COVER CROPS- A CLOSER LOOK STEPHANIE MCLAIN NATURAL RESOURCES CONSERVATION SERVICE; WORTHINGTON FIELD OFFICE

Transcription

1 COVER CROPS- A CLOSER LOOK STEPHANIE MCLAIN NATURAL RESOURCES CONSERVATION SERVICE; WORTHINGTON FIELD OFFICE

2 WHAT IS A COVER CROP? The definition of a cover crop is a crop planted primarily to manage soil fertility, soil quality, water, weeds, pests, diseases, biodiversity and wildlife in an agroecosystem. A crop that has lasting benefits for the crops planted around it A crop planting during the off season to provide additional protection and benefits Whatever you want it to be

3 NOT A NEW PRACTICE Cover crops were used extensively pre-1950 s Green manures, companion crops, winter time protection Pest management and weed control All options were on the table because no chemicals to make the job easier Crops and livestock were not separate operations Different times, but cover crops work in the same manner today as they did 50 years ago With a modern twist!

4 WHY NOW? Weed and insect resistance to chemicals Adaptation of pest stages to our cropping system Decreased infiltration of water due to poor soil structure World population is estimated to at 9.1 billion by 2050 Food production will need to increase by 70% 14 million acres of prime farmland lost to development from Energy demands- corn used for ethanol, increase dependence on petroleum based fertilizers to maintain production.

5 WHY COVER CROPS There are a tool Used primarily to improve soil health and function They are best used in combination with diverse crop rotation, no-till/strip till management practices and livestock This doesn t mean that they can t be used elsewhere

6 COMMON COVER CROPS Cereal rye-planted in the early fall, over winters and grows back Buckwheat-planted in the late summer, winter kills Oats-planted anytime, winter kills Radishes and Turnips-planted in the late summer/early fall, winter kills Clovers-some winter kill some grow back. All fix nitrogen Really can be anything

7 COVER CROPS-WHAT FOR? Improve soil quality Diversify cropping systems Supplemental forage Soil cover Feed the microbes Wildlife food or cover Cycle crop nutrients Fix atmospheric nitrogen

8 SOIL QUALITY Inherent properties of soil that can t be changed The percent of S, Si, Cl Location on the landscape The parent materials

9 SOIL ORGANIC MATTER OM drives the organisms responsible for building healthy soils Reservoir for water and nutrients Reduce soil compaction and increase water infiltration 5% of the soil but 90% of the function

10 SOM S NUTRIENT BANK ACCOUNT An acre of soil 6 deep weighs 2 million pounds 1% SOM = 20,000 lbs of SOM per acre 1% SOM has approximately 10,000 lbs Carbon 1,000 lbs Nitrogen 100 lbs Phosphorus 100 lbs Sulfur Mineralization rate of 2-3% of Organic Nitrogen to Inorganic Nitrogen lbs usable nitrogen per acre

11 COVER CROPS-WHAT FOR? Improve soil quality Diversify cropping systems Supplemental forage Soil cover Feed the microbes Wildlife food or cover Cycle crop nutrients Fix atmospheric nitrogen

12 DIVERSITY Only need 4-8 weeks of active growth to achieve the benefits Adding another crop to the rotation Diversity above = diversity below A 2 crop rotation alone struggles to improve soil health

13 MAJOR CROP TYPES Broadleafs and Grasses; Warm season and Cool season Cool season broadleaves: Clovers, brassicas, field pea, vetch Warm season broadleaves: Soybean, sunflower, cowpea, buckwheat Cool season grasses: Oats, winter rye, wheat, triticale Warm season grasses: Corn, millets, sorghum, sudangrass

14 COVER CROPS-WHAT FOR? Improve soil quality Diversify cropping systems Supplemental forage Soil cover Feed the microbes Wildlife food or cover Cycle crop nutrients Fix atmospheric nitrogen

