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Cumulative and Residual Effects of Two‐Phase Olive Mill Waste on Olive Grove Production and Soil Properties
Author(s) -
López-Piñeiro A.,
Albarrán A.,
Nunes J. M. Rato,
Peña D.,
Cabrera D.
Publication year - 2011
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2010.0230
Subject(s) - amendment , organic matter , chemistry , olea , soil water , total organic carbon , soil quality , soil conditioner , soil fertility , extraction (chemistry) , environmental science , environmental chemistry , pulp and paper industry , horticulture , soil science , organic chemistry , political science , law , biology , engineering , chromatography
Modern olive ( Olea europaea L.) mill extraction techniques generate a large amount of two‐phase olive mill waste (OMW) containing up to 90% organic matter. Recycling OMW as a soil amendment may represent a solution for its disposal, especially in Mediterranean areas, where many soils are characterized by very low organic matter levels. A 10‐yr field study was conducted to evaluate the long‐term sustainability of raw OMW disposal as a soil amendment on an olive grove in Elvas, Portugal. The soil was amended with OMW at rates of 0, 30, and 60 Mg ha −1 , dry weight equivalent, for 8 yr, with cumulative and residual effects being assessed in the last year and 2 yr after the last application. Long‐term applications of OMW to soil led to cumulative and residual effects on soil physical [aggregate stability and bulk density (D b )], chemical [total organic carbon (TOC) and its humified fractions, total N, available P, and K], and biochemical [dehydrogenase (DH), urease (UR), β‐glucosidase (GLU), alkaline phosphatase (PHO), and arylsulfatase (ARS) activities] properties, and contributed to an increase in olive yields compared with the control (>17%, >1.47 Mg ha −1 ). However, electrical conductivity (EC) rose significantly with OMW application, especially in the residual year, ranging from 0.513 dS m −1 for the unamended soil to 2.29 dS m −1 at the 60 Mg ha −1 application rate. Repeated addition of OMW to olive grove soils may be a useful strategy for recycling this organic amendment to improve soil fertility and increase yields. However, long‐term use of OMW increases the risk of soil salinity, especially if application rates are >30 Mg ha −1 .