Fig. 5
From: Performance-based criteria for safe and circular digestate use in agriculture
Combined effects of total ammonia nitrogen (TAN), potassium (K), and boron (B) on germination index (GI). (A) GI by cut-point combinations for TAN, K and B. Categories indicate whether each driver is below (↓) or above (↑) its cut-point (TAN = 1,122 mg N L− 1; K = 39,600 mg kg− 1; B = 22.5 mg kg− 1). Boxes show median and IQR; points are individual digestates samples. Dashed lines mark GI thresholds at 80% and 50%. Point color encodes the number of cut-points exceeded (0–3). (B) TAN–K scatterplots stratified by B (< 22.5 mg kg− 1 ≥ 22.5 mg kg− 1). Dashed lines indicate TAN and K cut points. Point color denotes GI class (> 80% non-phytotoxic; 50–80% moderately phytotoxic; < 50% highly phytotoxic).
