Effect of combined application of fertilizer and bacillus subtilis on grain yield and fertilizer utilization efficiency of summer maize (Zea mays L.)

Objectives Bacillus subtilis can improve soil nutrients, soil structure and fertilizer utilization efficiency, and promote decomposition of organic matter, crop growth and yield. Better understanding the effects of combined application of bacillus subtilis and fertilizer on nutrient uptake and utilization, and yield of summer maize can provide theoretical basis for increasing fertilizers efficiency and reducing agricultural non-point source pollutions.

Methods A field experiment was conducted in 2016 and 2017 using a high yielding maize cultivar of Denghai605. The experiment consisted of 5 treatments: no N fertilizer (CK), urea (U), manure (M), manure plus bacillus subtilis (MB), and urea plus bacillus subtilis (NB). The attributes of yield and fertilizer utilization of summer maize under different fertilization modes were analyzed.

Results Among the treatments, MB treatment had the best effect. Compared with M treatment, yield increase of MB treatment was 20.2%, the accumulation of nitrogen, phosphorus and potassium was increased by 30.8%, 63.5% and 30.8%, respectively, the partial productivity of fertilizer was increased by 20.7% on average in two years. Compared with U treatment, yield increase of UB treatment was 2.55%, the accumulation of nitrogen, phosphorus and potassium was increased by 12.5%, 10.6% and 3.84%, the partial productivity of fertilizer was increased by 3.18% on average in two years. The economic benefit of MB treatment was 16.9% higher than that of M treatment, and that of UB treatment was almost the same as that of U treatment. The yield and efficiency improvement was mainly result from dry matter accumulation and nitrogen accumulation, especially during post-silking period. The effect of manure plus bacillus subtilis treatment was better than that of urea plus bacillus subtilis treatment.

Conclusions Combined application of bacillus subtilis and fertilizers increases the biomass and yield of summer maize, and improves the nutrient accumulation and utilization. On the basis of the application of nitrogen fertilizer, the appropriate dose of bacillus subtilis not only increases yield and efficiency, but also improves economic benefits of maize. Manure with bacillus subtilis is one of the important measures to increase the fertilizer efficiency of summer maize.