Pig slurry incorporation with tillage does not reduce short-term soil CO2 fluxes

Tillage and organic fertilization impact short-term soil CO2 fluxes. However, the interactive effect of these two management practices has been rarely studied under field conditions. The objective of this study was to evaluate the impact of tillage (NT, no-tillage, and CT, conventional tillage) and fertilization strategy (PS, pig slurry, and MF, mineral fertilizer) on short-term soil CO2 fluxes in a rainfed Mediterranean agroecosystem. Soil CO2 fluxes were measured several times during two tillage and pre-sowing fertilization periods in 2012 and 2013 (7 and 6 times in 2012 and 2013, respectively). In the two years studied, tillage and fertilization significantly affected soil CO2 fluxes, but the interaction between both factors was not significant. The application of PS resulted in a sharp and immediate increase in the soil CO2 flux. One hour after the application of the organic fertilizer, soil CO2 emissions increased from 0.05 to 0.70 g CO2 m−2 h−1 and from 0.08 to 0.82 g CO2 m−2 h−1 in 2012 and 2013, respectively. Unlike fertilization, 1 h after tillage similar soil CO2 fluxes were observed in CT and NT plots. However, after 7 h, larger fluxes were observed in CT compared with NT in both years. Cumulative CO2 flux during the first 24 h after fertilization and tillage was about three- and two-fold greater in PS than in MF and in CT than in NT, respectively. The results of this study showed that in rainfed Mediterranean systems, soil management and fertilization have a noteworthy impact on short-term soil CO2 losses though no interactive effects were observed between both management practices.This research was supported by the Ministry of Economy and Competitiveness of Spain (AGL2010-22050-C03-01/02; AGL2013-49062- C4-4-R) and the COMET-Global project (FACCE-JPI grant)

Factores químicos, físico-químicos y físicos determinantes de los caracteres, propiedades y dinámica de la porosidad de los suelos

De lo expuesto en los apartados anteriores se deduce la gran importancia edafológica y agronómica que reviste el estudio de la porosidad del suelo, así como el de sus relaciones directas o indirectas con otras características químicas, físico-químicas y físicas que condicionan su comportamiento, en especial como medio en el que se desarrollan y crecen las plantas. Por ello se creyó conveniente iniciar una investigación que pudiera aportar los conocimientos básicos suficientes acerca de la porosidad de una serie de suelos típicos de la región de Andalucía Occidental y a un nivel de detalle que permitiera evaluar su incidencia sobre algunas características físicas, en particular las referentes a la retención de humedad. Esta propiedad es decisiva para la economía del agua, factor de la máxima importancia en dicha región dada su especial climatología y al que se han dedicado ya una serie de trabajos, diversos puntos de vista (MARTIN ARANDA y col., 1974, 1975). La selección de perfiles, así como el muestreo de los mismos, se llevó a cabo con el criterio que se detalla en el Capítulo 2. Para la caracterización cuantitativa de la porosidad, así como de sus diversas fracciones, ha sido necesaria la puesta a punto de determinadas técnicas, para completar la metodología necesaria en un trabajo de esta naturaleza. A este aspecto concreto se ha dedicado la fase preliminar del trabajo experimental. El estudio ha comprendido asimismo el análisis de las propiedades químicas y físico-químicas al objeto de establecer relacionas cualitativas y cuantitativas con la porosidad. Se ha prestado especial atención a la caracterización mineralógica de la fracción arcilla, factor que, como ya se ha comentado, decide en gran medida el comportamiento físico del suelo. Por otro lado, y con el fin de poder relacionar la porosidad de las propiedades de ella dependientes, se ha llevado a cabo una serie de análisis que ha supuesto, igualmente, la inclusión de técnicas normalmente no utilizadas hasta ahora en la caracterización de nuestros suelos, como han sido las de determinación de la expansión-contracción y la de estabilidad estructural. La determinación de los caracteres de la porosidad y propiedades dependientes se ha realizado durante un periodo en el que se ha tenido ocasión de disponer de distintas situaciones de humedad, incluyendo dos épocas extremas y bien definidas dentro del ciclo anual de humectación-desecación. En la primera fase del trabajo se tuvo en cuenta principalmente la situación en que los suelos se encontraban a capacidad de campo, como punto de referencia reproducible y esencial a efectos comparativos, por ser el normalmente aceptado a estos fines, precediendo en una fase ulterior a considerar la situación de máxima desecación. De esta forma, se pudo tener constancia, entre otros factores, de la variación máxima de la porosidad, es decir, de su dinámica natural, independientemente de las causas concurrentes en cada caso particular. En los capítulos que siguen se da cuenta de la metodología analítica empleada en el estudio de los diversos perfiles, así como de los resultados más sobresalientes obtenidos. Se hace finalmente un comentario sobre el alcance práctico del trabajo en relación con la fertilidad de los suelos considerados, y de manera muy especial con el aprovechamiento óptimo de las reservas de agua para diferentes cultivos, de común dedicación en el área experimental

