Organic fertilizers’ usage enhances crop productivity and improves soil fertility and the surrounding environment in livestock complexes. The presented study assessed the effect of biofertilizers and poultry-based organic fertilizers on rhizospheric microbial diversity, yield attributes, and productivity of spring barley (Hordeum vulgare L.). Conducting field experiments started in 2021 in Northern Kazakhstan’s Southern carbonated chernozem of the steppe zone. Poultry manure application had three doses (5, 10, and 15 t ha^-1), while four types of biofertilizer of microbial origin consisted of Compo-MIX, Agro-MIX, Agrarka, and Trichodermin-KZ. The poultry-based organic manure resulted in the highest number of nitrogen-fixing bacteria. By treating seeds with biofertilizers, Agrarka and Trichodermin-KZ, the organotrophic bacteria dominated the barley rhizosphere. The seed treatment with Agro-MIX, Trichodermin-KZ, and organic fertilizer (at the rate of 5 and 10 t ha^-1) resulted in a predominance of nonsymbiotic nitrogen-fixing bacteria. Combined analysis of variance revealed that, on average, the organic and biofertilizers significantly increased plant viability, 1000-grain weight, and grain productivity. Combined application of poultry manure (10 t ha^-1) and biofertilizer Trichodermin-KZ gave the highest average values of grain productivity, i.e., 1,550 and 1,490 kg ha^-1 (15.5 and 14.9 quintal ha^-1), respectively.

Keywords: Spring barley (Hordeum vulgare L.), poultry manure, biofertilizers, nitrogen-fixing and organotrophic bacteria, yield components, grain yield

Key findings: The presented study authenticated the positive effects of applying organic manure and biofertilizer on the yield attributes of spring barley. Seed treatment with biofertilizers, Trichodermin-KZ and Agrarka, and poultry-based organic manure (10 t ha^-1) significantly improved barley growth and productivity. In general, all treatments with biofertilizers provided better yields than the control.