Olive (Olea europaea) tree growth and development and the effect of intercropping with wheat (Triticum aestivum) or wheat undersown with white clover (Trifolium repens): A thesis submitted in partial fulfilment of the requirements for the Degree of Master of Applied Science at Lincoln University

Abstract

The study reported in this thesis was carried out during 2018/2019 at Lincoln University, New Zealand, to investigate olive growth and development and wheat yield performance in an olive wheat intercropping system.This experiment was laid out in a split design with three replicates. The main treatments were olive (Olea europaea) intercropped with wheat (Triticum aestivum), olive intercropped with wheat undersown with white clover (Trifolium repens) and fallow used as a control. Sub plots were three olive cultivars Frantoio, Leccino and Barnea. The main intercropping treatments had no significant effect on olive shoot elongation, leaf apperance, fresh and dry leaf weights and leaf nutrient contents. However, there were significant differences in leaf weight and nutrient content among cultivars. Leccino had the highest fresh and dry leaf weights. In terms of nutrient content, Barnea leaves contained the lowest nitrogen, phosphorus, potassium. Frantoio had the highest content of potassium and Leccino had the highest phosphorus content. It suggests that olive leaf could be used as animal fodder due to their high mineral content. This research suggests that undersown clover had no effect on wheat final yield and grain quality. When wheat is intercropped with olive, the wheat yield is likely to reduce by 25% because the tree canopy reduced the available radiation to wheat. However, it is likely that wheat grain quality will be improved by tree shading. Wheat canopy and phenology modelling suggests that in the Canterbury region at least, in an olive – wheat intercropping system, earlier wheat sowing is likely to result in a higher wheat yield. Late sowing is likely to increase the grain quality but also increase the nutrient competition between the wheat and olive trees.