Soil Health and Crop Productivity. Brian Wienhold USDA-ARS, Lincoln, NE

Transcription

1 Soil Health and Crop Productivity Brian Wienhold USDA-ARS, Lincoln, NE

2 Soil Health The continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. NRCS

3 Functions versus Indicators

4 Functions Substrate for plant growth Nutrient source Water storage Recycling and detoxifying others NRCS

5 Indicators Physical Aggregate Stability Available Water Capacity Bulk Density Infiltration Soil Structure Chemical Available Nutrients (N, P, K) ph Electrical Conductivity Biological Fauna Particulate Organic Matter Potentially Mineralizable N Enzymes Organic Carbon

6 Indicators Theme: Measurements of Soil Health Evaluation of the Solvita/Haney test John Sawyer Field indicators for quick assessment Doug Peterson Basic field indicators Mahdi Al-Kaisi Industry s role in developing metrics Debbie Reed Soil Health Institutes Role Wayne Honeycutt

7 Substrate for Plants Bulk Density Soil Structure

8 Substrate for Plants Bulk Density Definition Mass of soil per unit bulk volume. Threshold values Texture Optimum Root restricting Sandy loam < Silty loam < Silty clay <

9 Soil Composition Solid Water Air SOM

10 Substrate for Plants Wheel traffic Avoid wet soils Proper tire inflation Controlled wheel traffic Tillage Proper soil moisture Tillage pans

11 Substrate for Plants Soil Structure Definition The arrangement of primary soil particles into secondary units. Relationship with productivity aeration, rooting, infiltration and water availability

12 Aggregation

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14 Aggregation Maintain surface cover Protects the soil surface from raindrop impact Reduces the impact of wetting and drying cycles

15 Nutrient Source Essential nutrients element necessary for completion of the normal life cycle. Includes: C, H, O, N, P, K, Ca, Mg, S, Cu, Fe, Mn, B, Cl, Ni, and Mo. Types of nutrient cycles Role of organic matter

16 Nutrient Source Types of nutrient cycles Gaseous Oxygen, Carbon, Nitrogen Sedimentary - Phosphorus Macro N, P, K, S, Mg, Ca Micro Fe, Mn, Cu, Zn, Mo, B, Cl

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18 Nutrient Source Organic matter N, P, S, others Fertilizer management Rotations including legumes Cover crops Manure Wienhold et al., 2011

19 Integrated crop and livestock effects John Hendrickson Systems approach for improving soil quality Alan Franzluebbers Organic amendments and cropping diversification Matt Liebman Managing marginal soils Dave Muth

20 Water Storage Infiltration Drainage Available Water

21 Water Storage

22 Water Storage Theme: Linkage between soil health and water quality Economics of Soil Health and Water Quality Tom Buman Soil Erosion: Leading Cause for Damaging Soil and Water Quality Rick Cruse The Value of Improving Soil Health to Improving Water Quality Matt Helmers

23 Water Storage Infiltration Definition Entry of water into the soil Management Surface cover to maintain aggregation and avoid surface sealing. Avoid compaction to maintain macropores.

24 Water Storage Drainage Definition surface movement of excessive water. Management Maintain soil structure. Silt loam with 3% organic matter and a bulk density of 1.3 g/cm saturated conductivity is 1 in./hr. At a bulk density of 1.5 g/cm it is reduced to 0.4 in./hr.

25 Water Storage Available Water Definition Amount of water released between field capacity and the permanent wilting point. Silt loam with 3% organic matter and a bulk density of 1.3 g/cm will store 15 ½ in. of water. At a bulk density of 1.5 g/cm the same profile will store 14 in. of water. A 200 bu/ac corn yield will require ~22 in. of water. Each additional 10 bu. Increase in yield will require an inch of water.

26 Recycling and Detoxifying Decomposition biomass and nutrients Pesticides

27 Recycling and Detoxifying Decomposition biomass and nutrients

28 Recycling and Detoxifying Immobilization Decomposition Pesticides

29 Questions?

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