Figure 4 | Scientific Reports

Figure 4

From: Crop production kept stable and sustainable with the decrease of nitrogen rate in North China Plain: An economic and environmental assessment over 8 years

Figure 4

Effects of N rates on organic matter (A), nitrate-N concentration (B) in 0–30 cm soil layer, nitrogen content in 0–90 cm soil layer (C) fertilizer nitrogen loss and (D) at maize physiological maturity. Nitrogen rates in wheat and maize, respectively, are; 0 and 0 kg N ha−1 (N0), 168 and 129 N ha−1 (N1), 240 and 185 kg N ha−1 (N2), and 300 and 300 kg N ha−1 (N3) in 2009–2016. Nitrogen rates under RN2 treatment in wheat and maize are 0 and 0 kg N ha−1 in 2009–2011, and 240 and 185 kg N ha−1 in 2012–2016. Origin: June 2009. Each point is a plot mean. Year: the time to reach plateau value. Plateau: plateau value. NS: Not significant, P > 0.05. **Significant at the 0.01 probability level.

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