Conservation Crop Rotation (328)
328 - 1
Natural Resources Conservation Service
Conservation Practice Standard
NRCS, Georgia
April, 1999
328 - 1
CONSERVATION CROP ROTATION
(Acre)
Code 328
NRCS, Georgia
April, 1999
328 - 1
DEFINITION
Growing crops in a recurring sequence on the same field.
PURPOSES
This practice may be applied as part of a conservation management system to support one or more of the following:
- Reduce sheet and rill erosion.
- Reduce irrigation-induced erosion.
- Reduce soil erosion from wind.
- Maintain or improve soil organic matter content.
- Manage deficient or excess plant nutrients.
- Improve water use efficiency.
- Manage plant pests (weeds, insects, and diseases).
- Provide food for domestic livestock.
- Provide food and cover for wildlife.
CONDITIONS WHERE PRACTICE APPLIES
This practice applies to all cropland and other land where crops are grown.
This standard does not apply to pastureland, hayland, or other land uses where annual row or close growing crops are grown occasionally only to facilitate renovation or re-establishment of perennial vegetation. It does not apply to land devoted to orchards, vineyards, or nurseries.
CRITERIA
General Criteria Applicable to All Purposes Named Above
Crops shall be grown in a planned, recurring sequence except as outlined in Operation and Maintenance.
Crops shall be adapted to the climatic region and the soil resource. Adapted crops and varieties listed in appropriate university publications or other approved sources, shall be selected.
A conservation crop rotation may include crops planted for cover or nutrient enhancement.
The conservation crop rotation is considered to be complete when the last crop in the sequence is in place for the last year of the rotation.
Additional Criteria to Reduce Sheet and Rill Erosion
Crops shall be selected that produce enough above and below ground plant biomass to control erosion within the soil loss tolerance (T) or any other planned soil loss objective.
The amount of biomass needed shall be determined using current approved erosion prediction technology.
Calculations shall account for the effects of other practices in the conservation management system.
Additional Criteria to Reduce Irrigation Induced Erosion
To reduce erosion induced by sprinkler irrigation, crops or cover crops shall be selected that develop surface cover or canopy rapidly, or that produce the amount of residue needed to be maintained on the soil surface to achieve the soil loss objective. The amount of residue needed shall be determined by approved research.
Additional Criteria to Reduce Soil Erosion From Wind
Crops shall be selected that produce biomass in amounts adequate, and at the appropriate time, to control erosion to within the soil loss tolerance (T) or other planned soil loss objective.
The amount of biomass needed shall be determined using current approved wind erosion prediction technology. Calculations shall account for the effects of other practices in the conservation management system.
Additional Criteria To Maintain Or Improve Soil Organic Matter Content
Crops and tillage systems shall be selected that produce and maintain the amount of plant biomass needed on the soil surface to maintain or increase the soil organic matter content. The conservation crop rotation will meet the requirements outlined in Table 1.
If partial removal of residue by means such as baling or grazing occurs, enough residue shall be maintained to achieve the desired soil organic matter content goal.
Cover and green manure crops planted specifically for soil improvement may be grazed, as long as grazing is managed to retain adequate biomass.
Additional Criteria to Manage Deficient or Excess Plant Nutrients
Crop selection and sequence shall be determined using an approved nutrient balance procedure.
When crop rotations are designed to add nitrogen to the system, nitrogen-fixing crops shall be grown immediately prior to or interplanted with nitrogen-depleting crops.
To reduce excess nutrients, crops or cover crops having rooting depths and nutrient requirements that utilize the excess nutrients shall be grown.
Additional Criteria to Manage Plant Pests (Weeds, Insects, Diseases)
Crops shall be alternated to break the pest cycle and/or allow for the use of a variety of other control methods. Affected crops and alternate host crops shall be removed from the rotation for the period of time needed to break the life cycle of the targeted pest.
Resistant varieties, listed in appropriate university publications or other approved sources, shall be selected where there is a history of a pest problem.
Additional Criteria to Provide Food for Domestic Livestock
Crops shall be selected to balance the feed supply with livestock numbers. The needed amount of selected crops shall be determined using an approved forage-livestock balance procedure.
Additional Criteria to Provide Food and Cover for Wildlife
Crop selection shall be determined using an approved habitat evaluation procedure.
CONSIDERATIONS
When used in combination with cross wind sripcropping, contour stripcropping, or field stripcropping, the cropping sequence should be consistent with the stripcropping design.
When used in combination with residue management practices, selection of high residue producing crops and varieties, use of cover crops and adjustment of plant population and row spacing can enhance production of the kind, amount, and distribution of residue needed.
