| Field plot experiments were employed to investigate fertilization mechanisms with the technique of whole plastic-film mulching overlying soil and bunch planting (WFM) on dry-land wheat. The results showed that with annual rainfall became increased from 350 mm to 600 mm, the N, P, and K optimal fertilizing amounts of WFM were increased from 103.2 to 181.3 kg·hm-2 (N), 70.3 to 134.1 kg·hm-2 (P2O5) and 32.4 to 73.0 kg·hm-2 (K2O), respectively. The N, P, and K maximal fertilizing amounts of WFM were increased from 113.2 to 214.4 kg·hm-2 (N), 76.1 to 153.0 kg·hm-2 (P2O5) and 40.1 to 88.0 kg·hm-2 (K2O), respectively. The fertilizer use rates and efficiencies of WFM were improved significantly with the increased rainfall, which led the average N, P, and K fertilizer use rates elevated from 26.4%, 17.0%, and 20.2% to 32.8%, 22.6% and 26.8%, respectively, and the average N, P, and K fertilizer use efficiencies escalated from 8.8 kg·kg-1, 17.2 kg·kg-1, and 7.0 kg·kg-1 to 10.9 kg·kg-1, 22.9 kg·kg-1 and 9.3 kg·kg-1, respectively. The results showed that the fertilizer use rates and use efficiencies of WFM became decreased remarkably with the increased fertilization levels, which led the average N, P, and K fertilizer use rates dropped from 37.1%, 25.6% and 31.1% to 18.8%, 13.2% and 11.8%, respectively, and the average N, P, and K fertilizer use efficiencies lessened from 12.4 kg·kg-1, 25.9 kg·kg-1 and 10.7 kg·kg-1 to 5.9 kg·kg-1, 13.4 kg·kg-1 and 4.1 kg·kg-1, respectively. Therefore, apparent research progress was achieved by this research for mechanismstic study of highly efficient fertilizer utilization in dry land with WFM for wheat. |