Effects of long‐term nitrogen addition on water use by <i>Cunninghamia lanceolate</i> in a subtropical plantation
Bibliographic record
Abstract
Abstract The deposition of reactive nitrogen (N) has substantially increased in subtropical regions due to human activities. However, the effects of long‐term N addition on the water‐use efficiency of subtropical forests are poorly understood. Here, we conducted an 11‐year experiment in a subtropical Cunninghamia lanceolate plantation with four N‐addition levels: N0, N1, N2, and N3 (equivalent to 0, 6, 12, and 24 g N m −2 year −1 , respectively). A thermal dissipation probe system was used to calculate sap flow, and plant biomass carbon was assessed by field investigation. The whole‐plant water use and water‐use efficiency were estimated. In addition, the δ 13 C of tree rings was used to indicate the plant intrinsic water‐use efficiency. The results showed that N3 treatment significantly increased the annual sap flow velocity, especially in summer and winter. Annual water use, plant growth, and water‐use efficiency did not significantly differ among the N treatments, but water use tended to be higher in N3 treatment than in N0 treatment. Furthermore, the significant reduction of δ 13 C in N3 treatment than in N0 treatment supported the inference that N addition could increase water use. We conclude that long‐term addition of high levels (but not of low levels) of N increased whole‐plant water use in C. lanceolate plantations. Our findings indicate that N deposition accompanied by high temperature and drought events may negatively affect water balance in subtropical forests.
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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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".