Managing Compost Bedded-Pack Barn/Waste System

Transcription

1 Managing Compost Bedded-Pack Barn/Waste System Joseph Taraba Department of Biosystems and Agricultural Engineering University of Kentucky Compost bedded, loose housing, dairy barn concept Summarize barn structural components to optimize ventilation and circulation Understand the compost process Function and management of the compost bed The COMPOST BEDDED LOOSE HOUSING BARN and the solid composted waste is an important alternative manure management practice to allow flexibility in utilization of plant nutrients and organic matter for soil fertility. OTHER ENVIRONMENTAL BENEFITS: - Improved air quality odor, GHGs (?) - Reduced fly populations

2 Success for the dairyman is based on both: the management of the bed and the interaction of the bed and the surrounding managed environment within the structure Heat Water Heat Water Design Considerations Barn dimensions account for feed and water space Provide cow access along the long side of the barn to feed alley Fence on top of wall Orientation of barn Ridge opening (12.5 cm/5 m barn width) Design Considerations Eave overhangs 1/3 of eave height Concrete feed alleys: 4.25m to 5m wide No water access from pack Walkways every 40 to 45 m and at each end Gutters to reduce runoff Sidewall curtains to reduce cold winds & blown rain

3 Design Considerations Side wall opening above knee wall 4.5 to 5m Proximity to feed Build for maximum number of cows milking during year Consider milk production and cow size for area per cow Two types fans: HVLS ceiling fans for air speeds at cow level of 4 m/s Box Panel fans for air speeds up to 7 m/s The Ideal Composting Process NH 3 N 2 O CH 4 Management of the Bedded Compost Pack

4 Temperature Dynamics Adding feces, urine and bedding continuously changes static bed composting process Feces Urine Bedding For Equal Heat Loss Surface Areas : Compost Bed Aerobic Zone (20 cm tillage depth) Compost Bed Aerobic Zone (30 cm tillage depth) Compost Windrow Aerobic Zone Stirring the Bed Heat Loss to Air Surface Area (sq. ft.) Heat Generation Volume (cu ft) Compost Bedded Pack Profile 2 x per day Depth of Compost Bed religiously cm stirring depth with deep tillage Temp, o C C Aerobic Zone Rototiller tillage depth cm Ambient 60 to 120 cm 25 to 30 cm Ventilation/Circulation Air Aerobic/ Anaerobic Transition Zone Anaerobic Zone Soil

5 Compost Bed Temperature - C Dry Compost Bed Environment ~ 50% (wb) Summer 25 cm 20 cm 15 cm 10 cm 7.5 cm 5 cm 2.5 cm Surface Ambient T Aerating system, Suckling air 25 9:37 10:02 10:27 10:52 11:17 11:42 12:07 12:55 13:20 13:45 14:10 14:35 15:00 Time of Day MOST IMPORTANT MANAGEMENT FACTOR Biological activity generates heat which helps to dry the bedding material Too wet of a bedded pack reduces aeration, slows biological activity, slow heat generation, increases compaction and reduces water evaporation Bedding must absorb all the water from urine and manure that is not evaporated. Unless area per cow more than doubles in winter / wet season

6 Optimum Moisture Content for Conventional Maximum Composting Rate Higher MC of bedding (> 60%) compacts to high density under cow hoof pressure reduces void fraction and increases particle size Larger particle size of compost reduces oxygen diffusion and reduces heat generation Ahn, 2005 Microorganisms are not just on particle surfaces but interior can be anaerobic Kentucky has 2 seasons: warm (April - November) and cold (December - March) Argentina has 2 seasons: rain (October March) and no-rain (April September) Each season requires different management strategies for the barn and the compost bed cm stirring depth with sweep cultivator Rototiller tillage depth cm

7 Bed Cow Density,Temperature,and Bedding Use (Peanut Shells) m2/cow -- Kg Peanut Shells/cow Bedding added ~ 3 days 27 Bedding added ~ 3.3 days 34 Bedding added ~ 7.2 days C Temperatura Temperature Media of Bed de at la 20 Cama cm C Kg Bedding de cascara/vaca/día Added/cow/load Carga Bed Area/cow m2/vaca Type Bedding Materials A B Sawdust Sawdust + Shavings C Shavings Shavings

8 Bed Carbon/Nitrogen Ratio Green vs kiln dried sawdust Rice hulls Finely ground grain crop biomass (<2 cm) soybean straw wheat straw corn stover miscanthus sorghum stover Peanut shells Other ideas Need more definitive research and producer ideas and cooperation to answer these questions Carbon/Nitrogen Ratio Bedding Moisture (%-wb) 0"-4 (0 to 10 cm) Bedding Type Sawdust /Shavings Wheat Straw /Corn Stover Soybean Straw/Peanut Shells C/N Ratio Questions?

9 1400 # Holstein, 100 # milk/day, 75% in rest area 95 # water Voids 108 # water in rest area 95 # water 4 mph 100 ft 2 4 mph 100 ft # Holstein, 100 # milk/day, 75% in rest area 1400 # Holstein, 100 # milk/day, 75% in rest area Voids 108 # water in rest area 95 # water 120 # water 130 f 2 4 mph 100 ft # Bedding 4 mph

10 1400 # Holstein, 100 # milk/day, 75% in rest area 1400 # Holstein, 100 # milk/day, 75% in rest area Voids 108 # water in rest area 120 # water 130 f 2 Voids 108 # water in rest area 120 # water 130 f 2 X 4 mph 4 mph