Managing Fertility on Organic Farms

Will Glazik CCA- 4RNMS

What to Know?

• Soil testing and inputs• Standard vs. complete

• Prohibited vs. OMRI approved

• Soluble vs. slow release

• Annual vs. long term

• Crop needs

• Soil health tests

Look at the whole picture

• 23 different factors

• % base saturation

• Secondary and micros

Soil Health Test

• Looking beyond chemistry

• Soil respiration

• Water Extractable Carbon

Traditional Fertilizers

• Water soluble

• 1st year availability

• Fast reacting

Basic List Prohibited

• Anhydrous Ammonia• UAN (28% or 32%) • Urea• Potassium Chloride (potash)• DAP• MAP• 10-34-0 starter• Treated lagoon manure

Basic List OMRI

• Cover Crops• Dry bedding manure• Most compost• Potassium Sulfate (with no dust retardants)• Rock phosphate• Mined lime• Mined gypsum • Chilean nitrate • Fish fertilizer

Biological Fertilizer Inputs

• Tons available

• Limited regulation

• Check OMRI and certifier before applying

• Slow release

• Carbon based

• Long term build

Organic Fertilizers

What to Know?

• Crop rotations• Longer and more diverse is better

• Cover crop rotations • Mixes are great but don’t complicate

Strategies for Transition to Organic

Year 1, 2, and 3… or longer?

What do your fields need?

Organic Farmers must invest in soil health to drive and sustain productivity...

“Compared to conventional systems, organic crop production depends more heavily on soil biological processes to provide crop nutrition and sustain yields. Building and maintaining a healthy soil—rich in organic matter and beneficial organisms—is a top management priority.”

○ Reducing Risk through Best Soil Health Management Practices in Organic Crop Production, OFRF / USDA

...and to satisfy NOP standard:“Production practices implemented in accordance with this subpart must maintain or improve the natural resources of the operation, including soil and water quality” [§ 205.200].

“The producer must select and implement tillage and cultivation practices that maintain or improve the physical, chemical, and biological condition of soil and minimize soil erosion.”

“The producer must manage crop nutrients and soil fertility through rotations, cover crops, and the application of plant and animal materials.”“The producer must manage plant and animal materials to maintain or improve soil organic matter content…” [§ 205.203].

“The producer must implement a crop rotation including but not limited to sod, cover crops, green manure crops, and catch crops that provide the following functions…:

(a) Maintain or improve soil organic matter content;(b) Provide for pest management in annual and perennial crops;(c) Manage deficient or excess plant nutrients; and(d) Provide erosion control” [§ 205.205].

Understand Your Social &

Ecological Context

Cover The Soil at all times

Grow a Living Root 24/7

Reduce Chemical,

Biological, and Physical Stress

Synergize with Diversity: Crop Rotations and Cover Crops

Integrate Diversity Of

Animals

R. Archuleta

Certified Organic production is a major aspect of the farmer’s context!

Principles over technique, tool, or formula.1. Maximize Diversity

• “Corn/Bean” is not crop rotation in principle.2. Living Roots

• “Think beyond compaction”3.Maintain armor

• “Diverse mix of armoring”4. Disturb the soil as little as possible

• “Think beyond just tillage” Chemical, biological, physical . . . 5. Add Animals

• “Biological accelerators”

Well designed crop rotations are advantageous because of their contributions to SOIL FERTILITY,

weed management, pest management, disease management, labor allocation,

economic risk management…

http://www.robinsons.pe.ca/laerial2.html

Dr. Joel Gruver, 2019

:

Robson et al. (2002) Advances in Agronomy

Increasing Cropping System Diversity Balances Productivity, Profitability and Environmental HealthAdam S. Davis, Jason D. Hill, Craig A. Chase, Ann M. Johanns, Matt Liebman

Abstract

Balancing productivity, profitability, and environmental health is a key challenge for agricultural sustainability. Most crop production systems in the United States are characterized by low species and management diversity, high use of fossil energy and agrichemicals, and large negative impacts on the environment. We hypothesized that cropping system diversification would promote ecosystem services that would supplement, and eventually displace, synthetic external inputs used to maintain crop productivity. To test this, we conducted a field study from 2003–2011 in Iowa that included three contrasting systems varying in length of crop sequence and inputs. We compared a conventionally managed 2-yr rotation (maize-soybean) that received fertilizers and herbicides at rates comparable to those used on nearby farms with two more diverse cropping systems: a 3-yr rotation (maize-soybean-small grain + red clover) and a 4-yr rotation (maize-soybean-small grain + alfalfa-alfalfa) managed with lower synthetic N fertilizer and herbicide inputs and periodic applications of cattle manure. Grain yields, mass of harvested products, and profit in the more diverse systems were similar to, or greater than, those in the conventional system, despite reductions of agrichemical inputs. Weeds were suppressed effectively in all systems but freshwater toxicity of the more diverse systems was two orders of