Water balance simulation of a dryland soil during fallow under conventional and conservation tillage in semiarid Aragon, Northeast Spain

The definitive version is available at: http://www.sciencedirect.com/science/journal/01671987In Central Aragon, winter cereal is sown in the autumn (November–December), commonly after a 16–18 months fallow period aimed at conserving soil water. This paper uses the Simple Soil–Plant–Atmosphere Transfer (SiSPAT) model, in conjunction with field data, to study the effect of long fallowing on the soil water balance under three tillage management systems (conventional tillage, CT; reduced tillage, RT; and no-tillage, NT). This was on the assumption that soil properties would remain unchanged during the entire fallow season. Once the model was validated with data obtained before primary tillage implementation, the differences between simulated and observed soil water losses for the CT and RT treatments could be interpreted as the direct effect of the soil tillage system. The model was calibrated and validated in a long-term tillage experiment using data from three contrasting long-fallow seasons over the period 1999–2002, where special attention was paid to predicting soil hydraulic properties in the pre-tillage conditions. The capacity of the model to simulate the soil water balance and its components over long fallowing was demonstrated. Both the fallow rainfall pattern and the tillage management system affected the soil water budget and components predicted by the model. The model predicted that about 81% of fallow seasonal rainfall is lost by evaporation in long-fallow periods with both a dry autumn in the first year of fallow and a rainfall above normal in spring. Whereas, when the fallow season is characterised by a wet autumn during the first year of fallow the model predicted a decrease in soil water evaporation and an increase in water storage and deep drainage components. In this case, the predicted water lost by evaporation was higher under NT (64%) than under RT (56%) and CT (44%). The comparison between measured and simulated soil water loss showed that the practice of tillage decreased soil water conservation in the short term. The long-term analysis of the soil water balance showed that, in fallow periods with a wet autumn during the first year of fallow, the soil water loss measured under CT and RT was moderately greater than that predicted by the model.This research was supported by the Comisión Interministerial de Ciencia y Tecnología of Spain (grants AGF98-0261-CO2-02 and AGL2001-2238-CO2-01 and PNFPI pre-doctoral fellowship awarded to the first author) and the European Union (FEDER funds).Peer reviewe

Water balance simulation of a dryland soil during fallow under conventional and conservation tillage in semiarid Aragon, Northeast Spain

