Annexes

Annex I - Assumptions and sources of nutrient excretion calculations
Annex II - Emission of NH₃ from pig houses
Annex III - Slurry application techniques with limited NH₃ emission
Annex IV - Average composition of animal manure
Annex V - Fossil energy requirements for the production of inorganic fertilizer

Annex I - Assumptions and sources of nutrient excretion calculations

High producing animals

All the information on high producing animals originates from the Netherlands (WUMM, 1994) and refers to standard averages for 1992, from which more precise estimates e.g. nutrient content of live weight gain, etc. were derived. In this Annex some information is given for each type of animal. The distribution of N between faeces and urine was calculated from these data and data from Tamminga (1992).

Dairy cow

Data refer to the south-east part of the Netherlands where more maize silage is fed.
Milk production per year: 6000 kg with 3.47% protein.
Age first calving: 2.2 years; age of culling 4.6 years.
Meat production: 2 calves of 43 kg in 2.4 years; 80 kg live weight gain of cow.
Feed intake: 5381 kg DM, consisting of grass, maize silage and concentrate.

Sow

Production: 530 kg of piglets (incl. deaths), and 50 kg live weight gain of sow.
Annual feed intake: 1712 kg of which 615 kg in piglet feed and 1097 sow feed.
Average nutrient content piglet feed: 29.0 g N/kg and 6.3 g P/kg.
Average nutrient content sow feed: 25.4 g N/kg and 6.5 g P/kg.

Growing pig

Live weight gain: 85 kg in 119 days (from 25 to 110 kg)
Feed conversion ratio: 2.86.
Annual feed intake: 748 kg; 132 kg starter feed and 616 kg fattening feed.
Average nutrient content starter feed: 28.5 g N/kg and 5.8 g P/kg.
Average. nutrient content fattening feed: 27.0 g N/kg and 5.0 g P/kg.

Laying hen

Production cycle length: 419 days including 24 non-productive days.
Egg production: 17.7 kg.
Live weight gain during production period: 0.56 kg.
Annual feed intake: 42.11 kg.
Average nutrient content: 29.1 g N/kg and 6.2 g P/kg.

Broiler

Live weight gain: 1.84 kg in 42 days.
Feed conversion ratio: 1.91.
Annual feed intake: 30.6 kg.
Average nutrient content: 35.7 g N/kg and 5.7 g P/kg.

Low producing animals

For low producing animals the following assumptions have been made:

Dairy cow

Milk production: 700 kg/lactation.
Calving interval: 500 days = 0.73 calves per year of ca. 25 kg.

Average dry matter intake: 7.7 kg = 2810 kg p.a. consisting of ca. 50% straw, 10% concentrate and 40% green fodder.

Average nutrient contents: CP: 87 g/kg; DCP: 47.3 g/kg; P: 2.4 g/kg.

	N (kg/y)	P (kg/y)
Intake	39.1	6.7
Digestible intake	21.3	-
Retention	3.2	0.6
In faeces	17.9	6.1
In urine	18.1	0

Sow

Production: 140 kg of piglets (incl. deaths).

Feed intake: 3 kg = 1095 kg.

Feed consisting of ca. 20% broken rice, 30% rice bran and 50% waste including green feed and oil cakes.

Average nutrient contents: CP: 105 g/kg; DCP: 73.7 g/kg; P: 4.9 g/kg.

	N (kg/y)	P (kg/y)
Intake	18.3	5.4
Digestible intake	12.9	1.3
Retention	3.2	0.7
In faeces	5.4	4.1
In urine	9.7	0.6

Growing pig

Live weight gain: 70 kg in ca. 210 days.

Feed conversion ratio: 4.8. Feed intake = 70 * 4.8 = 336 kg per pig.

Annual feed intake = 336 * 365/210 = 584 kg per year.

Feed consisting of ca. 20% broken rice, 30% rice bran and 50% waste including green feed and oil cakes.

Average nutrient contents: CP: 105 g/kg; DCP: 73.7 g/kg; P: 4.9 g/kg.

	N (kg/y)	P (kg/y)
Intake	9.8	2.9
Digestible intake	6.9	0.68
Retention	2.7	0.6
In faeces	2.9	2.2
In urine	4.2	0.08

Laying hen

Egg production: 2.7 kg.

Feed intake: 31.0 kg.

Feed consisting of c. 35% broken rice, 30% rice bran and 35% waste including green feed, oil cakes and scavenged seeds.

Average nutrient contents: CP: 111 g/kg; DCP: 80.5 g/kg; P: 4.75 g/kg.

	N (kg/y)	P (kg/y)
Intake	0.55	0.15
Digestible intake	0.40	0.03
Retention	0.05	0.006
In faeces	0.15	0.12
In urine	0.35	0.024

Broiler

Live weight gain: 1.5 kg in 120 days.

