Determination of the extent area of interactions between the olive trees and cereals in an alley cropping system in Morocco
In an Agroforestry system, interactions between annual crops and perennial ones are complex. In the objective of elucidating the resultant of those interactions on the performances of the system olive tree - cereal crops, barley (Hordeum vulgare), durum wheat (Triticum turgidum) and soft wheat (Triticum aestivum) were cultivated between the rows of olive trees (Olea europaea) (10 x 10 m) under rainfed conditions. Cereals were sown according to two orientations: North - South and East - West. At maturity, assessment of cereals productions (yields and their components) was realized at various distances from olive tree rows. Under the weather conditions of the year (rainfall: 300 mm), the experiment showed that the height of plants (H) of various cereals is the parameter which illustrates the best representation models of its evolution in relation with distance (D) from olive tree row. The cereals with sowing realized according to the orientation East � West were the most successful. The models developed under this orientation were, respectively for barley and durum wheat H = -5.33D2 + 56.36D - 110.89 (R_ = 0.74) and H = -2.89D2 + 29.70D - 40.738 (R_ = 0.75). For cereals sown according to the orientation North � South, the models developed respectively for barley, durum wheat and soft wheat are: H = -1.39D2 + 16.99D - 22.245 (R_ = 0.75), H = -2.33D2 + 27.44D - 56.13 (R_ = 0.73) and H = -2.22D2 + 25.63D - 47.15 (R_ = 0.76).