Biodegradable Mulch Film Half-Life in Soil

The formula

This is the expression the tool evaluates. Every term is named underneath, with the unit it must be supplied in.

How the result is derived

Step by step, from the values you type to the figure on screen.

1. The 9 inputs are read from the form on every keystroke: Half-Life at Reference, Reference Soil Temperature, Reference Film Thickness, Mean Soil Temperature, Q10 Rate Factor, Moisture Factor, Film Thickness, Cropping Season Length and Target Residue.
2. Each value is checked against the accepted range in the input table below. A value outside its range stops the calculation rather than producing a misleading figure — the results blank out and a message appears.
3. The validated values are substituted into the expression above, which resolves Field Half-Life together with every supporting figure in one pass — no value is carried over from a previous entry.
4. The supporting outputs — Rate Constant, Temperature Factor, Remaining at Season End, Lost During Season and Time to Target Residue — come from the same pass, so they always describe the same case as the headline figure.
5. Results are rounded for display only. The full-precision value is used throughout the chain, so reading a rounded intermediate figure back into the tool by hand can shift the last digit.

What each input means

Where to read each value on the floor, the unit it must be in, and the range the tool accepts.

What the tool returns

The headline figure and every supporting value it is built from.

Worked example

The tool loads with this case already solved — the Field Half-Life shown above is its answer. Change one value and the difference from this baseline is the sensitivity of the result to that variable.

How to use it

1. Work through the input groups in order — Reference Behaviour and Field Conditions. The defaults are a realistic case, so you can change one value at a time and watch what moves.
2. There is no calculate button. Every figure recalculates as you type or drag, which is what makes this usable for a what-if sweep rather than a single answer.
3. Read Field Half-Life in the dark results panel — that is the headline figure, expressed in days.
4. Check the supporting rows underneath (Rate Constant, Temperature Factor, Remaining at Season End, Lost During Season and Time to Target Residue) before acting on the headline — they are where an implausible input usually shows itself first.
5. Reset to defaults returns every field to the reference case, which is the quickest way to check whether a surprising result came from the tool or from an input you had changed earlier.

Where this is used

• Process planning — establishing Field Half-Life before a trial is booked, so machine time and material in Agrotextiles & Environmental Shielding are committed against a calculated figure rather than an estimate.
• Costing and quotation — Field Half-Life is an input to the cost sheet, and quoting from a worked number rather than a remembered one is what keeps a margin intact.
• Troubleshooting — when the floor result drifts from plan, entering the measured values (starting with Half-Life at Reference) shows how much of the gap in Field Half-Life each variable explains.
• Teaching and study — the accepted ranges bracket normal Agrotextiles & Environmental Shielding practice, so moving one variable at a time shows the shape of the relationship rather than a single answer.

Assumptions and limits

• First-order kinetics assume degradation proceeds at a constant proportional rate, which biodegradation does not: there is usually an induction lag while the surface is colonised, then a faster phase, and the single rate constant here averages over both. The thickness correction is linear, appropriate for surface-driven attack and wrong once the film fragments and its surface area jumps. Degradation also effectively stops below about 10 °C, which a Q10 extrapolation will not show you. Compliance with EN 17033 or a comparable standard rests on soil burial testing, not on a projection.
• Every input is bounded to the range normal practice occupies (Half-Life at Reference 5 to 2000 days, Reference Soil Temperature 0 to 45 °C and Reference Film Thickness 5 to 80 µm, and so on for the rest). Those bounds are guard rails against typing errors, not a claim that the formula fails one unit outside them.
• The calculation is deterministic: the same inputs always give the same result. It carries no allowance for machine condition, operator skill, ambient conditions or lot-to-lot material variation unless an input above explicitly represents one.
• Nothing is sent anywhere. The maths runs in your browser, so the numbers you type never leave the page.

Questions people ask