Agronomic values of anaerobically digested cattle manure (ADM)

Transcription

1 Agronomic values of anaerobically digested cattle manure (ADM) Xiying Hao Agriculture and Agri-Food Canada, Lethbridge Research Centre Presented at 2014 Agri-Energy Forum, Pacific Agricultural Show

2 Livestock Current trend is towards large confined operations o Produce huge quantities of manure o Applied to relatively a small land area Alberta has 4.9 M cattle (40% of the national herd) o County of Lethbridge licensed feedlot capacity: ~900,000 head o Several feedlots >25,000 head Manure is disposed of rather than used as fertilizer Manure management is becoming a environmental issue

3 Livestock manure handling Manure in feedlot pen Bio-digestion Land application Composting Stockpiling

4 Digestate Anaerobic digestion (AD) of animal manure is an environmentally attractive option Anarerobically digested manure (ADM), also called digestate, is one of the final by-products of the biogas energy industry ADM is rich in available N and P

5 Objective: 5 To investigate agronomic values of the AD o o Barley forage yield Forage barley nutrient uptake and quality Soil quality Greenhouse gas emission 5

6 Materials and methods Five treatments and two application rates o (1) control: no amendment () o (2) fresh manure (M and M2) o (3) ADM (D and D2) o (4) liquid in ADM removed to produce separated solids (SS and SS2) o (5) SS processed into pellets (PE and PE2)

7 Materials and methods Materials: Fresh cattle manure (33-50% solid) Digestate (4-9% solid) Separated solids (24-44% solid) Pellets (65 to 80% solid) Experimental sites St. Albert (Central Alberta) Lethbridge (Southern Alberta)

8 Biogas plant Vegreville, AB

9 Materials and methods Two rates (Assuming 50% TN available for current crop year): 100 and 200 kg N per ha per year for Lethbridge 135 and 270 kg N per ha per year for St. Albert Recommended rate of synthetic fertilizer N for forage barley is 45 to 148 kg N ha -1 for irrigated soil and 45 to 113 kg N ha -1 for non-irrigated Black soil Surface applied without incorporation (no-till soil conservation practice) Manually raked soil surface to mix with top 2-5 cm soil Seeded on same day or one day after amendment application

10 Materials and methods 10 Duration: four years ( for Lethbridge, for St. Albert), Residual year in 2012 for Lethbridge Barley grown and harvested at the soft dough stage as forage for making silage feed AC Metcalf 2-row barley for 2008 to 2010, and Chigwell 2-row barley for 2011 and 2012.

11 Measurements 11 Yield, TN, TP and other macro (K, Ca and Mg) and micro-nutrients (Cu and Zn) contents Soil physical and chemical properties after four years GHG emission during the growing season over four years

12 Cattle manure Separated solids Pellets 1 Pellets 2

13 Application of amendment

14 Results 14 Initial soil conditions Site Soil Depth OM OC TN TP NH 4 -N NO 3 -N Olsen-P cm % % % % mg/kg mg/kg mg/kg Leth. D. Brown Irrigated St. Al. Black Rain-fed Green color indicate a higher NO 3 content than typically observed in soil

15 Weather conditions 15 Site Temperature Precipitation Seeding date Annual June-Sept Annual June-Oct Leth June June June July May Long-term St. Al June June June May Long-term Green color indicates a higher and red color lower than the long-term average

16 Metric t/ha Lethbridge barley forage yield (a) 1 X rate M D SS PE (b) 2 X rate PE and PE2 received pellet application in 2010, other years same as SS and SS2 M2 D2 SS2 PE2

17 Yield (kg ha -1 ) Year Julian date T ppt C mm Long-term Julia date

18 St. Albert barley forage yield (a) 1 X rate M D SS PE (a) 2 X rate M2 D2 SS2 PE PE and PE2 received no pellets in

19 Metric t/ha Yield difference compared to fresh manure at Lethbridge 6 (a) 1 X rate (b) 2 X rate 4 2 D-M SS-M PE-M D-M SS-M PE-M Avg Avg -2

20 Metric t/ha Yield difference compared to fresh manure at St. Albert 8 (a) 1 X rate (b) 2 X rate 6 4 D-M SS-M PE-M D-M SS-M PE-M Avg Avg

21 Lethbridge barley forage N uptake kg N / ha (a) 1 X rate M D SS PE (b) 2 X rate M2 D2 SS2 PE Avg Avg There were no pellets for 2008, 2009 and 2011

22 N uptake kg N / ha St. Albert barley forage N uptake (a) 1 X rate M D SS PE (b) 2 X rate M2 D2 SS2 PE Avg. There were no pellets in Avg.

