Research Objective

Project Description

To assess the impact of intercropping flax and chickpea on nitrogen (N) fixation of chickpea; to assess the impact of intercropping flax and chickpea on N transfer and N nutrition of flax.

Chickpea has an indeterminate growth habit and requires either a significant moisture and/or a nitrogen (N) stress to stop vegetative growth and shift the crop to seed set. Because of this growth habit, excessive vegetative growth and extended maturity can restrict the areas that are suitable for chickpea production. An ADOPT project was conducted at four sites in Saskatchewan in 2014 and 2015 to determine if intercropping a fixing legume such as chickpea with a non-fixing crop such as flax would provide sufficient competition for both N and soil moisture to hasten maturity in chickpea, thereby expanding potential chickpea production areas. The SPG funded project piggy backed on the ADOPT sites, and examined the impact of intercropping on N-fixation, and potential transfer of fixed N from chickpea to flax. We hypothesized that the competition for available soil N would limit soil N availability, thereby encouraging greater N-fixation in chickpea. Additionally, we hypothesized that fixed N would be transferred from the fixing chickpea to the non-fixing flax intercrop, thereby enhancing the overall N economy of the intercropped system relative to the monocropped counterparts. We used a 15N dilution technique to determine both N-fixation in chickpea and N transfer from chickpea to flax.


Generally, Nfixation levels were very low in 2014 at all sites, whereas modest levels of N fixation were achieved in 2015. No significant differences in per cent N derived from fixation were detected between monocropped chickpea and the intercropped counterparts at any of the sites, although data suggested a trend for increased N-fixation with intercropping, but only at one site. Additionally, total accumulation of fixed N typically was greatest in monocropped chickpea, which likely reflected the greater biomass associated with the monocropped versus intercropped chickpea. When total N accumulation by the intercropped system (i.e., the summed N accumulation in the chickpea and flax intercrops) was considered, no significant differences between treatments were detected. Transfer of N from chickpea to flax was detected at only one of the six harvested sites, and levels of transfer were very low (i.e., less than 9 kg N ha-1). Nonetheless, these results suggest that there is some potential for modest levels of N transfer to occur within intercropping systems.

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