Crop rotations and cover crops are keys to sustainable cropping systems. Sustainable systems utilize conservation crop rotations along with supporting practices like cover crops, residue management, and nutrient management to ensure long-term productivity while protecting natural resources. Cover crops provide benefits like increased soil organic matter, nitrogen for subsequent crops from legumes, and weed suppression. Key considerations for cover crops include species selection and termination. Sustainable crop rotations include a diversity of crops, minimize pests, and maximize benefits through keeping live cover on the land.

2. By
CROP ROTATIONS & COVER CROPS: KEYS
TO SUSTAINABLE CROPPING
SYSTEMS
By Mr. Allah Dad Khan
Former DG Agriculture Extension KPK
Province
Allahdad52@gmail.com
03329221298

3. CROP ROTATIONS & COVER CROPS : KEYS
TO SUSTAINABLE CROPPING SYSTEMS

4. SUSTAINABLE CROPPING SYSTEMS
• Conservation Crop Rotation
• Supporting Practices and Management
Activities
1. Cover Crops
2. Residue Management
3. Nutrient Management
4. Pest Management
5. Controlled Traffic
6. Precision Ag.

5. 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

6. SUSTAINABLE CONSERVATION
CROP 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.

7. 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.

8. 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

9. Barriers to Adopting/Changing
Crop Rotations
1.Income Potential and Markets
2.Equipment and Storage Needs
for Additional Crops Produced
3.Need for Livestock to Utilize
forages Produced
4.Rental Arrangements and/or
Land Availability
5.Pesticide, particularly
herbicide, Carry - Over

10. 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

11. 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.

12. 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.

13. Some Insects Controlled Partially or
Entirely by Rotation
Insect Susceptible Crop
Alfalfa Weevil Alfalfa
Corn Rootworm Corn
Colorado Potato Beetle Potatoes, Tomatoes
Wheat Stem Maggot Wheat
Pepper Maggot Peppers
Squash Cucurbits
Hessian Fly Wheat

14. Some Plant Diseases Controlled
Partially or Entirely by Rotation
Disease Major Crops Attacked
Bacterial Blight Wheat, Barley
Bacterial Wilt Alfalfa
Black Dot Potato
Black Shank Tobacco
Granville (Bacterial) Wilt Tobacco, Potato, eggplant
Northern Corn Leaf Blight Corn
Smut (corn) Corn
Stem Rot Peanuts
Verticillium Wilt Potato, Sunflower
White Mold Peanuts, Potato, Soybean

15. 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

16. 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

17. 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.

18. 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

19. 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.

20. 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.

21. 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.

22. Terminating Cover Crops
• Incorporation
• Flat Sweeps
• Mowing
• Winterkill
• Herbicides
• Rolling/crimping

23. 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.

24. 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.

25. Comments - Questions

26. Thank you very muchThank you very much