
In the Niger River Valley, as well as in some areas of preference, M. oleifera is most often produced in association with some vegetable crops, including onions. This association can involve significant agronomic and economic effects. Thus, the combined effect of the factors layout and plant cutting level of M. oleifera plants on the yield of Allium cepa (onion) bulbs was studied. These factors include three and two levels, respectively. Each level of the first factor has been combined with each of the two levels of the second giving thus six (6) treatments that are: A1B1, A1B2, A2B1, A2B2, A3B1 and A3B2. Also, in order to compare the results with a reference situation, a control treatment (T) where the onion plants were sub cultured in pure culture was carried out. The parameters measured are the weight and the diameter of the bulbs. The yield in terms of weight was reported per hectare under the different treatments then was evaluated. The statistical tests on the comparison of means showed that the yield in weight, the average weight and the mean diameter of the bulbs are not significantly different between the treatments at the threshold of 5%. The study also showed that the treatments A1B1, A2B2, A3B2 and the Control are the ones that best explain the variability of the weight according to the diameter of the bulbs with more than 50% of the inertia and that we can adjust a straight line to their respective clouds. These results show that farmers can associate M. oleifera with vegetables such as onions without risk of considerable loss of yield.