International Scholarly Research Notices

Research Article

Effects of Nitrogen on Temporal and Spatial Patterns of Nitrate in Streams and Soil Solution of a Central Hardwood Forest

Figure 4

Annual mean soil water N O 3 βˆ’ concentration (solid circles) and corresponding coefficients of variation (CV) (open circles) from 1989 (pretreatment year) to 2006 for (A) WS4 (control): solid line is soil water N O 3 βˆ’ versus yearβ€” 𝑦 = 1 0 7 . 8 βˆ’ 0 . 0 5 3 π‘₯ , π‘Ÿ 2 = 0 . 2 2 , 𝑃 < . 0 5 β€”and (B) WS3 (treatment): dashed curve is CV versus year and represents the following 2nd-order polynomial: 𝑦 = 1 5 0 4 3 6 3 βˆ’ 1 5 0 3 π‘₯ + 0 . 3 6 π‘₯ 2 , π‘Ÿ 2 = 0 . 5 3 , 𝑃 < . 0 1 ; solid curve is soil water N O 3 βˆ’ versus year and represents the following 2nd-order polynomial: 𝑦 = βˆ’ 9 7 0 1 6 + 9 7 . 0 π‘₯ βˆ’ 0 . 0 2 4 π‘₯ 2 , π‘Ÿ 2 = 0 . 5 3 , 𝑃 < . 0 1 .
138487.fig.004a
(a)
138487.fig.004b
(b)