The definitive version is available at: http://www.sciencedirect.com/science/journal/01671987In Central Aragon, winter cereal is sown in the autumn (November–December), commonly after a 16–18 months fallow period aimed at conserving soil water. This paper uses the Simple Soil–Plant–Atmosphere Transfer (SiSPAT) model, in conjunction with field data, to study the effect of long fallowing on the soil water balance under three tillage management systems (conventional tillage, CT; reduced tillage, RT; and no-tillage, NT). This was on the assumption that soil properties would remain unchanged during the entire fallow season. Once the model was validated with data obtained before primary tillage implementation, the differences between simulated and observed soil water losses for the CT and RT treatments could be interpreted as the direct effect of the soil tillage system. The model was calibrated and validated in a long-term tillage experiment using data from three contrasting long-fallow seasons over the period 1999–2002, where special attention was paid to predicting soil hydraulic properties in the pre-tillage conditions. The capacity of the model to simulate the soil water balance and its components over long fallowing was demonstrated. Both the fallow rainfall pattern and the tillage management system affected the soil water budget and components predicted by the model. The model predicted that about 81% of fallow seasonal rainfall is lost by evaporation in long-fallow periods with both a dry autumn in the first year of fallow and a rainfall above normal in spring. Whereas, when the fallow season is characterised by a wet autumn during the first year of fallow the model predicted a decrease in soil water evaporation and an increase in water storage and deep drainage components. In this case, the predicted water lost by evaporation was higher under NT (64%) than under RT (56%) and CT (44%). The comparison between measured and simulated soil water loss showed that the practice of tillage decreased soil water conservation in the short term. The long-term analysis of the soil water balance showed that, in fallow periods with a wet autumn during the first year of fallow, the soil water loss measured under CT and RT was moderately greater than that predicted by the model.This research was supported by the Comisión Interministerial de Ciencia y Tecnología of Spain (grants AGF98-0261-CO2-02 and AGL2001-2238-CO2-01 and PNFPI pre-doctoral fellowship awarded to the first author) and the European Union (FEDER funds).Peer reviewe

Simulating climate change and land use effects on soil nitrous oxide emissions in Mediterranean conditions using the Daycent model

In Mediterranean agroecosystems, limited information exists about possible impacts of climate change on soil N2O emissions under different land uses. This paper presents a modelling study with a dual objective. Firstly, the biogeochemical Daycent model was evaluated to predict soil N2O emissions in different land uses in a typical Mediterranean agroecosystem. Secondly, the study aimed to determine the impact of climate change on soil N2O emissions in different Mediterranean land uses over an 85-year period. Soil N2O emissions were measured in three land uses (cropland, abandoned land and afforested land) over 18 months (December 2011 to June 2013) in a characteristic Mediterranean site in Spain. For climate change simulations, Daycent was run with and without atmospheric CO2 enrichment using climate data from the CGCM2-A2 model. The cumulative N2O emissions predicted by the Daycent model agreed well with the observed values. The lack of fit (LOFIT) and the relative error (E) statistics determined that the model error was not greater than the error in the measurements and that the bias in the simulation values was lower than the 95% confidence interval of the measurements. For the different land uses and climate scenarios, annual cumulative N2O emissions ranged from 126 to 642 g N2O-N ha−1 yr−1. Over the simulated 85-year period, climate change decreased soil N2O emissions in all three land uses. At the same time, under climate change, water filled pore space (WFPS) values decreased between 4% and 15% depending on the land use and climate change scenario considered. This study demonstrated the ability of the Daycent model to simulate soil N2O emissions in different land uses. According to model predictions, in Mediterranean conditions, climate change would lead to reduced N2O emissions in a range of land uses.Jorge Álvaro-Fuentes acknowledges the receipt of a fellowship from the OECD Co-operative Research Programme: Biological Resource Management in Sustainable Agricultural Systems in 2013. Daniel Plaza-Bonilla received a “Juan de la Cierva” grant from the Ministerio de Economía y Competitividad of Spain. This study was also possible through funds provided by the Aragon Regional Government and La Caixa (grant GA-LC-050/2011), the Ministry of Economy and Competitiveness of Spain (grant AGL2013-49062-C4-4-R) and the COMET-Global project (FACCE-JPI grant). We are grateful to María José Salvador and Javier Bareche for laboratory assistance

