air. Broadcast digestate method did not affect the cumulative NH3–N losses obtained with different CC types. After urea top‐dressing at the V5‐V6 stage of maize, the cumulative losses of NH3 (during 150 h) were 2.99 kg NH3–N ha–1 with rye as previous CC and 2.49 kg NH3–N ha–1 with mustard. Our study shows that digestate injection before maize planting and urea top‐dressing application followed immediately by irrigation (15 mm) could be considered as useful strategies to mitigate NH3 volatilization and increase N use efficiency in maize.