Purple Top Turnip | Plants

Brassica rapa • Also known as: Turnip, Forage Turnip

Purple top turnip (Brassica rapa) is frequently incorporated into regenerative agriculture systems primarily as a component of multispecies cover crop cocktails. Its role as a cover crop is highlighted in systems aimed at extending grazing seasons, enhancing plant diversity, and increasing organic matter addition. Farmers utilize it in no-till systems to build soil health, break up plow layers, and improve water infiltration, especially in fragile soil types like sandy loam. While not a nitrogen fixer, its rapid growth can contribute significant biomass, aiding in carbon sequestration and weed suppression. Farmer experiences indicate its inclusion in diverse "cocktails" alongside crops like millet, cowpea, and radish, particularly after early forage harvests or on marginal lands. One farmer noted its use in a system aiming to improve soil fertility and drainage. While not explicitly mentioned as a pollinator attractant in these excerpts, its inclusion in diverse mixes suggests a broader ecological benefit. Challenges like turnip sawfly outbreaks have been observed, with one instance leading farmers to prioritize observation over immediate eradication, resulting in natural pest control by finches. Overall, purple top turnip serves as a versatile cover crop ingredient in regenerative strategies focused on soil building and livestock integration.

For a full botanical description see: Plants For A Future(opens in new window) (external link)

Regenerative Quick Profile

All recommendations assume integrated, regenerative practices—not conventional inputs.

Climate & Soil Fit

Climate: Tropical Rainforest, Tropical Monsoon, Tropical Savanna, Hot Semi-Arid (Steppe), Cold Semi-Arid (Steppe), Hot Desert, Cold Desert, Humid Subtropical, Oceanic (Maritime Temperate), Hot-Summer Mediterranean, Warm-Summer Mediterranean, Monsoon-Influenced Humid Subtropical, Subtropical Highland, Hot-Summer Continental, Warm-Summer Continental, Subarctic, Monsoon-Influenced Hot-Summer Continental, Tundra

Zones: USDA 5-9, Australian Zones 3-11

Optimal Soil: Loam Soil

System Role & Functions

Primary: Cover Crop System

Secondary: Forage Integration, Cash Crop With Services

Key Benefits: Weed Suppression

Management Level

Experience: Intermediate

Maintenance: High maintenance - Integrated fertility management and consistent moisture retention practices support its vigorous growth, while healthy soil ecosystems naturally mitigate pest pressures.

Value Streams

Cover crop (soil investment)
Soil building and erosion control
Livestock forage value

Regenerative Trait Ratings

How These Traits Are Calculated

Trait dimensions are ordered clockwise starting from the top of the chart (12 o'clock position):

1. System Value

Ecosystem service stacking across nitrogen, carbon, water, biodiversity

WHAT: Synthesizes the compounding value of multiple ecosystem services delivered simultaneously—nitrogen fixation, soil organic matter building, pollinator support, erosion control, and water infiltration improvement. This is the total regenerative impact beyond single-function metrics.

WHY: The highest-value cover crops deliver 3-5 significant ecosystem services at once. A legume that fixes nitrogen, builds biomass, supports pollinators, and improves water infiltration provides $150-300/acre in combined benefits versus $30-60 for single-function covers. This service stacking is the core principle of regenerative agriculture.

HOW: Scored via LLM synthesis of economics data, timeline benefits, and trait combinations. Exceptional (3.0): 4-5 major services stacked with strong economic value ratios. Typical (2.0): 2-3 moderate services. Limited (1.0): Single-function covers with minimal service stacking. Considers seed cost relative to benefit value.

2. Nitrogen Fixation

Biological nitrogen production via legume root nodule bacteria

WHAT: Measures the ability to convert atmospheric nitrogen (N₂) into plant-available ammonia through symbiotic bacteria in root nodules. Legumes form partnerships with rhizobium bacteria that fix 60-150 lbs N/acre/year, reducing or eliminating synthetic fertilizer needs for following crops.

WHY: Nitrogen is the most expensive fertilizer input in crop production ($0.50-1.00/lb). Cover crops with exceptional nitrogen fixation can provide $60-150/acre worth of fertility while building soil organic matter. This biological process also reduces groundwater contamination from nitrogen runoff and lowers farm carbon footprint.

HOW: Ratings based on annual nitrogen fixation capacity and reliability across soil conditions. Exceptional (3.0): Legumes like hairy vetch, crimson clover, and field peas fixing >100 lbs N/acre/year. Typical (2.0): Moderate fixers like red clover at 60-100 lbs N/acre/year. Limited (1.0): Non-legumes (grasses, brassicas) with zero fixation capacity.

