Intercropping with Soybeans and Peas
Prairies East Sustainable Agriculture Initiative Inc. (PESAI) – Arborg, MB
1. Gain experience in intercropping: observe and evaluate agronomic performance of intercropping compared to mono-cropping
2. Evaluate yield potential, land use equivalency and profitability of intercropping compared to mono-cropping
3. Overall, start a knowledge base on if and how intercrops can be utilized in cropping systems in the Interlake
This was the second successful year of experimenting with intercropping in the Interlake region of Manitoba. Treatments included three seeding rate combinations of pea-canola, soybean-flax, pea-flax and pea-oat compared to pea, canola, flax, soybean and oat monocrops. Results of the experiment including treatment descriptions, agronomic practices, yield, gross and marginal revenues and general observations are listed in Tables 2 and 3 and each intercrop treatment is discussed at the end of the report. The 2020 growing season at Arborg was dry with 70% of normal growing season precipitation (Table 1) compared to 55% of normal precipitation in 2019.
In both years of study, flax and pea have produced the highest marginal revenue of the monocrops. Canola was challenged with flea beetles and grasshoppers in 2020. Pea-canola was the only intercrop to consistently over-yield in 2019 and 2020 (Fig. 1) while marginal revenues were impressive for pea, pea-oat and pea-flax (Fig. 2). After two years of study in Arborg, we have been able to draw some conclusions on optimum seeding rate ratios, consistency of over-yielding and profitability (see individual intercrop treatment discussions). The pea-oat intercrop was sampled for total dry matter and forage nutrient analysis (Table 4) which will be helpful for livestock farmers
Intercropping is the practice of seeding, growing and harvesting two or more crops together. The concept is to utilize crop combinations that complement one another through mechanisms such as resource use efficiency and potentially result in over-yielding and greater profitability compared to monocropping. Careful consideration needs to be given to how the crops are be seeded, managed, harvested and separated. The most common intercrop grown commercially in Manitoba is pea-canola. Beginning in 2019, we started to test pea-canola, soybean-flax, pea-flax and pea-oat intercrop combinations at Arborg, MB. For each intercrop combination, 2-3 seeding rate ratios were tested and compared to pea, soybean, canola, flax and oat monocrops.
To assess the productivity of intercrops compared to their component crops grown in monoculture, the land equivalent ratio (LER) is used. LER is a ratio of the individual crop yields from the intercrop divided by the respective monocrop yield. It is desirable to achieve a LER > 1 which indicates over-yielding (more would be required to produce the same yield with as individual monocrops compared to the intercrop). Gross and marginal revenues are also calculated because seasonal growing conditions and market prices are important variables that affect the productivity, yield and economic return of cropping in a given year.