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Fig. 5. Soil NO3–N and NH4–N concentrations in the top 10 cm before (15 April) and after (5, 13, 19, and 31 May) litter application, incorporation, and rice planting, but before flooding, by location for five N-equivalent litter rates and an unamended control. Significant differences in soil NO3–N among litter rates occurred on 13 and 31 May. LSD0.05 values are 4.05 and 4.96 for 13 May and 3.65 and 4.47 for 31 May for comparing soil NO3–N among litter treatments and for comparing a litter treatment with the unamended control, respectively. Significant differences in soil NH4–N among litter rates occurred on 19 and 31 May. LSD0.05 values are 0.82 and 1.01 for 19 May and 0.69 and 0.84 for 31 May for comparing soil NH4–N among litter treatments and for comparing a litter treatment to the unamended control, respectively. Soil NO3–N decreased over time in the unamended control at PTBS (P = 0.001).
