Intercropping as a Weed Management Technique – Kali Kasper
Intercropping has many positive aspects involved. The method of intercropping reduces fertilizer and pest control problems which can be the most expensive inputs involved with crop production in Western Canada. When a barley-pea intercrop or a canola-pea intercrop, (which are common) are compared to those in a sole cropping system, both showed a reduction in land requirements, therefore efficiency in an intercropping system is higher versus monoculture.1
Solely considering weed control in regards to intercropping, the interruption of weed biomass accumulation is higher in intercropped systems compared to that in monoculture.2
If the intersown crop of choice is a low-growing smother crop, it has potential to reduce the yield of the main crop species, this is why all crops that are growing in the field should be considered as main crop species and one should not be chosen for its ability to smother competing plants.2 Another potential thing that can go wrong in the field with an intercropping system is an increased risk of disease. Often, to successfully accomplish weed suppression, higher seeding rates are used and disease pressure is therefore, increased.3
When ecological cost in an intercropping system is analysed compared to a sole cropping system, environmental benefits are in favour of intercropping, due to the fact that it provides diversification. That being said, mechanical processes (like seed separation and possibly making two passes with an air seeder) will cause more fuel to be burnt.
The economic cost of intercropping could be the reason why many producers will stay away from this cultural method. Time is added to seeding and harvest applications as well possible costs for seed separation after harvest. Problems can become evident during spring seeding applications when producers must decide how to sow the seed. Whether it is in the same row or alternating rows which would likely require two passes with the seeding implement. However, producers have the added benefit of a yield increase on the same amount of land, (a general increase in land equivalent ratio) and therefore, a higher economical return.4
I consider this tactic to be valuable in organic and conventional systems. Intercropping is a good means of weed control (along with other positive aspects) in organic production, but when considering conventional agriculture, it is becoming dire to incorporate diversification into crop rotations.
References
1) Intercropping a possibility for Saskatchewan’s organic crop farmers. 2013. Agriculture and Agri-Food Canada. http://www.agr.gc.ca/eng/science-and-innovation/science-publications-and-resources/agri-science-e-zine/agri-science-e-zine-sustainable-production-systems/?id=1368646738122
2) Dyck, Elizabeth, Liebman, Matt. 1993. Crop Rotation and Intercropping Strategies for Weed. Ecological Applications, Vol. 3, No. 1.
3) Cultivar Mixtures, Cover Crops, and Intercropping with Organic Spring Wheat. 2006. University of Manitoba. http://www.umanitoba.ca/outreach/naturalagriculture/articles/wheatintercrop.html#results_cultivar
4) Malhi, S. 2014. Improving crop yield, N uptake and economic returns by intercropping barley or canola with pea. Agricultural Sciences, 3, 1023-1033. doi: 10.4236/as.2012.38124.