3. Soil Building

Weighted: biomass production (60%) + root system depth (40%)

WHAT: Combines above-ground biomass production with root depth to measure total soil organic matter contribution. Biomass provides surface organic matter, while deep roots deposit carbon at depth and break up compaction layers.

WHY: Soil organic matter is the foundation of regenerative agriculture, improving water retention, nutrient cycling, and biological activity. Each 1% increase in soil organic matter holds an additional 20,000 gallons of water per acre and represents $500-1,000 in fertility value. Deep roots access subsoil nutrients and create channels for water infiltration.

HOW: Weighted formula prioritizes biomass production (60% weight) for immediate organic matter contribution, with root depth (40% weight) for long-term soil structure. Exceptional (3.0): High-biomass crops with deep roots like cereal rye (8+ tons biomass, 5+ ft roots). Typical (2.0): Moderate on both factors. Limited (1.0): Low biomass or shallow roots.

4. Weed Suppression

Physical competition through rapid establishment and dense growth

WHAT: Measures the ability to outcompete weeds through rapid germination, aggressive early growth, and dense canopy formation. Physical smothering and light competition reduce weed pressure without herbicides.

WHY: Weed management is a major labor and cost burden for farmers. Cover crops that effectively suppress weeds reduce herbicide costs ($20-60/acre), decrease cultivation passes (fuel + labor), and provide clean seedbeds for cash crops. This is especially valuable in organic systems where herbicide options are limited.

HOW: Ratings based on germination speed, tillering density, and canopy closure timing. Exceptional (3.0): Fast-establishing, dense-tillering crops like cereal rye, oilseed radish that close canopy within 3-4 weeks. Typical (2.0): Moderate establishment and coverage. Limited (1.0): Slow-establishing or sparse crops that allow weed competition.

5. Cold Hardiness

Winter survival for fall planting and spring green manure value

WHAT: Measures tolerance to freezing temperatures and ability to survive winter conditions. Winter-hardy cover crops can be fall-planted, overwinter as living mulch, and provide early spring growth before cash crop planting.

WHY: Fall-planted winter-hardy covers extend the growing season into unused months, capturing solar energy and preventing erosion during wet periods. Spring green manure from overwintered covers provides early nitrogen and biomass. This timing flexibility is critical in cold climates with short growing seasons.

HOW: Ratings based on minimum survival temperature and winter active growth. Exceptional (3.0): Winter-hardy crops like cereal rye, hairy vetch, crimson clover surviving to -20°F with active growth in spring. Typical (2.0): Moderate cold tolerance. Limited (1.0): Warm-season crops like buckwheat, cowpea killed by first frost.

6. Establishment Ease

Germination speed, soil requirement flexibility, planting window breadth

WHAT: Measures how easily the cover crop establishes from seed, including germination speed, tolerance for variable soil conditions, and flexibility in planting timing. Easy establishment means reliable stands without intensive management.

WHY: Difficult-to-establish covers increase risk of stand failure, wasted seed costs, and reduced benefits. Easy establishment crops tolerate late planting, poor seedbed preparation, and variable moisture—critical when cover cropping windows are narrow between cash crops. Reliable establishment ensures consistent soil building and weed suppression benefits.

HOW: Ratings based on days to emergence, soil condition sensitivity, and planting window breadth. Exceptional (3.0): Fast germinators like buckwheat (3-5 days) and cereal rye (5-7 days) with wide planting windows. Typical (2.0): Moderate establishment requirements. Limited (1.0): Slow or finicky establishers requiring precise conditions.

7. Adaptability

Weighted: climate tolerance (60%) + multi-benefit versatility (40%)

WHAT: Combines climate adaptability (temperature and rainfall range) with multi-benefit versatility (diverse ecosystem services) to measure overall system flexibility. High adaptability means the cover works across farm regions and provides multiple functions.

WHY: Farmers need cover crops that work reliably across diverse fields and provide stacked benefits. Climate-adaptable covers reduce risk in variable weather, while multi-benefit crops deliver nitrogen fixation + pollinator support + forage value simultaneously. This versatility maximizes return on cover crop investment.

HOW: Weighted formula prioritizes climate tolerance (60% weight) for geographic reliability, with multi-benefit value (40% weight) for functional stacking. Exceptional (3.0): Wide climate range + multiple significant benefits. Typical (2.0): Moderate on both factors. Limited (1.0): Narrow climate range or single-function crops.

8. Low Maintenance

Inverted from maintenance intensity—low inputs mean high scores

WHAT: Measures minimal input requirements for successful cover cropping. Low-maintenance covers require no irrigation, minimal fertility, easy termination, and tolerate variable management timing.

