Integrating plant growth microorganisms in potato farming reduce soil CO2 emissions and improve crop quality

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AbstractCurrent horticultural practices typically require high demands of fertilizers, leading to significant environmental impacts and increased production costs. Alternatives based on microbial inoculants have garnered considerable interest owing to their potential to enhance soil quality whilst reducing external inputs and costs, all without compromising productivity. This study aimed to compare the impact of four fertilizer application strategies, including mineral fertilizers and microbial inoculants, on crop yield, soil fertility and functionality and soil greenhouse gas emissions in potato production in Southern Spain. Four treatments were tested: (i) mineral fertilizers added to meet the crop's nutritional needs (F100); (ii) a 50% reduction of the F100 rate (F50); (iii) a 50% reduction of the F100 rate combined with the application of a formulation containing nutrient‐solubilizing bacteria, nitrogen‐fixing bacteria and non‐mycorrhizal fungi (BAI+FU) and (iv) a 50% reduction of the F100 rate combined with a formulation of N, P and K solubilizing bacteria (BAII). Results showed that crop yield was unaffected by the different fertilizer application treatments. However, the mean tuber weight and firmness were significantly higher under the BAI+FU treatment, indicating improved product quality. CO2 release rates decreased by 25%, 34% and 42% with F50, BAI+FU and BAII treatments, respectively, compared with F100. The N2O and CH4 emissions or soil nutrient contents were not affected by treatments, except for ammonium content, which was highest under the BAI+FU treatment. Additionally, whilst overall soil bacterial and fungal abundance was not significantly affected, the BAI+FU treatment resulted in a higher number of nirK (denitrification) and cbbL (carbon fixation) gene copies. Therefore, combining biofertilizers with reduced chemical fertilizer rates could represent a sustainable strategy for mitigating climate change whilst enhancing crop quality in potato production.