Cover Crops for Soil Health and Water Quality

Transcription

1 Cover Crops for Soil Health and Water Quality 2014 SURFACE WATER FORUM - NOVEMBER 12, 2014 JILL L. SACKETT EXTENSION EDUCATOR 1

2 BACKGROUND University of Minnesota Extension Local Extension Educator, Ag Production Systems Cover Crops/Conservation and e-learning USDA Sustainable Agriculture Research and Education (SARE) Minnesota SARE Co-coordinator Grants and Education 2

3 COVER CROPS - DEFINED A non-cash crop grown between two cash crops 3

4 POTENTIAL BENEFITS OF COVER CROPS Increase organic matter Decrease weed pressure Increase nutrient Alternative forage and availability grazing Increase water infiltration Potential alternative crop Increase water holding Wildlife habitat and feed capacity Increase microbial population Decrease soil erosion Decrease compaction 4

5 POTENTIAL RISKS OF COVER CROPS Increased management Establishment Water use Nutrient use Labor Termination Cost Persistence Management changes Tillage Nutrient application Equipment 5

6 SOIL HEALTH Soil Health = Soil Quality Supports the growth of high-yielding, high-quality, and healthy crops Looking for: Fertile Aggregation Resistant to erosion Water Infiltration Water holding capacity Low compaction Low disease Low weed numbers Soil organisms Soil organic matter and humus Resilient 6

7 WHY SHOULD WE CARE? All over the country [some soils are] worn out, depleted, exhausted, almost dead. But here is comfort: These soils possess possibilities and may be restored to high productive power, provided you do a few simple things. ~ C.W. Burkett,

8 WHY SHOULD WE CARE? Soil erosion Nutrient depletion and/or loss Organic matter depletion Compaction Flooding Ponding / Runoff Drought Herbicide resistance Bt resistance Energy dependence Volatile markets 8

9 COVER CROPS AND SOIL HEALTH Cover Crops help build soil quality Soil organic matter (and all that comes with it) Nutrients Microbial population Particularly fungi Saprophytes Arbuscular Mycorrhizi Small Grains Legumes Brassicas 9

10 ORGANIC MATTER IS THE DRIVER 10% more SOM in top 4 inches of soil (about ½ % increase) Additional ½ inch of available water / water storage Additional 10 #/A of mineralized N Tom Kaspar, USDA-ARS 10

11 SOM AND MICROBES Soil Organic Matter Increases water holding capacity Increases nutrient availability Increases water infiltration Increases resiliency Increases ability to deal with pest pressures Microbes Fungi and bacteria decompose plant material Arbuscular Mycorrhizi Associated with 70% of vascular plants Colonize up to 80% or plant host root length Sends out hairs that take up water and nutrients that it shares with plant Produces glomalin which helps with soil aggregate formation Larger invertebrates help with water infiltration, pest pressure 11

12 ROOTS AND SOIL HEALTH Bridging the Brown Rotations and Roots C/SB = active rooting 32% of year DryBeans/WinterWheat = active rooting 57% Corn/DryBeans/WinterWheatcover = active 76% 12

13 WATER QUALITY Nutrients Nitrogen Phosphorus Sediment Turbidity Chemicals Pesticides Antibiotics Bacteria 13

14 WATER QUANTITY Too Much Too little 14

15 SUBSURFACE TILE DRAINAGE SROC Study Nitrates in Drainage Water in Minnesota Carlson, Vetsch, Randall MN and IA Studies with Winter Cereal Rye as a cover crop 0-11% reduction 15

16 DRAINAGE AND NITRATE, CONTINUED Nitrates in Drainage Water in Minnesota Carlson, Vetsch, Randall 16

17 SUBSURFACE DRAINAGE AND NITRATE Subsurface Drainage N losses under row crops in corn belt lbs/acre Minnesota study = lbs/acre Research Mainly cereal rye, some oat Strock, et al = nitrate N reduction of 11% Kaspar, et al = nitrate N reduction of 53% 17

18 COVER CROPS AND WATER QUALITY Bridging the Brown It s all interconnected Soil quality and water quality Organic matter levels affect water infiltration, water holding capacity, nutrient availability, and cation exchange capacity 10% more SOM in top 4 inches (about ½ % increase) = additional ½ inch of available water and 10 lbs/acre of mineralized soil N (Kaspar) 18

19 EXAMPLE COVER CROP USE After early harvested crops After earlier corn and soybean varieties Into standing corn and soybean Waterways Open tile intakes Head lands Wet spots Buffers Flood plain areas 19

20 WHAT S THE HOLD UP? The corn soybean system Establishment / Termination Management changes Genetics Research Lacking but increasing (Minnesota and Midwest) Crop Insurance Timing Harvesting 20

21 TILLAGE Conservation Tillage > 30% cover Mulch Till Ridge Till Strip Till No Till 21

22 CROP ROTATION More than one or two crops Oxbo Corporation 22

23 Thank you. Jill L. Sackett, Extension Educator U of M Extension Regional Office 1961 Premier Drive, Suite 110 Mankato, MN sacke032@umn.edu The University of Minnesota is an equal opportunity educator and employer. In accordance with the Americans with Disabilities Act, this PowerPoint is available in alternative formats upon request. Direct requests to