Impact of changes in nitrogen and energy inputs at farm level. Léon Šebek. Efficiency and Environmental impact

Transcription

1 Impact of changes in nitrogen and energy inputs at farm level Efficiency and Environmental impact Léon Šebek Wageningen UR Livestock Research The Netherlands Innovative and practical management approaches to reduce nitrogen excretion by ruminants

2 Introduction (1) Challenge for farmers Produce sufficient food Reduce environmental impacts Dairy farm challenges Data source De Marke... Data since 1992

3 Experimental dairy farm De Marke Strict environmental objectives Whole farm approach for sustainable dairy farming Dry sandy soil

4 Objectives De Marke Objective Maximum %reduction Nitrogen (N) Ammonia 30 kg/ha, animal manure 70 Nitrate 50 mg/liter, upper groundwater 75 Nitrous oxides 3 kg/ha 66 Surplus farm balance 128 kg/ha, incl. deposition and symbiotic fixation 74 Phosphorus (P) Runoff / leaching 0.15 mg/liter, upper groundwater? Surplus farm balance 0.45 kg/ha, incl. deposition 99

5 Characteristics De Marke Animals Animal production Crop production Milking cows 78 Kg milk per cow 8720 Farm area (ha) 54.9 Young stock > 1 year 25 Kg milk per ha Grass (ha) 31.7 Young stock < 1 year 26 Fat content (%) 4.30 Maize (ha) 16.1 Young stock / milking cow 0.65 Milking cows per ha 1.4 Livestock Units per ha 1.7 Protein content (%) 3.42 Whole crop silage (ha) 7.1

6 Introduction (2) Dairy farm challenges Food production (milk and meat) Feed production (energy and protein)

7 Feed production on 50 ha of sandy soil using grass and maize (given a milk production of kg per ha)

8 Feed production for > kg milk/ha Feed purchase needed Protein (DVE) Energy (> kg milk/ha) Impact on environmental burdens? N-cycle

9 Nitrogen cycle Feed Cattle efficiency Herd Milk and meat Crop Crop efficiency Manure Ammoniaemission Soil Nitrate leaching N 2 O emission Fertiliser

10 Farm N cycle NH3 N2O MEAT ANIMALS CONCENTRATE MILK MANURE ROUGHAGE ROUGHAGE HERD MANURE NH3 DEPOSTION ROUGHAGE GRAZING MANURE IN PASTURES MANURE N2O NH3 N2O BIOL. N FIXATION CROP NH3 NH3 FERTILIZER SOIL NH3 N2O NH3 NH3 N2O NH3 = losses animals= input farm = internal cycling ACCUMULATION meat = output farm = farm components LEACHING N2O

11 Goals for sustainable dairy farming Maintain or increase food production Minimise environmental impact Minimise fertiliser purchase Minimise feed purchase Minimise N-surplus How to combine with feed production challenge?

12 Relationship between N-surplus and N-output Source: J. Bos et al., Nutrientmanagement at farm scale. First workshop of the EGF, Quimper, France 2003.

13 How was the low N-surplus achieved? Feeds Fertilisers Feeds Fertilisers Efficiency Efficiency

14 N-efficiencies De Marke 2009 Feeding, milk production, number young stock Low harvest losses 53% crops 93% 19% herd 22% manure 84% 83% 37% 26% Legislation (method) 88% soil 53% Crop rotation Restricted grazing Optimal supply (timing, dose) Legend: N-efficiency De Marke N-efficiency common Dutch practice

15 Herd efficiency relevant? Farm efficiency

16 Impact herd efficiency on farm efficiency

17 Efficiencies of cows and young stock

18 Impact herd efficiency on N-excretion

19 Excretion herd = kg N, kg P 2 O 5 Measure 0 Measure 1 Measure 2 Measure 3 Quotum kg 80 milking cows 7,25 young stock per 10 cows Young stock from 7,25 to 5,5 N-efficiency milking cows 2% increase N-efficiency Young stock 2% increase

20 Impact low N-inputs on Farm N-cycle

21 Decreasing inputs De Marke Feed N and P herd 22% crops 93% 84% Manure manure N and P Feeds? quantity quality 88% soil Fertiliser N and P

22 Impact low inputs on Rumen functioning

23 Decreasing N-surplus and rumen fermentation

24 Impact low inputs on Grass quality

25 Impact decreased fertiliser use on grass quality

26 Effect of decreasing grass quality High feed intake (> 110% of requirements) Milk production (protein) drop Less protein (DVE) available Problem also occurs at commercial farms that minimise environmental burdens

27 Simulation of rumen fermentation Bannink et al, Estimation of the stoichiometry of volatile fatty acid production in the rumen of lactating cows. Journal of Theoretical Biology: 238,

28 Feeding challenges resulting from decreased grass quality Problem Seems protein shortage Is (also) energy shortage Possible solutions Decrease passage rate through rumen Increase N fertiliser Pre-treatment of grass

29 Conclusions (1) High milk production per ha needs farm input of feed (protein) Environmental burdens decrease by lowering farm inputs Farm outputs (food) stay high by increasing efficiencies in farm cycles Herd, manure, soil and crops Herd efficiency is relevant Cow more efficient than young stock

30 Conclusions (2) Decreasing N and P excretion influences all (ex- and internal) farm cycles Feed quality (grass) difficult to maintain Lowers milk production Due to lack of both energy and protein Increases feed and/or fertiliser input Solution not yet clear Nutritional challenge Technical challenge

31 Thank you for your attention!

32 This presentation has been carried out with financial support from the Commission of the European Communities, FP7, KBB It does not necessarily reflect its view and in no way anticipates the Commission s future policy in this area. Innovative and practical management approaches to reduce nitrogen excretion by ruminants