Root distribution in apricot orchard (Prunus armeniaca L. 'Bulida') under trickle irrigation

Efficient irrigation and fertiliser application requires an understanding of the distribution of roots, water and soil nutrients in the soil profile. Root distribution in a cultivar is important for trickle irrigation design parameters and management. This information is not very contrasted in most situations. The objective of this study was to determine the root distribution in apricot (Prunus armeniaca L. 'Bulida'), for a plot of 10-year-old trees under trickle irrigation with two irrigation strategies. The experiment was developed in a loam-soil plot in Murcia (Spain). Root distribution was measured in a square grid of 15 points, 3 m long and 100 cm deep. Samples were collected at 10-cm increments. The majority of roots (95%) were located 50 cm deeper under emitters. Apricot root length (RLD) and weight densities increased for low quantities of irrigation water and decreased for high quantities. RLD decreased with depth for the two irrigation strategies. RLD differed 2.5-fold between irrigation strategies, from soil level to 25 cm depth. RLD was similar for the two strategies below 25 cm. Root distribution was fitted to the Greenwood root density distribution model. Root distribution data were used in a water balance experiment.