WHY: Cover crops compete for resources with cash crops in tight rotations. Low-maintenance covers fit easily into existing systems without adding labor, equipment, or input costs. Easy termination is especially critical—covers that are difficult to kill can become weeds and delay cash crop planting.

HOW: Inverted score from maintenance intensity trait (4.0 minus raw score). Exceptional (3.0): Self-sufficient crops like cereal rye, field peas requiring no irrigation or fertility, easily terminated by mowing or winter-kill. Typical (2.0): Moderate input needs. Limited (1.0): High-maintenance crops needing irrigation, heavy fertility, or difficult termination (herbicides, multiple tillage passes).

Ratings are based on documented performance in regenerative systems, not conventional high-input scenarios. All traits assume integrated management practices focused on soil health and ecosystem services.

Have a question about Purple Top Turnip?

Climate Suitability Assessment

Will this plant thrive in your climate?

IDEALLY SUITED

Köppen Zone: Cfa (Humid Subtropical), Cfb (Oceanic (Maritime Temperate)), Dfa (Hot-Summer Continental), Dfb (Warm-Summer Continental)
USDA Zone: 6a, 7a, 8a
Australian Zone: temperate
EU Climate Region: atlantic

Purple Top Turnip excels in regions with mild winters and moderate summers, typically found in Köppen Cfb and Dfb zones, USDA zones 7a-8b, Australian temperate regions, and EU Atlantic climates. These areas provide 150-250 frost-free days and temperatures between 60-75°F (15-24°C) during its primary growth periods. Consistent rainfall (30-50 inches/75-125 cm annually) supports reliable establishment and vigorous growth, often allowing for overwintering and early spring biomass production. Its ability to thrive as both a cash crop and a cover crop in these conditions leads to high yields and significant soil health benefits, with minimal need for intensive management or supplemental irrigation. Establishment success rates are consistently above 85%, and the plant reliably contributes to regenerative agriculture practices through biomass accumulation and nutrient cycling.

ADEQUATE

Köppen Zone: Csa (Hot-Summer Mediterranean), Csb (Warm-Summer Mediterranean), Cwa (Monsoon-Influenced Humid Subtropical), Cwb (Subtropical Highland)
USDA Zone: 5a, 5b, 9a, 10a
Australian Zone: subtropical
EU Climate Region: continental

Purple Top Turnip performs adequately in regions with distinct seasons, including Köppen Cfa, Csb, Dwa, and Dwb zones, USDA zones 5b-6b and 9a-10b, Australian subtropical regions, and EU continental climates. These areas offer growing seasons of 120-180 days, but may experience temperature extremes. While it can be grown as an annual, winter survival is not guaranteed in colder continental zones, and summer heat in subtropical or warmer temperate zones can lead to bolting and reduced root development, necessitating careful timing and potentially supplemental irrigation (10-20 inches/25-50 cm). Establishment success is good (70-85%) with proper management, and it provides valuable biomass and soil improvement, though yields may be 10-20% lower than in ideal conditions. It functions well as a cover crop during cooler months or as a short-season cash crop.

NOT RECOMMENDED

Köppen Zone: Af (Tropical Rainforest), Am (Tropical Monsoon), Aw (Tropical Savanna), ET (Tundra), BSh (Hot Semi-Arid (Steppe)), BSk (Cold Semi-Arid (Steppe)), BWh (Hot Desert), BWk (Cold Desert), Dfc (Subarctic), Dwa (Monsoon-Influenced Hot-Summer Continental)
USDA Zone: 2a, 3a, 3b, 4a, 11a, 12a

Purple Top Turnip is not recommended in regions with extreme cold winters or prolonged, intense summer heat, specifically Köppen Csa and BSh zones, USDA zones 3a-5a, and parts of the EU Mediterranean and Boreal regions. In cold zones (USDA 3a-5a), winter temperatures below -15°F (-26°C) cause near-certain winterkill, and short growing seasons limit its effectiveness. In hot, dry zones (Köppen Csa), summer heat above 80°F (27°C) induces bolting, reduces root development, and significantly increases water requirements (over 30 inches/75 cm annually), making intensive irrigation necessary and increasing costs. Establishment success is often below 70% due to these challenging conditions. Alternative plants like Winter Rye, Hairy Vetch, Cowpea, or Sorghum-Sudangrass are better suited to these environments for cover cropping and biomass production, offering greater resilience and economic viability.

Better alternatives for these "not recommended" zones: Winter Rye (Extremely cold-hardy cover crop that thrives in short growing seasons and provides excellent biomass.), Hairy Vetch (Cold-hardy legume that can be planted in late summer for overwintering and spring nitrogen fixation.), Cowpea (Heat-tolerant legume for summer cover cropping.), Sorghum-Sudangrass (High-biomass summer cover crop adapted to heat.)

