Overarching Principles of Soil Health

Transcription

1 Overarching Principles of Soil Health Francisco J. Arriaga Soil Management Specialist Dept. of Soil Science & UW-Extension Wisconsin Chapter of the Soil and Water Conservation Society February 20, 2014

2 Functions of Soil & Soil Health Soil health is the capacity of a specific kind of soil to function, within natural or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation. (Karlen et al., 1997) source: Brady & Weil, 1996

3 Soil Functions Indicators Medium for plant growth Recycle/store nutrients & organic materials Habitat for soil organisms Water storage & purification Texture Structure Infiltration & bulk density Water holding capacity Aggregate stability Soil organic matter ph Extractable N,P, & K Microbial biomass C & N Potentially mineralizable N Soil respiration

4 Soil as Three-Phase System 25% 25% Phases 50% Solid Liquid Gas PHASES Solid: Mineral Organic Liquid: Water & solutes Gas: N 2, O 2, CO 2 & others

5 Soil Structure Aggregates (peds) Source: ATTRA - Soil Quality Publication

6 Aggregate Stability & Soil Health Influenced by Organic matter and organisms Texture Rotation Tillage

7 Soil Properties Affected by SOM Physical infiltration water retention hydraulic conductivity bulk density Chemical CEC nutrient availability buffering capacity source: soilquality.org A2809 Table 6.3

8 Role of Soil Organic Matter Physical soil properties Chemical soil properties Sands: 3 5 meq/100 g Silt loam: meq/100 g Clays: meq/100 g Organic soils: meq/100 g Source: Magdoff and van Es, 2009

9 (Lado, Paz and Ben-Hur, 2004)

10 the Carbon Cycle Source: Magdoff and van Es, 2009

11 Farming for Soil Organic Matter (adapted from National Academy of Sciences, 2009)

12 How is Organic Matter Lost from Soil? Moldboard No Till Cumulative CO 2 (kg C/ha) Time Since Plowing (days) (Rochette and Angers, 1999)

13 Soil Carbon Accumulation & Management continuous corn corn-oats-pasture cool-season grass warm-season grass (Tracy and Zhang, 2008)

14 Water-stable Aggregates & Management SIZE (mm) FALL MB FALL CH NO-TILL CC CSb SbC SbSb Source: Kladivko et al.

15 Water Infiltration & Management Water infiltration of five different tillage systems NT=No-till ST=Strip-tillage (in-row) DR=Deep Rip CP=Chisel Plow MP=Moldboard Plow (Al-Kaisi, 2011) Approximately ¼ of water is lost from the soil with every tillage pass. source: M. Licht & M. Al-Kaisi, 2013

16 SOM & Soil Water Retention Plant Available Water (PAW = FC PWP) 40 WP % silt loam Soil Water Content, % FC % Difference in Plant Available Water = 0.5 inches/ft Soil Organic Matter, % 40 WP % loamy sand Soil Water Content, % FC % Difference in Plant Available Water = 0.3 inches/ft Soil Organic Matter, %

17 Corn Yield Tillage: conventional reduced no-till (Stine & Weil, 2002)

18 Tillage Trends: WDATCP WinTransect Data - Corn Tillage % No-till Chisel Moldboard Other 1 2 8

19 Tillage Trends: WDATCP WinTransect Data - Soybean Tillage % No-till Chisel Moldboard Other

20 The amount of residue on the soil surface is directly related to the erosion rate

21 Crop Residue & Soil Crusts Steps in Soil Crust Formation 1. Bare soil surface Soil surface with cover Plant & Soil Sciences elibrary 2. Source: Magdoff and van Es, 2009

22 Allowable Amount of Soil Erosion Typical T (tolerable soil loss) factor in WI range between 3-5 ton/ac/year How fast does soil form in WI? Wisconsin Glacial Period ended ~11,000 years ago Assuming a 5 deep profile, soil forms at a rate of per year (60 /11,000 years= /yr) In other words, it takes ~180 years for 1 of soil to form naturally in WI

23 Allowable Amount of Soil Erosion But, how much is 1 of soil? If a ft 2 of soil to 1 depth weighs ~7.5 lbs (assumes Db = 1.45 g/cm 3 ) Then, 1 acre of soil to 1 depth weighs 328,294 lbs, or 164 tons/ac Recall most T values in WI are 3-5 tons/ac/yr 5 tons soil/acre = 3.7 ounces soil/ft 2

24 Fertilizer Replacement Costs If a ton of soil has ~2.0 lb nitrogen, 9.0 lb P 2 O 5 and 31 lb K 2 O (10 ppm N, 20 ppm P, and 130 ppm K) 2013 replacement costs of $8.80 per ton of soil lost: N = $1.00, P 2 O 5 = $1.60, and K 2 O = $6.20 (assumes $450/ton urea, $350 ton of DAP, and $400/ton potash)

25 Soil Erosion Degrades Soil Health source: S. Papiernik, 2013

26 Soil Erosion Impacts Crop Productivity source: S. Papiernik, 2013

27 Why Does Soil Health Matters? Erosion level - Slight - Moderate - Severe Source: Arriaga and Lowery, 2003a

28 Compaction Destroys Aggregates granular compaction massive blocky (adapted from USDA Ag Bulletin 199)

29 How Can the Health of a Soil be Improved? Measurement Organic matter Infiltration Aggregation ph Microbial biomass Forms of N Bulk density Topsoil depth Available nutrients Process Affected Nutrient cycling, pesticide and water retention, soil structure Runoff and leaching potential, plant water use efficiency, erosion potential Soil structure, erosion resistance, crop emergence, infiltration Nutrient availability, pesticide absorption and mobility Biological activity, nutrient cycling, capacity to degrade pesticides Availability to plants, leaching potential, mineralization and immobilization rates Root penetration, water/air filled pores, biological activity Rooting volume, water and nutrient availability Capacity to support plant growth, environmental hazard (adapted from Karlen et al. SSSAJ, 1997)

30 It is About Management! Source: Case Quick Start Guide Licht & Al-Kaisi, 2004

31 Water Infiltration Field Day August 2013 Conventional No-tillage photos: Roger Schmidt, NPM Program

32 Root Growth Field Day August 2013 Conventional No-tillage photos: Roger Schmidt, NPM Program

33 CT Roto-tilled NT Soil Organic Matter Field Day August 2013 Organic matter oxidation Conc. H 2 O 2 NT Roto-tilled CT Aggregate stability Slake test photos: F. Arriaga, Soil Science

34 Rotation & Tillage Effect on Corn 0 lb N/ac 50 lb N/ac Corn Alfalfa Corn Soybean Corn Alfalfa Corn Soybean Grain yield, bu/acre Corn Alfalfa 100 lb N/ac Continuous Corn Corn Soybean Corn Alfalfa Continuous Corn 200 lb N/ac Corn Soybean Continuous Corn Continuous Corn CC chisel, disk & cultimulcher CA no-till CS no-till (Stanger & Lauer, Agron. J. 2008)

35 Closing Remarks Organic matter (OM) improves physical and chemical soil properties. Soil biological properties are also improved. Healthy soils are achieved through management practices that enhance SOC accumulation.

36 Thank You! Any Questions? Francisco J. Arriaga Office phone: