IMPROVING THE SOIL ENHANCES THE ENVIRONMENT. Protecting our resources

Transcription

1 IMPROVING THE SOIL ENHANCES THE ENVIRONMENT Protecting our resources

2 Contact Information Jerry L. Hatfield Laboratory Director National Laboratory for Agriculture and the Environment Director, Midwest Climate Hub 2110 University Blvd Ames, Iowa (fax)

3 Climate Change Precipitation changes Temperature changes Moving toward extremes

4 Soil Health Factors Water holding capacity Aggregate stability (infiltration) Rooting depth Nutrient cycling and nutrient availability Gas exchange between the soil and the atmosphere (oxygen and carbon dioxide) Residue cover (living or dead) Reduced tillage

5 Linkage to Environmental Quality Water quality Leaching Runoff Air Quality Particulate emissions Nitrous oxide Carbon dioxide

6 Observed U.S. Trends in Heavy Precipitation

7 Observed Change in Very Heavy Precipitation

8 Projected Precipitation Change by Season

9 Spring Precipitation (Ames) Ames Spring Precipitation Precipitation (inches) Year Spring Precip (March-May) Mean Spring Precip The increase in spring precipitation has decreased the number of workable field days in April through mid-may across Iowa by 3.7 in 1995 to 2010 compared to

10 Suitable Field Days Suitable Field Days (Apr 2 - Jun 3) versus April-May Rainfall, Iowa Average ( ) y = x R² = April - May Rainfall (inches)

11 WFD 8 Weekly Workable Field Days: Weekly Precipitation (All States) Precipitation (in)

12 Trends in Precipitation Increase in annual precipitation Shift in seasonality of precipitation

13 Precipitation (in) 40 Annual Precipitation- Minnesota Annual Spring Annual Summer Annual Linear (Annual) Linear (Spring Annual) Linear (Summer Annual)

14 Precipitation Minnesota 0.7 Season Annual to Total Annual- MN Spring Summer Linear (Spring) Linear (Summer)

15 Temperature Change by Decade

16 Projected Temperature Change

17 Ratio Minnesota Temperatures, Maximum Seasonal: Annual Max Temp- Minnesota Spring:Annual Summer:Annual Linear (Spring:Annual) Linear (Summer:Annual)

18 Ratio Minnesota Temperatures, Minimum 2 Seasonal: Annual Min Temperatures- Minnesota Spring:Annual Summer:Annual Linear (Spring:Annual) Linear (Summer:Annual)

19 Temperature Effects on Evaporation 14 Saturation Vapor Pressure (kpa) e* = exp(17.502t a /T a ) Air Temperature (C) ET = ρc p(t 0 T s ) r a + ρc p[e s T 0 e a ] γ(1 + r s ra )r a

20 Carbon Cycle Solar Radiation Carbon Water Nitrogen Soil surface Key Processes Photosynthesis Precipitation N Fixation Respiration Evaporation Mineralization Org Matter decomp Infiltration Denitrification Plant decomposition Runoff Plant decomposition Percolation Cycles interact over time and space with different rates

21 Organic Matter Effects on Available Water Capacity Silt loam Data from Soil Survey Investigation Reports (surface horizons only) - Sands: FL (n = 20) - Silt loams: IA, WI, MN, KS (n = 18) - Silty clay loams: IA, WI, MN, KS (n = 21) Sands AWC = (OM) r 2 = % 22.9% (% by Vol.) Silt loams AWC = (OM) r 2 = 0.58 Silty clay loams AWC = (OM) r 2 = 0.76 OM increase from 1% to 4.5% AWC doubles! Hudson, B. D Soil organic matter and available water capacity. J. Soil Water Conserv. 49(2):

22 Crop residue benefits Simple crop residue on the surface Feeding the complex soil biology working hard for you below the surface.

23 Passive protective blanket Active protective blanket

24 Solar Radiation Nitrogen Cycle Carbon Water Nitrogen Soil surface Key Processes Photosynthesis Precipitation N Fixation Respiration Evaporation Mineralization Org Matter decomp Infiltration Denitrification Plant decomposition Runoff Plant decomposition Percolation Cycles interact over time and space with different rates

25 Nitrogen Cycle Concerned about gaseous losses, N 2 O and nitrate NO 3 - N leaching Our ultimate goal should be to increase Nitrogen Use Efficiency (NUE)

26 General seasonal patterns for precipitation, nitrogen uptake rate by a corn crop, cropping system water use and periods potentially favorable for nitrate leaching from Midwestern corn production.

27 Sub-basin sub-basin border county drain corn soybean N

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29 Nitrous Oxide and Soil Water

30 Reducing N losses Reduction of either nitrate-n or nitrous oxide losses will not occur just by changing rate or form Have to couple rate, form, placement, and timing with water management Gas exchange (oxygen exchange) is a ancillary factor affecting nitrous oxide losses

31 Solar Radiation Carbon Water Nitrogen Soil surface Key Processes Photosynthesis Precipitation N Fixation Respiration Evaporation Mineralization Org Matter decomp Infiltration Denitrification Plant decomposition Runoff Plant decomposition Percolation Cycles interact over time and space with different rates

32 Erosion: How much is tolerable

33 The wind blows too

34 Good Soils = Good Yields Soybean yields across Iowa, Kentucky, and Nebraska County Yield (g m -2 ) Kentucky Iowa Nebraska 180 Y = X. r 2 = 0.72*** Kentucky (Double crop) Mean NCCPI

35 Maize County Yields 1000 Mean County Yield (g m -2 ) Y = X, r 2 = 0.58*** Kentucky Iowa NCCPI-AG

36 NCCPI Across the Midwest

37 CO2 loss (gco2/m2/h) Evaporation (mm/h) 5 4 CO 2 & H 2 O loss from Low vs High Disturbance Drills CO2 loss Evaporation None Low High Disturbance Type 0 0

38 Soil Degradation Spiral Poor Land Management Aggregation Degradation Compaction & crusting Water & Wind Erosion Plant Growth Soil Biology Yield Reduced Soil Productivity

39 Soil Aggradation Climb Efficiency Yield Profit Improved Water Improved Soil Structure Improved Nutrient Cycling Organic Matter Turnover Biological Activity

40 Soils and Environmental Quality Good soils have higher infiltration rates and greater gas exchange result is more water holding capacity and less runoff Attributes which increase soil biology and enhance the soil lead to greater aggregate stability and better nutrient cycling result is less leaching and runoff Increasing organic matter through soil biology will enhance the soil and has to be maintained to be effective