Better water management for the future of agriculture

Transcription

1 Better water management for the future of agriculture Helen Baulch

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3 If there is magic on this planet, it is contained in water. Loran Eisely

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6 Source: World Resources : People and Ecosystems: The Fraying Web of Life. World Resources Institute, Washington DC (2000). Figure 1: Freshwater availability: groundwater and river flow (2000). In UNEP/GRID-Arendal Maps and Graphics Library. Retrieved 15:50, March 26, 2008http://

7 Water. Valuable. Vulnerable.

8 2011 prairie flooding $4 billion in damages and lost agricultural revenues Alberta floods 2013 $ 5 billion

9 prairie drought was (previously) the most expensive natural disaster in Canadian history

10 10 November 6,

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12 Well contamination (Ontario) 7% -- both. 34% bacterial contamination 14% nitrate contamination <0.5% pesticides Goss et al

13 Well contamination 34% bacterial contamination 14% nitrate contamination Goss et al % 3-20%

14 Nutrient pollution 14 ://

15 Nutrient pollution $2.2 billion per year in the US 15 ://

16 Nutrient pollution Lakes respond to phosphorus in parts per BILLION levels 16 ://

17 r.usgs.gov/edu/irsprayhigh.html

18 All farmers are water managers r.usgs.gov/edu/irsprayhigh.html

19 All farmers are water Most arable production is based on natural precipitation managers Irrigation accounts for 80-90% of the world s consumptive use of water. Agriculture changes the land in ways that affect the quantity and quality of water. Nutrient pollution is the greatest water quality challenge in Canada & globally.

20 All farmers are nutrient managers

21 All farmers are nutrient managers Farming operations can contribute to nutrient pollution when not properly managed.

22 Nutrient pollution is the greatest water quality challenge in Canada & globally. Photo: Reuters

23 Food security Enough food to feed 7 billion + people. (now) 1 billion people are undernourished need 70% more food (population of 9 billion + dietary changes) +biofuels bioindustrial products

24 Food security Enough food to feed 7 billion + people. (now) 1 billion people are undernourished need 70% more food (population of 9 billion + dietary changes) Climate change will greatly affect global food production. Tim Wheeler, and Joachim von Braun Science 2013;341:

25 Food security Enough food to feed 7 billion + people. (now) 1 billion people are undernourished need 70% more food (population of 9 billion + dietary changes) FAO: There is no food security without water security Achieving food security requires management of water, land, aquatic resources, crops and livestock

26 Food security Enough food to feed 7 billion + people. (now) 1 billion people are undernourished need 70% more food (population of 9 billion + dietary changes) Opportunities (+risks + uncertainties) for Canada Tim Wheeler, and Joachim von Braun Science 2013;341:

27 Risks and uncertainties -- Canada Precipitation change by GCM model ensemble Red precipitation decrease very likely Blue - precipitation increase very likely White disagreement about sign of precipitation change (after IPCC 2007)

28 Risks and uncertainties -- Canada Climate change and variability: observed twentieth century droughts were relatively mild when compared to pre-settlement on the Prairies, but these periods are likely to return (and even worsen) during this century (Bonsal et al., 2013)

29 Risks and uncertainties -- Canada As demand for food increases so is competition for resources (water, land) -key-to-albertas-economy-2/

30 Food security Opportunities (+risks + uncertainties) for Canada Effects of nutrients on the environment Water security 30

31 The nitrogen cascade

32 Nitrous oxide (N2O) Potent, long-lived greenhouse gas. Contributor to stratospheric ozone depletion Produced during nitrification and denitrification *Mitigation potential n6679/fig_tab/392866a0_f1.html

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34 Experimental Lakes Area: Is C, N, or P to blame? Simple, but elegant experiment: Add C, N Add C, N, P Result: The part of the lake with P had an algal bloom. Policy change: 1972 Control P in sewage & laundry detergents Result (1970s/1980s):. Lake Erie considered recovered

35 Lake Erie is recovered?

36 Lake Erie is recovered? Why not? 1970s perspective: Point source: discharges occur to a body of water or into the atmosphere at a single location Can t control non-point sources Only controls were on point source (sewage) effluents Nonpoint sources (tributaries) now ~60% of load. (Could further reduce municipal inputs)

37 Lake Winnipeg - algal blooms covered 15,000 km2 in 2007 Photo: Reuters Image: Greenpeace Canada

38 OK, so what do we do? (prairies)

39 Solutions are context-dependent. Snowmelt-driven 39 hydrology restricted limited unlimited snow ice soil Jen Roste Photo: Jane Elliott

40 Snowmelt driven nutrient export Jen Roste, Jane Elliott South Tobacco Creek

41 Most phosphorus and nitrogen are transported in dissolved form. 41 Jen Roste, Jane Elliott South Tobacco Creek

42 Dissolved nutrients are difficult to control

43 % of land prepared for seeding Rapid changes in (some) agricultural practices

44 with implications for nutrient transport. Jen Roste, Jane Elliott South Tobacco Creek

45 drainage affects nutrient transport and downstream flood risk Smith Creek, SK

46 Runoff is a very small proportion of field-scale P budgets. Jen Roste, Jane Elliott South Tobacco Creek

47 This is a difficult message to convey.

48 Farmers are interested.

49 Farmers are interested. The most important thing, is making the right decisions re: application

50 Nutrient pollution Solutions aren t simple Wastewater treatment LIST A BUNCH OF BMPS>>>>>

51 Nutrient pollution Solutions aren t simple Management of nutrients has been identified as a grand challenge for the 21st Century by the U.S. Academy of Engineering

52 Lake Winnipeg Headwater dams Landowner-driven initiative Reduce flood risk P retention Nitrogen removal (Tiessen et al. 2011, Gooding 2015, Galuschik 2015)

53 Wastewater_tre twerpen-

54 The most important thing, is making the right decisions re: application Wastewater_tre twerpen-

55 The challenges for Canadian agriculture World food needs increasing. Climate change effects on global food production will be large. This will present Canada with major opportunities. But While temperature increases and precipitation change may be relatively benign for Canada, climate change effects are uncertain; extremes are expected to increase We are reaching limits of water allocation. Irrigated agriculture will face increasing competition from other water uses The South Saskatchewan river is fully allocated in southern AB.

56 The challenges for Canadian agriculture Agriculture is having important environmental impacts These impacts will have to be addressed. The prairies have been extensively drained to improve cultivatable land areas and workability. This has generated tensions between wetland conservation and agriculture. Recent wet years have focussed attention on downstream effects. There is a need to balance needs for food production with management of other environmental services.

57 The challenges for Canadian agriculture Nutrient pollution remains our grand challenge in terms of water quality. Nutrient export is a SMALL proportion of farm nutrient budgets These exports have had a large effect on our waters. 70% of Canada s nitrous oxide emissions is from agriculture (2013) Our Landscape & climate mean: Managing snowmelt is key. Need ways to manage dissolved nutrient fluxes. The most important thing, is making the right decisions re: application. Unique prairie challenges necessitate integrated solutions

58 Water. Valuable. Vulnerable. If there is magic on this planet, it is contained in water. Loran Eisely

59 If we're to have any hope of satisfying the food and water needs of the world's people in the years ahead, we will need a fundamental shift in how we use and manage water -- Sandra Postel