Graham, North Carolina
Alex and Betsy Hitt were forced to reevaluate their farm fertility program in 1990 when a nearby horse stable that had provided them with manure went out of business. The Hitts, who raise 80 to 90 varieties of vegetables and 160 varieties of cut flowers on their 5-acre farm, have created elaborate rotations involving cover crops to supply organic matter and nitrogen, lessen erosion, and crowd out weeds. “We made a conscious decision in our rotation design to always use cover crops,” Alex Hitt says. “We have to—it’s the primary source for all of our fertility. If we can, we’ll have two covers on the same piece of ground in the same year.”
Alex and Betsy designed their initial rotation scheme to include all their farmed acreage, using the guiding principle of separating botanical families to break disease and insect cycles. They intentionally incorporated as many variables as possible into that rotation (cooland warm-season crops, vegetables and flowers, heavy and light feeders, deepand shallow-rooted plants, etc.). Later, as they came to rely more on cover crops for organic matter maintenance, the Hitts tweaked their rotation to maximize cover crop growth periods. “We always lean towards [cover] crops that will grow us the most biomass and fix the most nitrogen,” says Alex. “These . . . usually . . . mature later and are harder to turn under and decompose.” Other criteria include ease of establishment, seed cost and availability, and adaptability to their climate.
The payoffs from the Hitts’ commitment to their rotation are clear. Their farm stays essentially free of soilborne diseases and pests, which they attribute to “so much competition and diversity” in the soil. They see little or no erosion, despite farming some fields that have as much as a 5% slope. Furthermore, they have discovered that their covers smother and crowd out weeds, and the timing and spacing variations within their rotation have improved weed control. “We either have a different crop [from season to season] or we’re planting it differently, so we don’t get the same weeds the same time every year,” Alex says. “When we went to a longer rotation and changed the timing, we noticed it quickly.
Their farm stays essentially free of soilborne diseases and pests, which they attribute to “so much competition and diversity” in the soil.They see little or no erosion, despite farming some fields that have as much as a 5% slope.
Over time, the Hitts’ rotation scheme has evolved in tandem with their production methods. Four different rotations are now used to maintain or boost soil quality in specific parts of their operation. For example, their main field is in a five-year rotation plan, while the addition of six movable 16-by-48-foot hoop houses used for season extension led to the creation of a special twelve-year rotation. Areas under large-scale multi-bay high tunnels, as well as fields with flood-prone or heavy soils, have their own three-year rotations.
The Hitts use a consistent approach to managing cover crops in all of their rotations, regardless of rotation length. “We have essentially arrived at two winter and two summer combinations of cover crops,” each of which always includes a legume and a grass, Alex explains. Typically, they plant rye and hairy vetch or sorghum sudan grass and cowpeas prior to lateplanted spring crops, no-tilled summer cash crops, and fall-planted cover crops. Oats and crimson clover or pearl millet and soybeans precede early-spring-planted crops and fall-planted cash crops. The Hitts alter these combinations if needed to prevent disease buildup. They sometimes “fine-tune” their rotation by inserting an extra planting of a wheat, barley, or triticale cover crop prior to a first tomato planting.
The Hitts are interested in expanding no-till planting on their farm and trying out cover crops, such as rape and forage radish, that can easily be turned under in spring—because these are followed by an early-springseeded rye and hairy vetch cover that is rolled down to create a mulch layer under their no-till summer-planted crops. “I am still working on getting the right coulter/ row openers for [no-till] seeding of certain flowers like zinnias and also sweet corn,” Alex says.
The Hitts’ flowers, fresh leafy greens, heirloom tomatoes, hot and sweet peppers, leeks, and other vegetables are popular with area chefs and at farmers’ markets in nearby Chapel Hill. Their main challenges, Alex says, are twofold: to choose which cover crops should precede and follow their diverse set of cash crops, and to determine optimal spacing and timing for their cash crops. “If cash crops go in and out basically at the same time, this makes it easier to choose a cover crop and its following cash or cover crop,” he says. “This also makes irrigation, cultivation, and other jobs more efficient.” Standardizing bed widths and lengths and the spacing used for transplants and direct-seeded crops has made their cash crop management “essentially automatic when it comes to planting, cultivating, irrigating, trellising, etc. There is no need to reset equipment or have different lengths of row covers if all the beds are the same.”
The Hitts are making the most of their efficiency gains. In recent years, although they’ve scaled their production down from 5 to 3 acres, they are realizing greater profits by continually refining and diversifying a lucrative set of cash crops. In recognition of their innovation and success, Alex and Betsy received the prestigious Patrick Madden Award for Sustainable Agriculture from USDA’s Sustainable Agriculture Research and Education (SARE) program in 2006.