Marsden Farm – Boone Cty, IA

Dr. Joel Gruver, 2019

Increasing Cropping System Diversity Balances Productivity, Profitability and Environmental HealthAdam S. Davis, Jason D. Hill, Craig A. Chase, Ann M. Johanns, Matt Liebman

Abstract

Balancing productivity, profitability, and environmental health is a key challenge for agricultural sustainability. Most crop production systems in the United States are characterized by low species and management diversity, high use of fossil energy and agrichemicals, and large negative impacts on the environment. We hypothesized that cropping system diversification would promote ecosystem services that would supplement, and eventually displace, synthetic external inputs used to maintain crop productivity. To test this, we conducted a field study from 2003–2011 in Iowa that included three contrasting systems varying in length of crop sequence and inputs. We compared a conventionally managed 2-yr rotation (maize-soybean) that received fertilizers and herbicides at rates comparable to those used on nearby farms with two more diverse cropping systems: a 3-yr rotation (maize-soybean-small grain + red clover) and a 4-yr rotation (maize-soybean-small grain + alfalfa-alfalfa) managed with lower synthetic N fertilizer and herbicide inputs and periodic applications of cattle manure. Grain yields, mass of harvested products, and profit in the more diverse systems were similar to, or greater than, those in the conventional system, despite reductions of agrichemical inputs. Weeds were suppressed effectively in all systems but freshwater toxicity of the more diverse systems was two orders of

Dr. Joel Gruver, 2019

§205.205 Crop rotation practice standard.The producer must implement a crop rotation including but not limited to sod, cover crops, green manure crops, and catch crops that provide the following functions that are applicable to the operation:

(a) Maintain or improve soil organic matter content;

(b) Provide for pest management in annual and perennial crops;

(c) Manage deficient or excess plant nutrients; and

(d) Provide erosion control.

What do the National Standards actually require? Dr. Joel Gruver, 2019

Simple rotations such as corn-soybean or

continuous corn w/ CCs are NOT explicitly

prohibited

Dr. Joel Gruver, 2019

My prioritiesSolve agronomic problems

(weeds, pests, diseases)

Enhance soil health

Offset inputs

Logistical efficiency

Labor allocation

Dr. Joel Gruver, 2019

Michael J. O’DonnellFebruary 19, 2020

Michael J. O’DonnellFebruary 19, 2020

Michael J. O’DonnellFebruary 19, 2020

Michael J. O’DonnellFebruary 19, 2020

Michael J. O’DonnellFebruary 19, 2020

4 Practical Transition and Organic Rotations

• 5 crop years- Baby Steps

• 2 crop years- Livestock + High Diversity

• 2 crop years- Grain Production/High Diversity

• 2 crop years- Grain Production/Low Diversity

Key of Success From Long-term Organic Farmers

• Extend crop rotation to 4+ crops/years• Always follow a cash crop with a cover crop• Never plant like crops back to back (grass-grass or legume-

legume)• Keep the soil covered at all time• Limit disturbance• Cover crop fallow or soil resting • Livestock helps• Transition is for building soil/not making money

5 Year Baby Steps

• Allows for an easy transition from conventional to organic

• Transition 1/5th of the farm every year

• Maintains a steady income but misses out on some organic markets early on

• Adds diversity to the crop rotation

• Sets up for strong organic corn crop

v

Iowa State University

5 Year

• Year 1- Non-GMO corn following cover crop, minimize herbicide, possibly cultivate, minimize fertilizer inputs

• Year 2- Non-GMO soybeans following cereal rye cover crop, no seed treatment, minimize herbicide, possibly cultivate

5 Year

• Year 3- Non-GMO corn following cover crop, no herbicides, minimize fertilizer inputs, prefer to fertilize with manures/compost

• Year 4- Transitional oats or wheat with alfalfa or hay mix underseeded in spring, clip in the fall

• Year 5- Transitional alfalfa or hay, bale two cuttings, clip two cuttings, if baled replace manure

3 year Low Production/High Diversity

• Fast transition to organic

• Not very profitable in transition

• Minimizes weeds

• Low maintenance

• Low inputs

• Sets up for fantastic organic corn

High Diversity with or without livestock

• Year 1- Transition oats or wheat with underseededred clover and alfalfa, clip or graze in fall and no till a cool season cover crop cocktail (cereal rye, annual ryegrass, vetch, triticale, kale, rapeseed, winter peas, barley, oats, etc.)

• Year 2- Clip or graze cover crop mix and no till summer cover crop cocktail (sorghum sudangrass, cowpeas, sunnhemp, buckwheat, millet, mustard, etc)

Low Diversity

• Fast transition to organic

• Moderately profitable but less than conventional

• Can build weed seed bank

• Moderate maintenance

• Moderate inputs

• Organic corn crop will be avearge

Low Diversity

• Year 1- Transitional soybean follow cereal rye cover crop, needs cultivated, can be sold for non-gmo, weed control normally good

• Year 2- Transitional wheat or oats, underseeded with red clover and clip or graze in fall

• What about just row crops (Corn/Bean) in transition? Is this a good idea?

• When might a longer transition (more than 3 years) be recommended?