Short communication Effect of inoculation and fertilization with phosphorus in the survival and growth of Pinus pseudostrobus, in eroded acrisols Mariela Gómez-Romero a , Roberto Lindig-Cisneros b, *, Cuauhtémoc Saenz-Romero c , Javier Villegas d a Escuela Nacional de Estudios Superiores (ENES) Unidad Morelia, Universidad Nacional Autónoma de México, Morelia, Michoacán, Mexico b Laboratorio de Ecología de Restauración, Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Campus Morelia, Michoacán, Mexico c Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolas de Hidalgo, Morelia, Michoacán, Mexico d Instituto de Investigaciones Agropecuarias y Forestales, Universidad Michoacana de San Nicolás de Hidalgo (IIAF-UMSNH), Km 9.5 carretera Morelia– Zinapécuaro, Tarímbaro, Michoacán 58880, Mexico A R T I C L E I N F O Article history: Received 5 November 2014 Received in revised form 15 April 2015 Accepted 23 May 2015 Available online xxx Keywords: Ecological restoration Plantation Symbiosis Revegetation Tree survival A B S T R A C T Loss of soils and the consequent damage at local and regional scales is one of the most severe and extensive environmental problems. When the soil structure, and even the soil itself, is lost, revegetation faces difficult obstacles, not least the availability of nutrients for plants. As part of a project to develop revegetation strategies in the gullies formed in acrisols, a revegetation assay was established with Pinus pseudostrobus, in which the effect of inoculation with the ectomycorrhizal fungus Pisolithus tinctorius and the addition of phosphorous (KH 2 PO 4 ) was tested. Five years after initial plantation, the inoculated and non-inoculated trees presented 86% and 65% survival, respectively, representing a difference of 21% between both groups (X 2 = 10.17; P = 0.001). Differences in growth were also correlated with inoculation; inoculated trees reached 158  5.4 cm in height and 4.8  0.16 cm in diameter, while non-inoculated trees reached 134  6.1 cm in height and 3.8  0.14 cm in diameter (P < 0.05 for both variables). These results indicate that inoculation allows this sensitive species to prosper in severely degraded soils and that phosphorus fertilization is not an effective measure. ã2015 Elsevier B.V. All rights reserved. 1. Introduction Soil degradation is a serious problem at global scale that has intensified with increased forest clearance (Sivakumar, 2007) and the consequences of this process are unproductive soils with loss in structure (Six et al., 2000) and in some cases severe erosion that is difficult to control (Yang et al., 2014). One clear example of this problem is presented in the soils of the acrisol group (FAO (Food and Agriculture Organization), 2006); these are evolved soils that have developed mainly over very acidic rocks or weathered clays. When these types of soils become degraded, fertility is very low, especially due to lack of phosphorous, which in turn limits the establishment of plants (Oliet et al., 2005). Under poor soil conditions, the use of fertilizers (McGrath et al., 2001) and biological agents such as mycorrhizal fungi may more efficiently contribute to increasing the availability and mobility of phospho- rous (Álvarez-Sánchez, 2009; Graf and Frei, 2013; Khabou et al., 2014). It has been reported that in mycorrhizal plants the mycelium is extensively distributed through the soil and contrib- utes to the absorption of nutrients and water (Agerer, 2001; Smith and Read, 2000). Pisolithus tinctorius (Pers.) Coker et Couch., is capable of forming mycorrhizas with a variety of hosts (Cairney and Chambers, 1997), and it has been reported to be capable of persistence under adverse conditions and in impoverished soils or perturbed terrain (García-Rodríguez et al., 2009) Previous studies demonstrate that it is possible to establish species of the genus Pinus in gullies formed in acrisols. In one such study, the species that presented the poorest performance seven years after initiation of the plantation was Pinus pseudostrobus (Gómez-Romero et al., 2012; Gómez-Romero et al., 2013). Because this sensitive species is a good research model for testing environmental stress ameliorating techniques, fertilization with phosphorous (KH 2 PO 4 ) and inoculation with Pisolithus tinctorius were evaluated over an five-year assay. The hypothesis was that the mycorrhizal pines would present greater survival and growth than the non mycorrhizal pines and that fertilizer alone would not * Corresponding author. Current Address: University of California Institute for Mexico and the United States (UC MEXUS), Riverside, California, United States of America. E-mail address: rlindig@cieco.unam.mx (R. Lindig-Cisneros). http://dx.doi.org/10.1016/j.ecoleng.2015.05.025 0925-8574/ ã 2015 Elsevier B.V. All rights reserved. Ecological Engineering 82 (2015) 400–403 Contents lists available at ScienceDirect Ecological Engineering journal homepage: www.elsevier.com/locate/ecoleng