Effects of Annual and Perennial Forage Systems on Forage Biomass and Quality, and Soil Microorganisms
Bibliographic record
Abstract
Annual and perennial forage systems which include leguminous species can serve as valuable feed sources for beef producers, due to their diverse growth forms, yield, and nutritional traits. However, limited research has compared the effects of these forage systems on the soil and its associated microbial communities. This study hypothesized that the different vegetative traits of annual and perennial forage systems would lead to variations in biomass yield and nutritive quality, resulting in distinct microbial communities under grazed and ungrazed conditions. The forage systems included (i) CDC Austenson barley (Hordeum vulgare L.) + 4010 pea (Pisum sativum L.) + Winfred forage brassica (Brassica oleracea L.× Brassica rapa L.) + Gorilla forage brassica (Brassica napus L.) (BRPEBRAS), (ii) AC Hazlet fall rye (Secale cereale L.) + Frosty berseem clover (Trifolium alexandrinum L.) (FRCLOV), (iii) AC Success hybrid bromegrass (Bromus riparius Rehm. × Bromus inermis Leyss.) + PS3006 alfalfa (Medicago sativa L.) (HBGALF), and (iv) AC Armada meadow bromegrass (Bromus riparius Rehm.) + AAC Mountainview sainfoin (Onobrychis viciifolia Scop.) (MBGSF). The 2-yr (2022 and 2023) study employed a random complete block design, consisting of n = 3 replicated paddocks/treatment, with the paddock average serving as the experimental unit. Soils were sampled prior to grazing, then 10 steers in 2022 and 13 steers in 2023, were turned out to graze. Forage biomass yields were the greatest in BRPEBRAS and HBGALF (P < 0.01), while botanical composition showed the least weed pressure in the perennial forages HBGALF and MBGSF (P < 0.01). Forage nutritive values were consistently greater in annuals where crude protein and energy were higher (both P < 0.01), and fibre fractions were lower (P < 0.01) than in perennials. In ungrazed forage systems, soil extracellular enzyme activity (EEA) of N-acetyl-β-glucosaminidase was greater in perennials in 2023 (P = 0.02). Potential C mineralization was consistently higher in perennials, but no differences were seen in microbial biomass C (MBC). The microbial metabolic quotient (qCO2) increased from 2022 to 2023 and was greatest in 2023 perennial forage systems (P < 0.01). The abundance of fungal microbial phospholipid fatty acid (PLFA) indicators tended to be greater in perennials. Soil microbial community composition (mol% PLFA) of annuals tended to have a greater proportion of bacteria while perennials had greater fungi. Comparing grazed and ungrazed perennial forage system soils in 2023 showed that grazing did not affect EEA, MBC or microbial metabolic quotient. Grazing tended to decrease short-term potential C mineralization, where decreases were seen at 7 d in MBGSF (P = 0.08). Few grazing differences were seen in PLFA abundance and community composition due to grazing. Within the constraints of the current study, the forage systems evaluated demonstrated varied potential to support grazing through yield and quality measures, and perennial forage systems tended to support greater fungal communities and have higher potential C metabolism compared to annual forage systems.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".