23 40 t Manure Simplified nutrient flow from fresh manure to digestate and separated solids Fresh manure 60% moisture TN content = 2.2% (DM) TP content = 0.7% (DM) Water N = 2.7 g/kg (DM) Water P = 0.9 g/kg (DM) 100 t Digestate 80 t Separate liquid Water N = 192 kg Water P = 61 kg 100% water 60% water 40% solid Water = 24 t Water N = 43 kg Water P = 14 kg DM = 8 t Org N = 176 kg Total P = 156 kg DM = 8 t Org N = 176 kg Total P = 156 kg Digestion Water = 92 t 50% C CH Water N = 219 kg 4 Water P = 70 kg 92% water DM = 8 t 8% solid Org N = 176 kg Total P = 56 kg Solid-liquid separation Screw press 20 t Separate solid Water = 12 t Water N = 27 kg Water P = 9 kg 60% water DM = 8 t 40% solid Org N = 176 kg Total P = 56 kg

24 Amendment comparison (same amount of dry matter) M D* SS PE Wet weight, tonne (50) DM (tonne) 8 8 (4) 8 8 Water, tonne (46) 12 4 Organic N, kg (88) Total P, kg (28) Water N, kg (109) Water P, kg 7 70 (35) 9 9 *Red font numbers inside bracket indicate actual amount of digestate applied relative to other amendments

25 Lethbridge barley forage P uptake kg P / ha (a) 1x rate M D SS PE (b) 2x rate M2 D2 SS2 PE Avg Avg

26 St. Albert barley forage P uptake kg P / ha (a) 1x rate M D SS PE (b) 2x rate M2 D2 SS2 PE Avg Avg

27 Ca/P ratio in Lethbridge barley forage (a) 1x rate M D SS PE 6 4 (b) 2xr ate M2 D2 SS2 PE Avg Avg. Optimum Ca/P ratio is 1.5 to 2 > Ca/P < 1 could cause hyperparathyroidism in cattle and decreased milk production and fertility (Smart and Cymbaluk 1997).

28 Ca/P ratio in St. Albert barley forage (a) 1x rate M D SS PE (b) 2x rate M2 D2 SS2 PE Avg Avg. Optimum Ca/P ratio is 1.5 to 2 > Ca/P < 1 could cause hyperparathyroidism in cattle and decreased milk production and fertility (Smart and Cymbaluk 1997).

29 K/(Ca+Mg) ratio in Lethbridge barley forage 4 3 (a) 1x rate M D SS PE 4 3 (b) 2x rate M2 D2 SS2 PE Avg Avg. K/(Ca+Mg) > 2.2 increases occurrence of grass tetany illness in cattle No pellets in 2008, 2009 and 2011

30 K/(Ca+Mg) ratio in St. Albert barley forage 4 3 (a) 1x rate M D SS PE 4 3 (b) 2x rate M2 D2 SS2 PE Avg Avg K/(Ca+Mg) > 2.2 increases occurrence of grass tetany illness in cattle No pellets in 2009

31 Other consideration Type of amendment used had minimum effect on feed quality in our 5-year study at two Alberta locations Other factors o Crop variety o Soil type o Weather condition o Agronomic practice (seeding date)

32 Summary Effective use and cycling of nutrients is critical for livestock crop production Digestate (liquid form) application seems to produce highest yields, N and P uptake Separated solids performed as well as fresh cattle manure Pellets did not performed as well as fresh manure We need to improve our understanding of nutrient behaviour to ensure long-term sustainability

33 Acknowledgements The workshop organizers Collaborators: o Alberta Agriculture and Rural Development (ARD) o University of Manitoba Technical staff at AAFC Lethbrige and ARD Ag-Tech Centre at Lethbridge Digestate from Highmark Renewables Inc.

34 Thank your