Managing nitrogen flows in dairy farming systems

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Managing nitrogen flows in dairy farming systems

Jean-Louis Peyraud

To cite this version:

Jean-Louis Peyraud. Managing nitrogen flows in dairy farming systems: Main issues and proposed options. RedNex Final conference, Aug 2013, Paris, France. �hal-01210715�

Innovative and practical management Innovative and practical management

approaches to

approaches to red reduce uce nitrogen n itrogen excretion by ruminants ex cretion by ruminants

Managing nitrogen flows in dairy farming systems:

Main issues and proposed options

Jean Louis Peyraud

A request from Ministry for Agriculture and Ministry for the Environment

• A synthesis of updated knowledge on N flows in livestock farming systems, from the animal to the regional scale,

with a specific focus on farm level taking account of all forms of N

• Identify possible actions to improve livestock farming

systems sustainability (e.g. techniques, management, re- design of systems, economic and policy incentives)

• Expert assessment based on the analyse of 1332 references conducted by a panel of 22 scientists from a wide range of

disciplines

Role of the dairy farming

systems on N flows

Animal manures have a major contribution to soil N supply – 2110 kt provided by mineral N

– 1820 kt provided by livestock manure (70% from the ruminants) – 520 kt provided by symbiotic fixation (forage legumes = 80%) Huge amounts of N are used for livestock enterprises

− More than ¾ ot total N used in agriculture is used for livestock

− Imports of very large amounts of soyabean meal in Europe . 50% of the protein used in intensive animal production

systems (apart forages)

. Equivalent to 19 M ha of ‘virtual land’

. 25% of grassland area on a CP basis

(Citepa, France)

Livestock plays a key role in N cycle

and emission of reactive Nitrogen

NH

emissions

(Leip et al., 2011)

European Nitrogen Assessment, 2011)

Total livestock N consumption and emission in different EU regions ^(kg

N/km²/an)

NO

emission

N consumption

Impacts of N losses from dairy systems depend of landscape sensitivity

Grassland (% AA)

Livestock concentration and short term rotational grassland AA (% total area)

(Greendairy project, Pflimlin et al, 2006)

93 23 266

20 240

15

117 33

257 10

155 10

502 5 349

3 N Balance

(kg/ha de AA) Nitrate content

(mg/L)

N flow in dairy

farming systems

Numerous and mutually dependant N flows

0 Manure

42

Crops Prod.

30 Anim Prod.

Feeds 50

Litter 2

96 Fertilizer 80

Manure 6

N Fixation 9

Seeds 1

Dairy and crops

80 ha, 82 LU, 25 ha cereals Farm N surplus = 76 kg / ha

Adapted from Jarvis et al (2011) with data from typical french farms

96 Fertilizer

Manure

N Fixation Seeds

42

Crops prod.

Fields 130 5

63

79

Herds Manure

storage

Dairy and crops

80 ha, 82 LU, 25 ha cereals Soil N surplus : 61 kg/ha

Animal housing

Numerous and mutually dependant N flows

Adapted from Jarvis et al (2011) with data from typical french farms

96 Fertilizer 80

Manure 6

N Fixation 9

Seeds 1

Fields 42 130 5

63

79

Animaux Bâtiment Stockage

Effluents

Herds Manure

storage

71 68

Feeds 50

Litter 2

96

0 Manure

Crops prod.

30 Anim Prod

Dairy and crops

80 ha, 82 LU, 25 ha cereals

Animal housing

Numerous and mutually dependant N flows

Adapted from Jarvis et al (2011) with data from typical french farms

96 Fertilizer 80

Manure 6

N Fixation 9

Seeds 1

42 Crops prod Fields

130 5

63

79

Animaux Bâtiment Stockage

Effluents

Herds Manure

storage

71 68

Feeds 50

Litter 2

0 Manure 30

Anim

Prod 10 5

NH

15 N

- N

O

3 48

NH

- N

- N

O

NO

, N org

Atmospehric N 20 Soil N variations + 15

Animal housing

Efficiency of farm : 48%

Adapted from Jarvis et al (2011) with data from typical french farms

Numerous and mutually dependant N flows

+ 1000 kg milk/ha  + 5.2 kg of N exported per ha and the milk response reached a plateau for large N inputs

The marginal efficiency is very low

(Rotz et al., 2005) – meta analysis

N inputs (kg/ha)

N outputs (kg/ha)

600

400

200

0

0 200 400 600

Beef

Dairy products Losses

Inputs (kg/ha) 200 600 milk N (kg/ha) 62 89

A major effect of stocking rate in the

excess of N at farm level

Options to improve N efficiency and to reduce

environmental impacts

Manure Herds

Soils Crops

Efficiency Drivers Knowledge

<20 to 35 %

Genetic merit Feeding practices Herd management

++

Options to increase N efficiency at farm level

Margins of progress +

Win-win strategy

Effect of herd management

- Age at first calving,

Increasing genetic merit moderately increases efficiency

- + 1000 kg/lactation = - 6% N excreted / t milk

- But associated to an increased demand of (imported) protein + 3 % of N conc/ton milk and + 6% N excreted / ha forage

Age at first calving 32 26 25 25 CP content (%DM) 14.3 14.8 15.2 13.1 Milk (kg/lactation) 7100 7450 9600 10200

(Delaby and Peyraud, REDNEX)

N excreted (kg/t milk)

0 5 10 15 20 25 30 35

Farm 1 Farm 2 Farm 3 Farm 4 Dairy cows

DC+heifers

Improve N efficiency: herd

managment and feeding (1)

Feeding management :

- Major effect of forage N content (grass > maize silage)

MS+GS 6 months + 6 months grazing = 121 kg N excreted MS 12 months = 91 kg N excreted /year

- Major effect of the supply of Metabolic protein + 200 g MP / day = + 18 kg N excreted / year - Supply of degradable N

A deficit of 5% do not affect animal performances

- The limitation of ruminal degradability of feed protein remains a major strake

Improve N efficiency: herd

managment and feeding (2)

Response curves of dairy production to N supply

80 85 90 95 100 105 110 115 120 25

27 29 31 33

2.0 2.2 2.4 2.6 Milk (kg/day) N excreted / N milk

+ 0,7

+ 0,5

MP supply/NE suply (PDIE/UFL)

0 -5

-10 -15

-20 -25

0 1

-1 -2 -3 -4

Milk response (kg)

MP supply High

Low Medium

Improve N efficiency: herd managment and feeding (3)

Degradable N deficit (%)

(Vérité and Delaby, 1998)

Manure Herds

Soils Crops

Losses Drivers Knowledge

20 to 80%

NH

Housing > grazing Housing >spreading

>storage Treatments

Large uncertainty

(emission)

Efficiency Drivers Knowledge

<15 to 35 %

Genetic merit ( eff) Feeding practices Herd management

++

Options to increase N efficiency at farm level

Margins of progress ++

Win-win strategy

Margins of progress +

Win-win strategy

Dairy cows

(100 kg N

excreded) Building Storage Soil

Soil 59 kg

41 kg

2.7 kg (7%)

1.1 kg

4.9 kg (8%)

0.4 kg 4.9 kg

(8%)

0.2 kg 6.4 kg

(11%)

0.1 kg

Localized application Injection

Feeding, Temp,

Civil engineering Treatment

(phase separation, composting, methanisation…)

N intake(g/d)

NH3-N-emissions(g/d)

Aguerre et al (2010)

600 700 800 900 20500

60 100 140 180 220

Reducing N emissions to increase available N for crops

Improve N efficiency:

management of manures (1)

NH₃ N₂O

Localized: 25-35 %

Injection : 70-90%

Agronomical valorisation : Prediction of N fertiliser value

short term (current year) Long term (second year)

(Task Force on Reactive Nitrogen, 2010).

