Influence of Fertilizer Nitrogen Source on Soil Physical and Chemical Properties
1982
Intrawech, A. | Stone, L. R. | Ellis, R. | Whitney, D. A.
The soil-dispersing potential of ammonium (NH⁺₄) has caused concern about the possible negative influence of anhydrous ammonia (NH₃) use on soil structure. In the fall of 1978, we collected disturbed and undisturbed soil samples to evaluate the influence of 10 years of annual application of four nitrogen (N) sources [NH₃, ammonium nitrate (NH₄NO₃), urea, and urea-ammonium nitrate solution (UAN)] on soil physical and chemical properties. A no-N check was included during the 10-year field study. Soil physical properties (saturated hydraulic conductivity, probe resistance at -⅓ bar soil water potential, core bulk density, water content at -⅓ and −15 bar soil water potential, particle-size distribution, geometric mean diameter of water-stable aggregates, and compactibility) were not significantly affected by fertilizer treatment. The application of all N sources reduced the soil pH significantly compared with the no-N check. In the 6- to 14-cm soil layer, the Zn concentration was significantly lower and the Mn concentration significantly higher in the N-source plots than in the no-N check. All treatments receiving fertilizer N yielded significantly more grain (1975 through 1977 mean) than the no-N check, with no significant difference in grain yield among the four N sources. Our study found that 10 years of annual application of four N sources (included NH₃) have had no measurable influence on soil structure and soil compactibility, compared with a no-N check.
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