Subsurface drainage and nitrogen management affects soil properties in upstate Missouri U.S.

Abstract

Enhanced efficiency nitrogen (N) fertilizer management may reduce environmental N losses and increase grain yields. The effect of N fertilizer management practices on soil properties is uncertain. In this 5-year study, we evaluated different N fertilizer management [non-treated control (NTC), fall applied anhydrous ammonia (AA) 190 kg N ha⁻¹ with nitrapyrin (fall AA + NI), preplant AA at 190 kg N ha⁻¹ (spring AA), top-dressed urea (TD urea) as 42 kg N ha⁻¹ SuperU and 126 kg N ha⁻¹ ESN as a 25:75 % granular blend] practices in free drained (FD) and non-drained (ND) soils for their impact on soil properties. In FD soils, N fertilization significantly (P < 0.05) increased soil pH, CEC, cations, and Bray I P compared to the NTC. Improved soil aeration and increased plant growth with TD urea and spring AA fertilizer treatments in FD soils increased soil organic matter (OM) 10–13 % and total organic carbon (TOC) 27–35 % compared to the NTC. Increased clay content and reduced silt content were observed in FD soils with N fertilizer treatments compared to NTC. However, fertilizer applications in ND soils had no effect on soil properties. Increased crop production with FD and 4R N fertilizer applications can improve soil properties with increased soil OM and TOC content. This suggests that a synergetic effect of N fertilization and soil drainage can improve soil health by increasing soil cation exchange capacity (CEC), OM, and TOC content.