Europ. J. Agronomy 53 (2014) 38–44 Contents lists available at ScienceDirect European Journal of Agronomy jo u r nal homep age: www.elsevier.com/locate/eja Impact of biochar application on plant water relations in Vitis vinifera (L.) S. Baronti a,∗ , F.P. Vaccari a,c , F. Miglietta a,c , C. Calzolari a , E. Lugato b , S. Orlandini e , R. Pini d , C. Zulian f , L. Genesio a,c a Institute of Biometeorology (IBIMET), National Research Council (CNR), Via G. Caproni 8, 50145 Florence, Italy b European Commission – JRC, Via E. Fermi 2749, 21027 Ispra (VA), Italy c FoxLab (Forest and Wood) Foundation E. Mach – Iasma, Via E. Mach 1, 38010 S. Michele all’Adige (TN), Italy d Institute of Ecosystem Studies (ISE), National Research Council (CNR), Via Moruzzi 1, 56124 Pisa, Italy e Department of Agri-food Production and Environmental Sciences-University of Florence, Piazzale delle Cascine 18, 50144 Florence, Italy f Marchesi Antinori srl, Piazza Antinori, 3 50123 Florence, Italy a r t i c l e i n f o Article history: Received 7 August 2013 Received in revised form 31 October 2013 Accepted 4 November 2013 Keywords: Biochar Leaf water potential Soil amendment Vineyard Water retention a b s t r a c t Soil water status plays an important role in growth-yield and grape quality of Vitis vinifera (L.). In some cases, periods of moderate water stress have been indicated to exert a positive effect on the quality of grape production. However, prolonged water stress may have a strong negative affect grapevine pho- tosynthesis and grape yield, especially in dry Mediterranean environments. Biochar is a co-product of a thermochemical conversion of biomass that is recognized to be a beneficial soil amendment, which when incorporated into the soil increases soil water retention. We investigated the effect of two rates of biochar application (22 and 44 ton ha -1 ) on plant water relations of V. vinifera in a field experiment in central Italy. Biochar obtained from the carbonization of orchard pruning waste was applied to the soil over two consecutive growing seasons. The treatments did not show a significant increase in soil hydrophobicity. Moreover, soil analysis and ecophysiological measurements indicated a substantial rel- ative increases in available soil water content compared to control soils (from 3.2% to 45% in the 22 and 44 ton ha -1 application rates, respectively) and in leaf water potential (24–37%) during droughts. © 2013 Elsevier B.V. All rights reserved. 1. Introduction In the Mediterranean area water scarcity is a major limiting factor for agriculture that currently accounts for the consumption of roughly 65% of available freshwater (Plan Bleu, 2011). Accord- ing to the IPCC (2007), the vulnerability of Mediterranean systems to water scarcity is predicted to increase in the near future as a consequence of larger inter-annual rainfall variability and higher frequency and intensity of extreme events such as droughts and heat waves. In this context, the identification and implementation of adaptation measures aimed at enhancing the resilience of the agroecosystems to water scarcity is a key priority to maintain both the quality and quantity of crop productions and protect water resources. Crop management strategies play an important role in the capa- bility of soils to hold nutrients and water. The depletion of soil organic matter in agricultural soils over the last century due to the management intensification, the sustained removal of crop ∗ Corresponding author. Tel.: +39 0553033711; fax: +39 055308910. E-mail address: s.baronti@ibimet.cnr.it (S. Baronti). residues and the use of chemical fertilizers (Das et al., 2005; Lal, 2009, 2004; Sharma et al., 2005), has had dramatic effects on the water holding capacity of soils (Blanco-Canqui and Lal, 2009), and on the capacity of plants to adapt to a changing climate. In recent years, the addition of biochar to agricultural soils has emerged as a feasible strategy to simultaneously enhance crop pro- ductivity and soil fertility (Major et al., 2010; Vaccari et al., 2011), decrease nutrient leaching (Laird et al., 2010), sequester organic carbon (Ventura et al., 2013; Woolf et al., 2010), reduce non-CO 2 green house gases emissions (Castaldi et al., 2011; Stewart et al., 2013; Zheng et al., 2012) and to increase soil water-holding capacity (Basso et al., 2013; Case et al., 2012; Kammann et al., 2011). Potential soil improvements depend on the physical and chemi- cal structure of the biochar, and on the rate of application to the soil (Novak et al., 2009; Van Zwieten et al., 2010). The increase of soil water-holding capacity that follows biochar addition (Case et al., 2012; Kammann et al., 2011) is related to the porosity and high spe- cific surface area (Verheijen et al., 2010), and the magnitude of this effect depends on feedstock type and pyrolysis conditions (Uzoma et al., 2011). Glaser et al. (2002) reported an increased in field capac- ity of 18% in Anthrosols rich in charcoal; a similar increase was reported in sandy soils by Lehmann et al. (2011). 1161-0301/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.eja.2013.11.003