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Record W7072824900

黄土高原和北美大平原主要农业土壤的有机C性质和动态对比研究

2003· other· zh· W7072824900 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

aboutThe title or abstract carries a Canadian signal from the geographic lexicon.
no affNo Canadian affiliation: this work is invisible to an affiliation-only frame.
No Canadian affiliation. An affiliation-only frame, the usual design, would never have seen this work. It is one of the works that make the case for inverting the frame.

Bibliographic record

VenueLanzhou University Institutional Repository · 2003
Typeother
Languagezh
FieldMedicine
TopicPrenatal Screening and Diagnostics
Canadian institutionsnot available
Fundersnot available
KeywordsBlack boxIdentification (biology)Process (computing)
DOInot available

Abstract

fetched live from OpenAlex

为了探讨土壤质量的可持续管理途径,采用对比研究方法研究了耕作、轮作、施肥对5种典型农业土壤中的总有机C、有机C的比重分组、有机C所结合的土壤颗粒大小分组、微生物体C、水溶性C的影响。5种土壤中黄绵土(Calcaric Cambisols, FAO)、灰褐土(Haplic Greyxems, FAO)和黑垆土(Calcic Kastanozems, FAO)采自黄土高原地区,典型褐灰钙土(Orthic Brown Chernozem)和典型黑灰钙土(Orthic Black Chernozem)采自加拿大北美大平原地区。\n 对3种不同开垦时间土壤系列中的有机C研究结果表明,黄绵土在开垦5年之后0-20 cm土层的总有机C损失了77%,有机C的损失速率为2.15 t C ha-1 yr-1。严重的土壤侵蚀是造成土壤有机C快速损失的主要原因。灰褐土在开垦后的42年中0-20 cm土层有机C损失了70%,损失速率为0.96-1.06 t C ha-1 yr-1。在灰褐土开垦之初,有机C的矿化分解是其损失的主要原因,随着开垦时间的延长,土壤侵蚀对有机C损失的影响逐渐上升为与矿化分解作用相同。北美大平原典型褐灰钙土的有机C随开垦时间的变化过程可以明显地从开垦40年处被分作2个阶段:开垦时间为40年的土壤其有机C损失了11%,损失速率为0.17 t C ha-1 yr-1;开垦时间为80年的土壤有机C损失了44%,损失速率为0.30 t C ha-1 yr-1。发生这一现象的原因是该地区在20世纪30年代曾发生过强烈的土壤风蚀,随后进行的一系列耕作和轮作体系改进有效地遏制了土壤风蚀并防止了土壤有机C的快速下降。3种土壤中轻组有机C的损失比总有机C更快:黄绵土和灰褐土在对应的时间段里轻组有机C分别损失了73%和90%,而典型褐灰钙土在相应的时间段里轻组有机C损失了70%和74%。3种土壤中与各级颗粒结合的有机C随开垦时间的变化过程与其总有机C和轻组有机C相似。\n 在位于加拿大Saskatchewan省西南部的典型褐灰钙土上的研究结果表明,几种在该地区盛行的轮作和耕作体系对土壤有机C及其分组有不同程度的影响。免耕(谷类作物-夏闲轮作,不施肥)7年后虽然0-5 cm和5-10 cm土层的总有机C和轻组有机C数量与传统耕作(谷类作物-夏闲轮作,不施肥)相同,但免耕0-5 cm土层砂粒组(>50 μm)中的有机C增加了69%。谷类作物连作与谷类作物-夏闲相比,10年后0-5 cm和5-10 cm土层的总有机C稍有增加,而轻组有机C则分别增加了24%和29%。该处理0-5 cm土层砂粒组、粗粉砂粒组(20-50 μm)、细粉砂粒组(2-20 μm)中的有机C分别增加了104%、11%和15%,5-10 cm土层微生物体C也显著提高了。将小麦-夏闲轮作体系转变成豆科作物牧草(苜蓿)12年后,0-5 cm和5-10 cm土层的总有机C增加了80%和27%,轻组有机C增加了245%和286%,重组有机C增加了63%和20%,2层中各级土壤颗粒中的有机C均显著地提高了。但水溶性有机C和微生物体C没有发生显著变化。\n 在Saskatchewan省中东部的典型黑灰钙土上,当自然植被下的土壤被开垦62年后(谷类作物-夏闲),0-5 cm和5-10 cm土层总有机C分别下降了42%和33%,轻组有机C分别下降了79%和74%,2层中砂粒组、粗粉砂粒组、细粉砂粒组中的有机C也显著地减少了,水溶性有机C和微生物体C的下降幅度更大。当将开垦50年后的耕...

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not 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.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesMeta-epidemiology (narrow), Insufficient payload (model declined to judge)
Consensus categoriesInsufficient payload (model declined to judge)
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: Not applicable
GenreCandidate signal: Other · Consensus signal: Other
Teacher disagreement score0.418
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0010.001
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0000.000
Science and technology studies0.0010.001
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0030.003

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.

Opus teacher head0.011
GPT teacher head0.205
Teacher spread0.195 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it