Investigating the value of companion cropping systems of chickpea and cereals for improved crop and fallow water use efficiency.

Full description

Everyone knows that Queensland grows the best chickpeas, but chickpeas leave the soil quite bare. This bare soil then reduces our fallow efficiency (amount of fallow rainfall captured for use by the next crop), which is a big problem in an area that relies on stored soilwater for yield.
Our team recently completed a study growing cover crops in the fallow to improve ground cover and soilwater available to the next crop, so we understand the value of ground cover and when we saw the opportunity to try growing the cover crop with our chickpeas we were keen to give it a go.
Companion crops are not new or novel, they are in every home vege garden; from marigolds to keep the pests out of tomatoes, or flowers to attract pollinators into the pumpkin patch. What is novel is doing this on a broadacre scale and with mechanically harvested crops.
A review by CSIRO (Fletcher et al 2016) showed potential to increase crop productivity with intercrops; particularly with ‘peaola’ (canola and fieldpea), which increase productivity by 50% in 24 of 34 studies reviewed. They also found cereal-legume intercrops to increase productivity in 64% of studies.
That review focused on temperate cropping areas of southern Australian and internationally, so the question remains whether these systems will perform in a sub-tropical environment and a farming system reliant on stored soilwater for yield stability.
Given our reliance on stored soilwater for maintaining grain yield and the fallow efficiency cost of low stubble cover following chickpea; we focused our efforts on wheat and chickpea, with the research questions of: Can we increase stubble cover after chickpea? and What is the yield impact of growing wheat and chickpea together as companion crops?