In addition to the quantity of residues remaining following harvest, a variety of types of residues is also important. The goal should be a minimum of three different species in a rotation, more if possible.
The percent of the time that living roots are present during a rotation is also important. The period that active roots are present varies considerably, ranging from 32% of the time for a corn-soybeans rotation to 57% for a beans-wheat rotation to 76% for a three-year beans-wheat-corn rotation (table 11.1).
As mentioned above, when soils are covered with living vegetation for a longer period of time, there tends to be decreased erosion as well as a decreased loss of nitrate and less groundwater contamination.
Table 11.1: Comparison of Rotations: Percent of Time Active Roots Are Present and Number of Species | |||
---|---|---|---|
Rotation | Years | Active Rooting Period (%) | Number of Species |
Corn-soybeans | 2 | 32 | 2 |
Dry beans-winter wheat | 2 | 57 | 2 |
Dry beans-winter wheat/cover | 2 | 92 | 3 |
Dry beans-winter wheat-corn | 3 | 72 | 3 |
Corn-dry beans-winter wheat/cover | 3 | 76 | 4 |
Sugar beets-beans-wheat/cover-corn | 4 | 65 | 5 |
Table of Contents
- About the Authors
- Preface
- Introduction
- 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
- Glossary
- Resources