Using Microbial Bioagents to Enhance the Nutritional Status of Annual Ryegrass

The challenge of today’s agriculture is to maintain stable production and at the same time improve soil conditions. Appropriate crop management can contribute to the increase of yields, nutritional status of plants, and below-ground biomass which consequently increases soil organic carbon (SOC). One promising approach to increase yield and reduce the use of synthetic fertilizers involves using plant growth-promoting microorganisms. The present study explores the possibility of applying microbial bioagents as a sustainable alternative to synthetic fertilizers in Italian ryegrass cultivation. Four microbial formulations, consisting of nitrogen-fixing bacteria, phosphate-solubilizing microorganisms, and beneficial fungi, were evaluated under full and reduced nitrogen fertilization regimes. The experiment consisted of the two levels of nitrogen fertilization, and the experimental treatments where four different microbial bioagents that were a combination of several different microorganisms were applied in four different application treatments (control (without microbial bioagents), in soil, on seed, and in soil and seed). The results indicate that by reducing mineral fertilization and using microbial bioagents we can achieve twice-as-high yields compared to the sole full mineral fertilization, significantly increasing the uptake of nutrients and SOC. The uptake of toxic trace elements also increased, however, all levels remained below permissible thresholds, ensuring feed safety. The findings highlight the potential of microbial bioagents to enhance soil health, improve plant nutrition, and increase ryegrass yields while reducing reliance on synthetic inputs, contributing to climate change mitigation through improved SOC storage, and presenting a pathway for sustainable agriculture.