Vegetable Systems Trial
The Vegetable Systems Trial is a side-by-side comparison of conventional and organic methods for growing vegetables.
Located at Rodale Institute’s main campus near Kutztown, Pennsylvania, the Vegetable Systems Trial (VST) was launched in 2016 with a global scope.
This unique long-term study explores a novel approach to link soil health to crop nutrient density to human health, by comparing side-by-side the impact of cropping systems and management practices on changes in soil health indicators and nutritional quality of vegetables, all within the same set of environmental conditions.
THE STUDY
In the Vegetable Systems Trial, vegetables including potatoes, sweet corn, green beans, winter squash, and lettuce are selected and grown side-by-side in organic and conventional cropping systems under intensive and reduced tillage practices. These crops represent tubers, fruits, and leaf vegetables.
Mirroring the most common vegetable production strategies throughout the United States, the VST has two unique cropping systems: organic and conventional. Within each system, two tillage practices are employed: intensive tillage and reduced tillage.
Data collected will measure:
- Differences in nutrient density of vegetables
- Differences in soil health over time
- Drought resilience
- Resilience to insects, diseases and weed pressure
- Profitability
Why does it matter?
The nutrient density of fruits and vegetables grown in the U.S. has declined in the past 50-70 years. That means many people today are struggling with “hidden hunger”—they’re getting enough calories but not the vital nutrients necessary for health.
While many agricultural management practices aim to promote healthy soil, not all lead to improved soil health.
WE NEED TO KNOW:
CROPPING SYSTEMS
Organic
Fertility is supplied through leguminous hairy vetch and cereal rye cover crops, complemented by applications of organic fertilizers and compost in the case of potatoes. Only OMRI-certified pesticides are used for pest control. Weeds are controlled by shallow cultivation using a Treffler cultivator before germination of crops in plots with intensive tillage practices, hill-side cultivation between raised beds covered with plastic mulch, or roll-crimping in reduced tillage with occasional high residue.
Conventional
A cereal rye cover crop is used, but unlike in the organic system, it is burnt down with the herbicide glyphosate prior to planting the vegetable crops. Soil amendments rely on synthetic nitrogen and potassium sources for fertility. Because the soil in VST has excessive phosphorus levels, this amendment is not included in the fertility program. Pests and pathogens are controlled using synthetic fungicides and insecticides.
MANAGEMENT PRACTICES
Intensive Tillage
This practice represents the vegetable grower’s standard practice, where the soil is intensively tilled using the moldboard plow, followed by disking and preparing raised beds covered with plastic mulch. Crops are transplanted using the water wheel transplanter attached to a tractor. Each 20-by-80-foot plot contains three raised beds.
Reduced Tillage
Reduced tillage practice, a comparison to intensive tillage, is introduced to enhance soil health over time. In this practice, a rotational tillage is employed. The soil is chisel plowed and then disked to seed cover crops in the fall. In spring, the cover crops in the organic system are roll-crimped to form a biological mulch to control weeds, whereas in the conventional system the cover crop is burnt down with herbicide. This practice uses either a no-till transplanter to transplant vegetable crops or the Monosem planter to seed snap beans directly into mulch.
PRELIMINARY RESULTS:
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Over time, the implementation of Intensive tillage depleted soil carbon and increased soil bulk density
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In the organic cropping system we saw a 30% increase in labile organic soil carbon from 600 to 900 mg/kg
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In the organic, reduced tillage system, carbon levels increased in the top 4-inches of soil
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soil organic matter increased by 1% which is equivalent to 11,600 pounds in an acre furrow slice
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A 1% increase in soil organic matter allows the soil to hold 20,000 gallons more water per acre
Research Staff
Dr. Gladis Zinati
Director, Vegetable Systems Trial
Dr. Gladis Zinati, director of the Vegetable Systems Trial and soil scientist, evaluates the impact of cropping systems and management practices on nutrient cycling, carbon sequestration, vegetable nutrient density, and plant resistance to pests.
She conducts research on no-till practices, fertilizers, cover crops, compost formulations, and biological tools to improve pest management. She has more than 30 years’ experience and holds undergraduate degrees in general agriculture and agriculture engineering; an M.S. in horticulture from the American University of Beirut; and a Ph.D. in soil fertility from Michigan State University. Before joining Rodale Institute in 2012, Dr. Zinati worked on projects evaluating management practices that optimize crop yields and reduce degradation of water quality at the University of Florida and Rutgers University.
Webinars
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Impact of Traditional and Regenerative Tillage on Soil Health and Nutrient Quality of Organic Broccoli
Originally aired December 6, 2023
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Soil Microbes and Bean Nutrient in Organic and Conventional Systems
Originally aired November 15, 2023
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Impact of Soil Management on Soil Health and Vegetables
Originally aired November 8, 2023
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Updates on the Vegetable Systems Trial: Soil Health and Vegetable Nutrient Quality
Originally aired December 7, 2022
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Research Update—Nutrients and Soil Health in the Vegetable Systems Trial
Originally aired October 20, 2021
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Impact of Management Practices on Colored-Potato Crop Nutrient Quality and Soil Health
Originally aired November 12, 2020
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Vegetable Nutrient Quality & Soil Health in the Vegetable Systems Trial, 4th Season Updates
Originally aired November 5, 2020
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Panel: Ask the Experts—How Regenerative Organic Agriculture Can Improve Human Health
Originally aired June 2, 2020
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Vegetable Production and Soil Health—Updates on the Vegetable Systems Trial
Originally aired November 6, 2019
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Growing Nutrient Dense Vegetables
Originally aired May 10, 2018
Regenerative Healthcare Programming
Are you interested in food as medicine, nutrient density, and farm-to-hospital models? Learn more about our Regenerative Healthcare programming at the link below.
Educational ProgramsOUR SPONSORS
Grantham Foundation for the Protection of the Environment
JHC Foundation
Johnny’s Selected Seeds
Orange County Community Foundation
PA Department of Agriculture
PA Vegetable Marketing & Research Program
Paloma Blanca Foundation
The GIANT Company
Wyncote Foundation
This material is based upon work supported by the following funders. The opinions expressed in this publication are those of the author(s) and do not necessarily reflect the views of the funders.