Nutrient Management in Organic Systems Chris Reberg-Horton, Greg Hoyt, Julie Grossman, John Spargo

What are the rules? “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 in a manner that does not contribute to contamination of crops, soil, or water by plant nutrients, pathogenic organisms, heavy metals, or residues of prohibited substances. “

Manures Raw animal manure, must be composted unless it is: (i) Applied to land used for a crop not intended for human consumption; (ii) Incorporated into the soil not less than 120 days prior to the harvest of a product whose edible portion has direct contact with the soil surface or soil particles; or (iii) Incorporated into the soil not less than 90 days prior to the harvest of a product whose edible portion does not have direct contact with the soil surface or soil particles;

Manures Does not need to be organic for the U.S. market Does not need to be organic for the E.U. any longer

The “National List of Allowed and Prohibited Substances helps understand acceptable commercial products List of exceptions to the general requirement that natural materials are allowed and synthetic materials are prohibited. (NOP § ) Rule of Thumb #1: all natural products are allowed, unless they listed as prohibited Rule of Thumb #2: All synthetic products (fertilizers, amendments, pesticides, growth regulators, etc.) are are prohibited unless specifically allowed

Certified Organic Compost from Manures Compost must have an initial Carbon:Nitrogen ratio of between 25:1 and 40:1. Producers using a windrow system must maintain the composting materials at a temperature between 131 deg. F and 170 deg. F for 15 days, during which time, the materials must be turned a minimum of five times. Prove it! Uncomposted manures and non-manure compost much more common.

So is organic agriculture reliant on manure? Yes and no Yes -current practices on most farms No – some outliers who are not Bob and Leda Muth Family Farm, Williamstown, NJ use municipal leaves as the ONLY fertility source

Outliers

Most organic farmers Manures obtained locally supply P, K, and micronutrients Cover crops supply additional N Possible purchasing of processed manures/animal by products

A lot of nutrients in litter NPKS lbs acre Turkey broiler litter 4 tons acre -1 supplies

What are the purchasing options? sourceprice per ton% N%P%Kprice/lb Nprice/lb pprice/lb k organic gem liquid fish 3.09/gal chilean nitrate Nutrimax Nature Safe feathermeal Allganic Potassium Sulfate Rose Acres litter compost Peruvian Bat Guano Perdue pellets

Phosphorous Rock phosphate – very low solubility Bone meal – more soluble

Potassium Muriate of potash (KCl) A mined substance of high solubility. [Prohibited] unless derived from a mined source and applied in a manner that minimizes chloride accumulation in the soil. Farmers mostly reliant on animal sources here, other regions use more KSO4 Potassium sulfate and sulfate of potash cannot be treated with anti-dust agents

Micro-Nutrients Micronutrients may be used only in cases where soil/plant nutrient deficiency is documented by soil or tissue testing. Sulfate formulations mostly A few borons allowed, but not the one with the ammonium

A lot of nutrients in litter NPKS lbs acre Turkey broiler litter 4 tons acre -1 supplies

Just manures would be a problem NPCuZn lbs acre Corn 150 Bushels acre -1 removes Broiler litter 4 tons acre -1 supplies

High Residue Problems Planting Soil drying - roll first - plant later Lodging of the cover crop and cash crop Planting problems in High Residue Systems Hair Pinning = Poor standsResidue accumulation

Weed control can be excellent

Soybean Yield < 7,0007-9,000>9,000 Rye Biomass (kg ha -1 )

COVER CROP P K lbs /acre SMALL GRAIN20170 CRIMSON CLOVER HAIRY VETCH18180 BARE SOIL 0 0 NUTRIENTS IN COVER CROP RESIDUE

Webster, USDA-ARS, Tifton, GA Pigweed as a Row Crop

Drainage issue for some soils and crops Rolling/crimping Crimson clover U.S. patent # 7,562,517 B1 2-row, 3 furrows roller/crimper1-row, 2 furrows roller/crimper

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