Quality of compost and bedding issues ---- Compost Bedded Loose Housing Dairy Barn

Transcription

1 Quality of compost and bedding issues ---- Compost Bedded Loose Housing Dairy Barn

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3 Success for the dairyman is based on both the management of the bed and Compost Bedded Pack the interaction of the bed and the Loose Housing Dairy Barn surrounding managed environment within the structural envelope

4 Management of the Bedded Pack

5 What we have learned from assessment of compost beds

6 Barn Facility Measurements

7 Environmental Measurements Air temperature, relative humidity, and air velocity and wind direction (0.05 and 1.2 m);

8 Bedding Temperature Measurement Bedding temperature surface and two different depths (0.10 and 0.20 m); Bedding Moisture Measurement Bedding moisture surface to 0.20 m

9 Stocking Density ft2/cow Recommended Recommended Stocking Density Adjusted Stocking Density ft2/cow

10 Average Water Holding Capacity = 72.7%

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12 8 deep Outside 4 deep Surface

13 Temporal Compost Bed Monitoring

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15 Winter Fall

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18 Bed Carbon/Nitrogen Ratio Carbon/Nitrogen Ratio Bedding Moisture (% - wb) 0"- 4" 80

19 Temporal Compost Bed Monitoring

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21 Stirring the Bed 2 x per day religiously Stirring Depth

22 Tillage

23 How Can You Reduce Bedding Use In Winter Allow cow access to pasture in good weather Increase air circulation in barn when cows are milking or in pasture But not to point of losing too much bed temperature Use kiln dry sawdust in winter, green sawdust during warmer weather Stockpile and/or store kiln dry sawdust under roof or tarp

24 Why Don t All Packs Work? Stocking density too many cows! Poor distribution of cows Bed material used straw, cedar Insufficient bedding volumes Inadequate/ineffective stirring Stirring frequency (less than 2x/day) Depth of stirring (<10-12 ) Compaction from tractors Starting pack in the late fall/winter Too much ventilation in winter no curtains Barn design flaws

25 What we have learned from assessment of barn structural details

26 Potential Design Flaws Not enough space per cow Proximity to feed Inadequate ventilation Not enough feed bunk Sidewalls too low (<16 ) space (24 to 30 per cow) Too close to other buildings Not enough water space Too small ridge opening (2 feet of tank perimeter Poor ridge opening design per 15 to 20 cows Fan availability/placement Cow flow/traffic Lack of eave overhangs or bottlenecks curtains to block rain and Waterers in pack cold wind Concrete base? Building orientation Walls along pack?

27 Barn Ventilation 45% 40% 35% 30% 25% 20% 15% 10% 5% 0% Box fans High Volume Low Speed Fans (HVLS) Natural ventilation Tunnel ventilation

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29 Ridge Design Name Open Ridge Open ridge with cover Overshot Hoop structure Capped ridge Recommended Type

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31 Airflow Patterns Overshot ridge - OVR Open ridge with chimney - ORC The smoke was visually observed when it was passed through and over the ridge opening

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33 Develop CFD model of compost barn Wind direction open ridge (OR) Wind direction Closed ridge Overshot

34 Develop CFD model of compost barn Wind direction Wind direction Overshot Wind direction

35 Position in the Landscape HIGH GROUND: -To reduce the effects of local obstructions such as trees and other buildings -Takes advantage of upslope air currents HILLSIDE CUTS: DEPRESSIONS: -In upland wind shadow -Bowl depression subject to temperature inversions -Does reduce winter radiation losses to sky

36 Feedbunk Space

37 Waterer Space

38 Compost Bedded Pack Success Maintain bed temperature for: destruction of pathogens increased moisture vaporization

39 To generate enough heat -Need to have a high porosity bed for a level of oxygen to sustain the compost process. (But not too high or too low) - Bed stirring - Bedding type - Bedding particle size

40 Stirring the Bed Wheels following tillage tool leads to compaction and lower temperatures Pulling tillage tool

41 Moisture Levels Just right leads to clean, comfortable conditions for cow Waterers in bed area can create a too wet condition Too wet leads to poor conditions and a dirty potentially cold stressed cow

42 Sawdust/ Shavings Type Bedding Materials Sawdust

43 Type Bedding Materials A B Sawdust Shavings C Sawdust/ Shavings

44 Type Bedding Materials Not Recommended Wood chips Hammer milled

45 What are Alternative Bedding Sources Efforts underway to increase sawdust supply Green vs kiln dried sawdust Ground corn cobs Finely chopped soy straw/stubble Kenaf? Peanut shells? Other ideas? Need more definitive research and producer ideas and cooperation to answer these questions

46 1:1 Chopped Straw:sawdust Ground Straw

47 Some Concerns for Greenhouse Gas Generation

48 Questions?

49 Soil Aggregate Microenvironment Model Distribution of physiological properties within an aggregate/particle. Lines represent isobars of O2 concentration (%). Coyne, Typical Soil Aggregate Sylvia, et al Prin. & Appl. Of Soil Micro. Pearson. Upper Saddle, NJ.

50 Structure Dimensions Barn Length - ft Width - ft Bedded Area Length - ft Width - ft

51 Roof Pitch Recommended

52 Barn Orientation 40% 35% Recommended 30% 25% 20% 15% 10% 5% 0% N (N-S) NE (NE-SW) E (E-W) NW (NW-SE) / \

53 Side Wall Eave Height Recommended

54 Recommended Recommended Ridge Opening to Barn Width Ratio

55 Ridge Opening Detail - Apparent vs Effective -

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57 Compost Bedded Pack Temp, of 24 to to 12 Depth of Compost Bed Ventilation/Circulation Air Ambient F Aerobic Zone Aerobic/ Anaerobic Transition Zone Anaerobic Zone Soil

58 Pack Moisture Control Biological activity generates heat which helps to dry the bedding material Bedding cannot absorb all the water from urine and manure without evaporation of water Too wet of a bedded pack reduces aeration, slows biological activity, slow heat generation and water evaporation

59 % Added Water Evaporated 66% 70% 85% 97% COMPOSTING BED MATERIAL INCREASES WATER EVAPORATION Composted Bedded Pack Water in Bedding % Added Water Evaporated 36% 53% 80% Bedded Pack 95% INCREASING AIR VELOCITY OVER BED MATERIAL INCREASES WATER EVAPORATION