Feed conversion ratio: 5. Feed intake = 5 * 1.5 = 7.5 kg per broiler.

Annual feed intake = 7.5 * 365/120 = 22.8 kg.

Feed consisting of ca. 35% broken rice, 30% rice bran and 35% waste including green feed, oil cakes and scavenged seeds.

Average nutrient contents: CP: 111 g/kg; DCP: 80.5 g/kg; P: 4.75 g/kg.

	N (kg/y)	P (kg/y)
Intake	0.41	0.11
Digestible intake	0.29	0.023
Retention	0.13	0.018
In faeces	0.11	0.087
In urine	0.17	0.005

Annex II - Emission of NH₃ from pig houses

Based on: Groenestein (1994)

The following methods are used to reduce NH₃ emission:

Flushing

The freshly deposited manure is flushed from the slurry pit under the slatted floor using aerated or acidified liquid manure. Both aeration and acidification reduce the NH₃ concentration in the slurry. Water is not used as flushing liquid because the addition of water will increase the volume and eventually increase the costs of transportation of the slurry. A design of a v-shaped gutter can be used to flush the slurry, when a flushing frequency of at least twice a day is needed. A second flushing system makes use of a smooth sloping floor underneath the slatted floor. The urine flows away immediately and the faeces is flushed out six times a day.

Reduction of surface area of slurry pit

Reducing the area of the slurry pit can be achieved by replacing part of the slatted floor with a solid floor. This is possible when animal movement is restricted and the place where the slurry is dropped is fixed. When animal movement cannot be restricted, a precondition to reduce ammonia emission is that the animals do not foul the solid floor.

Influence dunging behaviour

Dunging behaviour can be influenced to reduce fouling of the pen and ammonia emission.

Covering slurry

Covering the slurry with a liquid top layer of oil can prevent diffusion of ammonia from the slurry to the air in the house. Fresh faeces and urine fall through the oil and are covered directly.

Removal of slurry by scraper systems

Various designs of scraper systems beneath the slatted floor are possible. The pit floor itself can be designed in various ways. The smoothness of the floor determines how clean the floor can be scraped. Type of material and coating are important for the smoothness. If the floor slopes, the urine can flow away instantaneously. For emission prevention, the scrapers have to remove the slurry several times per day.

Annex III - Slurry application techniques with limited NH₃ emission

The development of slurry application techniques is based on two principles:

1. dilution of the slurry with water to reduce the NH₃ concentration, and thus the NH₃ vapour pressure in the slurry; and

2. minimization of exposure of the slurry to the air.

A 1:2, 1:3 or 1:4 slurry:water mixture is pumped into a conventional slurry spray tank or into a sprinkler system and spread over the surface. More water in the mixture results in a lower NH₃ concentration and, thus, lower NH₃ volatilization. Application of diluted slurry is also possible in irrigation systems other than sprinklers and often practised in combination with anaerobic lagoons.

This technique requires a sufficient water supply.

Raining-in

Artificial rain and slurry can be applied simultaneously in one operation, or first the slurry then the rain in two operations. For the first situation a special spray tank with two compartments (called Duospray) has been developed in the Netherlands. The compartment for the slurry has its spray head located slightly under the one for water.

A sprinkler installation can be used for the rain. Again, sufficient water should be available.

Immediate tillage

When the slurry is worked in, either simultaneously with application in one operation or in a second operation immediately after slurry application, the most important parameter influencing NH₃ volatilization is the intensity of the mixing of slurry and soil. A sufficient mix can be obtained by disc harrow, cultivator, plough, on rotary cultivator.

Sod manuring

A sod manuring machine cuts the sod of grassland. Cutting elements make narrow furrows of 5-7 cm depth, into which the slurry is deposited. The distance between the furrows is 20-30 cm. This machine causes considerable damage to the sod when compared with injection. NH₃ volatilization is minimal. Furthermore, the machine cannot be used when the soil is too hard and dry.

Injection

Slurry injection machines have knives to cut the sod and allow for placement of the slurry at 10-20 cm depth. Damage to the sod is limited and NH₃ volatilization minimal. When the soil is too hard and dry, this machine too cannot be used.

Drag hose machine

This machine consists of a row of hoses that end 5-10 cm above the soil surface or drag at the surface. The slurry is placed in strips of 5-10 cm width at a distance of about 30 cm. Compared to conventional surface spreading, this technique reduces the area of manure exposed to the air by 67-85%.

Drag foot machine

This is an innovation of the drag hose machine, specially designed for grassland. It adds to the drag hose machine foot-shaped components located at just above the soil surface level, but under the grass canopy. Slurry is thus deposited on the soil surface but covered by the green mass of growing grass.

