Crop rotation is planting different plants on the same land according to a planned (and scientifically appropriate) order. An example of such a rotation would be maize, then cotton, then sunnhemp, then soy beans. Traditionally, a key part of rotating crops is also adding nitrogen to the land through green manure as part of the rotation. Rotation of crops has several benefits. It doesn’t allow for pests or pathogens to grow in the same way they would if the same crop were planted year after year. The soil also gets a break. Rotation helps with the soil’s nutrition and structure if plants with shallow root and plants with deep roots are planted back to back.
Monoculture is the term used for planting the same plant in a field every year.
Green manure is a plant grown specifically for the purposed of plowing it down to act as a manure. However, they can be utilized for grazing while growing. Usually, farmers choose legumes or grasses as green manure. This type of fertilization adds nitrogen to the dirt, keeps the soil from eroding, makes the structure of the soil better, takes down leaching (and its associated nutrient loss), and generally helps with fertility. These plants get their start in the fall and get plowed in the spring before summer sowing.
Cover crop is a plant that grows quickly (i.e. cowpea, buckwheat, rye, vetch) that is sown on a field to keep the soil from eroding. They also make the soil more nutritious and contribute to having organic matter. They can be grown off-season (opposite seasons from the cash crops) or between rows of cash crops.
Plants to Sow After Wheat at the Start of July
- To add nitrogen plant: sweet clover, red clover, hairy vetch, soy beans, crotalaria, cowpea, winter pea
- To mitigate compacting issues plant: oilseed radish, tillage radish, annual ryegrass, brassicas (such as turnips)
- To add nutrients plant: oilseed radish, tillage radish, annual ryegrass, brassicas, buckwheat, cereal rye, and oats (with manure)
- To add some organic matter plant: annual ryegrass, cereal rye, sorghum sudan grass or oats
- To add or reserve moisture plant: teff, buckwheat or cowpea
- To use as hay plant: cereal rye, oats, triticale, sorghum sudan grass, teff, or field pea
- To mitigate weeds and diseases plant: buckwheat, cereal rye, mustard, oilseed radish or tillage radish
As a cover crop in the summer, choose winter pea, cowpea or crotalaria. They’ll be killed during the winter months and then add much needed nitrogen for the next year’s crop of grain.
A dry year calls for cowpea to be in the dirt by the end of July, since it can handle dry conditions, grows quickly and can get 140 lbs of nitrogen in one acre.
A wet year calls for winter peas to be planted by the end of July. They get killed by frost in January – if they’re planted after August, as opposed to cowpea which is done for with the first frost in late October. Austrian winter peas that produce flowers before winter will die during the frosts of winter and gain 180 lbs of nitrogen.
On the other hand, legumes get the most nitrogen buildup before producing flowers. During the spring, corn can be plant sans nitrogen fertilization if there’s enough nitrogen coming from decomposing winter peas or cowpeas. Alternatively, a farmer could use cheap soy bean or wheat as a cover crop (look for leftover soy bean or bin ruin seeds).
Following the harvest of wheat, more nutrients can be added by planting annual ryegrass, tillage radish or oilseed. They also mitigate compacting soil, particularly in areas where manure has been added.
Post-Early Soy Beans
To make the whole farm a sustainable system, a soybean crop that matures early makes it so that a farm can have two crops in one year.
- To get more organic matter in the soil, re-use nutrients and mitigate compaction, plant: annual ryegrass, oats, cereal rye, wheat, or spelt
- To suppress weeds and diseases in addition to mitigating compaction and re-using nutrients, plant: brassicas such as oilseed, turnips or tillage radish
- To produce more nitrogen for spring-sown corn, plant: winter pea, as it can gain 80 lbs of nitrogen. Without tilling, corn can be sown along with the winter pea. Simply spray to kill the peas a month after the corn crop pops up.
- DON’T plant cowpea since it will not germinate, but simply freeze during the winter.
Post-Late Soy Beans or Corn
Cereal rye is a great cover crop to plant after corn or soy that matures late, since it can mature before the cold comes. To help it grow in time, add manure (for nitrogen). Adding some nitrogen in the fall or spring to the cereal rye not only makes the cover crop better, it also lowers the need for adding nitrogen to the cash crop later. Cereal rye is great because it survives the winter, grows plenty of matter, and fights against nematodes and diseases.
Wheat is an alternative cover crop after soy and corn, but it takes a little longer to grow.
Post Corn Silage
Plant annual ryegrass, cereal ry, winter pea, oats, oilseed, tillage radish or turnips. What a farmer chooses depends on their schedule.
- Before the middle of September, plant winter pea. It produces much nitrogen.
- Late September requires a grass as a cover crop, and an added sprinkle of nitrogen.
- Farmers who also raise livestock should consider a crop that can be grazed like annual ryegrass, cereal rye, oats, oilseed, turnips or forage radishes.
Problems with Monocultures
After years and years of the same crop, diseases and pests who prey on that crop, increase. The soil becomes depleted where the roots grow, making the plants grow poorly due to lack of nutrition.
Solutions with Crop Rotation
- Higher yields due to the aid of the previous year’s crop.
- Fewer diseases, pests and weeds. Cover crops such as cowpeas completely wipe out weeds that may want to spring up.
- Better soil with a better balance and availability of nutrition. Deep-rooted crops draw nutrients upward.
- Rotation creates a better balance of labor year-round. Different crops have different times for harvest and planting.
- Some crops may be affected by poor seasons, while others still do well.
- Different crops mean different residues, creating a balance. Some may produce little residue, while others produce much.
In the end, rotating crops should be a help to the farmer either financially or otherwise.
What Good Crop Rotation Looks Like
- It is done considering the local climate and the farm’s budget.
- It utilizes the property well.
- There are enough crops that add nutrients and organic matter back into the soil.
- It creates enough food for the farm’s animals.
- It is systemized to capitalize on the particular farm’s labour and budget.
- It works to fend off diseases, pests and weeds.