Efectos de las técnicas de preparación del suelo y de la planta en repoblaciones con "Pinus halepensis" en medios mediterráneos semiáridos: resultados de un ensayo a corto y medio plazo

A 5-year study of reforestation of a semiarid Mediterranean ecosystem with Pinus halepensis is presented. A total of 60 treatments were tested resulting from 12 site preparation ¥ 5 plant preparation techniques. Site preparation techniques showed a greater effect than plant improvements. Interactions between both factors were not significant.. The best result was obtained by the addition of fresh organic waste into the subsoiling line. Subosiling promotes higher survival than holes (0.91 and 0.75, respectively). The effect of the amendment increases till the fourth year. Protection with tubes was very effective in increasing height, but the effect is short-term. The magnitude and length of treatment effects showed a big temporal variability over the study period.Se estudian los efectos de distintos tratamientos de preparación del suelo y planta sobre la supervivencia y desarrollo de una repoblación de pino carrasco a medio plazo (5 años). Se ensayaron 60 tratamientos como resultado de la combinación de 12 tratamientos de suelo y 5 de planta. Las técnicas de preparación de suelo mostraron mayor influencia en los crecimientos que las de preparación de planta. No se detectaron ninguna interacción entre ambas técnicas. La adición de una enmienda orgánica fue la técnica que produjo mayor aumento de los crecimientos, manteniéndose su efecto durante todo el periodo de tiempo. Entre las diversas formas de adición ensayadas, el residuo fresco (sin compostar) añadido dentro del surco de plantación fue la que obtuvo mejores resultados. La tasa de supervivencia obtenida es muy satisfactoria (0,91 a los 5,5 años de la plantación). La repoblación en hoyos mostró una supervivencia significativamente menor que el resto de tratamientos ensayados (0,75). De los tratamientos de planta ensayados solo la instalación de tubos protectores presenta un efecto positivo significativo, aunque es a corto plazo. La magnitud y duración de los efectos de los distintos tratamientos sobre la repoblación varía a corto y medio plazo

Effect of water erosion and cultivation on the soil carbon stock in a semiarid area of South-East Spain

An experiment to evaluate the impact of water erosion and cultivation on the soil carbon dynamic and carbon stock in a semiarid area of South-East Spain was carried out. The study was performed under three different land use scenarios: (1) forest; (2) abandoned agricultural field; and (3) non-irrigated olive grove. Experimental erosion plots (in olive grove and forest) and sediment traps (in the abandoned area) were used to determine the carbon pools associated with sediments and runoff after each event occurring between September 2005 and November 2006. Change in land use from forest to cultivated enhanced the risk of erosion (total soil loss in olive cropland seven-fold higher than in the forest area) and reduced the soil carbon stock (in the top 5 cm) by about 50%. Mineral-associated organic carbon (MOC) represented the main C pool in the three study areas although its contribution to soil organic carbon (SOC) was significantly higher in the disturbed areas (78.91 ± 1.81% and 77.29 ± 1.21% for abandoned and olive area, respectively) than in the forest area (66.05 ± 3.11%). In both, the olive and abandoned soils, the reduction in particulate organic carbon (POC) was proportionally greater than the decline in MOC. The higher degree of sediment production in the olive cropland had an important consequence in terms of the carbon losses induced by erosion compared to the abandoned and forest plots. Thus, the total OC lost by erosion in the sediments was around three times higher in the cultivated (5.12 g C m−2) than the forest plot (1.77 g C m−2). The abandoned area displayed similar OC losses as a result of erosion as the forest plot (in the measurement period: 2.07 g C m−2, 0.63 g C m−2 and 0.65 g C m−2 for olive, forest and abandoned area, respectively). MOC represented the highest percentage of contribution to total sediment OC for all the events analysed and in all uses being, in general these values higher in Olive (74–90%) than in the other two areas (55–80%). The organic carbon lost was basically linked to the solid phase in the three land uses, although the contribution of DOC to total carbon loss by erosion varied widely with each event. Data from this study show that the more labile OC fraction (POC) lost in soil in the cultivated area was mainly due to the effect of cultivation (low overall biomass production and residue return together with high C mineralization) rather than to water erosion, given that the major part of the OC lost in sediments was in the form of MOC.This research was supported with founds from the Projects: ERHIBAC (GGL2004-03179 BTE) Spanish CICYT, the Project 3027/PI/05, Murcia Regional Government (SENECA Foundation) and RESEL project founded by the Spanish Ministerio de Medio Ambiente.Peer reviewe

