Contents lists available at ScienceDirect Scientia Horticulturae journal homepage: www.elsevier.com/locate/scihorti Comparative study effects between manure application and a controlled- release fertilizer on the growth, nutrient uptake, photosystem II activity and photosynthetic rate of Olea europaea L. (cv. ‘Koroneiki’) T. Chatzistathis a, *, I.E. Papadakis b , A. Papaioannou c , C. Chatzissavvidis d , A. Giannakoula e a Hellenic Agricultural Organization (H.A.O.) ‘Demeter’, Institute of Soil and Water Resources, 57001, Thermi, Thessaloniki, Greece b Laboratory of Pomology, Agricultural University of Athens, Iera Odos 75, 11855, Athens, Greece c Department of Forestry and Natural Environment, Aristotle University, 54124, Thessaloniki, Greece d Department of Agricultural Development, Democritus University of Thrace, Orestiada, Greece e Department of Agriculture, International University of Greece, 54700, Sindos, Thessaloniki, Greece ARTICLE INFO Keywords: Organic fertilization Cow manure Goat manure Photosynthetic rate PSII activity Carbohydrates ABSTRACT Organic fertilization has been proposed as an alternative method, in the frame of sustainable agriculture, to enhance soil fertility and satisfy the nutritional needs of crops, without the input of chemical fertilizers. A six- month pot experiment, with 3 soil amendments, used as organic fertilizers (cow manure-CM, goat manure-GM, and their mixture, i.e. CM + GM) and a controlled release fertilizer (CRF) was conducted, in order to investigate if the growth, nutrient uptake, photosystem II (PSII) activity, photosynthetic rate and total sugars of Olea europaea L. (cv. ‘Koroneiki’) plants were influenced by the kind of fertilization. The highest plant biomass, macronutrient content and PSII activity were found in the CRF treatment. In contrast, significantly lower photosynthetic and transpiration rates were recorded in the CRF due to the lower stomatal conductance. Translocated sugars were higher in the CM + GM treatment, while total sugar concentration did not significantly differ among the treatments. Despite the highest content of all macronutrients, Fe and Mn recorded in the CRF, the lowest foliar P, K, Mg, Zn and Cu concentrations revealed that the higher nutrient accumulation, compared to the organic treatments, should be ascribed to the higher plant biomass, rather than to higher nutrient uptake. From the above data, it is clear that the kind of organic/inorganic fertilization significantly influenced soil organic C content, fertility, growth, nutrient uptake and the physiology of olive plants. Thus, the kind of manure (s) used to enhance soil fertility and support crop production should be seriously taken into consideration by the olive growers before its/their use. 1. Introduction Olive tree culture is the most important tree crop species for the Mediterranean countries, since it has a high agronomic, economic and ecological importance, while it also produces high quality olive oil, rich in oleuropein, tyrosol, hydroxytyrosol, oleic, linoleic, elenolic, caffeic, ferulic, gallic, benzoic and o-coumaric acid, substances that are related to human health protection (Therios, 2009; Chatzistathis and Therios, 2012). It has been referred that excess inorganic fertilization, especially with N, is a common problem and there is no real need to provide N fertilization to olive trees every year (Fernandez-Escobar et al., 2009, 2012; 2015). On the other hand, many olive groves in the olive- pro- ducing countries (old groves, usually of cv. ‘Koroneiki’, grown on slopes, with low soil fertility and organic matter content) are traditionally managed (i.e. they are not irrigated and fertilized with inorganic fer- tilizers, but only manures are applied) (Chatzistathis et al., 2016). The cultivar ‘Koroneiki’ is the most economically important one for the Greek climate and soil conditions, producing high olive oil quality, which has beneficial effects for human health. In addition, ‘Koroneiki’ is often cultivated in sloppy areas, with the soil properties described above; this is why these olive groves usually have low productivity. Thus, it is needed to enhance the low productivity of these tradi- tional olive groves in a sustainable, economic and environmental friendly way, and the most suitable tool to achieve this purpose is the organic fertilization (via the reuse of by-products of animal or vegetal origin). For this purpose, organic amendments (e.g. composts, pruning materials, manures) may be used for crop fertilization, improvement of soil physical properties and enhancement of soil organic C. Date palm https://doi.org/10.1016/j.scienta.2020.109176 Received 18 July 2019; Received in revised form 27 December 2019; Accepted 2 January 2020 ⁎ Corresponding author. E-mail address: chchatzista@gmail.com (T. Chatzistathis). Scientia Horticulturae 264 (2020) 109176 0304-4238/ © 2020 Elsevier B.V. All rights reserved. T