Soil Health. National Science Teachers Association Los Angeles, California March 31, Sidney W. Davis Assistant State Soil Scientist - California

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1 Soil Health National Science Teachers Association Los Angeles, California March 31, 2017 Sidney W. Davis Assistant State Soil Scientist - California Zahangir Kabir Soil Health Regional Specialist- CA, NV & Pac Is.

2 Dominant farming systems: poor soil health? Photos: Bianca Moebius-Clune

3 Poor Soil Health Practices Fallow Intensive Tillage practices No residue cover

4 Raindrops Impact on Bare Soil Dislodging soil particles and splashing them 3 to 7 ft away Raindrop splash pattern from a slope landscape, (Envr. Soil Physics, Hillel, 2005) Splash Sheet Rill Gully Channel erosion

5 Breakdown of Soil Structure by Habitual Tillage To single grain (structureless) and loss of From granular structure Soil Organic Matter (Both soils are Columbia very fine sandy loam)

6 Downward Spiral of Soil Degradation in annual systems 1. Intensive tillage, residue oxidizes rapidly, low diversity, no surface cover Platy structure indicative of Soil Compaction 2. Soil organic matter decreases, plow pan forms at depth 4. Surface becomes compacted, crust forms 3. Aggregates break down 6. Soil organic matter, nutrients, and top soil lost 8. Crop yields decline 9. Environmental services lost 5. Infiltration decreases, runoff & wind erosion increases 7. Ponding & persistent wetness, but LESS soil water storage; less rooting; nutrient reservoir depletes; less diversity of soil organisms, more diseases Modified from Building Soils for Better Crops

7 Lake Erie Becomes Eerie Dramatic algal bloom resulting from eroded nutrients finding their way into waterways, streams and lakes. National Geographic, 2013

8 Conservation Practices No-till/Strip-till Crop rotation USDA-ARS Degradation of soil organic matter and structure can be reversed!

9 Conservation Practices Idaho Soil and Water Conservation District

10 Grower-Collaborator Field Site Winter Fallow (NCC) Winter Cover Crop (CC) Same soil type, both fields, side-by-side comparison

11 Discharge Hydrograph Comparing Growers Fields m m 3 / s m3s m m mm 29 Mon Dec AM 29 December 2003 Early Cover Storm Crops Season (December 29th, 2003) Cover Cropped ( m3) Non Cover Cropped ( m3) Precip (49.7 mm) 9AM 12PM 3PM 6PM 12/29/2003 3:00:00 AM - 12/29/2003 9:00:00 PM Fallow m3s mm 3AM 25 Wed Feb February 2004 Late Storm Precip. Season (February 25th, 2004) Cover Cropped ( m3) Non Cover Cropped ( m3) Precip (52.7 mm) 6AM 9AM 12PM 3PM 6PM 9PM 26 Thu 3AM 6AM 9AM 12PM 3PM 2/25/2004 2:00:00 AM - 2/26/2004 4:00:00 PM Storm event 1 Storm event 2 Kabir & Horwath

12 Grower Field Total Winter Discharge Comparisons Fallow (NCC) Cover Crops Precipitation Discharged as Runoff Average Peak Runoff Velocity 16.3% 0.52 m/s 0.9% 0.24 m/s Kabir & Horwath

13 Walnut Orchard: Fallow and Cover Crop in Solano County Field with no cover crop Field with cover crop Identical Soil Types (Soil Hydrologic Group B) Photo taken on February 07, 2017

14 Almond Orchard: Fallow and Cover Crop in Yolo County Photo taken on February 21, 2017

15 Fallow and Cover Crop Fields in Yolo County Photo taken (T. Rolfes) on January 8, 2017

16 Mycorrhizal hyphae network extending the root zone of a cover crop: the crop provides sugar energy from sun light; the hyphae mines water and minerals for the cover crop. D. Read

17 Soil Aggregate Stability 60 Hyphal length = (%WSA) Fallow Rye Oats Rye + Oats Mycorrhizal hyphal length (m g -1 ) Kabir and Koide, 2002

18 Management Challenges of Cover Crops Adoption in California May delay planting of the main crop Pest and disease may carry over to the main crop Water use and nutrient competition Economic loss May interfere harvesting of the main crop

19 Cover Cropping in Furrows R. Smith, UCCE

20 Growing Cover Crops in Vineyards Mountain terrane Alternate rows S.W. Davis, NRCS Chuck Ingels, UCCE

21 May interfere in Almond Harvesting

22 Organic Matter boosts Water Holding Capacity (Hudson, 1994, as redrawn in Franzluebbers, 2010)

23 What is Soil Health? The continued capacity of a soil to function as a vital, living ecosystem that sustains plants, animals, and humans (NRCS, 2015).

24 Important Soil Functions Support productive plants and livestock Be stable and resist erosion Efficient at cycling nutrients internally Allow H 2 O to enter quickly & store Drain well to avoid drowning plant roots Resist pests, pathogens, and disease Help plants grow during stressful events

25 Soil Health Principles & Soil Function Provide Continuous Living Roots Minimize Disturbance Maximize Biodiversity Maximize Soil Cover

26 Soil Health Principles & Soil Function Provide Continuous Living Roots Protects Soil Maximize Biodiversity Minimize Disturbance Maximize Soil Cover Minimize Disturbance & Maximize Soil Cover Maintain stable aggregates Reduce erosion and runoff risk Buffer temperature Reduce evaporation Maintain soil organic matter Water-holding capacity, infiltration, storage Nutrient-holding capacity Habitat

27 Soil Health Principles & Soil Function Provide Continuous Living Roots Maximize Biodiversity Minimize Disturbance Feeds Soil Biota Maximize Soil Cover Maximize Biodiversity & Maximize Living Roots Break disease/pest cycles Stimulate/change belowground diversity Increase soil organic matter Increase nutrient cycling Enhance plant growth Increase predator & pollinator populations

28 Agricultural Management Practices and Soil Health Choose practices that feed the soil organisms and protect their habitat (soil aggregate) Lehman, R. M., et al. (2015). J. Soil Water Conserv. 70(1): 12a-18a.

29 Upward Spiral Soil Health Management Systems for Healthy Soils 9. Crop yields increase, lower cost, lower risk 7. Less energy and tillage needed, more water stored, better rooting, more nutrient access, greater soil organism diversity, less disease 8. Field conditions are more resilient and consistent 5. Infiltration increases, erosion by wind and water decreases 3. Aggregates rebuilt 1. Reduced tillage, increased biomass with more rooting, higher diversity, surface cover 4. Available water holding capacity increases 2. Soil organic matter increases, reduced compaction from rooting, decreased erosion 6. More soil organic matter, nutrients, and top soil built Modified by Dr. Dorn Cox from Building Soils for Better Crops

30 SOM and Nitrogen application Regenerative Agriculture Apply 1/3 rd less irrigation water 240 N lbs/ac 3 % SOM 0.5% SOM 120 N lbs/ac Jesse Sanchez San Joaquin Valley farmer Sano Farm in Firebaugh, CA

31 SOM and Nitrogen application Soil Health Practices rebuilds SOM, increases Soil Fertility and reduce Weed Pressure Weed pressure is low thus reduce herbicide N lbs/ac 5 % SOM 0.9 % SOM 50 N lbs/ac 1990 New Salem, North Dakota 2016 Rocky Bateman 5 th generation farmer

32 Fuel cost and Yield of Wheat Soil Health Practices reduce Fuel Cost and increase Crop Yield Fuel cost 50 bushels/a 16 Bushels/A Reduced 25% 1990 New Salem, North Dakota 2016

33 Thank You!