Page 130 - Nutrient Management Planning Guide

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Estimating Manure Inventory

The Leaning 2 x 4 Method Used to

Estimate Height of a Pile

A 4.9 m (16 ft) board is leaned against a solid pile of cattle manure. An arbitrary point is selected on the board that is 0.9 m above the surface of the ground and 2.0 m from the end of the board (Figure 4.1.5).

Figure 4.1.5 Solid Manure Pile

The ratio between these measurements is: Rise: Slope Length Ratio = 0.9 m ÷ 2.0 m = 0.449

Since it can be assumed that this ratio will be the same between the height of the pile and the total length of the board, the height of the pile is:

Height of the pile (m) = length of the board (m) x rise:slope length ratio = 4.9 m x 0.449

= 2.2 m is the height of the pile

Estimating Diameter of a Pile »

For round piles, measure the circumference around the base of the pile. Circumference and diameter of a circle are directly proportional according to the following relationship:

Diameter = Circumference ÷ π

For windrows with rounded contours, measure the total length of the pile along the ground and then estimate the length along the top of the pile; this should be shorter. The difference between these two measurements is an acceptable estimate of the diameter of the partial sphere formed by the two rounded ends of the pile (Figure 4.1.2). In theory, the width of the pile is also an acceptable estimate of diameter. Since there can be considerable difference between these measurements, the diameter that is used for the volume calculation is the average of these two measurements:

Diameter = (Windrow Bottom Length – Windrow Top Length + Windrow Width) ÷ 2

Estimating the Diameter of a Pile

A rounded pile of manure has a measured circumference of approximately 22 m. π

= 3.1416. The diameter of this pile is: Diameter (m) = Circumference ÷ π

= 22 m ÷ 3.1416

= 7.0 m is the diameter of the pile

Calculate Volume of a Pile

Once all necessary dimensions have been measured (or calculated) (i.e., height, diameter), the next step is to calculate volume using the stepwise calculations in the rightmost column of Figure 4.1.2.