Optimising the root traits of summer maize to improve nutrient uptake and utilisation through rational application of urea ammonium nitrate solution

The production of summer maize is greatly affected by nitrogen (N) sources through regulating root growth and distribution. Four N treatments in the field experiment were designed as UAN (urea ammonium nitrate solution was applied under traditional side-dressing method), urea (urea was applied under traditional side-dressing method), UWFI (UAN was applied underwater and fertiliser integration technology) and CK (no N applied). The results showed that the root length density, surface area density and volume of DH605 (mid-late hybrid) and DH518 (mid-early hybrid) under UWFI were higher than other treatments, especially in shallow layers. The root absorption area of each soil layer under N application treatments varied with the growth stage. The grain yield and the accumulations of N, P and K in the shoots showed the trend of UWFI > UAN > urea > CK. Compared with UAN and urea, the nitrogen agronomic efficiency of UWFI treatment increased by 40.5 similar to 78.6%, and the nitrogen partial factor productivity increased by 4.75 similar to 7.61%. Consequently, rational application of UAN would improve root traits, nutrient uptake and utilisation, and yield of summer maize.

Automated summary

The production of summer maize is significantly influenced by nitrogen sources, which affect root growth and distribution. Applying urea ammonium nitrate solution underwater and using fertiliser integration technology can improve root traits and nutrient uptake in summer maize, leading to higher grain yield. Rational application of this method increases nitrogen agronomic efficiency and nitrogen partial factor productivity.