Note: Zones listed above represent climates where this plant can produce reliably with reasonable management. Climate zones not mentioned would require intensive climate modification (greenhouses, extensive infrastructure) and are not economically viable for regenerative agriculture purposes.

Soil Suitability Assessment

Which soil types work best for this plant?

IDEALLY SUITED

Loam Soil

This plant thrives in these soil types without requiring amendments or remediation. Natural soil conditions support optimal growth and productivity.

ADEQUATE

Clay Soil, Rich Soil, Sandy Soil

This plant performs acceptably in these soil types with moderate, manageable remediation such as pH adjustment, compost addition, or drainage improvement. The required amendments are practical and cost-effective for regenerative agriculture.

NOT RECOMMENDED

Acidic Soil, Alkaline Soil, Desert Soil, Rocky Soil, Saline Soil, Wet Soil

Growing this plant in these soil types would require impractical remediation such as complete soil replacement, extensive amendments, or cost-prohibitive infrastructure. These conditions are not economically viable for regenerative agriculture.

Note: Soil suitability assessments focus on remediation requirements. "Ideally Suited" means the plant generally thrives without the need for substantial amendments, "Adequate" means manageable remediation (lime, compost, mulch), and "Not Recommended" means impractical soil changes would be required. Climate factors like rainfall and temperature also influence success.

Seasonal Considerations

Planting timing, growth duration, and harvest windows

Brassica rapa offers excellent flexibility for diverse cropping systems. For spring planting, sow after the last expected frost when soil temperatures consistently reach 50°F (10°C). It establishes quickly, often within one to two weeks, and can provide a valuable nutrient scavenger before a warm-season cash crop. In milder climates (Cfa, Cfb, Csa, Csb), it can be planted in late summer to provide fall growth and potentially overwinter, though hard freezes may induce dormancy or termination. For fall planting in colder zones (Dfa, Dfb, Dwa, Dwb), aim to sow at least 6-8 weeks before the first expected frost to allow for substantial growth. This timing is crucial for building biomass and improving soil structure before winter dormancy. Termination can be achieved through tillage or roller-crimping. In many regions, Brassica rapa will not reliably overwinter and will naturally terminate with significant cold, making it an ideal low-residue winter cover. Consider frost-seeding in early spring for a rapid, early-season cover crop if your rotation allows. Its peak biomass is typically achieved within 6-10 weeks of planting, depending on conditions.

System Role & Multi-Benefit Value

Functional roles, integration strategies, and stacked benefits

Functional Role

Total System Value

Purple top turnip offers substantial system value beyond direct harvest, contributing to whole-farm resilience. As a cover crop, it enhances soil health by adding organic matter, improving water infiltration, and breaking compaction, especially when used in multispecies mixes. Its rapid growth in cooler weather makes it ideal for fall cover, scavenging residual nutrients and preventing leaching. While not a primary cash crop, its value as forage for livestock, as seen in grazing systems, adds direct economic benefit. Ecosystem services include improved soil carbon sequestration due to increased biomass and microbial activity. By diversifying crop rotations and cover cropping strategies, turnips help mitigate risks associated with monocultures, pests, and extreme weather events, contributing to a more robust and adaptable farming operation. Its inclusion in cover crop cocktails, as demonstrated in various case studies, amplifies these benefits by working synergistically with other species.

Integration Characteristics

Multi-Benefit Value: Not Recommended - Primarily a food crop, it also contributes to soil organic matter through its biomass, offering moderate support for the soil ecosystem.

Sources behind this view

Research

Functional traits in cover crop mixtures: Biological nitrogen fixation and multifunctionality (opens in new window)
Mixed cover crops with diverse plant types (legumes, brassicas, grasses) offer multiple farm benefits (ecosystem services) better than single-species stands. Complementary traits enhance sustainabilit

Management & Care Requirements

Integration guidance, maintenance needs, and care practices

How to Integrate This Plant

Purple top turnip (Brassica rapa) is effectively integrated into regenerative systems primarily as a cover crop, offering multiple benefits. Its roles include adding organic matter, suppressing weeds, breaking up compaction, and serving as a forage source. Compatible practices include multispecies cover crop cocktails, interceding, and incorporation into no-till systems. Turnips can be planted as part of summer or fall mixes, contributing to soil health improvements relatively quickly. Early contributions in Year 1-2 include scavenging nutrients, improving soil structure, and providing a food source. Over time, they contribute significantly to building soil organic matter and enhancing nutrient cycling. The multi-benefit stacking involves improving soil physical properties, enhancing biological activity, and providing a quick biomass source for livestock, thus reducing reliance on external inputs and increasing farm resilience.

