The effect of liquid hog manure and commercial fertilizer on nutrient movement in a sandy soil
Bibliographic record
Abstract
A two-year field study was initiated ín the spring of 2OO2 to investigate the effects of liquid hog manure and commercial fertilizer applications on the leaching losses of soil water and nutrient on a field síte situated over the Assiniboine Delta Aquifer (ADA) at Carberry, MB.The study used two methods for determining soil water and NO3-N leaching losses: traditional soil sampling and large intact soíl core lysimeters.By the end of the two years, the highest rate of hog manure, cropped fertilizer and fertilizer fallow plots had 23g,2sg and 22T kg No3-N ha-1, respectively, within the root zone, which was significantly higher than the control, 2500 gal ac-1 and 5000 gal ac-1 plots (61 ,107 and 123 kg NO3-N ha-1, respectively).The highest rate of manure and the two commercial fertilizer treatments had greater cumulative amounts of NO3-N within the root zone than what Manitoba Agriculture guidelines considers excessive (i.e.168 kg NO3-N ha- 1¡.Soil sampling showed leaching losses of nitrate-nitrogen from all treatments, however little movement of Mehlích-3 phosphorus was observed after two years of this study.There was a distinct rate effect as nitrate-nitrogen concentrations of B, 1 1 , 15 and 23 mg NOa-N kg-1 were found in the control, 2SO0 gal ac-1, 5000 gal ac-1 and 7500 gal ac-1 treatments at the 20-30 cm depth after two years, respectÍvely.Nitrate-nitrogen concentration was increased by the application of commercial fertilizer (i.e. 12 mg kg-1) above both the control (i.e.2 mg kg-1) and manure (ie.6 mg kg-1¡ plots at a depth of 75cm after two years.However below 75cm, the NOa-N concentration was usually higher in the manure plot than the cropped fertilízer plot.Greater availability of nutrients from the commercial fertilizer compared to the hog manure resulted in higher crop yÍelds, which limited soil water movement and the downward movement of nitrate-nitrogen.While leachate containing nitrate-nitrogen was expected from the fallow lysimeters, the amount of water (48 mm) and nitrate (18 kg ha-1) leached from the control lysimeter shows that soil organic matter breakdown can result in loss of nitrate- nitrogen from these sandy soils without the additions of fertilizer or manure.Nitrate-nitrogen concentration in the leachate ranged from 10 mg Nos-N L-1 to 122 mg NOg-N L-1.Wh¡le the concentration of nitrate-nitrogen within the leachate was at a consistent level from May 2004 to November 2004,leachate amount showed a seasonal trend of higher volumes in spring and fall.After two years, this study shows that even under below normal precipitation levels nitrate- nitrogen will be lost from a dryland agricultural system subjected to various rates and sources of nitrogen application, however nitrate-nitrogen losses can be minimized through proper agricultural management.llt
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| 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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 source (direct Gemma or distilled Codex), 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".