ARCHIVE: Nitrate Vulnerable Zones (NVZs) - Guidance for Farmers. Standard values, manure sampling (Leaflet 3 - PB12736c)

1. Standard values needed to calculate your manure storage capacity requirements and compliance with the livestock manure N farm limit

The standard values in Tables 14 are calculated from the daily values given in Schedule 1 of the Regulations. You must use these values to calculate:

  • your required manure storage capacity (see Leaflet 4), and
  • your compliance with the livestock manure N farm limit (see Leaflet 5).

In the case of permanently housed pigs and poultry, you may use alternative approaches (i.e. ENCASH or sampling and analysis) to derive alternatives to the “Total N produced by livestock” figures in Tables 2 and 3 below.

The Tables also provide figures for the number of animals per hectare that will supply the livestock manure N farm limit of 170 kg N/ha/yr. These figures are to be used as a guide only and to provide a rough indication of how close your farm is to the limit given the number of livestock on your farm.

The figures provided in Tables 2 and 3 are based on an assumed level of occupancy by livestock. If the occupancy on your farm is different to the occupancy values shown in the tables, you should adjust the values of total N produced and volume of excreta using the following equation:

Actual total N produced/excreta = Standard value (from table)      x Actual occupancy
Standard occupancy

Actual volume of excreta = Standard value (from table)      x Actual occupancy
Standard occupancy

Table 1: Nitrogen and excreta production from cattle

Cattle Total N produced (kg/year)
(notes a, b)
Volume of excreta (m³/month) Animal numbers per ha to comply with maximum N loading (170 kg/ha N per year)
1 calf (all categories) up to 3 months 1.4 (note c)  0.21 121
1 dairy cow from 3 months and less than 13 months 29 (note d) 0.60 5.9
1 dairy cow from 13 months up to first calf 61 1.20 2.8
1 dairy cow after first calf (over 9000 litres milk yield) 115 1.92 1.5
1 dairy cow after first calf (6000 to 9000 litres milk yield) 101 1.59 1.7
1 dairy cow after first calf (up to 6000 litres milk yield) 77 1.26 2.2
1 beef cow or steer (castrated male) from 3 months and less than 13 months 28 (note c) 0.60 6.1
1 beef cow or steer from 13 months and less than 25 months 50 0.78 3.4
1 female or steer for slaughter 25 months and over 50 0.96 3.4
1 female for breeding 25 months and over weighing up to 500 kg 61 0.96 2.8
1 female for breeding 25 months and over weighing over 500 kg 83 1.35 2.0
1 non-breeding bull 3 months and over 54 0.78 3.1
1 bull for breeding from 3 to 25 months 50 0.78 3.4
1 bull for breeding 25 months and over 48 0.78 3.5

Notes:

  1. Includes an allowance for N losses from livestock housing and manure storage.
  2. Different units are used for cattle less than 13 months – see notes c & d below.
  3. Total N produced (kg) during the two months that the animal is in this category.
  4. Total N produced (kg) during the ten months that the animal is in this category.

Table 2: Nitrogen and excreta production by pig places

Pigs Occupancy (%) Total N produced
(kg/year)
(note a)
Volume of excreta
(m³/month)
Animal places per ha to comply with maximum N loading (170 kg/ha N per year)
1 weaner place, 7 to 13 kg 71 1.0 0.03 170
1 weaner place, 13 to 31 kg 82 4.2 0.05 40.5
1 grower place, 31 to 66 kg (dry fed) 88 7.7 0.10 22.1
1 grower place, 31 to 66 kg (liquid fed) 88 7.7 0.18 22.1
1 finisher place, 66 kg and over (dry fed) 86 10.6 0.13 16.0
1 finisher place, 66 kg and over (liquid fed) 86 10.6 0.26 16.0
1 maiden gilt place, 66 kg and over 80 11.1 0.13 15.3
1 sow place, 66 kg and over, with litter, up to 7 kg, fed on diet supplement with synthetic amino acids 100 16.0 0.33 10.6
1 sow place, 66 kg and over, with litter, up to 7 kg, fed on diet without synthetic amino acids (low protein diet) 100 18.0 0.33 9.4
1 breeding boar place, from 66 kg to 150 kg 100 12.0 0.15 14.2
1 breeding boar place, 150 kg and over 100 17.5 0.26 9.7

Notes:

  1. N produced in excreta is per pig place and includes an allowance for N losses from livestock housing and manure storage.

Table 3: Nitrogen and excreta production by poultry places

Poultry Occupancy (%) Total N produced
(kg/year)
(note a)
Weight of excreta
(tonnes/month)
Animal places per ha to comply with maximum N loading (170 kg/ha N per year)
1000 replacement layer pullet places, up to 17 weeks 89 210 1.1 800
1000 laying hens in cages, 17 weeks and over 97 400 3.5 420
1000 laying hen places, free range1, 17 weeks and over 97 530 3.5 (note b) 320
1000 broiler places 85 330 1.5 510
1000 replacement broiler breeder pullet places, up to 25 weeks 92 290 1.1 590
1000 broiler breeder places, 25 weeks and over 95 700 3.4 240
1000 turkey places (male) 90 1,230 4.3 140
1000 turkey places (female) 88 910 3.2 190
1000 duck places 83 750 2.5 230
1 ostrich 100 1.4 0.05 (note b) 121

Notes:

  1. N produced in excreta is per 1000 poultry places (except ostriches) and includes an allowance for N losses from livestock housing and manure storage.
  2. When calculating storage requirements, you should make an allowance for the proportion of time that birds are not housed. Commonly, free range laying hens are housed for 80% – 90% of the time.

Table 4: Nitrogen and excreta production by sheep, goats, deer and horses

Livestock type Total N produced
(kg/year)
(notes a, b)
Volume of excreta per livestock type (m³/month) Animal numbers per ha to comply with maximum N loading (170 kg/ha N per year)
1 lamb, 6 to 9 months 0.5 (note c) 0.05 340
1 lamb, 9 months and over, to first lambing, first tupping or slaughter 0.7 (note d) 0.05 242.8
1 sheep, less than 60kg, after lambing or tupping. For ewes this includes one or more suckled lambs up to 6 months 7.6 0.10 22.4
1 sheep, over 60kg, after lambing or tupping. For ewes this includes one or more suckled lambs up to 6 months 11.9 0.15 14.3
1 goat 15.0 0.10 11.3
1 deer for breeding 15.2 0.15 11.2
1 deer, other 12.0 0.11 14.2
1 horse 21.2 0.74 8.1

Notes:

  1. Includes an allowance for N losses from livestock housing and manure storage.
  2. Different units are used for lambs – see notes c & d below.
  3. Total N produced (kg) during the three months that the animal is in this category.
  4. Total N produced (kg) assuming the animal is in this category for six months.
ADLib logo Content provided by the Agricultural Document Library
© University of Hertfordshire, 2011