Animal manures and other sources of Phosphate, Potash, Magnesium and Sulphur

A guide to the total and available phosphate, potash and magnesium contents of some manures.

Typical phosphate, potash and magnesium contents in some animal and other organic manures. These can be used as default contents in the absence of actual measured or declared values.

		DM	Total nutrients				Available nutrients(1)
			Phosphate P2O5	Potash K2O	Magnesium MgO	Sulphur(2) SO3	Phosphate P2O5	Potash K2O
Fresh FYM(3)		%	kg/t				kg/t
	Cattle	25	3.2	9.4	1.8	2.4	1.9	8.5
	Pig	25	6.0	8.0	1.8	3.4	3.6	7.2
Slurries		%	kg/m3				kg/m3
	Cattle(4)	6	1.2	2.5	0.6	0.7	0.6	2.3
	Pig(4)	4	1.5	2.2	0.7	0.7	0.8	2.0
Separated slurries (liquid)		%	kg/m3				kg/m3
	Strainer box (cattle)	1.5	0.3	1.5	ND	ND	0.15	1.4
	Weeping wall (cattle)	3	0.5	2.3	ND	ND	0.25	2.1
	Mechanical separator (cattle)	4	1.2	2.8	ND	ND	0.6	2.5
	Pig	3	1.1	2.0	ND	ND	0.6	1.8
Separated slurries (solid)		%	kg/t				kg/t
	Cattle	20	2.0	3.3	ND	ND	1.0	3.0
	Pig	20	3.7	2.0	ND	ND	1.9	1.8
Poultry manures		%	kg/t				kg/t
		20	8.0	8.5	2.7	3.0	4.8	7.7
		40	12	15	4.3	5.6	7.2	14
		60	17	21	5.9	8.2	10.2	19
		80	21	27	7.5	11	12.6	24
Biosolids		%	kg/t				kg/t
	Digested cake	25	11	0.6	1.6	8.2	5.5	0.5
	Thermally dried	95	55	2.0	6.0	23	28	1.8
	Lime stabilised	25	7.0	0.7	2.4	7.4	3.5	0.4
	Composted	40	10	3.0	2.0	6.1	5.0	2.7
Composts		%	kg/t				kg/t
	Green	60	3.0	6.8	3.4	3.4	1.5	5.4
	Green/food	60	4.9	8.0	3.4	5.1	2.5	6.4
Wastes		%	kg/t or kg/m3				kg/t or kg/m3
	Paper crumble (chemically/physically treated)	40	0.4	0.2	1.4	0.6	ND	ND
	Paper crumble (biologically treated)	30	3.8	0.4	1.0	2.4	ND	ND
	Mushroom compost	35	5.0	9.0	ND	ND	ND	ND
	Water treatment cake	25	3.4	0.4	0.8	5.5	ND	ND
	From food industry (general)	5	0.7	0.2	ND	ND	ND	ND
Digestates – Whole		%	kg/t or kg/m3				kg/t or kg/m3
	Food based	4.1	1.1	2.4	0.2	0.2	0.7	2.2
	Crop based	5.5	1.7	4.4	0.6	0.6	1.0	4.0

⁽¹⁾Nutrients available to the next crop (kg/tonne of product, not %).
⁽²⁾See below for sulphur availability.
⁽³⁾Potash values will be lower if FYM is stored in the open for long periods.
⁽⁴⁾Adjust nutrient contents if % DM is higher or lower.
DM = Dry matter.
ND = No data.
To convert kg/t to units/ton, multiply by 2.
To convert kg/m³ to units/1000 gallons, multiply by 9.

Sulphur availability from organic materials

Organic materials contain valuable amounts of crop-available sulphur and recent research has quantified sulphur supply from livestock manures and biosolids applications. Sulphur from autumn applications may be lost via overwinter leaching. The quantity leached will depend on soil type and overwinter rainfall and is likely to be higher on light textured soils in high rainfall areas.

Organic material		% total SO3 available
Autumn applied		%
	Livestock manures	5-10
	Biosolids	10-20
Spring applied
	Cattle FYM	15
	Pig FYM	25
	Poultry manure	60
	Cattle/pig slurry	35
	Biosolids	20

The importance of laboratory analysis and sampling

The nutrient content of organic manures on farms vary widely and so it is better to have a laboratory analysis carried out to get the correct values specifically for the farm and the year in question. However, it is important that the sample taken for analysis is truly representative. This means that sampling should be undertaken according to the protocol given in the AHDB Nutrient Management Guide (RB209), Section 2 Organic Manures.

In the absence of a recent analysis, and where thorough sampling can not be done, these typical values represent an alternative for nutrient planning purposes.