Fig. 4 Initial inorganic N (NO3 + NH4) plus cumulative mineralized N extracted in repeated leachings during a 189-d incubation from 29 April to 4 Nov. 1998. Data are means of two duplicate soil samples from three replicates of continuous corn (CC), corn–soybean (CS), and corn–soybean–wheat/alfalfa–alfalfa (CSWA) rotations managed at zero N (0N), low N (LN), or high N (HN) fertilization incubated at field soil temperature. Error bars represent ± one standard error of the mean. For each measurement, bars within fertilizer or rotation treatment with the same letter are not significantly different according to Tukey's honestly significant difference (P < 0.05)
