AMES, Iowa – Organic production and consumption continue to grow, with the industry generating nearly $40 billion annually. With over 5.4 million acres in organic production in the United States alone, producers want to be sure they are at the cutting edge of growing practices.
A new publication from Iowa State University Extension and Outreach titled "Crop Rotations, Composting and Cover Crops for Organic Vegetable Production" (HORT 3052) provides detailed information on those three important aspects of organic production.
The publication is written by Kathleen Delate, professor and extension organic specialist in horticulture and agronomy, and Ajay Nair, assistant professor and extension vegetable specialist at Iowa State.
“With the increased interest in organic farming due to high premium prices and the use of environmentally-benign farming techniques," Delate said, "this publication answers key questions we typically receive from producers transitioning to organic farming: What is the best crop rotation to use, how can cover crops fit into the system and what are the advantages of compost over manure?”
The importance of crop rotation to the overall quality of an organic farming system is discussed in depth. The publication looks at its use in enhancing soil fertility, its effect on water quality and ways the rotation can be used to impact disease, insect and weed management. A four-year crop plan is also included.
“Crop rotations are required in organic production in order to build soil quality, help break up weed and disease cycles and increase biodiversity on the farm,” Delate said.
While crop rotations does its part in improving soil quality, the use of animal manure or compost provides additional nutrients.
“Manure and compost are the most common forms of applied fertility on organic farms, due to the requirement for no petroleum-based fertilizers,” Delate said. “By using manure or composted manure, farmers are recycling nutrients from livestock in their soils, saving money by using local sources of fertility, and practicing climate-smart agriculture by sequestering carbon and conserving soil moisture.”
A technique that is common on organic farms and is becoming more readily used in conventional farming systems is cover crops. Cover crops can help improve soil health, improve water-holding capacity, suppress weeds and reduce soil erosion. The publication highlights these benefits while also discussing organic no-till practices.
“Cover crops are required in organic production and provide many benefits,” Delate said. “Since they cover the soil they prevent soil erosion, sequester carbon, add nutrients, help mitigate nutrient leaching and improve water quality. Research in our organic transition plots at the ISU Neely-Kinyon Memorial Research and Demonstration Farm has shown less nitrate loading in plots with cover crops and greater soil respiration which is associated with higher numbers of soil microbial populations that increase nutrient cycling and hold nutrients in soil and the plant.”