ATLANTIC SOIL AND WATER CONSERVATION CHALLENGES

Transcription

1 ATLANTIC SOIL AND WATER CONSERVATION CHALLENGES Gordon Fairchild, Ph.D., P.Ag., Soils Specialist, ECSWCC and Jean-Louis Daigle, P.Eng., P.Ag., Director, ECSWCC Environmental Farm Planning Worshop Crystal Palace Convention Centre, Moncton, NB March 30, 2001 Agriculture in Atlantic Canada climate: humid & temperate (high rainfall) much is on hilly, rolling land, much is on soils naturally susceptible to erosion : from morainal deposits soils strongly leached, acidic (Podzols) soil loamy or sandy in texture dense subsoils that impede drainage 1

2 Atlantic Soil and Water Conservation Challenges The climate, soils naturally susceptible to erosion, intensive agriculture in some areas, and economic constraints have led to several soil & water conservation challenges for Atlantic Canada Atlantic Soil and Water Conservation Challenges The climate, soils naturally susceptible to erosion, intensive agriculture in some areas, and economic constraints have led to several soil & water conservation challenges for Atlantic Canada soil erosion & soil degradation NPS pollution -fertilizer,, pesticide & manure use water quality & protection of water supplies water for irrigation habitat & biodiversity climate change 2

3 Many Atlantic soils show serious soil erosion and degradation Excessive Soil Erosion by Water Excess Runoff Soil Compaction Loss of Organic Matter Loss of Available Soil-Water Loss of Crop Productivity Estimated annual on-farm costs at 40 million dollars in Atlantic Canada by AAFC in 1985 Sol Erosion & Degradation (Soil Quality) It is estimated that 60-70% PEI & NB potato land experiences excessive soil loss as a result of farming undulated slopes 3

4 Causes and effects of soil degradation AAFC. (1995) The Health of Our Soils Soil Erosion and Degradation AAFC. (1995) The Health of Our Soils 4

5 Sheet & rill Soil soil Management erosion are & Conservation being addressed by: 1. Better Crop Rotation 2. Strip cropping 3. Winter cover crops 4. Conservation tillage 5. Green manures 6. Residue management 7. Mulching 1, & rill & gully soil erosion (steeper fields) by: 8 8,9 8. Cross-slope & contour cropping 9. Diversion terraces & grassed waterways 10. Sub-surface drainage, subsoiling & 4x4 tractors 11. Straw cover, mulches

6 Some progress, with over 20,000 acres in each of NB & PEI protected with appropriate combinations of: diversion terraces grassed waterways strip cropping residue management mulching crop rotation cover crops etc Soil Erosion and Degradation Do Soil and Water Conservation Systems work? AAFC Study - Effectiveness of Terracing Systems NW NB on NSCP SQEP Benchmark sites 20/22 Site 20 Up & down - slope cultivation, no terraces Site 22 Cross-slope cultivation, diversion terraces, grassed waterways 6

7 Soil and Water Conservation Systems AAFC Study - Effectiveness of Terracing Systems NW NB on NSCP SQEP Benchmark sites 20/22 Runoff & soil loss were greatly reduced on site with soil and water conservation system. Terraces and grassed waterways very effective mm Runoff (mm) Crg(90) Pa(91) Pa(92) C(93) Pa(94) Moy (90-94) Terrasse terraced Sens Up & de down la pente slope t/ha Site 22 Soil loss (t/ha) Crg(90) Pa(91) Pa(92) C(93) Pa(94)Moy (90-94) terraced Terrasse Sens Up & de down la pente slope Soil and Water Conservation Systems Challenges to the Adoption of Conservation Practices: Market Pressures & Land Value Land Availability and Land Tenure Farming Efficiency & Land Lost Economics of Soil Conservation?? Before

8 More concern recently for Water Quality & Farm Runoff Issues Concern for cattle access to streams as a cause of streambank erosion, sediment in streams, soil compaction and coliform contamination of water & streambank fencing 8

9 Events such as the Walkerton tragedy have served to served to heighten awareness of Water Quality & the protection of Water Supplies Walkerton E.coli 0157:H7 Outbreak Tragedy & Reality agricultural runoff was a source of contamination of the well water in the Walkerton tragedy, even if it was not the only cause. Agriculture is going to be under increasing public scrutiny and pressure for water quality reasons. 9

10 Heightened public interest in Watercourse Protection & Riparian Management Ex: NB Watershed & Wellhead Protection for Drinking Water Supplies aimed mostly at NPS - fertilizer, pesticides & bacteria 10

11 What is agriculture s role in water quality? Agriculture and Agri-Food Canada. (2000) Point-source pollution: industrial plant, smoke stack, etc. Easier to identify and control Non Point-source pollution (NPS): all of the field or diffuse runoff pollution sources in a watershed, eg: farms, forestry, roads, etc. Diffuse source is harder to identify and control Agriculture is Non Point-source pollution (NPS): 11

