Seedlings per Hectare
Calculates seedlings per hectare based on row and plant spacing.
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Seedlings per hectare from spacing
To get seedlings per hectare you use pl/ha = 10,000 / (row spacing · in-row spacing), both spacings in meters and the 10,000 standing for the m² in a hectare. Some Brazilian benchmarks worth keeping in mind: eucalyptus 3 × 2 m = 1,667 pl/ha, coffee 3 × 1 m = 3,333 pl/ha, soybean 0.50 × 0.05 m = 400,000 pl/ha, corn 0.80 × 0.20 m = 62,500 pl/ha. Take 3 m between rows and 2 m within the row and you land on 10,000 / 6 ≈ 1,667 pl/ha. Swap the species or the management and the same field ends up holding wildly different plant counts.
Applications
It shows up in silviculture (eucalyptus, pine), in row-crop agriculture, across INCRA agrarian reform settlements, in EMBRAPA cultivar recommendations, and whenever someone budgets a seedling purchase for a reforestation project.
FAQ
Why does eucalyptus use such low density? The crowns need room to spread if the trees are going to build wood volume. That's why 1,667 pl/ha is the usual figure for sawmill-grade timber, while stands grown for charcoal push past 2,000 pl/ha.
Does the formula account for borders and roads? No, what you get is the theoretical population. In real planning you'll want to knock off 5–10% for carreadores (internal roads) and the field edges.
Where do I find recommended spacing? Technical bulletins from EMBRAPA, IBÁ (silviculture) and Embrapa Café list recommended spacing broken down by region, soil and what the crop is grown for.
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