Crop rotation is an integral part of the crop production system. A well-planned crop rotation will:
- increase yields.
- aid in maintaining soil organic matter levels.
- protect against soil erosion.
- improve resilience against weather extremes.
- help to disrupt insect, disease and weed cycles.
- provide residual nitrogen from legumes in the rotation.
- spread workload, labour and equipment logistics.
The basic rule of crop rotation is that a crop should never follow itself. Continuous cropping of any crop will increase the buildup of diseases and insects specific to that crop and will potentially result in heavier infestations and reduced yields.
The greatest benefit from crop rotation comes when crops, including cover crops, grown in sequence are from different families; monocots (grasses) and dicots (broadleaves). The fibrous root systems of cereal and forage crops (including red clover) are excellent for building soil structure and helping to prevent compaction. The advantage of including wheat in the rotation often goes beyond the wheat year. Table 1-1 management consideration for various crop rotations provides an example of response to a crop following various crops in a rotation.
Table 1-1. Management Consideration for Various Crop Rotations
| Crop | Previous Crop | |||||
| Corn | Soybeans | Cereals | Forages | Edible Beans | Canola | |
| Corn | high residue volume to manageyield depressionless herbicide rotation/weed control optionscorn rootworm slugs (in short term no-till) | greater herbicide rotation/weed control optionsincreased European chafer risk (light-textured soils) | high residue in no-till system if straw wasn’t removed could keep soils coolergreater herbicide rotation/weed control optionsgreater cover crop options | increased wireworm risk in grassy sod | no issues | reduced mycorrhizae = less P uptakepotential reduced crop growth |
| Soybeans | high residue volume to managegreater herbicide rotation/weed control optionsslugs (short term no-till) | yield depressionlow residue return – declining soil organic matterless herbicide rotation/weed control optionsincreased risk of soybean root diseases, white mould, soybean cyst nematode, | herbicide rotation optionsslugs could be issue (over-winter cover) | increased wireworm risk | increased risk of white mouldsoil degradation | increased risk of white mouldpotential reduced crop growth |
| Winter Cereals | increased Fusarium head blight risk | planting date issues depending on length of season bean variety | increased risk of seedling, root and leaf diseasesreduced herbicide rotation/options | increased risk of wireworm feeding | earlier harvest makes timely planting easier | may cause a slight reduction in growth |
| Spring Cereals | high residue can affect seedbed preparation | no issues | increased risk of seedling, root and leaf diseases | increased risk of wireworm | no issues | no issues |
| Forages | high residue can affect seedbed preparation | limited weed control optionspotential for herbicide carryover | limited weed control options | autotoxicity if re-seeded too soonlimited weed control options | no issues | no issues |
| Dry Edible Beans | no issue | increased risk of root rots, white mould | slugs may cause damage in no-till | slugs in no-tillreduced herbicide options | soil degradationincreased root rotsincreased white mould yield depression | white mouldmay cause a slight decrease in growth |
| Canola | slugs may cause damage in no-tillharvest is too late for planting winter canolapotential for herbicide carryover | increased risk of root rots, white mould | no issues | slugs may reduce stand | increased risk of white mould | yield depressionincreased root rotsincreased white moulddecreased soil structure |
Most of the characteristics of a healthy soil have a direct or indirect link to other aspects of crop management.