A browser soil lab. You take a piece of tired ground, feed it organic matter, and watch what comes back over two years — with an untreated control plot sitting right beside it the whole time so you can see what would have happened if you'd done nothing. Three tabs, three scales: thirty dump-truck loads, a measured field dose, and a single kitchen scrap in a pot.
Every farmer answers one question every morning: what does this land need right now? You can't teach that with a list of N-P-K numbers. You teach it by letting a kid pour a treatment onto dead ground and watch the canopy close — or fail to. The control plot is the whole point. Without it, every garden looks like a success.
This is a teaching model, not a soil simulator. The growth is a tuned logistic curve, calibrated so that at the documented dose you land near the documented result from the real study. It is honest about direction and rough magnitude; it is not predicting your actual backyard. Soil is local — pH, texture, climate, what grew there before. The lab can't know your dirt. Tony can. Go ask your dirt.
No real units of mass or area inside the curve — dose is shown as a multiple of the study's documented amount. The numbers on the gauges are indices anchored to the published outcomes, not field measurements of your plot.
Lab of the OPA Agriculture Suite. Sibling to the Population Dynamics Lab (College III life sciences). Filed under College III — Agriculture & Animal Intelligence, Building 3 (Old McDonald Farm / AG Center). Department Chair: Tony "Arkansas Farm Boy" Williams. Cross-listed to College IX (Stephens Science · soil chemistry) and ELUSK drone/LiDAR for canopy survey.
Built by Travis Jenkins (User Zero) with Claude. The instrument exists because the line "feed the land and the land feeds you" deserves a plot a twelve-year-old can run, not just a poster on the barn wall.
Two state variables advance month by month for 24 months: soil quality S and biomass / canopy B. Organic matter builds the soil; the soil sets how much the plant can grow.
Each month the organic input pushes soil quality up toward a maximum, with a small natural decay:
Higher organic matter (om) and dose raise the ceiling S approaches. This is why manure and meal keep paying off across a second season — they're still feeding the microbes.
Biomass follows the classic logistic curve, but its carrying capacity K is set by the soil quality and the amendment's nutrient fit:
Same equation that drives the Population Dynamics Lab — a population of leaves instead of rabbits.
Degraded pasture is held hostage by invasive grass. The coffee-pulp blanket's job isn't only feeding — it's removal. A high smother value lifts the growth rate r by clearing the competition, which is why the control plot stalls near 20% canopy while the treated plot runs to ~80%.
Calibrated so soybean meal and cattle manure clear a higher net than rapeseed meal, matching the published ~1.46× and ~1.42× advantage.
No weather, no pests, no real soil texture or pH starting point, no leaching, no crop rotation effects beyond the single curve, no over-winter dynamics. Excess-nitrogen yield penalty is modeled only as a gentle plateau at high dose. The model is freshman-grade by design. v0.2 scopes: a pH axis (so eggshells matter mechanistically), a weather seed, and a real multi-season rotation.
Cole & Zahawi (2021), Ecological Solutions and Evidence (British Ecological Society; doi:10.1002/2688-8319.12054). ETH-Zürich & University of Hawaiʻi. Thirty dump-truck loads of coffee pulp, a half-meter-thick layer over a 35×40 m plot of degraded former pasture in Coto Brus, Costa Rica, with a matched untreated control. Two years later: ~80% canopy cover on the treated plot vs ~20% on the control, canopy four times taller, and carbon/nitrogen/phosphorus all significantly elevated. The pulp smothered the invasive pasture grass that had been blocking forest succession.
Cen et al. (2020), PeerJ 8:e9668 (doi:10.7717/peerj.9668). A two-year winter-wheat / summer-maize rotation at a constant nitrogen base rate, comparing rapeseed meal, soybean meal, and cattle manure against a no-amendment control. Yield increases of +161% (rapeseed meal), +299% (soybean meal), and +256% (cattle manure). Net income for soybean meal and cattle manure ran ~1.46× and ~1.42× that of rapeseed meal. Soybean meal led on the soil-quality index; manure led on soil pH and microbial biomass.
Banana peels: Khanyile et al. (2024), Agriculture 14(11):1894 — review of six prep methods (ash, biochar, powder, extract, filtrate, composite). Potassium-rich; banana–orange composite the standout, dried peel close behind; biochar's effect on plant height came out statistically insignificant — a reminder that "organic" doesn't auto-mean "works."
Eggshells: groundnut and tomato trials (Tandfonline 2022; ResearchGate 2025) — calcium carbonate source; applied before sowing beats after flowering; higher rates raise soil pH and calcium uptake. Eggshell + fruit-peel combo gave the highest maize yield in one trial and nudged acidic soil to neutral.
Rice / potato / pasta water: mostly horticultural folklore. Washed rice water has some study support as a mild fertilizer (a centuries-old Japanese practice); pasta and potato water are largely starch that feeds soil microbes — a light snack, not a real feed. Salt fries roots; too much starch can grow harmful bacteria. A plant's diet can't be all carbs.
Tab evidence bars reflect this gradient: peer-reviewed field study → reviewed but seedling-stage → kitchen anecdote.