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Keyline Plow Line Layout Calculator

Work out how many parallel plow lines you'll need to cover a paddock's cross-slope width, from your chosen implement/plow spacing — the real calculable piece of a Keyline-pattern cultivation layout.

Parallel plow lines needed67
Total width covered201.0 m

How to measure your inputs

  • Paddock width: the cross-slope distance from your Keyline out to the paddock boundary, measured perpendicular to the Keyline's direction.
  • Line spacing: your plow or cultivation implement's working width — your own equipment choice, not something this calculator determines.

Methodology

Simple coverage arithmetic: number of lines = ceiling(paddock width ÷ line spacing); total coverage = line count × line spacing. No spacing formula is applied — published Keyline design method (P.A. Yeomans) doesn't define one; spacing is an equipment/design choice.

Why plow line spacing is your choice, not a formula

What the Keyline and Keypoint actually are

In P.A. Yeomans’ Keyline design method, the Keypoint is where a primary valley’s slope suddenly steepens; the Keyline is the contour line running through that point. Cultivation lines run parallel to the Keyline — above it, paralleling upslope; below it, paralleling downslope — which drifts runoff gently from wet valley floors toward drier ridges instead of letting it concentrate and erode.

Why spacing itself has no calculable formula

Unlike terrace vertical interval (which is derived from slope geometry), Keyline plow line spacing is fundamentally an equipment choice — it matches the working width of whatever plow or cultivation implement is doing the work. There’s no slope-based or soil-based formula to derive it from, which is why this calculator doesn’t try to invent one — it takes your chosen spacing as a given and calculates the one thing that is genuinely calculable: how many lines and how much width that spacing covers.

What this calculator is actually useful for

Once you know your implement’s working width, this tells you how many passes you’ll need to cover a paddock’s cross-slope width, and the total width actually covered — useful for planning time, fuel, and whether your last pass will need adjusting to fit the paddock boundary exactly.

Frequently asked questions

What is the Keyline in Keyline design?

The contour line running through a primary valley’s Keypoint — the point where the valley floor’s slope suddenly steepens. Cultivation lines are laid out parallel to this line, which is the foundation of the whole Keyline pattern.

How do I choose my plow line spacing?

It’s determined by your cultivation implement’s working width — a wider plow or ripper covers more ground per pass, so lines are spaced accordingly. There’s no separate "ideal" spacing to calculate; it follows directly from whatever equipment you’re using.

Why doesn’t this calculator suggest an ideal spacing for me?

Because there isn’t a real slope-based or soil-based formula for it in the published Keyline method — spacing is an equipment/design decision, not a calculated output. Presenting an invented "ideal" figure would be less honest than just doing the real arithmetic on the spacing you’ve already chosen.

Does Keyline design work on any slope?

It’s designed around primary valleys with an identifiable Keypoint, which exists on most sloped agricultural land with some drainage pattern — very flat land or land without a clear valley/ridge structure doesn’t have a meaningful Keypoint to work from.