Cropping System and Type of Pig Manure Affect Nitrate‐Nitrogen Leaching in a Sandy Loam Soil
Bibliographic record
Abstract
The application of livestock manure can result in the loss of nitrate‐nitrogen (NO 3 − ‐N) and degrade surface and groundwater. A 3‐yr lysimeter study was set up to compare the effect of cropping system and nitrogen (N)‐ and phosphorus (P)‐based pig manure application rates on the loss of water and NO 3 − ‐N below the root zone. The experiment was a split‐plot design with annual and perennial cropping systems as the main factor. Five nutrient management treatments were the subplots: N‐based liquid pig manure application; P‐based liquid pig manure application, N‐based solid pig manure application, P‐based solid pig manure application, and a control without amendment. The results showed that 40 to 60 kg NO 3 − ‐N ha −1 was lost from the annual plots in 2010 and 23 to 60 kg NO 3 − ‐N ha −1 in 2011, whereas a negligible amount of NO 3 − ‐N was lost from the perennial (<1 kg ha −1 ) plots in both years. The application of solid pig manure on a P basis followed by urea in subsequent years reduced the risk of NO 3 − ‐N leaching over the course of the rotation, likely due to immobilization of N by the straw in the solid pig manure. Our study showed that a perennial cropping system consisting of a mixture of grasses has the capacity to receive and utilize significant amounts of nutrients with negligible amount of nutrient leakages to the adjacent environment. The inclusion of grasses in a crop rotation and their use to take up excess nutrients are sustainable practices that will benefit the environment. Core Ideas Similar amounts of water were lost from perennial and annual cropping systems. Significant amounts of nitrate were lost from annual vs. negligible amounts from perennial crops. Phosphorus‐based solid pig manure reduced nitrate leaching from annual crop.
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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 | 0.001 | 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 | 0.000 |
| 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".