Advantages of bi-cropping field beans (Vicia faba) and wheat (Triticum aestivum) on cereal forage yield and quality

ABSTRACT In organic production systems, penalties in cereal forage yield and low crude protein (CP) concentration are mainly caused by limited soil nitrogen (N) availability, which can be addressed by using cereal/grain legume bi-cropping systems. To confirm this, a bi-cropping experiment with spring wheat cv. Paragon and faba beans cvs. Fuego and Maris Bead were conducted in 2 years, using a randomised complete block design and sowing the crops in a replacement design series. In 2016, the wheat forage yield in sole cropping exceeded that in bi-cropping by 58%. In 2015, the wheat forage harvest index (HI) in bi-cropping was 14% higher than that in sole cropping, but in 2016 it was 7% lower. In both years, bi-cropping increased the CP and the grain N uptake in the wheat compared with that sole cropping, by 25% and 17%, respectively. The chlorophyll concentration index (CCI) in the wheat was 2.2 times higher in bi-cropping than in sole cropping and 34% higher in the alternate rows systems compared with the broadcast system. In 2015, the efficiency of N use (NLER) in bi-cropping was 50.7% higher than that in sole cropping. Alternate row bi-cropping improved NLER over broadcast by 37.9%. Faba bean rust disease was more severe in Fuego than in Maris Bead. In conclusion, bi-cropping in uniform alternate row spacing can improve productivity and nutritional quality of wheat forage, compared with sole cropping. The bi-crop bean cultivars Fuego and Maris Bead can, improve wheat straw CP and reduce rust disease severity, respectively.