20 40 60

20 40 60

80 100

80 100

- Prediction based on classifying per "type of product” is not sufficient

- Decision support systems to predit N bio disponibility (based on knowledge of the dynamics of volatilisation and mineralisation of N compounds -Azofert) - It still remains difficult to precisely adjust mineral N supply

Improve N efficiency:

management of manures (2)

Liquidphases

Liquidmanures (dairy) Liquid manures (pig) Solid manures

Manure Herds

Soils Crops

Efficiency Drivers Knowledge

Medium (> 40%)

High inputs ( eff) Grassland, legumes,

crop rotation

+

Losses Drivers Knowledge

20 to 80%

NH

Housing > grazing Housing>spreading

>storage Treatments

Large uncertainty

(emission)

Margins of progress ++

Some trade-off

Efficiency Drivers Knowledge

<15 to 35 %

Genetic merit ( eff) Feeding practices Herd management

++

Options to increase N efficiency at farm level

Margins of progress ++

Win-win strategy

Margins of progress +

Win-win strategy

Using pasture for regulating and recycling N flows

- Efficient N recycling thanks to an active crop throughout the year

50 55 60 65 70

80 90 100

N balance (kg N/ha/y)

N leached(kg N/ha/y) Maize

Grass

Maize silage 12 months 6 months

grazing 0 6 months

N intake (F+ C) 2.8+2.5 6.4+1.3

N excreted (ton/y) 3.7 4.8

Spreadable N (ton/y) 2.7 4.2

ForageN/spreadable N 0.99 1.21

40 cows, 7500 kg milk

Improve N efficency:

rotation and land use (1)

(from Peyraud et al., 1995 and Vérité and Delaby, 2000)

Chardon (2008)

- Less volatilisation than in barn (10% vs 25% N excreted)

- Losses of nitrate are low (so long as stocking rate is moderate and

grassland is not ploughed before 4-5 years)

Using forage legumes

-

Increase protein autonomy for animal feeding . Tall legumes are good companion for Maise silage . Mixed sward allow high animal performances

. Grain legumes (peas) can replace soyabean meal for pig and dairy - Increase Energy autonomy : the production of 1 UFL (7100 kJ NE) of

forage requires 1,2 (PRG), 0.9 (maize silage), 0.4 MJ (PRG-WC)

(Besnardet al., 2006)

- Increase autonomy for Nmin thanks to atmospheric fixation of N:

180 to 200 (pea), 150 to 250 (white clover), 300 kg N/ha (Lucerne)

(Vertèset al., 2010)

- Productivity per unit area might be reduced

Improve N efficency:

rotation and land use (2)

Using N fixing intermediate crops

Without NFIC With NFIC

Improve N efficency:

rotation and land use (3)

(Leterme and Morvan, 2010)

0 100 200 300 400 500 600

01/01/1996 09/02/2000 19/03/2004 27/04/2008

Cumulative leaching (kg N ha

N MIN

N MIN + NFIC -

Manure

Manure+NFIC

Improving landscape management (denitrification, NH3 captation)

Collective manure management for exporting

Relocating animals Locking forward

synergies between farms (forages, straw,

manure…)

Changing local farming systems

Options to better use N at landscape level

Herds

Manure Soils and

Crops

Farm

Grazing

Herds

Manure Soils and

Crops

Farm

Grazing

Conclusions

Farm level

- Efficiency of N is low, varies depending on the scale considered and results of complex interactions

- Increased efficiency of the cow does not always lead to an increased efficiency at the farm scale

- Integrated vision of the livestock production systems is required

- Trade off between water quality (NO

) and air quality (NH

, N

O) - There are some possibilities for using better and less N

Landscape level

- Risks and impacts depend on the characteristics of the territories:

need to better account of the local territorial vulnerability - Concentration of farming systems is crucial for the impacts

- Optimisation at farm scale might not be sufficient to reduce impacts.

Options were identified

Manure Herds

Soils Crops

N conc, N min Reduce Inputs

Maximise internal recycling Herd feeding and management

- MP supply (rumen degradability, AA profile) - Tolerable deficit in the supply of degradable N - Heifers number

Land management

- Forage and grain legumes - Grassland within the rotation - Cash crops

- High quality forages

Manure management

- NH₃ looses (feeding, storage, application) - Treatment (anaerobic, composting, phases,

separation, normalisedfertilisers…) - Prediction of the availability of N

Limits :

- Productivity per ha, acceptability

-Increased sensitiveness to unforeseen events -Need of indicators to evaluate the system and to

propose ways of progresses

increase efficiency

Options were identified

Thank you for your attention