Agriculture &amp; Soil

Seed Rate

S = D \times A

Total seed needed from sowing density and area.

Plant Population

N = \frac{A}{s_r \times s_p}

Number of plants from row and plant spacing.

Fertiliser Requirement

F = \frac{R \times A}{c}

Fertiliser product needed to supply a target nutrient rate.

Nutrient from Fertiliser

n = F \times c

Actual nutrient delivered by a mass of fertiliser.

Irrigation Water Requirement

V = A \times d

Water volume to apply a given depth over a field.

Crop Water Use (ET)

NEWAdvanced

ET_c = K_c \times ET_0

Crop water demand from a crop coefficient and reference ET.

Livestock Stocking Rate

SR = \frac{N}{A}

Number of animals per unit of grazing land.

Feed Conversion Ratio

FCR = \frac{F}{G}

Feed eaten per unit of body-weight gain.

Soil Bulk Density

\rho_b = \frac{m_s}{V}

Dry soil mass per unit volume — a measure of compaction.

Soil Moisture Content

\theta = \frac{m_w - m_d}{m_d} \times 100

Gravimetric water content of soil by weight.

Germination Rate

G = \frac{n_g}{n_t} \times 100

Percentage of sown seeds that sprout.

Harvest Index

NEWAdvanced

HI = \frac{Y_{econ}}{Y_{bio}}

Fraction of total plant mass that is harvestable grain.

Post-Harvest Loss

L = \frac{m_i - m_f}{m_i} \times 100

Percentage of harvest lost during storage.