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)

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

The use of double-cropping in combination with no-tillage and optimized nitrogen fertilization reduces soil N2O emissions under irrigation

The irrigation systems of the Ebro valley can lead to high N2O emissions. The effects that crop diversification, such as double-cropping in combination with conservation tillage and different N fertilizer ratios, has on soil N2O emissions have not been extensively studied in this region. The goal of this research was to measure N2O soil emissions and determine the tillage practices and N fertilization rates that provide the lowest emissions when combined with double-cropping systems. The work compared monocropping maize (MC) versus legume-maize double-cropping (DC) with two tillage systems (conventional tillage, CT; and no-tillage, NT), and three mineral N fertilization rates (zero, medium and high). Pea for grain (2019), vetch for green manure (2020), and vetch for forage (2021) were the legumes employed. The N2O emissions ranged from 0 to 15.5 mg N2O-N m−2 d−1 and were concentrated in the fertilization periods. Soil temperature and water filled pore space (WFPS) content significantly influenced soil N2O emissions. For both cropping systems, the conditions with the highest N2O emissions were soil temperatures above 20 °C and a WFPS of 50–60 %. The use of legumes facilitated reduced N fertilization in DC without affecting crop yield and led to reduced N2O emissions in this cropping system. DC reduced the emission factor (EF), which in all cases was lower than the default IPCC EF (1 %). With DC, a medium N fertilization rate produced similar yields to the high rate commonly applied by farmers, and also entailed lower N2O emissions. The no-tillage system, although producing higher levels of N2O, achieved lower yield-scaled N2O emissions due to greater crop yields. This work underlines the advantages of using double-cropping no-tillage systems combined with medium rates of N fertilization to reduce soil N2O emissions.The authors would like to thank Carlos Cortés and Silvia Martí for laboratory and field assistance. This research work was financially supported by the Ministerio de Ciencia e Innovación of Spain (project AGL2017-84529-C3-3-R; PhD fellowship PRE2018-084610)

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

Modelling soil organic carbon stocks and their changes in the northeast of Spain

40 Pags., 6 Tabls., 7 Figs. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1365-2389Currently, there is little information about soil organic carbon (SOC) stocks and changes in Mediterranean areas at a regional scale. We modelled an area of 95 269 km2 in northeast Spain using the Global Environmental Facility Soil Organic Carbon (GEFSOC) system to predict SOC stocks and changes in pasture, forest and agricultural soils. The spatial distribution of the different land-use categories and their change over time was obtained by using the Corine database and official Spanish statistics on land use from 1926 to 2007. The model predicted the largest current SOC stock in forest soils at 578 Tg C. Agricultural soils were the second largest SOC reservoir, containing 244 Tg C. During the last 30 years, the model predicted a total SOC gain in the 0–30-cm soil layer of 34 Tg C. Forest and grassland-pasture soils had a decline in their stored SOC of 5 and 3 Tg C, respectively, because of the reduction in the soil surface occupied by both classes. The greatest SOC gain was predicted in agricultural soils with 42 Tg C caused by changes in management, which led to increases in C inputs. Although model uncertainty was not quantified, some hypothetical assumptions about the initialization and parameterization of the model could be potential sources of uncertainty. Our simulations predicted that in northeast Spain soil management has contributed to the sequestration of substantial amounts of atmospheric CO2 during the last 30 years. More research is needed in order to study the potential role of soils as atmospheric CO2 sinks under different managements and climatic conditions.Jorge Álvaro-Fuentes was awarded a Beatriu de Pinós Postdoctoral Fellowship by the Comissionat per a Universitats i Recerca del Departament d’Innovació, Universitats i Empresa, of the Generalitat de Catalunya.Peer reviewe

