Open Access
Soil water retention and soil compaction assessment in a regional-scale strategy to improve climate change adaptation of agriculture in Navarre, Spain
(MDPI, 2021) Antón Sobejano, Rodrigo; Ruiz Sagaseta de Ilurdoz, Alberto; Orcaray Echeverría, Luis; Arricibita Bidegáin, Francisco Javier; Enrique Martín, Alberto; De Soto García, Isabel Sonsoles; Virto Quecedo, Íñigo; Zientziak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
The aim of this study was to evaluate the effectiveness of the different agricultural management adaptive strategies considered in the framework of a regional climate change adaptation roadmap in Navarre (Spain), from the point of view of soil physical indicators associated to soil compaction and water retention. These indicators were chosen as representative of the potential of these strategies to improve the soil physical condition. That for, the effectiveness of conservation agriculture (CA), crop rotations (ROT), additions of organic matter (ExO), irrigation (IRR) and innovative grassland management (GSS) was assessed by monitoring soil bulk density (BD) and soil available water holding capacity (AWHC) in a network of 159 agricultural fields across homogeneous agro-climatic zones in the region. A sampling protocol designed to compare groups of plots with or without adaptive practices, and with equal soil characteristics within each zone, allowed to determine the effect size of each strategy (measured as response ratios, RR, calculated as the relative value of BD and AWHC in fields with adaptive management vs. without). Both parameters responded to soil and crop management, although the observed effect was highly variable. Only the ExO strategy showed an overall positive effect on BD. ROT, IRR and GSS displayed no effect and, in the case of CA, the effect was negative. In terms of AWHC, although the results within the zones were heterogeneous, the overall effect associated to the strategies ROT, ExO, IRR and GSS was neutral, and only CA resulted in an overall negative effect. The observed variability in terms of the effectiveness of the five strategies tested in this region highlights the need to understand the complexity of interrelationships between management and dynamic soil properties at the regional scale.
Open Access
Oinez Basoa: using school-managed afforested land for soil education in Navarre, Spain
(Universia España, 2019) Virto Quecedo, Íñigo; Imbert Rodríguez, Bosco; Peralta de Andrés, Francisco Javier; De Soto García, Isabel Sonsoles; González Tejedor, Iñaki; Antón Sobejano, Rodrigo; López Goñi, Irene; Martínez, Maite; Arias, Isabel; Enrique Martín, Alberto; Ciencias; Zientziak; Gobierno de Navarra / Nafarroako Gobernua
El estudio del suelo en la educación secundaria es un tema de debate ya que, a pesar de la creciente preocupación por el suelo en las ciencias ambientales, sigue siendo poco considerado en los planes de estudio y programas oficiales de educación preuniversitaria. En este trabajo presentamos los resultados de un estudio de caso realizado con una clase de 4º grado de educación secundaria obligatoria, donde se utilizó una secuencia didáctica que incluye datos reales obtenidos en una cronosecuencia de reforestación. La repoblación forestal formó parte de las actividades realizadas por la red de escuelas a las que pertenecía la escuela, con el objetivo de mitigar las emisiones de gases de efecto invernadero resultantes de su actividad anual de recaudación de fondos. En un primer paso, se determinaron una serie de indicadores edáficos y de la vegetación en el suelo reforestado, utilizando un enfoque de espacio por tiempo con un suelo cultivado cercano (correspondiente a la situación original del suelo reforestado) y un bosque maduro (similar a la situación objetivo de la reforestación). Se observó que los índices de biodiversidad de plantas, carbono de la biomasa microbiana y C orgánico total, y los de descomposición de la materia orgánica en el suelo reforestado se encontraron en una situación intermedia entre el suelo cultivado y el bosque maduro. En particular, se verificó un secuestro efectivo de C atmosférico a partir de una diferencia de 12,41 ± 1,06 Mg de C orgánico por hectárea en el suelo reforestado en comparación con el control cultivado. Los datos emitidos a partir de este análisis se utilizaron para preparar una actividad de aprendizaje cooperativo de tipo puzzle, que se integró en la secuencia didáctica diseñada para introducir los conceptos de sucesiones ecológicas y el ciclo del carbono. Esta propuesta se centró especialmente en el papel del suelo como omponente del ecosistema y dentro del ciclo del C. El éxito de la implementación de esta secuencia se probó utilizando test de conocimientos previos y finales. Los resultados de estas pruebas mostraron una mejora general (42,8 puntos en la prueba final frente a 23,3 en la prueba inicial) en relación con los conceptos evaluados. Sin embargo, se observaron diferencias en relación a la progresión realizada por los estudiantes, que fue mejor en las preguntas relacionadas con los ecosistemas que en las directamente relacionadas con el suelo como consecuencia del peor conocimiento previo sobre el suelo. A partir de estos resultados, llegamos a la conclusión de que el desarrollo de herramientas educativas que permitan a los estudiantes de secundaria abordar casos reales en las que el suelo se considera un componente clave del ecosistema, puede ser eficaz para avanzar hacia un aprendizaje significativo sobre los suelos y las propiedades del suelo, que parecen no suficientemente entendidos por los alumnos de educación secundaria.