Saltation transport on a silt loam soil in northeast Spain

16 Pags., 4 Tabls., 4 Figs. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-145XThe Ebro River valley in Northeast Spain experiences regularly strong west-northwest winds that are locally known as cierzo. When the cierzo blows, wind erosion may potentially occur on unprotected agricultural lands. In this paper the first results of field measurements of soil characteristics and saltation transport in the Ebro River valley near Zaragoza are presented. An experiment was conducted on a silt loam soil in the summers of 1996 and 1997. Two plots of 135×180 m were both equipped with a meteorology tower, three saltiphones (acoustic sediment sensors) and ten sediment catchers. The plots were different with respect to tillage practices. One plot received mouldboard ploughing followed by a pass of a compacting roller (conventional tillage—CT), whereas the other plot only received chisel ploughing (reduced tillage—RT). Soil characterizations indicated that soil erodibility was significantly higher in the CT plots than in the RT plots. Consequently, no significant saltation transport was observed in the RT plots during both seasons. In the CT plot, four saltation events were recorded during the 1996 season and nine events during the 1997 season. Most events were preceded by rainfall during the previous one or two days, which reduced saltation transport significantly. It is concluded that the occurrence of wind erosion in the Ebro River valley depends on the timing and type of tillage, distribution of rainfall and soil-surface crusting.The WELSONS project is funded by the European Union under Contract No. ENV4‐CT95‐0182. Peer reviewe

An evaluation of wind erosion hazard in fallow lands of semiarid Aragon (NE Spain)

32 Pags.- 5 Tabls.- 4 Figs. The definitive version is available at: http://www.jswconline.org/Long fallowing (16-17 months), in the cereal-fallow rotation, may favour soil losses by wind erosion in agricultural soils of semiarid Aragon (NE Spain). With the objective of evaluating the risk of wind erosion in this area, soil losses for the most critical period of fallow (February-April) were estimated from a total of 67 fallow fields by using the Wind Erosion Equation (WEQ). All soils were medium-textured soils being the loam the most frequent textural class (45%). The CaCO3 content in the soil was higher than 200 g kg-1 in 90% of the fields. Mouldboard plough, chisel plough, and disk harrow were the main primary tillage tools used by farmers during fallow. Soil cover by crop residues was negligible (20 Mg ha-1). The WEQ estimated erosion reductions to tolerable levels if reduced tillage, with chiseling as primary tillage, is adequately adopted in the dryland cereal production areas of semiarid Aragon.This research was supported by the Comisión Interministerial de Ciencia y Tecnología (Grant no. AGF98-0261-CO2-02).Peer reviewe

Do no-till and pig slurry application improve barley yield and water and nitrogen use efficiencies in rainfed Mediterranean conditions?

Tillage and N fertilization strategies including mineral and organic sources need to be studied in combination given their importance on the production cost that farmers face and their potential interaction on crop performance. A four-year (2010–2014) experiment based on barley monocropping was carried out in NE Spain in a typical rainfed Mediterranean area. Two tillage treatments (CT, conventional tillage; NT, no-tillage) and three rates of N fertilization (0; 75 kg N ha−1, applied at top-dressing; 150 kg N ha−1, applied at pre-sowing and at top-dressing at equal rate), with two types of fertilizers (ammonium-based mineral fertilizer and organic fertilizer with pig slurry), were compared in a randomized block design with three replications. Different soil (water and nitrate contents) and crop (above-ground biomass, grain yield, yield components and N concentration in biomass and grain) measurements were performed. Water- and nitrogen use efficiencies (WUE and NUE) as well as other N-related indexes (grain and above-ground biomass N uptake; NHI, nitrogen harvest index; NAR, apparent nitrogen recovery efficiency) were calculated. Barley above-ground biomass and grain yield were highly variable and depended on the rainfall received on each cropping season (ranging between 280 mm and 537 mm). Tillage and N fertilization treatments affected barley grain yields. No-tillage showed 1.0, 1.7 and 6.3 times greater grain yield than CT in three of the four cropping seasons as a result of the greater soil water storage until tillering. Water scarcity during the definition of the number of spikes per m2 under CT would have compromised the compensation mechanism of the other two yield components. Pig slurry application led to the same (3 of 4 years) or higher (1 of 4 years) grain yield than an equivalent rate of mineral N fertilizer. Regardless the N origin, barley yield did not respond to the application of 150 kg N ha−1 split between pre-sowing and top-dressing compared to the 75 kg N ha−1 rate applied as top-dressing. A significant nitrate accumulation in the soil over the experimental period was observed under CT. Greater barley water use efficiency for yield (WUEy), N uptake and grain N content were found under NT than CT in three of the four cropping seasons studied. Moreover, for a given N rate, the use of organic fertilization increased significantly the WUEy as an average of CT and NT. When CT was used, a greater NHI was observed when using pig slurry compared with mineral N as an average of the four years studied. However, the use of different N fertilization treatments (rates or types) under CT or NT did not increase the NUE compared with the control. Our study demonstrates that the use of NT and the application of agronomic rates of N as pig slurry leads to greater barley yield and water- and nitrogen-use efficiencies than the traditional management based on CT and mineral N fertilization.We thank Silvia Martí, Carlos Cortés, Ana Bielsa, Maria José Salvador, Josan Palacio and Héctor Martínez for their technical assistance. Daniel Plaza-Bonilla received a Juan de la Cierva Postdoctoral Grant from the Ministerio de Economía y Competitividad of Spain. This research was supported by the Ministerio de Economía y Competitividad of Spain (grants AGL2007-66320-C02-01, AGL2010-22050-C03-01/02 and AGL2013-49062-C4). This paper has been produced within the context of the Red SIRENA network (Ref. AGL2015-68881-REDT) funded by the Ministerio de Economía y Competitividad of Spain

