Effect of slow-release nitrogen fertilizer on the vertical distribution of root and soil nutrients in the middle and later stage of wheat

Background

Nitrogen (N) input is crucial for increasing soil nutrients and improving crop root architecture. Slow-release N fertilizer has been expected to regulate soil nutrient supply in the middle and later growth stage of wheat, but its effect on root architecture and soil nutrients and their interactions remains unclear.

Methods and aims

The self-made root canal-soil column system was used to investigate the effects of sulfur-coated urea (SCU), urea (U) and compound fertilizer (CF) on the vertical distribution of wheat root and soil nutrients.

Results

The vertical distributions of root length, length density and dry weight in 0 − 90 cm soil layer increased first and then decreased after booting. Compared with U and CF treatment, SCU treatment increased the total root length by 26.16% and 29.60%, and increased the total root dry weight by 24.24% and 38.05% at the maturity stage, respectively. The dry weight per unit length in 40 − 90 cm soil layer in SCU treatment was higher than that in U (+ 17.23%) and CF (+ 11.85%) treatment. SCU treatment significantly increased the alkali-hydrolyzed N content in 0 − 40 cm soil layer at the maturity stage, but showed no significant difference in 40 − 90 cm soil layer with U and CF treatment.

Conclusions

SCU application was conducive to the synergism of soil alkali-hydrolyzed N content and root distribution, which not only increased N supply in topsoil and avoided N leaching into deep soil, but also increased the root growth, contributing greatly to delaying root senescence in the later growth stage and improving grain yield.