IMPACT OF LEGUMES AND CEREALS ON OLIVE PRODUCTIVITY IN THE SOUTH MEDITERRANEAN

Abstract

Intercropping of trees with crops on the same piece of land at a given time has been hypothesized to: enhance crop yield, increase land-use and improve land equivalent ratio (LER). To address this hypothesis, we evaluated two legumes faba bean, lentil and three cereals durum wheat, soft wheat and barley grown in olive (Olea europea) agroforestry during two growing seasons (Y) with contrasting weather (Y1: 2015-2016 and Y2: 2016-2017) under a Mediterranean climate of north western Morocco. We assessed the effect of annual crops on olive growth and yield; the effect of trees on annual crop growth, yield components, and final yields; finally, we calculated the land equivalent ratio (LER) of olive agroforestry to assess the productivity of the associations. Legumes had no effect on olive growth and yield, while cereals negatively affected shoot elongation and olive yield compared to olive in sole crop. Olive limited crop growth and yield of all associated crops and yield reduction was around 33 % for legumes and 47 % for cereals in agroforestry than sole crop. The magnitude of reduction was higher in Y1 than Y2. Similar responses were found when comparing crops at different distances from trees. Annual crops generally had lower biomass and yield, near the trees compared to the middle of tree inter-rows, causing significant spatial heterogeneity in crops. The LER reached 1.36 with lentil and 1.33 with faba bean, the lowest LER was recorded with durum wheat in both years with 1.01 in Y1 and 1.02 in Y2, and the highest LER with cereals was registered with soft wheat and reached 1.19 in Y1.