Fig. 2
From: Biological and synthetic approaches to inhibiting nitrification in non-tilled Mediterranean soils
Soil mineral nitrogen evolution over 60 days post-fertilization in the form of NH4+ (a), NO3− (b) and the NO3−-N/NH4+-N ratio (c). Control = sorghum without fertilization; AS = sorghum fertilized with ammonium sulfate; AS + D = sorghum fertilized with ammonium sulfate + DMPP. Different letters indicate significant differences using the Duncan test (p < 0.05; n = 4)