Effects of Irrigation with Treated Wastewater on Root and Fruit Mineral Elements of Chemlali Olive Cultivar

Twenty-year-old "Chemlali" olive trees trained to vase and rainfed were investigated in either "on" (2004) or "off " (2003) year. A randomized block design with three blocks and three treatments was used and each experimental plot consisted of nine olive trees. Three treatments were applied: (1) rainfed conditions (RF, used as control treatment); (2) irrigation with well water (WW); and (3) irrigation with treated wastewater (TWW). Irrigation with TWW led to a significant increase of root N, P, Ca, Zn, Mn, Na, and Cl concentrations, in particular in the on-year. Data showed significant differences, between the two years, for the concentration of the mineral elements in the roots, with general lower values in the on-year, probably as a consequence of nutrients movement upward in the tree. Fruit N, P, K, Zn, Mn, and Cl contents were significantly higher in TWW irrigated trees with respect to both RF and WW trees, whereas similar values for Ca, Mg, Na, and Cl contents were measured for WW and TWW irrigated trees. The irrigation with TWW allowed to reuse problematic waters and to save nutrients inputs in the olive orchard thus moving towards a more sustainable management of olive orchards in countries where water is the major limiting factor for agriculture

Effects of long term irrigation with treated wastewater on leaf mineral element contents and oil quality in Olive cv. Chemlali

Water is one of the most limiting factors in agriculture, particularly in arid areas such as Tunisia. Olives are the most important tree fruit in the country and are cultivated over 1.6 million hectares. An olive grove of cv. Chemlali was irrigated either by using treated wastewater (TWW) or fresh water (FW) from 2002 to 2012. The aim of this 10-year study was to investigate the effects of irrigation with TWW on both quality parameters (i.e. K232, total phenols, free fatty acids, etc.) and content of mineral elements in the leaves. Data obtained indicated no effects of the irrigation on parameters such as oil content and K270, either by using TWW or FW, and significant effects only after 10 years on free acidity and K232. Instead, palmitoleic and stearic acid contents significantly decreased after 10 years of irrigation with TWW with respect to FW irrigation. TWW irrigation also increased the content of total phenols, chlorophyll, and minor and major nutrients in the leaves

Irrigation with treated wastewater affected the minor components of virgin olive oil from cv. Chemlali in Tunisia

Water limitation for agriculture is a problem in many countries and irrigation with treated wastewater (TWW) can be a tool to face the decreasing availability of water for important domestic crops such as olive. Taking into account this aspect, a research was carried out for 13 years in an olive grove (Chemlali cultivar) located in the area of Sfax (Tunisia). Two different irrigation treatments were applied: (a) irrigation with good quality water (GQW) and (b) irrigation with TWW. The main objective of this 13-year study was to verify the effects of the irrigation with TWW vs. GQW on some minor parameters of the virgin olive oil. Many oil parameters significantly increased in the TWW irrigated plot, in particular lutein, total tocopherols, squalene, campesterol and stigmasterol whereas β-carotene, α-tocopherol, δ-tocopherol, β-sitosterol and total sterols decreased with respect to the GQW treatment. Irrigation with TWW can be a possible tool to irrigate olive groves with two positive effects: saving of freshwater and production of olive oil of good quality

Effects of Irrigation with Treated Wastewater on Root and Fruit Mineral Elements of Chemlali Olive Cultivar

Twenty-year-old “Chemlali” olive trees trained to vase and rainfed were investigated in either “on” (2004) or “off” (2003) year. A randomized block design with three blocks and three treatments was used and each experimental plot consisted of nine olive trees. Three treatments were applied: (1) rainfed conditions (RF, used as control treatment); (2) irrigation with well water (WW); and (3) irrigation with treated wastewater (TWW). Irrigation with TWW led to a significant increase of root N, P, Ca, Zn, Mn, Na, and Cl concentrations, in particular in the on-year. Data showed significant differences, between the two years, for the concentration of the mineral elements in the roots, with general lower values in the on-year, probably as a consequence of nutrients movement upward in the tree. Fruit N, P, K, Zn, Mn, and Cl contents were significantly higher in TWW irrigated trees with respect to both RF and WW trees, whereas similar values for Ca, Mg, Na, and Cl contents were measured for WW and TWW irrigated trees. The irrigation with TWW allowed to reuse problematic waters and to save nutrients inputs in the olive orchard thus moving towards a more sustainable management of olive orchards in countries where water is the major limiting factor for agriculture

