Greenhouse gas emissions from St. Emmanuel and the Holland Marsh in Joann Whalen McGill University January 22, 2018

Transcription

1 Greenhouse gas emissions from St. Emmanuel and the Holland Marsh in 2017 Joann Whalen McGill University January 22, 2018

2 80 0'0"W 75 0'0"W 70 0'0"W 65 0'0"W 55 0'0"N CANADA 55 0'0"N Québec 50 0'0"N 50 0'0"N Ontario St. Emmanuel 45 0'0"N Harrow Holland Marsh 45 0'0"N U S A 80 0'0"W 75 0'0"W 70 0'0"W 65 0'0"W Agricultural Greenhouse Gas Program Research Sites 2

3 Greenhouse Gas Emissions from Organic Muck Soils under Vegetable Production Southern Canada, in particular the Holland Marsh (8500 ha), is known for its organic muck soils of high agricultural value, representing one of Canada s most extensive vegetable-producing regions, generating $35 to $58 million in Gross Domestic Product each year (Vander Kooi 2009). In the Holland Marsh, vegetable crops are irrigated and water table management is practiced. Cultivation and the application of N fertilizers contribute to the decomposition of organic matter and loss of nitrogen through denitrification products (nitrous oxide, N 2 O and dinitrogen N 2 ). 3

4 Greenhouse Gas Emissions from Organic Muck Soils under Vegetable Production Research Objective: Collect data on greenhouse gas emissions (CO 2, CH 4 and N 2 O) from organic muck soils under onion, carrot and cover crop production in the Holland Marsh region of Bradford, Ontario. 4

5 Biological processes leading to GHG production Carbon dioxide (CO 2 ) is produced through microbial and plant respiration Plant roots Soil organic matter decomposition Aerobic soil conditions Methane (CH 4 ) is produced through microbial respiration Fermentation by methanogens However, CH 4 is also consumed by another group of soil microorganisms, the methanotrophs Fermentation by methanogens Anaerobic soil conditions Thus, agricultural soils are a net source of CO 2 and a net sink of CH 4 5

6 Biological processes leading to GHG production Nitrous oxide (N 2 O) is produced through microbial respiration N 2 O NO N 2 O NO N 2 O NH 4 + NO 3 - N 2 Nitrification Aerobic soil conditions Nitrifierdenitrification Denitrification Anaerobic soil conditions Agricultural soils are a net source of N 2 O 6

7 Greenhouse gases were collected by the non-flowthrough non-steady-state chamber method 7

8 Plexiglass bases inserted to 10 cm depth during the growing season 8

9 Headspace gases sampled periodically during the growing season 9

10 Headspace gases sampled periodically during the growing season 10

11 15

12 15

13 15

14 Urea fertilizer added to 5 replicate chambers 14

15 Urea fertilizer added to 5 replicate chambers 15

16 Urea fertilizer added to 5 replicate chambers 16

17 Urea fertilizer added to 5 replicate chambers 17

18 Onion growing in the chamber bases 18

19 Carrot growing in the chamber bases 19

20 Cover crop growing in the chamber bases 20

21 15

22 Greenhouse gas measurements 12 sampling events from May 19 to August 23, 2017 Bruker GC-450 with autosampler Picarro G2201-i Analyzer for δ 13 CO 2 and δ 13 CH 4 Expect delivery of Picarro G5131-i Analyzer to measure δ 15 N 2 O isotopomers 22

23 Ancillary measurements Soil temperature (hand-held digital thermometer) Soil moisture (hand-held TDR) Soil extractable NH 4 and NO 3 concentrations 23

24 Greenhouse Gas Emissions from Mineral Soils under Field Crop Production Research Objective: Collect data on greenhouse gas emissions (CO 2, CH 4 and N 2 O) from mineral soils used for field crop production processing peas, followed by a cover crop in St. Emmanuel, Quebec. 24

25 Pea crop at the St. Emmanuel site 25

26 Pea crop at the St. Emmanuel site 26

27 Pea crop at the St. Emmanuel site 27

28 After pea was harvested, the field was plowed, fertilized and planted with a cover crop 28

29 Parameters measured CO 2, CH 4 and N 2 O concentrations 14 sampling dates from June 8 to November 15, 2017 Soil temperature and moisture Soil physical and chemical properties Bulk density, total C and N, ph, Mehlich-3 P, K and Al, KCl-extractable NH 4 and NO 3 29

30 RESULTS 30

31 Very wet and cold growing season! 31

32 32

33 N 2 O flux was positive (net source) 33

34 N 2 O Flux (mg/m 3 ) N 2 O flux at all sites in the 2014 season May Jun Jul Aug Sep Date Site 1 Site 2 Site 3 Site 4 Site 5 Agricultural muck soils are a small net source of N 2 O 34

35 CO 2 flux was generally positive (net source) 35

36 CH 4 flux was generally negative (net sink) 36

37 Gas fluxes at St. Emmanuel in 2017 CO 2 emissions o Higher CO 2 flux in mid-summer (root respiration and SOM decomposition). CH 4 emissions o Site is a net sink for CH 4. N 2 O emissions o Peak fluxes on July 18 and July 28, Low emissions at other sampling dates (pea was not fertilized, fall-seeded cover crop absorbs NH 4+ and NO 3- from organic N sources). 37

38 Biological processes that produce GHGs N 2 O, N 2 CH 4 NO, N 2 O CO 2 NH 4+, NO 3 - Organic C Anoxic soil Well-aerated soil

39 We now have capacity to separate these biological processes in the field / from field-collected samples N 2 O, N 2 CH 4 NO, N 2 O CO 2 NH 4+, NO 3 - Organic C Anoxic soil Well-aerated soil

40 Physical processes that are responsible for GHG fluxes CO 2, CH 4, N 2 O Production and release N 2 O, N 2 CH 4 Organic NO, compounds N NH 4+, NO 3-, H 2 PO 4-, SO 2-2 O 4 CO 2 Consumption and retention

41 Residence time of gases in soil related to 1. Soil temperature (biological activity/diffusion rate) 2. Soil moisture 3. Porosity / tortuosity (diffusion path) 4. Other? CAN / SHOULD WE MEASURE THIS IN THE FIELD? CO 2, CH 4, N 2 O Production and release N 2 O, N 2 CH 4 Organic NO, compounds N NH 4+, NO 3-, H 2 PO 4-, SO 2-2 O 4 CO 2 Consumption and retention

42 Acknowledgements Thanks to Alexia Bertholon, Wasiq Ikram, Yawen Shen, Ahammad Kamal, Alp Aykul and Hicham Benslim for field and technical assistance. Thank you to Dr. Adamchuk and Dr. Madramootoo s groups for field support. Thank you to Kevin Vander Kooi and Shawn Janse the Muck Crops Research Station, and to Doug Weening for access to fields and logistic support at the Holland Marsh. Thank you to Guy Vincent for access to the field and logistic support at St. Emmanuel. 42

43 QUESTIONS?