Where erosion induced by sprinkler irrigation is a concern, residue management, basin tillage (dammer-diker), contour farming or contour stripcropping can reduce the hazard.
Where maintaining or improving soil organic matter content is an objective, the effects of this practice can be enhanced by managing crop residues, utilizing animal wastes, or applying mulches to supplement the biomass produced by crops in the rotation.
Where excess plant nutrients or soil contaminants are a concern, rotating deep rooted crops or cover crops with shallow rooted crops can help recover the nutrient or contaminant from the soil profile.
Where precipitation is limited or erratic, moisture can be conserved for crop use by maintaining crop residues on the soil surface to increase infiltration and to reduce runoff and evaporation.
Crop damage by wind erosion can be reduced by this practice by selecting crops that are tolerant to abrasion from wind blown soil or tolerant to high wind velocity. If crops sensitive to wind erosion damage are grown, the potential for plant damage can be reduced by residue management, field windbreaks, herbaceous wind barriers, or other methods of wind erosion control.
Soil compaction can be reduced by this practice when rotations including deep rooted crops (able to extend to and penetrate the compacted soil layers) are used in combination with deep tillage, controlled traffic, or management of grazing animals to prevent, or breakup, compacted layers.
PLANS AND SPECIFICATIONS
Specifications for establishment and operation of this practice shall be prepared for each field or treatment unit according to the Criteria, Considerations, and Operation and Maintenance described in this standard.
Specifications shall be recorded using approved specification sheets, job sheets, narrative statements in the conservation plan, or other acceptable documentation.
OPERATION AND MAINTENANCE
Rotations shall provide for acceptable substitute crops in case of weather related or economic reasons. Acceptable substitutes are crops having similar properties that meet the criteria for all the resource concerns identified for the field or treatment unit.
NRCS, Georgia
April, 1999
328 - 1
NRCS, Georgia
April, 1999
328-6
Table 1
Conservation Crop Rotation Index Values
The conservation crop rotation will have an index value of 0.00 or greater (in other words, not a negative value) in order to meet this standard.
The index value for the conservation crop rotation will be calculated by adding the index values all of the crops included in the rotation. See the examples on the last page of this table.
A. Conservation Crop Rotation Index Values for High Residue Summer Crops1/
RotationSummer CropOther Conservation Cycle Tillage Crop & Crop Rotation (years) Type Tillage Type Index Value
1Conventional Till0.00
1Mulch-Till or Ridge-Till2/0.01
1No-Till or Strip-Till2/0.02
1Conventional TillandCover Crop3/ (Conventional Till)0.00
1Conventional Till andCover Crop (Mulch-Till or Ridge-Till)0.01
1Conventional TillandCover Crop (No-Till or Strip-Till)0.02
1Conventional TillandSml. Grain4/ (Conventional Till)0.00
1Conventional TillandSml. Grain (Mulch-Till or Ridge-Till)0.01
1Conventional TillandSml. Grain (No-Till or Strip-Till)0.02
1Mulch/Ridge-TillandCover Crop (Conventional Till)0.00
1Mulch/Ridge-TillandCover Crop (Mulch-Till or Ridge Till)0.01
1Mulch/Ridge-TillandCover Crop (No-Till or Strip-Till)0.02
1Mulch/Ridge-TillandSml. Grain (Conventional Till)0.01
1Mulch/Ridge-TillandSml. Grain (Mulch-Till or Ridge-Till)0.02
1Mulch/Ridge-TillandSml. Grain (No-Till or Strip-Till)0.03
Index Values for High Residue Summer Crops (continued):
RotationSummer CropOther Conservation Cycle Tillage Crop & Crop Rotation (years) Type Tillage Type Index Value
1No-Till or Strip-TillandCover Crop (Conventional Till)0.02
1No-Till or Strip-TillandCover Crop (Mulch-Till or Ridge-Till)0.08
1No-Till or Strip-TillandCover Crop (No-Till or Strip-Till)0.15
1No-Till or Strip-TillandSml. Grain (Conventional)0.03
1No-Till or Strip-TillandSml. Grain (Mulch-Till or Ridge-Till)0.11