La protección de los suelos de Aragón frente al cambio climático

1 copia .pdf (28 Pags.- Fots.- Tabls.- Figs.) de la presentación original de los autores durante la Jornada Técnica "Cada año es el año del suelo: una mejor gestión para un mayor aprovechamiento” celebrada en Zaragoza, Diputación General de Aragón, Edificio Pignatelli, Sala de la Corona, el 21 de enero de 2016. Organizada por la Oficina Agrícola de la Embajada de Holanda en España. Zaragoza , 21 de enero de 2016Muy pocas directivas proponen objetivos para reducir y controlar las amenazas (i.e., erosión, pérdida de materia orgánica, pérdida de biodiversidad, contaminación). Tres de las principales amenazas -compactación, sellado y salinización- no son recogidas en las principales políticas europeas (Directiva Marco del Agua, nitratos, PAC …) (Glaesner et al. Sustainability 2014). La legislación vigente admite la merma de las funciones del suelo, pero muy pocas directivas están orientadas a mejorar esas funciones.Índice: 1. La importancia de la protección del suelo.- 2. Los suelos de Aragón y su protección frente al cambio climático.- 3. Consideraciones finalesPeer reviewe

Beneficios agroambientales de la reducción del laboreo en los secanos semiáridos del valle del Ebro

10 Pags.- 3 Tabls.- 3 Figs.[ES] Después de analizar la tendencia actual al aumento de la superficie cultivada con siembra directa o no laboreo y al descenso de la superficie total de barbecho y la del barbecho mantenido con laboreo tradicional, se presenta una síntesis de los resultados obtenidos en las últimas dos décadas sobre los beneficios derivados de la reducción del laboreo, a través de la adopción de técnicas de agricultura de conservación (laboreo reducido y no laboreo) y su influencia en algunos parámetros edáficos, agronómicos y medioambientales en los sistemas de cultivo de secano semiárido del Valle del Ebro. La conclusión es evidente. El uso de dichas técnicas, especialmente el no laboreo, como alternativa al laboreo intensivo tradicional, es una estrategia recomendable para mejorar tanto la calidad y productividad del suelo como la conservación y sostenibilidad de dichos agrosistemas.[EN] In the context of the current nationwide trend towards the increase in the proportion of cultivated land with no tillage and the decrease of total fallowed land area including that of traditional tilled fallow, the authors overview selected results obtained during the last two decades on the beneficial influence of conservation agriculture practices (reduced tillage and no-tillage) in soil, agronomic and environmental parameters in semiarid dryland farming systems of the River Ebro Valley. In the light of the results presented, it becomes evident that adopting conservation tillage technologies, especially no-tillage, is a viable alternative to conventional tillage for improving not only soil quality and productivity but also the conservation and sustainability of those agricultural systems.Peer reviewe