Costs of these systems will vary strongly depending on local prices and conditions, e.g. irrigation will be less expensive than an injector (Schulte, 1993), but it requires sufficient water as well as an appropriate layout of the farmland. Costs of immediate tillage are negligible, but requires adjusted labour management and is only applicable on arable land before sowing.

Most other techniques mentioned require substantial investments in machinery. In the Netherlands, the additional costs above that of a slurry spray tank are:

-injector:	ca. NLG. 30,000, (US$ 17,600)
-sod fertilizer:	ca. NLG. 27,500, (US$ 16,200)
-drag foot:	ca. NLG. 29,000, (US$ 17,000).

Because of the differences in capacity, application costs of manure with the above machinery by contractors are ca. NLG. 5, 8 and 5 per m^3, (US$ 2.9, 4.7 and 2.9),respectively compared to NLG. 4.- (US$ 2.4) for surface application by a slurry spray tank (IKC, 1993b).

The benefits of N gains through reduced emission generally outweigh the investment costs, if additional slurry storage capacity permits proper timing of application (costs of additional storage were included in the calculations; Wijnands et al., 1987). Availability of capital may however be a limiting factor for investment in such machinery, especially in developing countries.

Annex IV - Average composition of animal manure

Animal manure consists of more than only N and P, and many positive claims of manure utilization are related to other nutrients. However, the composition of manure is highly variable. For slurry, nutrient content is correlated to the dry matter content but variation remains high as feed characteristics and, particularly for N, manure management are highly variable (Fleming and Mordenti, 1993). For farmyard manure, this variation is even higher due to the added variation of characteristics and amounts of bedding material (Müller, 1980). Therefore these values should only be regarded as very rough indications.

	DM	N-tot	P	K	Ca	Mg	Na	Mn	Source
Cattle - FYM	710-775	16.0-38.0	3.8-11.9	3.7-6.9	1.2-6.5	1.6-3.0		0.05-0.11	3
Cattle - slurry	40-100	2.4-5.1	0.4-0.9	2-5.3		0.2-0.7			1
Cattle - slurry	95	4.4	0.8	4.6	1.5	0.6	0.7		2
Cattle - FYM	215	5.5	1.7	2.9	2.9	0.9	0.7		2
Cattle - urine	25	4.0	0.09	6.6	0.07	0.12	0.7		2
Pigs - slurry	30-88	3-6.8	0.9-1.8	1.7-3.7		0.5-0.7			1
Growing pigs-slurry	75	6.5	3.9	6.8	3.5	1.5	1.0		2
Sows - slurry	55	3.6	3.6	3.6	4.6	1.2	0.6		2
Sows - FYM	230	7.5	3.9	2.9	6.4	1.5	0.7		2
Sows - urine	10	2.0	0.9	2.5	0.6	0.1	0.1		2
Poultry - manure	230-630	12.5-51	4.6 - 10	4.9 - 11		1.7-2.1			2
Laying hens - slurry	145	10.6	3.5	5.1	12.3	1.2	0.8		2
Broilers - FYM	580	26.0	10.5	17.8	14.7	3.6	3.0		2
Broilers - FYM	777-864	22.4-35.2	7.7-13.0	14.8- 20.7	11.2-16.3	2.6-3.1	3.1-5.1	0.085-0.21	3

Sources:	1: Fleming and Mordenti (1993), range of means from various publications.
	2: IKC (1993a).
	3: Müller (1980), recalculated means from various publications.

Annex V - Fossil energy requirements for the production of inorganic fertilizer

Fossil energy requirements for artificial fertilizer production vary, mainly depending on the type of fertilizer which is produced and, to a lesser extent, the technology used. In table XIV, present and practical minimum energy requirements for some specific types of fertilizer are given as well as average requirements for N, P and K.

	19831	Practical minimum2	The Netherlands, 19943
Urea	76.26	54.2
Ammonia nitrate	66.59	50.7
Ammonia sulphate	58.05	39.3
Average for N	78.134	-	38.9
Rock phosphate A	2.12	-
Rock phosphate B	4.27	-
Rock phosphate C	7.10	-
Single superphosphate, non-granular	5.05	-
Single superphosphate, granular	8.55	-
Triple superphosphate	2.8 or 8.2	0.9
Average for P2O5	17.455	-	4.3
Average for K2O	13.706	-	2.6

¹: Mudahar and Hignett, 1987a.
²: Mudahar and Hignett, 1987b.
³: Brand and Melman, 1993; including packaging and transport.
⁴: World average including packaging, transport and application of 8.59 MJ/kg N.
⁵: World average including packaging, transport and application of 9.75 MJ/kg P₂O_5.
⁶: World average including packaging, transport and application of 7.32 MJ/kg K₂O.