Integration Practices & Management

Regenerative farmers integrate purple top turnip (Brassica rapa) primarily as a versatile cover crop within diverse cropping and grazing systems. Establishment often involves no-till drilling, with seeding rates and timing adjusted based on soil type and desired outcomes, such as weed suppression or organic matter addition. Turnips can be included in multispecies cover crop mixes, planted after early forage harvests or in fall sequences to build soil health, enhance nutrient cycling, and break up compaction. When integrated with grazing, turnips can extend feed availability. Farmers utilize them in rotational or mob grazing systems, allowing livestock to consume the crop, thereby incorporating manure and stimulating subsequent growth. The timing of grazing and subsequent rest periods are critical for plant recovery and soil benefits. Termination strategies are varied. Natural winterkill is common, especially in colder climates, simplifying management. Alternatively, turnips can be grazed down or terminated through mowing or crimping. Some systems may still employ herbicide termination, though less common in strictly regenerative approaches. Management focuses on soil fertility, with turnips generally having moderate needs, and competition management, ensuring they don't outcompete desired cash crops in intercropping or relay cropping scenarios. Farmers like the Pattons have encountered challenges, such as pest outbreaks like the turnip sawfly, highlighting the importance of observation and integrated pest management rather than immediate eradication. Turnips serve as a valuable component in crop rotations, contributing biomass and improving soil structure for subsequent cash crops.

Management Profile

Maintenance Intensity: Not Recommended - Integrated fertility management and consistent moisture retention practices support its vigorous growth, while healthy soil ecosystems naturally mitigate pest pressures.

Sources behind this view

Videos & Podcasts

Community

Purple top turnips are versatile for human food (roots mashed/sautéed, greens cooked/raw), livestock feed (chickens, pigs), and cover cropping for soil organic matter. They can deter nematodes and sup

Read more (opens in new window) permies.com

Research

Short-term effects of brassica cover crops on soil quality indicators in organic production in high tunnels (opens in new window)
In Polish high tunnels, turnip and swede cover crops boosted soil organic matter, improved soil structure, and increased beneficial bacteria populations, including nitrogen-cycling microbes, over thre

Economics & Value Streams

Direct harvest, system benefits, ecosystem services, and risk diversification

Comprehensive economic analysis including direct harvest value, system enhancement contributions, ecosystem services, value timeline, and risk diversification strategies.

Cover Crop Investment

Metric	Value
Seed Cost	$25-50/acre $62-124/ha
Termination Cost	20-60 49-148
Biomass Production	2-5 4-11
N Fixation Value	N/A N/A
Weed Control Savings	15-40 37-99

Cover crops are soil investments, not cash crops. Economics measured in soil health gains, input reduction, and subsequent crop performance. Values show direct costs and estimated benefits.

System Enhancement Value

Beyond cost recovery: soil building, nitrogen, biomass, and weed suppression

Soil Building & Weed Suppression

Purple top turnips offer significant benefits beyond direct harvest. As a component of cover crop mixes, they enhance soil health through organic matter addition and improved soil structure, as seen in the no-till systems described in,, and. Their rapid growth can outcompete weeds, reducing weed pressure in subsequent cash crops. In forage integration systems, they provide valuable, nutrient-dense forage for livestock, contributing to weight gain and reducing the need for purchased feed. The integration of turnips into systems like Peculiar Farms demonstrates their role in reducing water usage and eliminating the need for external amendments by relying on manure. Furthermore, their inclusion in multispecies cocktails, as detailed in and, supports a more resilient and biodiverse farming system. Their ability to break up compaction also contributes to improved water infiltration and root penetration for subsequent crops.

Erosion Control

Variable, dependent on density and integration within a mixed cover crop system.

While not a primary windbreak species, purple top turnips, when grown as part of a diverse cover crop mix, can contribute to soil surface stabilization and reduced wind erosion. The biomass produced, especially when left as residue or incorporated through grazing, helps to break up the 'plow layer' and improve soil structure, making it less susceptible to wind damage. As noted in and, cover-cropped fields demonstrated significantly less wind erosion compared to untreated fields, leading to better soil health and reduced risk of topsoil loss. This stabilization is crucial in fragile sandy loam soils prone to wind action, as highlighted in.

