Agriculture & Soil

Farming by numbers: crop yield, seed rate, irrigation, fertiliser, livestock and stocking

Agriculture & Soil formulas turn farming into clear, usable numbers, helping you calculate everything from crop yield, seed rate and plant population to irrigation needs, fertiliser use, livestock stocking and feed efficiency. This category is useful for students, exam practice and real-world farm planning, because these calculations support better decisions, healthier soil, improved productivity and more efficient use of water, nutrients and land.

Crop Yield

Y = \frac{P}{A}

Production per unit area of land.

Seed Rate

S = D \times A

Total seed needed from sowing density and area.

Plant Population

NEWIntermediate

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

Number of plants from row and plant spacing.

Fertiliser Requirement

NEWIntermediate

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)

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

NEWIntermediate

FCR = \frac{F}{G}

Feed eaten per unit of body-weight gain.

Soil Bulk Density

NEWIntermediate

\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

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.