The Hitts are convinced that the complexity built into their rotations has led to a reduction, rather than an increase, in their workload. Alex—who has found time over the years to volunteer for SARE committees— estimates that about ten days of work are required to manage the cover crops within his rotations each year. A week is used in the fall to seed, prepare, and hill 3 acres. In the spring, covers are mowed weekly as needed, and beds are turned under or rolled prior to planting. Once cash crops are harvested, rotational units are mowed, disked, and seeded with a summer cover crop, all in the same day. After eight weeks, this summer cover is mowed down and disked in preparation for another cash or cover crop planting.
The Hitts believe such time is well spent. “There are a billion benefits from cover crops,” Alex says. “We have really active soil—we can see it by the good crops we grow, and by the problems we don’t have. The whole [farm] is really in balance, and the rotation and cover crops have a lot to do with that.”
—UPDATED BY AMY KREMEN
ALEX AND BETSY HITT’S ROTATIONS
Key: O-CC = oats with crimson clover. R-HV = rye with hairy vetch. SG-CP = sudan grass with cowpeas. M-SB = millet with soybeans. FP = fall planted.
Main field rotation: 5 years
Year 1. O-CC → spring lettuce followed by summer flowers → R-HV.
Year 2. Peppers (half no-till into rye/hairy vetch) → O-CC.
Year 3. Half hardy flowers/1st summer flowers → SG-CP → O-CC.
Year 4. Spring vegetables followed by summer flowers → overwintered flowers (no cover crop).
Year 5. Overwintered flowers → SG-CP → O-CC.
Rotation for 16-by-48-foot sliding tunnels: 12 years
Year 1. O-CC → tunnel moves over → tomatoes → fall-planted hardy vegetables → tunnel moves off.
Year 2. FP hardy vegetables → M-SB lettuce and late-winter-planted vegetables.
Year 3. Overwintered bulb crops → late-summer lettuce → late-winter-planted vegetables.
Year 4. Late-winter-planted vegetables → tunnel moves off → M-SB → O-CC.
Year 5. O-CC → tunnel moves over → melons, cucumbers → FP hardy vegetables → tunnel moves off.
Year 6. FP hardy vegetables → M-SB → overwintered bulb crops planted → tunnel moves over.
Year 7. Overwintered bulb crops → late-summer lettuce and late-winter-planted vegetables.
Year 8. Late-winter-planted vegetables → tunnel moves off → M-SB → O-CC.
Year 9. O-CC → tunnel moves over → tomatoes → FP hardy vegetables → tunnel moves off.
Year 10. FP hardy vegetables → M-SB → overwintered bulb crops planted → tunnel moves over.
Year 11. Overwintered bulb crops → late-summer lettuce and late-winter-planted vegetables.
Year 12. Late-winter-planted vegetables → tunnel moves off → M-SB → O-CC.
Rotation for heavy and flood-prone soils: 3 years
Year 1. Winter squash into no-till into rye/hairy vetch residue → O-CC.
Year 2. Sweet corn (part no-till) → R-HV
Year 3. Mixed vegetables and flowers, grown using no-till if possible → R-HV.
Rotation for multi-bay tunnels: 3 years
Year 1. Tomatoes half no-till into rye w/ hairy vetch residue → O-CC.
Year 2. Mixed early and mid-season flowers → R-HV.
Year 3. SG-CP → half wheat w/ crimson clover, half rye w/ hairy vetch (prior to tomatoes).
Table of Contents
- About the Authors
- Healthy Soils
- Organic Matter: What It Is and Why It's So Important
- Amount of Organic Matter in Soils
- The Living Soil
- Soil Particles, Water, and Air
- Soil Degradation: Erosion, Compaction, and Contamination
- Nutrient Cycles and Flows
- Soil Health, Plant Health, and Pests
- Managing for High Quality Soils: Organic Matter, Soil Physical Condition, Nutrient Availability
- Cover Crops
- Crop Rotations
- Animal Manures for Increasing Organic Matter and Supplying Nutrients
- Making and Using Composts
- Reducing Erosion and Runoff
- Preventing and Lessening Compaction
- Reducing Tillage
- Managing Water: Irrigation and Drainage
- Nutrient Management: An Introduction
- Management of Nitrogen and Phosphorus
- Other Fertility Issues: Nutrients, CEC, Acidity, and Alkalinity
- Getting the Most From Routine Soil Tests
- Taking Soil Samples
- Accuracy of Recommendations Based on Soil Tests
- Sources of Confusion About Soil Tests
- Soil Testing for Nitrogen
- Soil Testing for P
- Testing Soils for Organic Matter
- Interpreting Soil Test Results
- Adjusting a Soil Test Recommendation
- Making Adjustments to Fertilizer Application Rates
- Managing Field Nutrient Variability
- The Basic Cation Saturation Ratio System
- Summary and Sources
- How Good Are Your Soils? Field and Laboratory Evaluation of Soil Health
- Putting It All Together