Liquid Nutrient Enrichment Field Trials
Citation: Schmidt H-P, Pandit BH, Cornelissen G, Kammann CI (2017). Biochar-based fertilization with liquid nutrient enrichment: 21 field trials covering 13 crop species in Nepal. Land Degradation & Development 28(8): 2324–2342. https://doi.org/10.1002/ldr.2761
What it is: A program of 21 on-farm trials in Nepal. Biochar from flame-curtain kilns was loaded with cow urine or dissolved NPK and placed in the root zone at low doses. Controls got the same nutrients without biochar, so the trials isolate biochar’s role as a nutrient carrier.
Key figures
| Figure | Value | Where | Check |
|---|---|---|---|
| Trials and crops | 21 field trials, 13 crop species | Abstract | ✓ abstract |
| Enriched-biochar dose | 0.5–2 t ha⁻¹ into the root zone | Abstract | ✓ abstract |
| Nutrient load per tonne of biochar | 60–100 kg N, 5–60 kg P₂O₅, 60–100 kg K₂O | Abstract | ✓ abstract |
| NPK-enriched biochar vs the same NPK without biochar | +20% ± 5.1% yield (4 trials) | Abstract | ✓ abstract |
| Urine-enriched biochar + compost vs farmer practice (urine-blended compost) | +123% ± 76.7% yield (13 trials) | Abstract | ✓ abstract |
| Urine-enriched vs NPK-enriched biochar, same nutrient dose | +103% ± 12.4% (4 trials) | Abstract | ✓ abstract |
| Soils | Described as rather fertile silt loams | Abstract | ✓ abstract |
Use with care
- The large gains come from enriched biochar placed in the root zone at ≤2 t ha⁻¹, not from bulk raw char. Don’t transfer them to broadcast applications.
- The +123% comparison is against local organic practice, not mineral NPK, and its spread (±76.7%) is wide.
- The full text wasn’t accessible for this check. Trial-level details (crop list, sites, enrichment timing) still need confirming against the paper.
Related: urine-enhanced biochar field trial (the pumpkin trial before this program) · Biochar Inoculation for Fertilizer · Key Sources