Intercropping and Crop Rotation for Sustainable Farming

Why we Should be Using Intercropping and Crop Rotation

Soybean and flax intercrop with one another. https://greener4life.com — Soybean and flax intercrop example. Photo: Alexis Stockford

Both Intercropping and Crop Rotation are different ways of setting up a multi-cropping system.

There is one primary difference between how these two farming methods achieve that goal. Intercropping uses spatial diversification(alternate crops mixed together in the available area). Crop rotation gets based on temporal diversification(changes over time).

After learning about the problems with monocultures, I wanted to learn about some more sustainable farming practices.

Intercropping has been used since our earliest farming methods. Over time it has dropped out of favor. Modern farming equipment has generally focused on maximizing the automation of a single-crop type.

For Crop Rotation, 2 or more crops get rotated, so we will plant one crop on the land, and after it gets to harvest, we can now grow the next crop type.

The different crops that get selected for both of these methods are essential. Care must be taken to choose the proper crop types making sure that they have different nutritional needs, rooting/canopy heights, etc.

To maximize the productivity of monoculture production requires increased inputs. These inputs result in compromising our soil health. The nitrate, phosphorous, pesticide runoff/leaching into our soils and greenhouse gas emissions into the air.

These practices not only reduce the quality of our soil's health but also negatively alter our water and air.[12] Multiple cropping systems could allow more farms to move away from these systems and use more sustainable farming methods.

Moving to multi-cropping methods will help us achieve a more sustainable crop production and help keep our soil naturally nutrient-rich. Keep reading to find out the main types of Intercropping and Crop Rotation systems currently getting used.

Video Different Multi-Cropping Methods

What is Intercropping

You will need to use a mixture of crops with different rooting ability, canopy structure, height, and nutrient requirements. The selected plants' goal is to maximize the utilization of the growth resources available on the land.[13]

While Intercropping just means that you will grow 2 or more crops at one time on one piece of land. There are multiple ways people have been setting up an intercropped area. We will cover the commonly used intercropping setups that are already well established today.

When intercrops were composed of two or more main crops, weed biomass in the intercrop filed was significantly lower than monoculture and crop rotated fields.[16]

If your primary goal is just to reduce the number of weeds growing on the land, Intercropping would be your best choice. While crop rotation does help to limit weed growth, it was not as efficient as intercropping.

The Different Types of Intercropping

ROW INTERCROPPING

For row intercropping, we need at least two crops in the same field, with each of the crop types grown in their own distinct row[6]. The first row will contain plant A the next row plant B, then back to plant A. So, for row intercropping, you will alternate the crop type of each row that you plant.

Crops are selected based on the specific combination of plants, their spacing, and planting dates[6].

Most large and even many smaller farms tend to stay away from using this method. Row intercropping can make controlling weeds, planting, harvesting, and everyday care for the crops much more difficult[7].

Having the alternating rows so close together limits the use of most traditional farming equipment.

PATCH INTERCROPPING

You will place your primary crop in rows. The secondary crops will get placed in the unfilled spaces between the central plant.

Filling in these areas with another crop type will reduce the room for weeds to grow.

STRIP INTERCROPPING

To perform strip intercropping, we will put the plants into long rows called strips. For large-scale farming, the strips need to be wide enough for machinery to perform separate production of each crop type[4].

Strips of the crop usually contain multiple rows of the same plant before alternating to the other crop type. Rows need to be wide enough to allow the use of farm equipment.

Strip intercropping is the easiest to implement for many large production environments since you can use standardized farm equipment on the strips.

MIXED INTERCROPPING OR MIXED CROPPING

Mixed intercropping again use at least two different crop types getting grown at the same time. But this time, we will not design any specific crop rows.

Examples of mixed intercropping of annual crops are the practice of growing corn, bean, and squash in Central America and forage sorghum with silage corn in Oregon. In Canada, research showed increased production per land area by growing together soybean and corn for silage in the same rows.

cropsreview.com

The Seeds that are going to get planted are all grouped and mixed together. Plants grown under this system commonly compete with one another for resources and room. It is most common in areas where a high crop failure rate is typical.

RELAY INTERCROPPING OR RELAY CROPPING

Relay cropping almost seems like a mix of both intercropping and crop rotation.

At the start, we will only plant one crop type. As the crop matures, but before we have harvested it, we will plant the second crop type. So for part of the season, the plants will share the same stretch of land.

Having the crops mixed in will help to increase solar radiation and heat available[8].

MULTI STORIED INTERCROPPING

Also called multi-layer cropping and multi-tier cropping. You will generally see this used in plantation crops.

The taller plants require intense lighting conditions with high evaporation. The ground plants need to thrive in shady conditions with high humidity for this intercropping system to get used efficiently.

Many plantation crops maximize the use of solar energy provided when under high plant density. This allows the farmer to utilize vertical space more efficiently.[17]

ALLEY INTERCROPPING

Alley cropping involves selecting one plant to provide support to protect the main crop in some way. There are two Alley Cropping methods currently in use(guard and trap crops).

Guard Crops

These will provide protection for the main crop. The main plant gets placed in the center of the filed. Another hardy or possibly thorny crop(depending on what we are attempting to keep out) will get planted surrounding the main one.

Trap Crops

These are usually crops like mustard, Alfalfa, marigold that can attract pests like insects preventing them from ruining the main plant. When correctly implemented, it can help to reduce the need to use pesticides.