12 Surface Water Quality Key issues of surface water contamination in agricultural regions in Canada are: sediment nutrients pesticides bacteria sediment entering surface water Sediment enters streams from soil erosion sediment can fill in streams and ditches sedimentation can reduce or elimination aquatic habitat sediment carries with it bound to the sediment: nutrients ( N & P) - eutrophication organic matter - soil degradation pesticides bacteria 12

13 Nutrients, bacteria and pesticides enter surface waters chiefly from: Nitrogen (N): in runoff from fertilizer and manure Phosphorus (P): mostly as P attached to sediments; some as soluble-p. (soils with high soil test P a problem) Bacteria: in runoff from manure (tile drains, septic systems, sewage sludge) Pesticides: in runoff from fields (spills, filling sprayers, spray drift, etc.) Sediment in farm runoff after very heavy showers (NW NB) Black Brook 6,000 t / yr? 13

14 N and P in surface waters eutrophication - the excess phosphorus (P) in runoff from fertilizer and manure causes a growth of algae in the water. This algal bloom consumes oxygen in the water, killing fish or reducing aquatic habitat Nutrients: N and P in surface waters eutrophication - nitrogen (N) can sometimes be the cause eutrophication in estuarine waters. The anoxic conditions may affect aquaculture (shellfisheries) or reduce aquatic habitat HighNH 4 + can also affect fish in streams 14

15 Nutrients: N and P in surface waters NB AAFC Black Brook Watershed study, : PEI concentrations of nutrients in surface water Nitrate-N ranged 2 to 9 mg/litre Phosphate generally < 100 mg/litre (1 mg/litre background) (AB, QC guidelines lower) (G. Somers, PEIDFE) surface water nitrate concentrations have risen, but may have stabilized? Pesticides in surface waters concentrations rarely exceed drinking water guidelines, but sometimes aquatic guidelines 15

16 Bacteria in surface waters Bacteria can be and are sometimes found in surface waters, particularly near manured fields Ground Water Quality Key issues of groundwater contamination in agricultural regions in Canada are: nitrates (methhemoglobinemia, cancer) pesticides bacteria 16

17 Agro-chemical entry into groundwater AAFC The Health of Our Soils Agro-chemical entry into groundwater Pesticide movement into groundwater is related to: solubility,.the more soluble a pesticide, the more likely it is to leach into groundwater. stability (or persistence).the longer the pesticide remains, the more likely it is to leach into groundwater. Our newer generation of pesticides today are less soluble, lower dose, less persistent and less likely to leach into groundwater today than years ago. 17

18 Bacteria entry into Ground Water Usually related to: poor well construction (too shallow, poor cap, poor grout, shallow grout, poor initial disinfection) wells location too close to manure storage, manure runoff, manure application, or septic systems preferential transport through tile drains abandoned wells etc Ground Water Quality Nitrate concentrations in groundwater can be elevated in some intensively agricultural areas some potato production areas NW NB, Grand Falls, Drummond, Saint-André some BC interior valleys Abbotford-Sumas aquifer BC 18

19 NB, NS, PEI studies. Ground Water Quality Pesticides can be found in groundwater, but are usually well below drinking water quality guidelines Ground Water Quality ** Bacteria can be found in groundwater AB % QC NB Man PEI NS ** indicates «presence» of total coliform, not E. coli 0157:H7 19

20 Soil and Water Conservation Challenges & Issues water quantity issues (both surface & ground water): for irrigation for habitat & biodiversity Sharing water resources: who gets the top priority? Low Flow Maintenance Soil & Water Conservation may now also have to account for Climate Change considerations? 20

21 Possible Atlantic Climate Change Considerations slightly increased annual precipitation? (or decreased?) warmer winters, earlier & larger runoff? growing season and temperature? increase (?) decrease (?) increasing climate variability, eg: droughts, floods, temperature? increased frequency of intense rainfalls? Increased climate variability in the intensity of storm events increased runoff & erosion? Drummond NB farm - 40 mm intense rainfall event during 15 min 21

22 Atlantic Soil and Water Conservation Challenges The climate, soils naturally susceptible to erosion, intensive agriculture in some areas, and economic constraints have led to several soil & water conservation challenges for Atlantic Canada soil erosion & soil degradation NPS pollution -fertilizer,, pesticide & manure use water quality & protection of water supplies water for irrigation habitat & biodiversity climate change Tools For Change & Adaptation Environmental Farm Plan EFP workbook BMP Development Codes of Practice Agri-Conservation Clubs Economic benefits of S &W Conservation Precision Agriculture & Env. Geomatics Program Incentives or Tax Benefits Self assessment 22

23 EFP Tools must be an integrated approach The Win-Win Approach Air Quality BMPs Water Quality Soil Health Tools For Change & Adaptation EFP workbook Environmental Farm Plan (EFP) Self assessment Environmental Farm Planning Workshop Crystal Palace Convention Centre, Moncton, NB March 29-31,