Long-term Effect of a Single Application of Organic Refuse on Carbon Sequestration and Soil Physical Properties

Restoration of degraded lands could be a way to reverse soil degradation and desertification in semiarid areas and mitigate greenhouse gases (GHG). Our objective was to evaluate the long-term effects of a single addition of organic refuse on soil physical properties and measure its carbon sequestration potential. In 1988, a set of five plots (87 m2 each) was established in an open desert-like scrubland (2–4% cover) in Murcia, Spain, to which urban solid refuse (USR) was added in a single treatment at different rates. Soil properties were monitored over a 5-yr period. Sixteen years after the addition, three of the plots were monitored again (P0: control, P1: 13 kg m–2, P2: 26 kg m–2 of USR added) to assess the lasting effect of the organic addition on the soil organic carbon (SOC) pools and on the physical characteristics of the soil. The SOC content was higher in P2 (16.4 g kg–1) and in P1 (11.8 g kg–1) than in P0 (7.9 g kg–1). Likewise, aerial biomass increased from 0.18 kg m–2 in P0 up to 0.27 kg m–2 in P1 and 0.46 kg m–2 in P2. This represents a total C sequestration of 9.5 Mg ha–1 in P2 and 3.4 Mg ha–1 in P1, most of the sequestered C remaining in the recalcitrant soil pool. Additionally, higher saturated hydraulic conductivity, aggregate stability, and available water content values and lower bulk density values were measured in the restored plots. Clearly, a single addition of organic refuse to the degraded soils to increase the potential for C sequestration was effective.Peer reviewe

Long-term Effect of a Single Application of Organic Refuse on Carbon Sequestration and Soil Physical Properties

Restoration of degraded lands could be a way to reverse soil degradation and desertification in semiarid areas and mitigate greenhouse gases (GHG). Our objective was to evaluate the long-term effects of a single addition of organic refuse on soil physical properties and measure its carbon sequestration potential. In 1988, a set of five plots (87 m2 each) was established in an open desert-like scrubland (2–4% cover) in Murcia, Spain, to which urban solid refuse (USR) was added in a single treatment at different rates. Soil properties were monitored over a 5-yr period. Sixteen years after the addition, three of the plots were monitored again (P0: control, P1: 13 kg m–2, P2: 26 kg m–2 of USR added) to assess the lasting effect of the organic addition on the soil organic carbon (SOC) pools and on the physical characteristics of the soil. The SOC content was higher in P2 (16.4 g kg–1) and in P1 (11.8 g kg–1) than in P0 (7.9 g kg–1). Likewise, aerial biomass increased from 0.18 kg m–2 in P0 up to 0.27 kg m–2 in P1 and 0.46 kg m–2 in P2. This represents a total C sequestration of 9.5 Mg ha–1 in P2 and 3.4 Mg ha–1 in P1, most of the sequestered C remaining in the recalcitrant soil pool. Additionally, higher saturated hydraulic conductivity, aggregate stability, and available water content values and lower bulk density values were measured in the restored plots. Clearly, a single addition of organic refuse to the degraded soils to increase the potential for C sequestration was effective.Peer reviewe

Agrarian landscapes in the Iberian Iron Age: Mountain communities and land use in southeastern Iberia