Alternate bearing affects nutritional status and net assimilation rate of an irrigated olive grove under arid conditions

Alternate bearing is a typical behavior of various fruit tree crops and is common among olive cultivars (Olea europæa L. var. sativa Hoffm. e Lk.). Since this phenomenon affects yield and consequently oil production, it is a concern for olive oil industry in order to offer a constant olive oil amount each year. A 4-year field experiment was conducted on cv Chemlali olive trees in ‘on’ and ‘off’ years in order to study, under arid conditions, both annual macro-element balance and net photosynthetic activity. Shoots growth was much higher in the ‘off’ year with respect to the ‘on’ one (+11.70 cm vs. +2.60). Net photosynthesis rate was much higher in the ‘off’ year with respect to the ‘on’ year and the highest values were observed at spring, when there is an intense vegetative growth. Differences for the mineral elements were observed between the ‘on’ and ‘off’ years. Nitrogen accumulated in leaves mainly in spring in the ‘off’ year, whereas high N values were detected also at the end of summer in the ‘on’ year. Consequently, N fertilization can be accomplished in February–March and possibly after harvest (November–December) to be used at budburst in the successive season. A difference was found between leaf P concentrations in ‘on’ or ‘off’ years from flowering to fruit-set, with the lowest values in the ‘on’ year, in particular in June–July. A supply of P at autumn–winter and partially in spring–summer in particular in an ‘on’ year would be appropriate. K accumulated in leaves in ‘on’ year from spring to summer, thus a supply of K in January–February, before new vegetation, for trees either in ‘on’ or ‘off’ year can be necessary for supporting and implementing the root system activity and the successive shoot growth (‘off’ year) and fruit development (‘on’ year). These results should be useful to partially reduce, through an appropriate fertilization schedule, the alternate bearing in olive tree

Chemlali olive trees in an irrigated grove: Effects of tree age on virgin olive oil quality and mineral nutrient distribution in roots, leaves and fruits

Introduction. The effects of tree age on the quality of olive oil are not very clear. Data on the mineral element content in different plant organs of cv. Chemlali are also very scarce, and the correlation between tree age and mineral content is still unclear. Materials and methods. A two-year study was conducted on irrigated 'Chemlali' olive trees of two different ages (12 years old vs. 24 years old) in order to verify possible effects on either the nutritional balance in different plant organs (leaves, roots, fruits) or the virgin olive oil (VOO) quality. Results and discussion. The 24-year-old trees showed a higher mineral concentration with respect to 12-year-old trees in roots and fruits, whereas the opposite was reported for the leaves. Total phenols and induction time values were significantly lower in VOO from 24-year-old trees. Palmitic, palmitoleic, stearic and linoleic acid concentrations were higher in VOO of 24-year-old trees. Conclusion. These results can be useful in order to discriminate the characteristics of VOO obtained from trees of different ages and the mineral content data can be used for the optimization of the fertilization schedules with respect to the olive tree age for more sustainable management of olive groves

Irrigation with treated wastewater affected the minor components of virgin olive oil from cv. Chemlali in Tunisia

Water limitation for agriculture is a problem in many countries and irrigation with treated wastewater (TWW) can be a tool to face the decreasing availability of water for important domestic crops such as olive. Taking into account this aspect, a research was carried out for 13 years in an olive grove (Chemlali cultivar) located in the area of Sfax (Tunisia). Two different irrigation treatments were applied: (a) irrigation with good quality water (GQW) and (b) irrigation with TWW. The main objective of this 13-year study was to verify the effects of the irrigation with TWW vs. GQW on some minor parameters of the virgin olive oil. Many oil parameters significantly increased in the TWW irrigated plot, in particular lutein, total tocopherols, squalene, campesterol and stigmasterol whereas β-carotene, α-tocopherol, δ-tocopherol, β-sitosterol and total sterols decreased with respect to the GQW treatment. Irrigation with TWW can be a possible tool to irrigate olive groves with two positive effects: saving of freshwater and production of olive oil of good quality