1No-Till or Strip-TillandSml. Grain (No-Till or Strip-Till)0.20
21-year Conventional Till and 1-year Perennial Sod0.05
21-year Mulch-Till or Ridge-Till and 1-year Perennial Sod0.06
21-year No-Till or Strip-Till and 1-year Perennial Sod0.10
31-year Conventional Till and 2-years Perennial Sod0.10
31-year Mulch-Till or Ridge-Till and 2-years Perennial Sod0.11
31-year No-till or Strip-Till and 2-years Perennial Sod0.20
41-year Conventional Till and 3-years Perennial Sod0.20
41-year Mulch-Till or Ridge-Till and 3-years Perennial Sod0.22
41-year No-Till or Strip-Till and 3-years Perennial Sod0.40
B. Conservation Crop Rotation Index Values for Low Residue Summer Crops5/
RotationSummer CropOther Conservation Cycle Tillage Crop & Crop Rotation (years) Type Tillage Type Index Value
1Conventional Till-0.10
1Mulch-Till or Ridge-Till-0.09
1No-Till or Strip-Till-0.07
1Conventional Tilland Cover Crop (Conventional Till)0.00
1Conventional Tilland Cover Crop (Mulch-Till or Ridge-Till)0.00
1Conventional Tilland Cover Crop (No-Till)0.00
1Conventional Tilland Sml. Grain (Conventional Till)0.01
1Conventional TillandSml. Grain (Mulch-Till or Ridge-Till)0.01
1Conventional TillandSml. Grain (No-Till)0.01
1Mulch-Till or Ridge-Till and Cover Crop (Conventional Till)0.00
1Mulch-Till or Ridge-Till and Cover Crop (Mulch-Till or Ridge-Till)0.00
1Mulch-Till or Ridge-Till and Cover Crop (No-Till)0.00
1Mulch-Till or Ridge-Till and Sml. Grain (Conventional Till)0.01
1Mulch-Till or Ridge-Till and Sml. Grain (Mulch-Till or Ridge-Till)0.01
1Mulch-Till or Ridge-Till and Sml. Grain (No-Till)0.01
1No-Till or Strip-TillandCover Crop (Conventional Till)0.01
1No-Till or Strip-TillandCover Crop (Mulch-Till or Ridge-Till)0.01
1No-Till or Strip-Tilland Cover Crop (No-Till)0.03
1No-Till or Strip-TillandSml. Grain (Conventional Till)0.02
1No-Till or Strip-TillandSml. Grain (Mulch-Till or Ridge-Till)0.03
1No-Till or Strip-TillandSml. Grain (No-Till)0.10
21-year Conventional Till and 1-year Perennial Sod0.04
21-year Mulch-Till or Ridge-Till and 1-year Perennial Sod0.05
21-year No-Till and 1-year Perennial Sod0.10
Index Values for Low Residue Summer Crops (continued):
RotationSummer CropOther Conservation Cycle Tillage Crop & Crop Rotation (years) Type Tillage Type Index Value
31-year Conventional Till and 2-years Perennial Sod0.08
31-year Mulch-Till or Ridge-Till and 2-years Perennial Sod0.09
31-year No-Till or Strip-Till and 2-years Perennial Sod0.16
41-year Conventional Till and 3-years Perennial Sod0.16
41-year Mulch-Till or Ridge-Till and 3-years Perennial Sod0.18
41-year No-Till or Strip-Till and 3-years Perennial Sod0.32
C. Conservation Crop Rotation Index Values for Winter Crops Followed by Summer Weeds
RotationSummer CropOther Conservation Cycle Tillage Crop & Crop Rotation (years) Type Tillage Type Index Value
1Annual WeedsSml. Grain (Conventional Till)0.01
1Annual WeedsSml. Grain (Mulch-Till or Ridge-Till)0.05
1Annual WeedsSml. Grain (No-Till)0.15
1Annual WeedsNone0.03
_____
1/ High Residue Summer Crops include corn and grain sorghum.
2/ Refer to Residue Management Standards 329-A, 329-B, and 329-C for descriptions of these tillage types.
3/ Cover Crops include small grain and legumes that are killed prior to maturity by herbicides or mechanical means.
4/ Small grain represents winter small grains (such as rye, wheat, oats, and barley) harvested for grain production.
5/ Low Residue Summer Crops include cotton, peanuts, soybeans, tobacco, vegetables, and other summer crops that are not considered to be high residue crops.
Example #1:
Crop YearCrop and Tillage PlannedIndex Value
1Conventional corn0.00
2Conventional cotton -0.10
Total = -0.10 (This index value is a negative number. Therefore, this rotation does not meet the standard.
Example #2:
Crop YearCrop and Tillage PlannedIndex Value
1No-till corn0.02
2No-till cotton & no-till small grain0.10
3Conventional peanuts -0.10
Total = 0.02 (This index value is a positive number. Therefore, this rotation meets the standard.)
NRCS, Georgia
April, 1999