Figure 1

Ammonium treatments altered soil nitrogen dynamics and plant N uptake. (a) Diagram of pot-grown tomato plants where water, low NH₄⁺(6.5 μg NH₄⁺-N g^-1 soil), and high NH₄⁺ (65 μg NH₄⁺-N g^-1 soil) treatments were injected into buried soil rings. (b) and (c) NH₄⁺-N and NO₃^--N concentrations per gram of patch soil in the three treatment groups at 5, 29, 53, and 96 hrs after injection. (d) and (e) atom percent ¹⁵N in roots and shoots 5, 29, 53, and 96 hrs after injection of the three treatment groups with ¹⁵N labeled NH₄⁺ fertilizer. Data represent the mean ± SEM of 3 biological replicates. Within each graph, means followed by different letters are significantly different from one another at P < 0.05 (two-way ANOVA with Tukey-Kramer HSD test).