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Field Notes

The research side of permaculture.studio.

Verification record

Every claim in this article was checked against the abstracts of the papers it cites, by a separate pass that was given those abstracts and nothing else. A claim marked supported carries the sentence that supports it, quoted verbatim below.

References
14
Claims checked
6
Fully supported
6
Checked on
Nov 5, 2026

Claim by claim

  1. A single-season field trial in Bita District, southwestern Ethiopia, tested coffee husk biochar and blended NPSB fertilizer together on bread wheat under limed and unlimed conditions, with three replications.

    SupportedField trialField trial

    “In the Bita District of Southwestern Ethiopia, the limited use of lime and coffee husk biochar constrains soil fertility improvement and wheat yields. To address this challenge, a field experiment was conducted during the 2023 main cropping season to evaluate the effects of integrating coffee husk biochar and blended NPSB fertilizer under limed and unlimed conditions on the yield and yield components of bread wheat. The experiment consisted of three levels of coffee husk biochar (2.5, 5, and 7.5 t ha -1 ) combined with three rates of NPSB fertilizer (50, 100, and 150 kg ha -1 ), along with two positive controls (5 t ha -1 biochar and 100 kg ha -1 NPSB) and one negative control (no fertilizer). Treatments were arranged in a randomized complete block design with three replications in a factorial arrangement.”

    The abstract fully describes the trial conducted during the 2023 main cropping season in Bita District, testing the combined treatments under limed and unlimed conditions with three replications.

    Checked by google/gemini-3.8-flash on Nov 5, 2026

  2. The interaction between coffee husk biochar and NPSB fertilizer significantly increased grain yield.

    SupportedField trialField trial

    “The results indicated that the interaction between coffee husk biochar and NPSB fertilizer significantly increased grain yield.”

    The claim is directly supported by a verbatim statement in the abstract.

    Checked by google/gemini-3.8-flash on Nov 5, 2026

  3. The highest reported grain yield, 3.59 tonnes per hectare, came from 5 tonnes per hectare of coffee husk biochar plus 100 kilograms per hectare of NPSB under limed conditions.

    SupportedField trialField trial

    “The highest grain yield (3.59 t ha -1 ) was obtained from the application of 5 t ha -1 coffee husk biochar combined with 100 kg ha -1 NPSB fertilizer under limed conditions.”

    The source directly confirms that the highest grain yield of 3.59 t ha-1 was achieved with 5 t ha-1 coffee husk biochar combined with 100 kg ha-1 NPSB fertilizer under limed conditions.

    Checked by google/gemini-3.8-flash on Nov 5, 2026

  4. That same treatment gave the largest reported net benefit, 276,280 Birr per hectare, with a marginal rate of return of 22,076 percent.

    SupportedField trialField trial

    “This treatment also provided the greatest economic return, with a net benefit of 276,280 Birr ha -1 and a marginal rate of return (MRR) of 22,076%.”

    The abstract confirms that this treatment produced the greatest economic return with a net benefit of 276,280 Birr per hectare and an MRR of 22,076%.

    Checked by google/gemini-3.8-flash on Nov 5, 2026

  5. Under unlimed conditions the same combination of biochar and NPSB gave the highest reported net benefit, 197,080 Birr per hectare.

    SupportedField trialField trial

    “Under unlimed conditions, the same combination yielded the highest net benefit (197,080 Birr ha -1 ).”

    The abstract explicitly states that under unlimed conditions, the same combination of biochar and NPSB fertilizer produced the highest net benefit of 197,080 Birr per hectare.

    Checked by google/gemini-3.8-flash on Nov 5, 2026

  6. In a different system, greenhouse pineapple on a clayey Ferralsol, charcoal fines applied alone reduced readily available water by up to 16.5 percent, and only co-application with poultry litter improved water availability.

    SupportedLaboratory studyLaboratory study. Shown under laboratory conditions, not in the field.

    “The combined application of charcoal fines and poultry litter was essential for significantly increasing both total (TAW) and readily available water (RAW). In contrast, the sole application of charcoal fines was detrimental, reducing RAW by up to 16.5%.”

    The abstract confirms that in a greenhouse experiment with pineapple on a clayey Ferralsol, sole application of charcoal fines reduced readily available water by up to 16.5%, whereas combined application with poultry litter was essential to increase water availability.

    Checked by google/gemini-3.8-flash on Nov 5, 2026

What this does and does not prove

It proves that every DOI cited resolves to a real registered work whose returned DOI matches the one requested, that none of them is retracted, and that each claim has a named sentence in a cited abstract behind it.

It does not prove that the paper as a whole supports the claim. An abstract can overstate its own findings, and a sentence can be read out of context. That is why the quote is printed here rather than summarised: if the check is wrong, you can see that it is wrong.

Evidence grading is automatic and conservative. Anything it cannot classify is marked unclassified rather than flattered upward.