The Effects of Mixed Hardwood Biochar, Mycorrhizae, and Fertigation on Container Tomato and Pepper Plant Growth

Biochar (BC) has the potential as a peat moss alternative for container plant growth. Three experiments were conducted to evaluate the effects of mixed hardwood BC, compost types, mycorrhizae, and fertigation on container-grown tomato and pepper growth. In experiment 1 (Exp1), BC at 50%, 70%, and 90% (vol.) were mixed with 5% vermicompost (VC) with the rest being a commercial peat moss-based substrate (CS) and fertigated at 200 or 300 mg L−1 N. In experiment 2 (Exp2), 80% BC was mixed with chicken manure compost (CM; 5% or 10%) and CS and fertigated at 100 or 200 mg L−1 N. In experiment 3 (Exp3), 90% BC was blended with CS and fertigated at 200 or 300 mg L−1 N. Mixes in all the three experiments were added with or without mycorrhizae. Results showed that, compared with CS, in Exp1 tomato and pepper plants grown in BC-VC mixes had similar soil-plant analyses development (SPAD), growth index (GI), and total dry weight (TDW); in Exp2 and Exp3, plants in BC mixes (80% or 90%) had lower GI and TDW. In conclusion, BC (≤70%) amended with VC mixes could be used for container tomato and pepper production without negatively affecting plant growth, while BC (80%, 90%) mixes could have some negative impacts on plant growth.