Advantages of Intercropping
1. Greater Crop Yields
2. Helps to control weeds and insects
3. Reduces the amount of soil erosion
4. Can increase profits by intercropping with cash crops
5. A proper intercrop will take nutrients from multiple layers of the soil helping to maintain soil fertility
6. Increases plant productivity and utilizes ground the resources more efficiently
7. With adequately selected plants, you avoid inter-crop competition allowing more crop plants per unit of area.
8. It can prevent total crop failures from abnormal weather patterns.
9. One crop type is usually selected to provides natural shade and support to some of the others. This can allow you to grow plants that enjoy shady conditions by naturally giving relief from the intense summer heat.

Disadvantages of Intercropping
1. Generally harder to plant and harvest the crops
2. Most modern farm machinery is designed to work on a single crop type. A lot of the work that could get automated must now be done by hand. Not only will harvesting take longer, but it will also require more hands in the field(strip intercropping attempts to remove these hurdles).
3. When land gets transitioned from a mono-crop to inter-crop, there is a higher initial cost for the landowners.
4. Deficiencies or irrigation water in some crops will be harder to correct and manage without affecting there surrounding neighbors.

What is Crop Rotation

As stated above, with crop rotation, the entire area will grow the same crop at one time and then move on to another type of plant.

Specific crop types are selected so that nutrients taken by one crop type will get restored by a future crop type that will get grown later.

If the goal is to suppress the growth of weeds, the success is highly dependent on the crop sequence selected. The goal is to choose crops that will vary in their resource competition pattern, allelopathic interference, soil disturbance, and mechanical damage. All of these factors can help to prevent a large number of particular weed species.

Example of how to fotate different crops in the field for planting. https://greener4life.com — Example of how to fotate different crops in the field for planting

Different Types of Crop Rotation

From what I could find, crop rotation can work a little differently depending on the crop type and how the land gets setup.

The first way is to grow a monoculture field. But we will rotate the single crop type that we are growing each year.

We can set up our field to grow one crop type in each area. The following year the field will get rotated. Items that used large amounts of nitrogen would get planted in the ground that had grown items like legumes(which add nitrogen back into the soil).

This allows us to create multiple crop types each year while allowing us to rotate the crop type grown in each location.

Example of Crop Rotation Systems by Time [1]

1)One Year Rotation
Maize - Mustard
Rice - Wheat

2)Two Year Rotation
Maize - Mustard-Sugarcane - Fenugreek
Maize - Potato - Sugarcane - Peas

3) Three Year Rotation Maize - Wheat - Mung - Mustard
Cotton - Oat - Sugarcane - Peas - Maize - Wheat

Field Systems

Instead of growing only one crop type a year, we can split the land into different parts. Each year they will rotate the kind of crop planted in each location.

The most common setup currently for agriculture that attempts not to use any fertilizers is the four filed system setup[3].

Many home gardeners like to use the rotating system to keep the soil high with nutrients without having to use bottled fertilizers on the ground.

Again, care needs to be taken to select the right plant types to ensure that the nutrients that get used by one crop are getting returned to the soil by another.

Advantages of Crop Rotation
1. Improved Yield
2. Increase Crop Production
3. Reduce Pests and Diseases
4. Helps to maintain Soil Fertility
5. Lower Chance of Entire Crop Failure
6. Suppress the growth of weeds

Disadvantages of Crop rotation
1. Weed Management Can Be More Difficult, depending on the crops mixed together.
2. Hard to use current Agriculture Machinery
3. More Labor Intensive / Expensive to Setup
4. Improper Selection of Crops Could Result in Same Problems as Monocultures.

Multiple Cropping And Importance of Beneficial Soil Fungi

We already know that the diversity of different plant species in natural grasslands had been proven to improve plant productivity above and below the ground. But recent research shows a relationship not just with the plants selected. But also with fungi(like saprotrophic and pathogenic) present in the soil determines how well the plants can share their resources.[14]

Fields that were treated by an antifungal were not able to correctly share resources. Fungi help to move different soil nutrients to the plants that need them. When legumes put nitrogen into the ground, fungi can move it to the other crops that require it. Current research shows that they not only redistribute nutrients but also have the power to redistribute water resources to where needed.

When intercropping is used without these fungi, it resulted in a minimal increase in the production of the crops involved compared to their monoculture counterpart.

While there are a few plant families that do not form an association with these fungi like Cruciferae family(broccoli, mustard) and the Chenopodiaceae family(lambsquarters, spinach, beets).[15] They are an essential aspect of soil health often overlooked.

Multipcropping And Plant Selection

Permaculture talks about planting plants like tomatoes, eggplants, and potatoes, and how this mix is not a propper cropping system. These plants have very similar nutritional needs and are susceptible to many of the same pests and diseases. Try to select crop types that are from different families. Tomatoes, eggplants, and potatoes are all part of the same family. Each of them is a type of nightshade plant[11].

When crops get setup and use plants with similar needs, the result is not much better. It provides a minimal benefit over a monoculture system.

Summary

While I personally think that mixed intercropping is the best way to keep our soil nutrient-rich and limit the growth of weeds. Unfortunately, I can not see large farms starting to use it any time soon. The added costs and additional labor required to add to most large scale farms will prevent it from becoming widespread.

I can some large farms moving towards strip intercropping. It has many of the same benefits as other intercropping methods. But it will still allow most farms to perform most of the current automation used with existing farm equipment.

However, having the crops separated into one type for each harvest like crop rotation is guaranteed to allows easy setup of farming machinery to take care of the plants.

From watering to harvesting, a lot of the process can get automated. Most of the machinery farms currently possess are designed to work on a single crop or monoculture field much more efficiently.

To get the full benefits from intercropping, it is vital for the land to already have healthy soil fungi. Without these fungi, many of the advantages of both intercropping and crop rotation will not be possible to achieve.