Ecosystem Service Contributions

Environmental contributions: carbon, pollinators, wildlife, and water

Carbon Sequestration: Purple top turnips, as annual cover crops, contribute to soil carbon sequestration through the addition of biomass to the soil. Their rapid growth and high biomass production, especially when managed within a diverse cover crop system, can increase soil organic matter over time, sequestering atmospheric carbon.
Pollinator Support: Low, as purple top turnips are primarily grown for their root and foliage and are not typically a significant nectar or pollen source for pollinators compared to flowering cover crops.
Wildlife Habitat: Moderate. The foliage can provide forage for certain wildlife species, and the root system can improve soil structure, indirectly benefiting soil-dwelling organisms. When left as residue, it offers some cover.
Water Quality: Not applicable

Value Timeline: Soil Building Process

When you'll see results: immediate soil benefits, compounding over seasons

Years 1-2

Initial soil stabilization and erosion control, addition of organic matter to the soil surface, weed suppression, and provision of supplemental forage for livestock if grazed.

Years 3-5

Improved soil structure leading to better water infiltration, increased earthworm populations, and reduced weed pressure in subsequent cash crops. If used consistently in forage systems, soil fertility and organic matter content will begin to show more pronounced improvements. Potential for reduced reliance on external inputs like fertilizer and herbicides.

Years 10-20

Significantly enhanced soil health characterized by improved water holding capacity, increased nutrient cycling, and greater resilience to environmental stresses. Long-term reduction in the need for synthetic inputs. Established benefits in livestock production due to sustained forage quality and quantity.

20+ Years

Mature development of a highly regenerative soil ecosystem with robust soil organic matter, excellent water management capabilities, and a self-sustaining nutrient cycle. The farm system becomes highly resilient and potentially a net sink for carbon.

Farm Risk Reduction

How this reduces farm risk: lower input costs and better soil resilience

Multiple Revenue Streams: Livestock forage, cash crop services (e.g., weed suppression, soil health improvement), direct cash crop harvest (if marketed as such), soil carbon sequestration credits (potential future income stream).
Temporal Income Spread: Provides immediate benefits through cover crop establishment and grazing, with ongoing soil health improvements that yield long-term dividends. Value is realized through annual forage production and the sustained enhancement of the agricultural system's productivity and resilience.
Market Risk Hedge: Reduces reliance on external inputs (fertilizers, herbicides) by improving natural soil fertility and weed suppression, thus lowering input costs and market price volatility for these commodities. Provides an alternative forage source, hedging against drought or poor pasture conditions. Enhances overall farm resilience, making it less susceptible to market shocks or extreme weather events.

Sources behind this view

Videos & Podcasts

Cover crops attract beneficial insects and pollinators, suppress pests, and improve soil biology. Mimicking nature's integration of animals and plants, alongside practices like no-till and diversity,

Gabe Brown | 1st Annual SSHC (opens in new window) | Jump to 36:41 (opens in new window)
Utilize multi-species cover crops based on specific 'resource concerns' to improve soil health, nitrogen fixation, and water retention. Integrate livestock for grazing, calving, and overwintering, enh

GFE 2016 - Gabe Brown "Cover Crops for Grazing" (opens in new window) | Jump to 4:27 (opens in new window)
Cover crops support livestock integration by providing forage and stimulating soil biology through grazing. They also significantly reduce soil erosion by 90%+, protecting the topsoil layer and enhanc

Cover Crops and Their Impacts on Soil Health with Dr. Olivia Caillouet (opens in new window) | Jump to 4:36 (opens in new window)
Discusses the positive impacts of cover crops on soil health, including increased organic matter, improved biology, reduced compaction, and cooler soil temperatures. Highlights earthworm activity and

Todd Kimbrell | 1st Annual SSHC (opens in new window)

Community

Cover crops offer cost-effective benefits for soil health, including building organic matter, managing nutrients (nitrogen scavenging and fixation), suppressing weeds and pests, and improving soil str

Read more (opens in new window) ucanr.edu
Seven strategies accelerate cover crop ROI: managing weeds, grazing, addressing compaction, transitioning to no-till, improving soil moisture, managing nutrients (using legumes like Hairy Vetch/Austri

Read more (opens in new window) sustainableagriculture.net
Cover crops offer cost-effective benefits for soil health, including building organic matter, managing nutrients (nitrogen scavenging by grasses/brassicas, fixation by legumes), suppressing weeds, and

Read more (opens in new window) ucanr.edu

Research

Economics of Cover Crops (opens in new window)
Cover crops can be profitable if they produce enough biomass, offering economic benefits through grazing, reduced inputs, carbon credits, and monetization of soil services.
Cover Crops and Ecosystem Services: Insights from Studies in Temperate Soils (opens in new window)
Cover crops build soil organic matter (0.1-1 Mg/ha/yr), reduce erosion by up to 80%, improve soil structure, recycle nutrients, and suppress weeds. They can be grazed or hayed without harming soil or
Enhancing Sustainable Farming and Climate Resilience: The Role of Cover Crops (opens in new window)
Cover crops boost soil health, fix nitrogen, suppress weeds, and sequester carbon, enhancing farm profitability and climate resilience. Addressing adoption challenges is key.
Evaluating Cover Crops for Benefits, Costs and Performance within Cropping System Niches (opens in new window)
Review of cover crops highlights benefits (pest control, soil health, yield) and costs. Best species identified for different seasons/regions. Rye excels in winter, C4 grasses in summer. Legumes fix N

Regenerative Suitability Details

Comprehensive trait ratings for system integration assessment

Comparative ratings for this plant across key regenerative agriculture traits.

