Influence of Varying Degrees of Straw Production and Removal on Soil Properties and Crop Yield: Two-year Results
Notice bibliographique
Résumé
Straw residue retention has many benefits: mitigating soil organic matter loss; recycling macro and micronutrients; reducing runoff and evaporation, increasing water infiltration; along with promoting microbial abundance and activity. However, increasing straw demand for livestock feed and bedding, in addition to pulp, cellulosic ethanol, and fibreboard production, necessitates investigating where straw harvesting works best agronomically, environmentally, and economically. Limited information exists on straw removal effects in modern crop rotations with high-yielding varieties. Moreover, its impact has never been assessed on a landscape-scale, where soil organic matter and crop productivity differ greatly among landscape positions. The objective of this study was to examine the effects of different straw production and removal rates on soil properties and crop yield over a three-year cereal (spring wheat), pulse (field pea), and oilseed (canola) rotation in both high (depression) and low (knoll) straw producing landscape positions. A three-year study was established in 2023 at two landscape positions (≈85 m apart) in a typical south-central Saskatchewan hummocky agricultural field near Central Butte. At each landscape location, four treatment plots consisted of varying degrees of crop straw residue removal: i) no straw removal─both wheat straw (2023) and pea straw (2024) retained; ii) half straw removal─alternating wheat straw (2023) and pea straw (2024) retention and removal from plots; and iii) complete straw removal (straw harvested annually). Consistent with wheat production in 2023, the field pea yield in the depression was greater than the knoll for straw (1.5×) grain (3.9×), and total (1.9×) biomass; primarily, reflecting the more favourable soil moisture conditions in the lower landscape position. The lack of significant effect of post-harvest wheat straw residue treatment on pea yield the following year may reflect field pea’s lower water requirement. Greater grain (4.1×), straw (1.6×), and total (1.9×) biomass WUE of field pea growing in the depression, compared with the knoll, agrees with the 2023 wheat yields and may reflect the greater water-holding capacity and fertility of the depressional soil. The reduced WUE of grain (26%) and total (19%) yields in the depression following 100% straw removal, is indicative of decreased moisture availability concomitant with greater soil surface water evaporation loss following straw removal. The wetter spring soils supported the greatest microbial biomass in 2024, which was reduced 25% by straw removal in the depression, due to the removal of substrate for growth. Straw retention and greater microbial biomass was associated with a 44% reduction in soil NO3 supply rates in the first two months, which may be explained by microbial immobilization. The infiltration rate Kfs increased with 50% straw removal, compared with no straw removal and was attributed to drier surface soil and greater cracking. There were larger runoff losses of NO3 in post-harvest simulated snowmelt from the more fertile depressional soils in both 2023 and 2024. Diminished losses of NO3 (67%) and PO4 (43%) on the knolls with complete straw retention reflects reduced meltwater velocity. The impact of straw removal on crop yield and soil properties thus far have been relatively small, with more effects observed in the wetter depressional areas where there is greater straw production. Future work will examine the impact of straw removal on canola yield and other soil properties in the third year of removal treatment (2025), in addition to the economic implications of straw harvesting.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,002 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,001 | 0,000 |
| Méta-épidémiologie (sens large) | 0,001 | 0,001 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,001 | 0,001 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,001 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,003 | 0,001 |
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
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».