Nitrogen Management for Improving Root and Shoot Components of Young ‘Arbequina’ Olives

Abstract

<jats:p>The impact of nitrogen application on the growth of olive trees has been well studied. However, little is known about the role of levels and forms of N on the development of roots and physiological traits during establishment of young trees. The objective of this 2-year study was to evaluate the influence of N source and level on shoot morphology (tree height, stem diameter, and branch number) and physiology [leaf area and fresh weight, photosynthesis (P<jats:sub>n</jats:sub>), transpiration (<jats:italic>E</jats:italic>), and stomatal conductance (<jats:italic>g</jats:italic><jats:sub>s</jats:sub>)], root components (length, diameter, surface area, and fork number) and N content of young olive (<jats:italic>Olea europaea</jats:italic> cv. Arbequina) cuttings. Three-month-old olive cuttings were planted in 15-L pots filled with a growing substrate composed of peatmoss + bark + sand (2:1:1/by volume) and placed in a screen house. Two N levels, 2.8 and 5.6 g/tree, and control (0 N) and four N sources, calcium nitrate (CN, 12%N, 17%Ca<jats:sup>+2</jats:sup>), ammonium nitrate (AN, 35%N), urea (46%N), and the slow-release Osmocote (OSC, 18%N, 6%P, 12%K) were evaluated. Effects of low– (2.8 g/tree) and high N (5.6 g/tree) levels on shoot components (plant height, diameter, branch number, leaf area, and fresh weight) and gas exchange (P<jats:sub>n</jats:sub>, <jats:italic>g</jats:italic><jats:sub>s</jats:sub> and <jats:italic>E</jats:italic>) were similar implying that the low rate of N was adequate for the establishment of young olive cuttings. Nitrogen sources, particularly AN and CN had significant effects on shoot and root morphology, physiology, and leaf and root N concentration. In fact, AN and CN were the best fertilizer sources for olive transplants in term of root and shoot growth. Overall, 2.8 g/tree N level and AN or CN sources were the best treatments for newly established olive ‘Arbequina’ trees. Root components treated with high N rate (5.6 g/tree N) using the slow-release fertilizer (OSC) was similar to those treated with the low AN rate (2.8 g/tree N). Therefore, for nursery containerized olive trees of ‘Arbequina’ or other cultivars with comparable growth rates, we recommend to apply the CN or AN source at 2.8 g/tree N or the controlled-released fertilizer OSC at 5.6 g/tree N.</jats:p>

An Assessment of Treated Greywater Reuse in Irrigation on Growth and Protein Content of Prosopis and Albizia

“…A higher growth rate can be attributed to higher nutrient levels in greywater water compared to control (Table 1). Nutrient levels play a key role in plant morpho-physiology such as photosynthesis, root and shoot growth, and flower and fruit quality [27][28][29][30][31]. The significant increase in shoot growth is coupled normally with a reduction in nutrient and protein concentration in the tissues due to the dilution effect [32].…”

Direct Seeding and Transplanting Influence Root Dynamics, Morpho-Physiology, Yield, and Head Quality of Globe Artichoke

“…Farming systems, nitrogen management, cultivar selection, and planting methods such as direct seeding and transplanting are cultural strategies that greatly influence root and shoot growth, yield, and fruit quality in high-value vegetable crops [ 1 , 2 , 3 , 4 ]. In bell pepper ( Capsicum annuum ), earlier studies comparing direct seeding with containerized transplants produced in nurseries showed significant effects on growth (leaf area and shoot weight) and developmental stages in the field [ 5 ].…”

“…Root traits such as root length, root surface area, and length intensity ( L a; total root length per specific area in the soil profile) can significantly affect plant morphology and leaf physiology, as reported in globe artichoke and olive crops [ 3 , 4 , 13 ]. Planting methods can also affect early root development, root and shoot biomass allometric partitioning, fruit development, and marketable yields [ 2 , 14 , 15 ].…”