Trait	Suitability	Explanation
Cold Hardiness	Adequate	Purple top turnip offers moderate resilience to cooler temperatures (Zone 5-7), providing valuable fall growth and soil cover, with potential for winter survival in milder conditions.
Weed Suppression	Ideally Suited	Its rapid growth and dense canopy effectively outcompete weeds, quickly establishing ground cover and contributing to a healthy soil ecosystem.
Nitrogen Fixation	Not Recommended	As a brassica, turnips enhance soil health by scavenging available nutrients and improving soil structure, rather than fixing nitrogen.
Root System Depth	Adequate	The developing taproot, reaching 2-3 feet, aids in breaking up soil compaction and accessing deeper nutrients, contributing to soil health.
Biomass Production	Adequate	This fast-growing brassica yields significant biomass, enriching soil organic matter and improving soil structure, with benefits for compaction relief.
Establishment Ease	Adequate	Quick germination and vigorous early growth allow this turnip to establish readily, outcompeting weeds and integrating seamlessly into the cropping system.
Multi Benefit Value	Not Recommended	Primarily a food crop, it also contributes to soil organic matter through its biomass, offering moderate support for the soil ecosystem.
Climate Adaptability	Adequate	Thrives in cooler seasons across a wide range of climates (zones 3-10), requiring adequate moisture for optimal performance and contributing to resilient cropping systems.
Maintenance Intensity	Not Recommended	Integrated fertility management and consistent moisture retention practices support its vigorous growth, while healthy soil ecosystems naturally mitigate pest pressures.

Comparative System: Ratings compare plants within their economic category (e.g., cover crop nitrogen fixation compared to other cover crops, not to all plants). Individual farm conditions and management practices significantly influence actual performance.

Learn More

Why farmers use this plant and additional resources

Why Regenerative Farmers Use This Plant

Purple top turnip offers significant regenerative benefits as a cover crop, primarily through its rapid biomass accumulation and exceptional nutrient scavenging capabilities. While not a legume, it excels at capturing residual soil nitrogen that might otherwise leach away, making these nutrients available for subsequent cash crops. In a typical growing season, a well-established stand can produce 2-4 tons of dry matter per acre (4,500-9,000 kg/ha), with a significant portion of this biomass returning valuable organic matter to the soil upon decomposition. This decomposition process, which can occur within 30-60 days under favorable conditions, releases scavenged nutrients, effectively acting as a nutrient bank for the next cash crop. Turnips can scavenge 50-100 lbs of nitrogen per acre (56-112 kg/ha) from deeper soil profiles or decomposing organic matter. In systems where nitrogen fertilizer costs can range from $0.50 to $1.00 per pound, the ability to retain and re-release 40-60 lbs N/acre (45-67 kg/ha) can translate to direct savings of $20-$60 per acre.

Integrating purple top turnip into crop rotations provides multiple system benefits beyond nutrient management. Its vigorous early growth offers effective weed suppression, outcompeting many common annual weeds for light, water, and nutrients within 30-45 days of planting, thereby reducing the need for costly and environmentally impactful weed control measures. The dense foliage also provides excellent ground cover, significantly reducing soil erosion from wind and rain by up to 70% compared to bare ground, particularly on bare fields during fallow periods. Furthermore, the extensive root system, which can reach depths of 12-30 inches (30-75 cm), helps to break up soil compaction and improve water infiltration. As the roots decompose, they create macropores that enhance aeration and drainage, leading to improved soil structure and reduced runoff. This improved soil structure and reduced erosion contribute to long-term farm resilience and productivity.

Quantitatively, the ecosystem services provided by purple top turnip are substantial. Its rapid growth cycle allows it to capture atmospheric carbon and incorporate it into the soil biomass, contributing to soil organic matter (SOM) buildup over time. Consistent use in a rotation can increase SOM by 0.1-0.3% annually. The fibrous root system also enhances soil aggregation, improving water holding capacity by up to 10-15% in some cases, which is critical for drought resilience. While not a primary pollinator attractant, its flowers can provide a late-season nectar source for some beneficial insects, and the increased soil biological activity fostered by its residue decomposition supports a healthier soil ecosystem overall.

