Abstract
Mixing plant species in agroecosystems is highlighted as an agroecological solution to reduce pesticides and fertilizers while maintaining profitability. In the French context, intercropping frost-sensitive legume crops with winter oilseed rape is potentially interesting and began to be implemented by farmers. In this study we aimed at measuring the services and disservices of this intercrop with three different legume mixtures, in terms of growth and yield for rapeseed, ground cover of weeds in autumn and damage caused by rape winter stem weevil. The experiment was carried out at four sites from 2011 to 2014. We showed higher total aerial dry weights and total aerial nitrogen contents in the intercrops compared to sole winter oilseed rape in November. The companion plants contributed to the control of weeds and the mitigation of rape winter stem weevil damage, notably through the increase in the total aerial weight. In spring, after destruction of the companion plants, the intercrops had partially compensated a reduction in the N fertilization rate (–30 kg per hectare) in terms of aerial nitrogen content in rapeseed, with no consequences on the yield which was maintained or even increased. There were probably other interactions such as an improvement in rapeseed root exploration. The consequences were an increase in the nitrogen use efficiency in intercrops. The intercrop with faba bean and lentil showed the best results in terms of autumn growth, weed control, reduction in rape winter stem weevil damage, and rapeseed N content in spring and yield. Intercropping frost-sensitive legume crops with winter oilseed rape is thus a promising way to reconcile yield and reduction in pesticides and fertilizer use and perhaps to benefit more widely to the cropping system.
Highlights
Despite significant gains in productivity, intensive agriculture is criticized for its harmful effects on the environment (Tilman et al, 2002)
The aerial dry weight of the companion plants was approximately half of that of the winter oilseed rape (WOR), and was significantly higher for bean + lentil (BL) compared to grass pea + fenugreek + lentil (GFL) and VVT (Fig. 1; Tab. 4)
The total aerial dry weight was significantly higher for the intercrops (WOR + companion plants) compared to sole WOR and ranked as follows: WOR + BL = WOR + VVT > WOR + GFL > Sole WOR (Fig. 1; Tab. 4)
Summary
Despite significant gains in productivity, intensive agriculture is criticized for its harmful effects on the environment (Tilman et al, 2002). Mixing plant species can result in improving productivity, pest regulation, carbon and nutrient sequestration (Malézieux et al, 2009). Most studies reported a yield reduction of the cash crop (Bergkvist, 2003; Carof et al, 2007; Picard et al, 2010; White and Schott, 1991), even if a few ones reported no yield loss (Ilnicki and Enache, 1992). The yield reduction mentioned before occurred for systems where the living mulch was still growing during the main phases of yield components establishment in the spring (Carof et al, 2007; Hiltbrunner et al, 2007)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
