The effects of straw mulching combined with nitrogen applications on the root distributions and nitrogen utilization efficiency of summer maize

Field experiments were conducted to evaluate how different straw mulching modes combined with nitrogen (N) fertilization affect root distributions and N utilization efficiency of summer maize. Four N rates—no (N0), low (N1), medium (N2), and high (N3)—were combined with surface straw mulching (Treatment B) and deeply buried straw mulching (Treatment S), with traditional cultivation as control (CK). Treatment S significantly promoted deep root growth, and root length density (RLD) increased with N rate; SN2 and SN3 increased average RLD in >40 cm soil layers by 67.5% and 68.1%, respectively. Treatment B significantly increased RLD only in 0–30 cm layers. With increasing N, yield responses under B were not significant (BN3 +0.4%), whereas under S they first increased then decreased. In SN2, apparent recovery efficiency of N (REN), plant N uptake, and yield increased by 66.8%, 20.4%, and 9.3%, respectively. The rational tillage–fertilization model for the Hetao Irrigation District is deeply buried straw combined with medium N fertilizer.

Wan-feng Zhang, Shu-qing Yang, Ya-hong Jin, Peng Liu, Shuai Lou