Agrarian landscapes are among the least understood features of first millennium B.C. societies in the western Mediterranean. Studies of such landscapes in the context of the Iberian Iron Age have been based essentially on the archeological record in places used for purposes other than farming, particularly settlements and areas reserved for burials and rituals, or on the identification of the possible use of fertilizers. Here we present a multiproxy analysis of an agrarian landscape based on geoarchaeological and paleoenvironmental studies in a mountainous region in southeastern Iberia. The findings confirmed the existence of farmland cultivated as early as the first millennium B.C. in the high Jutia Valley in the Spanish province of Albacete. These results suggest that coordinated analyses can be highly useful for identifying enduring agricultural practices, while contributing to a fuller understanding of western Mediterranean agrarian landscapes and their millenarian resilience, attributable to the coevolution of human communities and the environmen

Relationship of Weather Types on the Seasonal and Spatial Variability of Rainfall, Runoff, and Sediment Yield in the Western Mediterranean Basin

Rainfall is the key factor to understand soil erosion processes, mechanisms, and rates. Most research was conducted to determine rainfall characteristics and their relationship with soil erosion (erosivity) but there is little information about how atmospheric patterns control soil losses, and this is important to enable sustainable environmental planning and risk prevention. We investigated the temporal and spatial variability of the relationships of rainfall, runoff, and sediment yield with atmospheric patterns (weather types, WTs) in the western Mediterranean basin. For this purpose, we analyzed a large database of rainfall events collected between 1985 and 2015 in 46 experimental plots and catchments with the aim to: (i) evaluate seasonal differences in the contribution of rainfall, runoff, and sediment yield produced by the WTs; and (ii) to analyze the seasonal efficiency of the different WTs (relation frequency and magnitude) related to rainfall, runoff, and sediment yield. The results indicate two different temporal patterns: the first weather type exhibits (during the cold period: autumn and winter) westerly flows that produce the highest rainfall, runoff, and sediment yield values throughout the territory; the second weather type exhibits easterly flows that predominate during the warm period (spring and summer) and it is located on the Mediterranean coast of the Iberian Peninsula. However, the cyclonic situations present high frequency throughout the whole year with a large influence extended around the western Mediterranean basin. Contrary, the anticyclonic situations, despite of its high frequency, do not contribute significantly to the total rainfall, runoff, and sediment (showing the lowest efficiency) because of atmospheric stability that currently characterize this atmospheric pattern. Our approach helps to better understand the relationship of WTs on the seasonal and spatial variability of rainfall, runoff and sediment yield with a regional scale based on the large dataset and number of soil erosion experimental stations.Spanish Government (Ministry of Economy and Competitiveness, MINECO) and FEDER Projects: CGL2014 52135-C3-3-R, ESP2017-89463-C3-3-R, CGL2014-59946-R, CGL2015-65569-R, CGL2015-64284-C2-2-R, CGL2015-64284-C2-1-R, CGL2016-78075-P, GL2008-02879/BTE, LEDDRA 243857, RECARE-FP7, CGL2017-83866-C3-1-R, and PCIN-2017-061/AEI. Dhais Peña-Angulo received a “Juan de la Cierva” postdoctoral contract (FJCI-2017-33652 Spanish Ministry of Economy and Competitiveness, MEC). Ana Lucia acknowledge the "Brigitte-Schlieben-Lange-Programm". The “Geoenvironmental Processes and Global Change” (E02_17R) was financed by the Aragón Government and the European Social Fund. José Andrés López-Tarazón acknowledges the Secretariat for Universities and Research of the Department of the Economy and Knowledge of the Autonomous Government of Catalonia for supporting the Consolidated Research Group 2014 SGR 645 (RIUS- Fluvial Dynamics Research Group). Artemi Cerdà thank the funding of the OCDE TAD/CRP JA00088807. José Martínez-Fernandez acknowledges the project Unidad de Excelencia CLU-2018-04 co-funded by FEDER and Castilla y León Government. Ane Zabaleta is supported by the Hydro-Environmental Processes consolidated research group (IT1029-16, Basque Government). This paper has the benefit of the Lab and Field Data Pool created within the framework of the COST action CONNECTEUR (ES1306)