Productivity and Nitrogen Use of Ancient and Modern Barley Genotypes Under Different Tillage Systems and Nitrogen Nutrition Strategies

Conservation tillage and microbial nitrogen fertilisation are increasingly recognised as important components of sustainable cereal production. However, their combined effects on ancient barley remain insufficiently investigated, and little is known about the genotype-specific responses of ancient and modern barley to contrasting tillage systems and nitrogen nutrition strategies under different hydrothermal conditions. This study investigated genotype-specific responses of Hordeum vulgare var. rimpaui (ancient barley) and H. vulgare (common barley) to ploughing, reduced tillage, and strip-till in combination with mineral or microbial nitrogen fertilisation. The responses of both barley genotypes were strongly influenced by agronomic management and seasonal weather conditions, although the response patterns differed. Mineral nitrogen fertilisation enhanced vegetative growth and nitrogen uptake, whereas inoculation with Methylobacterium symbioticum was associated with improved nitrogen utilisation and assimilate partitioning. In ancient barley, microbial fertilisation increased thousand-grain weight and harvest index, whereas in common barley it resulted in the highest grain yield, harvest index, and nitrogen harvest index. Under the favourable hydrothermal conditions encountered in the study, conventional ploughing produced the highest grain yields—5.88 t ha−1 for H. vulgare var. rimpaui and 9.58 t ha−1 for H. vulgare—along with greater biomass production and nitrogen uptake. Strip-till improved nitrogen utilisation efficiency, whereas both conservation tillage systems increased the harvest index and nitrogen harvest index of ancient barley. Under less favourable conditions, strip-till tended to increase grain yield in both genotypes. These findings suggest that the relative performance of ploughing and strip-till depended on the prevailing hydrothermal conditions. During favourable growing seasons, conventional ploughing supported greater biomass production and grain yield, whereas under less favourable conditions, strip-till tended to improve grain yield and nitrogen utilisation. Microbial fertilisation may further enhance nitrogen utilisation and assimilate partitioning, although the magnitude and nature of the response are genotype-specific.