Intercropping of field pea with annual legumes for increasing grain yield production

In temperate regions, normal-leafed field pea still represents an important crop for grain and animal consumption, even though there is increasing interest in afila type cultivars because of their better standing ability. The effect of dual legume intercropping on grain yield of normal-leafed pea was studied during 2015 and 2016 in order to reduce lodging, to improve grain yield stability and to analyse the competitiveness of field pea with annual legumes and wheat. The research involved six species grown as sole crops: normal-leafed pea (Pisum sativum L. (Partim)), semi-leafless pea (Pisum sativum L. (Partim), faba bean (Vicia faba L. (Partim)), white lupin (Lupinus albus L.), fenugreek (Trigonella foenum-graecum L.) and wheat as a control (Triticum aestivum L. emend. Fiori et Paol) and intercrop mixtures of normal-leafed pea with other five species. Grain yield (t ha(-1)), yield components, land equivalent ratio, relative crowding coefficient and aggressivity value for grain yield were monitored. The highest grain yield of normal-leafed pea (2.87 t ha(-1)) was obtained from the mixture with semi-leafless pea in 2015 and from the mixture of wheat + normal-leafed pea (5.26 t ha(-1)) in 2016. The lowest number of pods and seeds per plant was formed by normal-leafed pea as a sole crop in 2015 (5.2 and 19.2, respectively). The obtained results showed that a thousand seed weight differed between treatments; however, the differences were not significant. The highest land equivalent ratio (1.40), relative crowding coefficient (4.44) and the positive value of aggressivity (0.19) were observed in the mixture of fenugreek + normal-leafed pea. The results demonstrated that semi-leafless + normal-leafed pea and fenugreek + normal-leafed pea are the most beneficial mixtures for grain production, while faba bean was a less suitable component for intercropping with normal-leafed pea.