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CROP ROTATIONS & COVER CROPS: KEYS TO SUSTAINABLE CROPPING

SYSTEMS

By Mr. Allah Dad Khan Former DG Agriculture Extension KPK

Province Allahdad52@gmail.com

03329221298

CROP ROTATIONS & COVER CROPS : KEYS TO SUSTAINABLE CROPPING SYSTEMS

SUSTAINABLE CROPPING SYSTEMS

• Conservation Crop Rotation• Supporting Practices and Management

Activities1. Cover Crops2. Residue Management3. Nutrient Management4. Pest Management5. Controlled Traffic

6. Precision Ag.

CROP ROTATIONS & COVER CROPS : KEYS TO SUSTAINABLE CROPPING SYSTEMS

Points for Discussion

• Benefits of Crop Rotations

• Managing Cropping Systems for Resource Protection and Profitability

• Sod Based Rotations

• Enhancing Crop Rotations with Cover Crops

• Tips for Assisting with the Planning and Refinement of Conservation Crop Rotations

SUSTAINABLE CONSERVATIONCROP ROTATIONS

• Insure Long-term Productivity

• Treat Natural Resource Concerns within the Field (at the source).

• Provide for Continued Profitability.

• Maximize Benefits through Inclusion of Management and Supporting Practices.

Options for Crops /Covers in Crop Rotations

• Plant type: Grasses, Legumes, other Broadleaf Crops

• Single Crop Annually –Multiple Crops Annually

• High Residue vs. Low Residue

• Perennials: (Sod Based Rotations)

• Cover Crops

• Fallow

• Living Mulches, e.g. in orchards and with other perennial crops.

Potential Benefits through Sustainable Crop Rotations

• Improved Yields and Crop Quality• Enhanced Erosion Protection • Reduced Runoff and Pollutants in Runoff• Increased Soil Organic Matter• Increased Biological Activity in the Soil• Improved Efficiency of Nutrient Cycling and

Utilization• Reduced Soil Compaction and Improved

Soil Condition

Barriers to Adopting/Changing Crop Rotations

1. Income Potential and Markets2.Equipment and Storage Needs

for Additional Crops Produced3.Need for Livestock to Utilize

forages Produced 4.Rental Arrangements and/or

Land Availability5.Pesticide, particularly

herbicide, Carry - Over

Barriers to Adopting/Changing Crop Rotations

5. Increased Requirement in Management Skills and Information

6.Crops that Are Pest Hosts or Have Allelopathic Effects

7.Suitability of Soils for Production of Alternative Crops

8.Suitability of Climate for Production of Alternative Crops

Impacts of Sustainable Crop Rotations on Soil Quality

• High residue crops and perennials (sod) increase SOM.

• High residue crops and perennials (sod) reduce soil erosion.

• Diversity in crop rotations increases biological activity in the soil and diversity of soil biota.

• Many perennial species and some annuals have deep extensive root systems that reduce soil compaction and improve soil condition.

Impacts of Sustainable Crop Rotations on Water Quality

• High residue crops and perennials reduce the amount of sediment and other particulate matter leaving a field.

• Live vegetation captures and cycles excessive nitrates and other nutrients in the soil.

• Crop residues and perennial vegetation help reduce and filter runoff.

Some Insects Controlled Partially or Entirely by Rotation

Insect Susceptible CropAlfalfa Weevil Alfalfa

Corn Rootworm Corn

Colorado Potato Beetle Potatoes, TomatoesWheat Stem Maggot Wheat

Pepper Maggot Peppers

Squash Cucurbits

Hessian Fly Wheat

Some Plant Diseases Controlled Partially or Entirely by Rotation

Disease Major Crops AttackedBacterial Blight Wheat, BarleyBacterial Wilt AlfalfaBlack Dot PotatoBlack Shank TobaccoGranville (Bacterial) Wilt Tobacco, Potato, eggplantNorthern Corn Leaf Blight CornSmut (corn) CornStem Rot PeanutsVerticillium Wilt Potato, SunflowerWhite Mold Peanuts, Potato, Soybean

Benefits of Cover Crops in Crop Rotations

• Increase Cover and SOM

• Leguminous Cover Crops Produce Nitrogen for Subsequent Crops

• Attract Beneficial Insects and other Predators of Insect pests

• Can Provide Weed Suppression and Allelopathic Effects

Benefits of Cover Crops in Crop Rotations

• Can Serve as a Trap Crop for Control of Insect Pests

• Can Reduce Soil Compaction (e.g. forage radishes)

• Can Capture and Cycle Residual Nitrogen or Nitrogen Released from Decaying Residues (cereal rye and forage radishes)

• Some Species, e.g. certain Brassicas, provide a Biofumigation Effect.

• Enhance Biological Activity in the Root Zone

Concerns with Cover Crops in Crop Rotations

• Species Selection

• Termination of the Cover Crop

• Planting into the Residues

• Nutrient Management for the Cover Crop and the Following Crop.

• Species that Can Become Weed Pests.

Examples of Nitrogen Provided by Legumes at Full Biomass

Legume Range of Nitrogen Contribution

Berseem Clover 100 – 200 lbs./ac.Cowpeas 100 – 150 lbs./ac.Crimson Clover 70 – 150 lbs./ac.Hairy Vetch 120 - 180 lbs./ac.Red Clover 70 – 150 lbs/ac.Sweet Clover 100 – 200 lbs./ac.Winter Peas 100 – 160 lbs. ac.

Managing Cover Crops Profitably

Contributions of Cover Crops to Weed Management

• Allelopathic Effects • Suppression by Residue Cover 1. Increases with increasing quantity 2. Declines with decomposition of residue 3. Provides greatest control of small-seeded species that require light for germination.• Maximize effects by use of cover crops that

produce large amounts of biomass and use of implements that pack or compress mulch.

Contributions of Cover Crops to Weed Management

• Allelopathic Effects• Suppression by Residue Cover 1. Increases with increasing quantity 2. Declines with decomposition of residue 3. Provides greatest control of small-seeded species that require light for germination.• Maximize effects by use of cover crops that

produce large amounts of biomass and use of implements that pack or compress mulch.

Crops with Demonstrated Allelopathic Effects

• Rye (cereal)• Sudangrass• Sorghum x sudangrass Hybrids• Sweet Clover (Yellow Blossom)• Sunflowers• Black Mustard• White Mustard• Rapeseed• Hairy Vetch• Wheat• Other Examples: Little Bluestem, Black Walnut, Some

Oak Species.Problem: May also affect some crops.

Terminating Cover Crops

• Incorporation

• Flat Sweeps

• Mowing

• Winterkill

• Herbicides

• Rolling/crimping

Characteristics of Sustainable Crop Rotations

• Provide satisfactory erosion control and enhancement of soil condition.

• Utilize supporting management and practices as needed, e.g. residue mgt., cover crops, & controlled traffic.

• Use longer periods of perennial crops and high residue crops on highly erodible soils and on soils with low inherent SOM.

• Are built around the priority crops.• Provide an opportunity for continued profitability,

at least in the long term .• Maintain compatibility with the total farm operation.

Characteristics of Sustainable Crop Rotations

• Include a diversity of crops/vegetative types.• Use a combination of species (crops and covers)

and a sequence to minimize pest problems, break pest cycles, and promote healthier crops.

• Maximize benefits and sustainability by keeping live cover on the land to the extent feasible.

• Provide for nutrient needs of all crops, including covers.

• Include deep rooted grass cover crops, as needed, to capture and cycle nitrates in the soil and to reduce soil compaction.

Comments - Questions

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