Biochar soil amendments in southwestern Québec, Canada: an investigation of impact on crop yields, interaction with N fertilizer and characterization of the biochar volatilome
Notice bibliographique
Résumé
Biochar, produced from waste materials has shown promise for increasing crop yields while simultaneously sequestering atmospheric carbon into soils. When this project began, little data was available about biochar effects under temperate-zone field conditions. Therefore, the first goal of this project was to determine whether biochar can improve crop yields under Québec, Canada field conditions. The results of a three-year field experiment demonstrate that biochar produced from softwood chips, applied once to a loamy sand soil at 20 Mg ha-1, increases yield and grain N uptake of corn by 14.2 and 18.2 %, respectively, while yield and grain N uptake of soybean and switchgrass were not affected by biochar soil amendment. Biochar, applied once to a sandy clay loam at 20 Mg ha-1 increased soil organic carbon concentration under switchgrass and corn by more than the amount of carbon contributed by biochar. In order to further understand the mechanisms underlying the effects of biochar on corn yield and N uptake, two greenhouse experiments were conducted. In the first greenhouse experiment, biochar interactions with N fertilizer were examined to determine if biochar soil amendments improve N fertilizer recovery efficiency in temperate field soil. Corn was grown on soil amended with factorial combinations of biochar rate (0 and 20 Mg ha-1) and N fertilizer (0, 75, 150, 225 and 300 kg N ha-1). Plants were harvested at (1) the mid-vegetative stage for analysis of root structure, root and shoot biomass, plant N uptake and plant available N in soil and (2) at tasseling for analysis of root and shoot biomass, plant N uptake and plant available N in soil. Biochar increased soil available NH4-N, cation exchange capacity, root growth and root metabolic activity and N uptake at the R1 stage. Fertilizer recovery efficiency was increased in the presence of biochar when N fertilizer was applied at 75 and 150 kg N ha-1. Biochar stimulated early root development, allowing plants to take advantage of increased NH4-N retention concentration in soil by biochar thereby increasing FRE at the R1 stage at lower application rates.In the final chapter, biochar properties were linked to effects on plant growth using greenhouse and germination experiments along with redundancy analysis. Corn was grown in the greenhouse on soil amended with 26 Mg ha-1 softwood biochar produced at 500 ºC (PYR) or biosolids biochar produced at 270 ºC or 320 ºC (ALT and AHT, respectively). Plants were harvested at the V3 stage for analysis of root structure, root and shoot biomass, plant N uptake and plant available N in soil. A germination assay assessed the importance of biochar characteristics on germination, root and shoot development after four days. ALT negatively affected root development and biomass accumulation due to high N and volatile matter contents. AHT reduced root length due to a high H/C and volatile matter content but increased N mineralization in soil, biomass accumulation and N uptake in plants at the V3 growth stage. The high proportion of fixed C in PYR led to positive effects on root growth but did not alter biomass or N uptake. Results suggest that PYR increases plant resilience to drought and nutrient stresses while ALT and AHT provide fertilization value and increase N uptake at the V3 growth stage. Overall, this project determined (1) a suitable softwood biochar application rate to increase corn yields under Québec climate conditions, (2) that biochar can contribute to increased fertilizer recovery efficiency in corn production for temperate soils and (3) how biochar properties alter corn root development and N uptake. The benefits of this project include (1) increased corn yields in Québec, (2) improved fertilizer efficiency in Québec and (3) recycling of papermill and biosolid wastes; these aspects contribute to the economics of corn production and protection of the environment as a result of reduced N fertilizer application.
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Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,002 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
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Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».