Page 133 - Nutrient Management Planning Guide

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Chapter 4.1

Calculating Bulk Density

A 20 L (5 gal) pail filled with material from a manure pile weighs approximately 19.48 kg (42.95 lbs). The bulk density of the material in the pail is:

Pail volume (m 3 )

= pail volume (L) x conversion factor (Table 4.1.3) = 20 L x 0.001 m 3 /L = 0.02 m 3

Bulk density (kg/m 3 ) = weight ÷ pail volume = 19.48 kg ÷ 0.02 m 3

= 974 kg/m 3 is the approximate bulk density of the material in the pail

Determining Bulk Density of Poultry Litter »

in the Barn

For most broiler operations, it may be just as easy to determine bulk density of the litter before it is removed from the barn, particularly if it is to be spread immediately. This is convenient if manure is sampled for analysis at the same time. Bulk density can be determined using the same procedure outlined above with two differences:

Instead of sampling from different points on the pile, •

sample litter from different points in the barn. Scraping off the surface layer of the pack before •

sampling is not required.

Calculate Weight of a Pile

Total weight of solid manure in a pile or windrow is calculated by multiplying bulk density of the material by the estimated volume of the pile:

Total weight of pile (t) =Bulk density, kg/m 3 × Volume, m 3 ÷ 1000 kg/t

Calculating the Weight of a Pile of Manure

After taking several samples at different points of the pile, the average weight of material in a 20 L (5 gal) pail is estimated to be 19.48 kg. The estimated density is 974 kg/m 3 . Putting this together with a volume of 203 m 3 :

Total weight of pile (t)

= (Bulk density, kg/m 3 × Volume, m 3 ) ÷ 1000 kg/t = (975 kg/m 3 x 203 m 3 ) ÷ 1000 kg/t = 197,925 kg ÷ 1000 kg/t

= 198 t is the total weight of the pile of manure

Figure 4.1.7 Sampling Perpendicular to the Pile Surface

tip

Bulk density can be expressed as kg/m 3

or kg/L and volume as m 3 or L. The numerical result from the weight calculation will be the same.