15 SUPPLEMENTAL FORAGE Grazed or chopped for silage High protein levels Sorghum sudan grass, radish, turnips, cereal rye, clovers Add another level of use to cropland Double cropping Livestock are a walking vat of microbes

16 COVER CROPS-WHAT FOR? Improve soil quality Diversify cropping systems Supplemental forage Soil cover Feed the microbes Wildlife food or cover Cycle crop nutrients Fix atmospheric nitrogen

17 SOIL COVER Conserves moisture, cushions the impact of a raindrop and provides habitat for large soil organisms-earthworms Protection:

18 MORE ON PROTECTION

19 MORE ON PROTECTION

20 NOT PROTECTED VS PROTECTED

21 WHEN SOIL TEMPS REACH:

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24 COVER CROPS-WHAT FOR? Improve soil quality Diversify cropping systems Supplemental forage Soil cover Feed the microbes Wildlife food or cover Cycle crop nutrients Fix atmospheric nitrogen

25 LIVING ROOTS Cover crops supply food (active carbon like glucose and proteins) to the microbes to feed on. In the soil, there are 1,000 to 2,000 times more microbes associated with living roots than in bare or tilled soil. The microbes in turn build SOM and store soil nutrients. Winter cover crops soak up excess soil nutrients and supply food to all the microbes in the soil during the winter months rather than microbes having to use up SOM reserves for nutrients. In a conventional tilled field, soil nutrients are quickly released as SOM is burned up and the microbes and soil organisms habitat are destroyed.

26 LIVING ROOTS 10-40% of photosynthesis is exuded from plant root into the soil

27 LIVING ROOTS

28 LIVING ROOTS

29 COVER CROPS-WHAT FOR? Improve soil quality Diversify cropping systems Supplemental forage Soil cover Feed the microbes Wildlife food or cover Cycle crop nutrients Fix atmospheric nitrogen

30 POLLINATOR FOOD

31 COVER CROPS-WHAT FOR? Improve soil quality Diversify cropping systems Supplemental forage Soil cover Feed the microbes Wildlife food or cover Cycle crop nutrients Fix atmospheric nitrogen

32 CYCLE CROP NUTRIENTS

33 CAPTURE CROP NUTRIENTS

34 FIXING CROP NUTRIENTS

35 WHAT IS SOIL HEALTH? The continued capacity of the soil to function as a vital living system that sustains plant, animal and human life

36 WHAT DOES A HEALTHY SOIL HAVE? Aggregate stability

37 WHAT DOES A HEALTHY SOIL HAVE? Increased Water Holding Capacity

38 WHAT DOES A HEALTHY SOIL HAVE? Greater resilience to weather events

39 WHAT DOES A HEALTHY SOIL HAVE? Improved ability to cycle nutrients

40 WHAT DOES A HEALTHY SOIL HAVE? A diverse and active community of soil organisms

41 MORE ABOUT SOIL MICROBIOLOGY A teaspoon of soil contains over a billion bacteria Millions of fungi, algae, protozoa and dozens of nematodes

42 THE UNSEEN MAJORITY

43 All visible life above ground All microscopic life below ground

44 MICROBES ARE ECOSYSTEM FUNCTION Decomposition Relationships Nutrient Cycling

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46 THERE IS A LARGE GROUP OF FARMERS MAKING COVER CROPS WORK FOR THEM Gabe Brown Clay Mitchell John Burke Henry Miller Steve Groff Dave Brandt Ray Gaesser Dan DeSutter Jamie Scott

47 NORTH CENTRAL SARE WEBSITE

48 EVEN IN MN

49 COVER CROP SURVEY 750 farmers responded the winter of 2012/ % yield increase in corn 11.6% yield increase in soybeans Greater significance in the hardest hit drought areas: 11% & 14.3% respectively 303 acres of cover crop planted per farm with plans to increase that 40-50%

50 PROOF IN THE YIELD

51 QUESTIONS? THANK YOU!