Handbook of plant and soil analysis for agricultural systems

[SPA] Este libro recopila diferentes protocolos para el análisis de plantas y suelos para sistemas agrícolas. Nuestro objetivo es proporcionar un conjunto completo de indicadores para evaluar la productividad de los cultivos, la calidad de los cultivos, la calidad del suelo y la fertilidad del suelo con procedimientos y métodos viables y sólidos. La evaluación de la sostenibilidad de los agroecosistemas requiere la selección de indicadores adecuados y su medida. El presente manual ha compilado diferentes indicadores para evaluar el crecimiento de los cultivos, la incidencia de plagas y enfermedades, el rendimiento de la granja, la calidad de los cultivos y las características nutricionales, los análisis físicos del suelo, los análisis químicos del suelo y los análisis biológicos del suelo. El libro está organizado en tres partes: i) análisis de plantas y cultivos, ii) análisis físico-químicos del suelo y iii) análisis biológicos del suelo. En total, proporcionamos 90 procedimientos para el análisis de plantas y suelos, incluida la importancia y las aplicaciones, el principio del método descrito, los reactivos necesarios, los materiales y equipos, la descripción detallada del procedimiento, los cálculos necesarios y algunas observaciones específicas.[ENG] This books compiles different protocols for analysis of plant and soil for agricultural systems. We aim to provide a complete set of indicators to assess crop productivity, crop quality, soil quality and soil fertility with feasible and robust procedures and methods. The assessment of the sustainability of agroecosystems needs the selection of suitable indicators and their measure. The present handbook has compiled different indicators to assess crop growth, incidence of pests and diseases, farm yield, crop quality and nutritional characteristics, soil physical analyses, soil chemical analyses and soil biological analyses. The book is organized in three parts: i) plant and crop analyses, ii) soil physicochemical analyses and iii) soil biological analyses. In total we provide 90 procedures for plant and soil analysis, including the importance and applications, the principle of the method described, the reagents needed, the materials and equipment, the detailed description of the procedure, the calculations required and some specific remarks.This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No 72800

Towards mitigation of greenhouse gases by small changes in farming practices: understanding local barriers in Spain.

Small changes in agricultural practices have a large potential for reducing greenhouse gas emissions. However, the implementation of such practices at the local level is often limited by a range of barriers. Understanding the barriers is essential for defining effective measures, the actual mitigation potential of the measures, and the policy needs to ensure implementation. Here we evaluate behavioural, cultural, and policy barriers for implementation of mitigation practices at the local level that imply small changes to farmers. The choice of potential mitigation practices relevant to the case study is based on a literature review of previous empirical studies. Two methods that include the stakeholders? involvement (experts and farmers) are undertaken for the prioritization of these potential practices: (a) Multi-criteria analysis (MCA) of the choices of an expert panel and (b) Analysis of barriers to implementation based on a survey of farmers. The MCA considers two future climate scenarios ? current climate and a drier and warmer climate scenario. Results suggest that all potential selected practices are suitable for mitigation considering multiple criteria in both scenarios. Nevertheless, if all the barriers for implementation had the same influence, the preferred mitigation practices in the case study would be changes in fertilization management and use of cover crops. The identification of barriers for the implementation of the practices is based on the econometric analysis of surveys given to farmers. Results show that farmers? environmental concerns, financial incentives and access to technical advice are the main factors that define their barriers to implementation. These results may contribute to develop effective mitigation policy to be included in the 2020 review of the European Union Common Agricultural Policy

Soil aggregation and organic carbon protection in a no-tillage chronosequence under Mediterranean conditions