Farmers in various regions have found success with purple top turnip as a versatile cover crop. In the Pacific Northwest of the USA, it's often interseeded into wheat fields in late summer to scavenge nitrogen and provide grazing for livestock before a spring cash crop. In the UK, it's used in arable rotations to build soil organic matter and improve soil structure, typically terminated by grazing or mowing before planting winter cereals. Australian farmers in dryland farming systems utilize its drought tolerance and nutrient scavenging to build resilience in their soils, often planting it after a cereal harvest to capture late-season moisture and nutrients. In Brazilian coffee plantations, it can be used as a green manure crop or intercrop, planted during the rainy season or cooler, drier months and incorporated into the soil or left as residue to improve fertility and soil health between rows. In the southeastern United States, it is frequently incorporated into pasture renovation programs or used as a winter cover crop in vegetable rotations. In the corn-soybean rotations of the US Midwest, it is often interseeded or planted after harvest to scavenge nutrients and provide fall growth before winterkill.

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Purple top turnips are versatile for human food (roots mashed/sautéed, greens cooked/raw), livestock feed (chickens, pigs), and cover cropping for soil organic matter. They can deter nematodes and sup

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Purple top turnip is a versatile cool-season cover crop maturing in 45-65 days. It serves as livestock forage (15-25% protein leaves, 10-15% protein bulbs), green manure, and decompaction tool, scaven

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How to Integrate This Plant

Practical guidance for regenerative systems

Establishing purple top turnip is straightforward, with flexibility in seeding rates and methods. For broadcast seeding, rates of 5-10 lbs/acre (5.6-11.2 kg/ha) are typically recommended, while drilled seed rates can be slightly lower, around 3-7 lbs/acre (3-8 kg/ha), to ensure optimal spacing and seedling vigor. The ideal planting depth is shallow, between 0.25-0.5 inches (0.6-1.3 cm), as turnips require good seed-to-soil contact for germination. In the Northern Hemisphere, planting can occur from early spring (March-April) through late summer (August-September), with fall plantings benefiting from cooler temperatures and increased moisture for rapid establishment within 10-20 days. In the Southern Hemisphere, this translates to planting from September to November for spring growth or February to April for autumn growth. For drilled rows, spacing is often set at 6-12 inches (15-30 cm) apart.

Management of purple top turnip focuses on maximizing its growth for biomass production and nutrient scavenging before termination. It requires approximately 1 inch (2.5 cm) of moisture per week, either from rainfall or irrigation, especially during establishment. While turnips are relatively drought-tolerant once established, they perform best with adequate moisture. Fertility needs are minimal, as their primary role is nutrient scavenging; however, they respond well to compost applications or incorporation of previous crop residues, especially in nutrient-poor soils. Biological fertility approaches are preferred; incorporating compost or well-composted manure before planting can provide a good nutrient base. The plant establishes rapidly, typically within 14-30 days, and reaches maturity or peak biomass in 45-90 days, growing to a height of 1-3 feet (0.3-0.9 m). Pest and disease management should prioritize biological controls and crop rotation; healthy soil biology fostered by cover cropping generally reduces pest pressure, and beneficial insects are attracted to the flowers if allowed to bolt. As the turnip belongs to the Brassica family, resistant varieties can be chosen, and monocropping should be avoided.

Termination and residue management for purple top turnip should follow the regenerative termination hierarchy. The preferred termination hierarchy begins with natural winterkill in colder climates where temperatures consistently drop below -5°C (23°F) or below 15°F (-9°C). Where winterkill is insufficient or unreliable, grazing with livestock (sheep or cattle) is an excellent option, providing nutrition for animals while reducing biomass and incorporating residue into the soil through hoof action, typically 2-3 weeks before planting the next crop. Mowing or crimping are effective mechanical termination methods, with crimping at the 50% bloom stage being ideal for creating a dense mulch that suppresses weeds. If regenerative termination methods are exhausted or not feasible, herbicide can be used as a last resort, applied when the plant is actively growing, typically 10-14 days before planting the subsequent cash crop to ensure complete kill and residue breakdown. Expect residue to decompose within 30-60 days, releasing scavenged nutrients. A nitrogen credit of 50-70 lbs N/acre (56-78 kg/ha) can be expected from a well-managed stand, with 60-70% of captured nutrients becoming available within 30-60 days post-termination. To prevent unwanted reseeding, termination should ideally occur before flowering and seed set. Turnips generally do not pose a significant reseeding risk in most temperate climates, but monitoring for volunteer plants in subsequent years is advisable.

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