Carbon sequestration potential of residues of different types of cover crops in olive groves under mediterranean climate

Abstract

The maintenance of plant cover between olive grove lanes until the beginning of spring is a soil management alternative that is gradually being adopted by olive growers. As well as protecting the soil from erosion, plant covers have other advantages such as improving the physicochemical properties of the soil, favouring its biodiversity and contributing towards the capturing of atmospheric carbon and its fixation in the soil. A trial was conducted over three growing seasons in an olive plantation situated in southern Spain. It was designed to evaluate the C fixation potential of the residues of the cover species Brachypodium distachyon, Eruca vesicaria, Sinapis alba and of spontaneous weeds; and also to study the decomposition dynamics of plant residues after mowing cover. After 156 and 171 days of decomposition, the species that released the largest amount of C was Brachypodium with values of 2,157 and 1,666 kg ha -1 respectively, while the lowest values of 461 and 509 kg ha -1 were obtained by spontaneous weeds. During the third season (163 days of decomposition) and due to the weather conditions restricting the emergence and growth of cover, spontaneous weeds released the most C with a value of 1,494 kg ha -1 . With respect to the fixation of C, Sinapis records the best results with an increase in soil organic C (SOC) concentration of 7,690 kg ha -1 . Considering the three seasons and a depth of 20 cm, the behaviour sequence of the different species in favouring the fixation of soil organic C was Sinapis > Brachypodium > spontaneous weeds > Eruca.Additional key words: carbon release; cover crops; soil carbon fixation. Resumen Potencial de secuestro de carbono de residuos de diferentes tipos de cubiertas en olivar bajo clima mediterráneoEl mantenimiento de una cubierta vegetal entre líneas de olivo hasta el comienzo de la primavera es una alternativa de manejo de suelo que está siendo gradualmente adoptada por los olivareros. Así como la protección del suelo contra la erosión, las cubiertas vegetales tienen otras ventajas como la mejora de las propiedades físico-químicas del suelo, favorecer su biodiversidad y contribuir a la captura de carbono atmosférico y su fijación en el suelo. Se ha realizado un ensayo durante tres campañas en una plantación de olivos situada en el sur de España. Éste fue diseñado para evaluar el potencial de fijación de C en residuos de cubiertas de las especies Brachypodium distachyon, Eruca vesicaria, Sinapis alba y de hierba espontánea; y también para estudiar la dinámica de descomposición del residuo tras el desbroce de la cubierta. Después de 156 y 171 días de descomposición, la especie que más cantidad de C liberó fue el Brachypodium con un valor de 2.157 y 1.666 kg ha -1 respectivamente, mientras que los valores más bajos fueron 461 y 509 kg ha -1 y se obtuvieron por la hierba espontánea. Durante la 3.ª campaña (163 días de descomposición), debido a las condiciones climáticas, se vio restringida la emergencia y el crecimiento de la cubierta. La hierba espontánea *Correspo...

A renewed view of conservation agriculture and its evolution over the last decade in Spain

“…Particularly with regard to erosion (McGregor et al,1990;Baker et al, 2002;Espejo-Perez et al, 2013); increased organic matter content (Ordóñez Fernández et al, 2007a;González-Sánchez et al, 2012;Repullo-Ruiberriz de Torres et al, 2012); improved water infiltration (Thierfelder and Wall, 2009);water usage (Blanco-Canqui and Lal, 2007); water quality (Jordan and Hutcheon, 1997); reduced water pollution (Fawcett, 1995); biodiversity enhancements (López-Fando and Bello-Pérez, 1997;Kladivko, 2001); reduced CO 2 emissions (Lal, 2005;Carbonell-Bojollo et al, 2011). Likewise, several studies demonstrate the technical viability of CA in terms of yields when compared to TT (Cantero-Martinez et al, 2003;Van Den Putte et al, 2010) and also regarding the economical revenue for farmers (Uri et al, 1999;García-Torres et al, 2003).…”

A Technical-Economic Comparison between Conventional Tillage and Conservative Techniques in Paddy-Rice Production Practice in Northern Italy

“…Conservation agriculture practice is often associated with the adoption of cover crops, providing specific agronomic advantages, such as improving some physic-chemical properties of the soil and biodiversity [13], in addition to ensuring an adequate protecting cover of the soil until a new crop is grown, with additional decompaction effects and help in controlling soil-borne diseases [14,15].…”

Assessing Local Uncertainty of Soil Protection in an Olive Grove Area with Pruning Residues Cover: A Geostatistical Cosimulation Approach

“…Cover crops of grass, spontaneous weeds and leguminous plants have been investigated (Saavedra & Pastor, 2002). Researchers have also recently begun to study cruciferous cover crops (Repullo-Ruibérriz de Torres et al, 2012) because they produce a great amount of residues and release glucosinolates (Alcántara et al, 2011). These herbaceous cover crop systems, however, require careful agronomic management.…”

“…These herbaceous cover crop systems, however, require careful agronomic management. In contrast, pruning residues used as mulch cover protect the soil for longer time periods (at least 2 years) than cover crops (Repullo et al, 2012). This aspect is of great interest to farmers because olive tree trimming is generally performed biannually.…”