Low-intensity soil management systems like no-tillage (NT) are being increasingly accepted as an essential part of sustainable farming systems. The objective of this work was to study the effects of NT maintenance over time on soil aggregation and soil organic carbon (SOC) protection on a semiarid Mediterranean agroecosystem. A NT chronosequence was established with five phases: (i) conventional tillage (CT); (ii) NT for 1 year (NT-1); (iii) NT for 4 years (NT-4); (iv) NT for 11 years (NT-11) and (v) NT for 20 years (NT-20). N fertilization was based on pig slurry for the whole experimental area. Soil samples were collected from four depths (i.e., 0–5, 5–10, 10–20, 20–30 cm). Dry and water-stable aggregates, SOC concentration and C concentration of water-stable aggregates were measured. SOC concentration reached its maximum value after 11 years under NT. However, the differences between NT phases were only found in the 0–5 cm soil depth. In soil surface (i.e., 0–5 cm), water-stable large macroaggregates (2–8 mm) were 0.02, 0.12, 0.32 and 0.31 g g− 1 dry soil for the NT-1, NT-4, NT-11 and NT-20 phases, respectively. C concentration of microaggregates increased in relation with the number of years under NT. SOC and water-stable macroaggregate stratification were greatest with the increase in the years under NT, emphasizing the close relationship between SOC and aggregation. In Mediterranean semiarid agroecosystems, the increase in the proportion of stable macroaggregates and the enrichment of C concentration within microaggregates are two main mechanisms of SOC protection when NT is maintained over time.This research was supported by the Comision Interministerial de Ciencia y Tecnologia of Spain (AGL 2004-07763-C02-02 and AGL 2010-22050-C03-01). D. Plaza-Bonilla was awarded with a FPU fellowship by the Spanish Ministry of Education. Jorge Álvaro-Fuentes acknowledges the Consejo Superior de Investigaciones Científicas (CSIC) for his contract within the “Junta para la Ampliación de Estudios” (JAE-DOC) programme co-financed by the European Social Fund

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

Is it feasible to reduce tillage and N use while improving maize yield in irrigated Mediterranean agroecosystems?

Mediterranean rainfed areas are transformed into irrigation to stabilize or increase crop yields. The gradual occupation of irrigation leads to an increase in nitrogen use and intensity of tillage. The aim of this work was to evaluate the combined impact of tillage systems and mineral N fertilization rates on maize grain yield, water and nitrogen use efficiencies (WUE and NUE) under Mediterranean irrigated conditions. The study was carried out in NE Spain during three maize growing seasons (i.e. years 2015, 2016 and 2017). A long-term (LTE) tillage and N rate field experiment established in 1996 under rainfed conditions was transformed into irrigation with maize (Zea mays L.) monoculture as cropping system in 2015. Three types of tillage (conventional tillage, CT; reduced tillage, RT; no-tillage, NT) and three mineral N fertilization rates (0, 200, 400 kg N ha-1) were compared in a randomized block design with three replications. In 2015, an adjacent experiment (short-term experiment, STE) with the same layout was set up in an area previously managed under long-term rainfed NT for the last 21 years. Soil water (SWC) and nitrate (SNC) content were quantified. Maize above ground biomass and N uptake, grain yield and yield components, grain N were measured at harvest. The WUE for above ground biomass and yield (WUEB and WUEY, respectively) and NUE, as well as other N-related indexes (nitrogen harvest index, NHI; apparent nitrogen recovery efficiency, NAR) were calculated. In the long-term tillage and N fertilization combination (LTE), the reduction of tillage (NT and RT) led to greater grain yield when applying 200 and 400 kg N ha-1 compared to the use of the same rates under CT. Differently, in the sort-term experiment with preceding NT (STE), tillage systems did not influence grain yields, while N application led to greater yields than the control (0 kg N ha-1). In both situations (LTE and STE), NT and RT enhanced SWC before planting leading to greater crop growth compared to CT. The lack of available water under CT caused lower maize above-ground biomass, yield, and yield components in LTE and, therefore, lower WUEB and WUEY. In LTE, the use of long-term CT led to a significant accumulation of nitrate compared to NT. Differently, in the STE, SNC did not show differences between tillage systems. In the LTE, water and N were used more efficiently to produce above-ground biomass and grain yield in RT and NT. Our study shows that in Mediterranean agroecosystems transformed into irrigation the use of NT and RT with medium rates of N leads to greater maize yield, WUE and NUE than the traditional management based on CT with high rates of mineral N. In rainfed areas with long-term history of no-till, this soil management system can be successfully maintained if transformed into irrigation.We would like to thank the field and laboratory technicians Javier Bareche, Carlos Cortés, Barbara Jelcic and Silvia Martí. This research work was financially supported by the Ministerio de Economía y Competitividad of Spain (project AGL2013-49062-C4-1-R; PhD fellowship BES‐2014‐070039). DPB received a Juan de la Cierva postdoctoral grant from the Ministerio de Economía y Competitividad of Spain (IJCI-2016-27784)