Figure 5.
The leaching NO3−-N as affected by different treatments during the water spinach growing season. Different lowercase letters on the top of vertical bars indicate significant differences between treatments (P < 0.05). CK-control (without N fertilizer and soil amendments); NPK- conventional chemical fertilization; LBC, MBC and HBC- chemical fertilizer (NPK) plus 12 t ha−1, 24 t ha−1, 48 t ha−1 biochar, respectively; NPKM-NPK plus 12 t ha−1 manure.