Open Access
Irrigation and SOC sequestration in the region of Navarre in Spain
(FAO, 2021) Virto Quecedo, Íñigo; Antón Sobejano, Rodrigo; Enrique Martín, Alberto; Orcaray Echeverría, Luis; Arias Fariñas, Nerea; Ciencias; Zientziak
The project REGADIOX, funded by the European Commission LIFE Program was based on the establishment of a regional-scale network of representative agricultural plots in three irrigation districts in Navarre (NE Spain). The project allowed for a rational evaluation of soil organic C (SOC) sequestration and greenhouse gases (GHG) emissions balances by using paired comparisons in terms of soil characteristics in irrigated vs rainfed plots. The results showed a clear influence of irrigation in soil condition, arising from greater SOC storage. The net effect was however modulated by soil characteristics and management practices, in so far as the different agricultural strategies did have different potential to sequester SOC and/or reduce GHG emissions. While permanent crops with green cover (which was possible thanks to irrigation) or semi-permanent crops as alfalfa were win-win strategies with positive C balances, intensive systems with two crops per year, although they also contributed to SOC gains, represented increased GHG emissions. The observed changes in SOC associated to irrigation with different managements also showed that irrigation adoption can alter the soils’ capacity to provide key ecosystem services beyond biomass production, as changes in soils properties related to SOC, such as water-holding capacity or soil erodibility were also observed. These changes were, however, not straightforward and varied depending on soil type, climate and time under irrigation.
Open Access
Changes in the soil inorganic carbon dynamics in the tilled layer of a semi-arid Mediterranean soil due to irrigation and a change in crop: uncertainties in the calculation of pedogenic carbonates
(Elsevier, 2024) De Soto García, Isabel Sonsoles; Barré, Pierre; Zamanian, Kazem; Urmeneta Martín-Calero, Henar; Antón Sobejano, Rodrigo; Enrique Martín, Alberto; Virto Quecedo, Íñigo; Ciencias; Zientziak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Soil inorganic carbon (SIC) accounts for more than one-third of the total soil carbon pool, but the effect of agricultural management on carbonates dynamics in Mediterranean semi-arid calcareous soils has largely been ignored and remains unclear. However, SIC plays a key role in physical, chemical and, biological properties of soils, which in turn can affect plant growth and productivity. Based on a 7-year field experiment in a paired irrigated and non-irrigated trial, with two different crops (maize and wheat), we investigated the effects of the land use change (from non-irrigated wheat to irrigated maize) on the SIC dynamics in the topsoil (0¿30 cm) of a carbonate-rich soil in Navarre, northern Spain. The results obtained using the accepted equation for determining carbonate type showed that during the 7-year study period, irrigation application and the crop change modified the carbonate typology (lithogenic and pedogenic) in a very short period, without affecting the total SIC content. The main drivers of pedogenic carbonate formation in this case appear to be the water volume and the type of organic matter entering the soil (from C3 plants or C4 plants). However, the equation seems to be strongly dependent on the type of soil organic carbon, which can introduce uncertainties when used to determine the proportion of pedogenic carbonates in soils experiencing a crop change from C3 to C4 plants.
Open Access
Organic carbon storage and dynamics as affected by the adoption of irrigation in a cultivated calcareous mediterranean soil
(Frontiers Media, 2022) Antón Sobejano, Rodrigo; Derrien, Delphine; Urmeneta Martín-Calero, Henar; Van der Heijden, Gregory; Enrique Martín, Alberto; Virto Quecedo, Íñigo; Zientziak; Estatistika, Informatika eta Matematika; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ciencias; Estadística, Informática y Matemáticas; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Irrigation is in the spotlight of land-use planning in semi-arid and sub-humid regions. It can be a promising practice to promote soil organic C storage (SOC), although it may also involve an increase in soil GHG emissions. Assessing the impact of its adoption on SOC storage is crucial to better understand its potential role in terms of agricultural sustainability and climate policies. In this study, we measured and modeled the changes in soil organic C storage and dynamics in the tilled soil layer (0-30 cm) of an experimental field on a calcareous soil with two different crops (maize, a C4 plant, and wheat, a C3 plant), cultivated with and without irrigation for 7 years. We hypothesized that changes in SOC storage occur when introducing irrigation and/or different crops in an agrosystem, and that they would be related to changes in the incorporation of crop residues, their partitioning between the labile and the stable fraction, and C losses bymineralization. Our results validated theses hypotheses only partially. Over the 7-year study period, irrigation significantly increased total (TOC) and sand-size (50-2,000 µm) particulate organic C (POC50-2,000) stocks in the tilled layer (0-30 cm): +7.1%TOC and +12.1%POC50-2,000 for maize, and +7.0 and +12.3% for wheat. A parallel two-pool SOC model based on TOC and POC50-2,000 fractions and the C3-C4 plant shift allowed understanding that the observed changes in SOC storage were most likely related to an increase in C inputs from crop residues, and to a more efficient incorporation of these residues with irrigation. The mean residence time of SOC in the two modeled pools did not allow to support our hypothesis of changes in SOC mineralization with irrigation. The limitations of SOC fractionation, which implied that some labile fractions might have been lost from POC50-2,000 and recovered in the fraction identified as slow-turning, together with the interaction of the carbonate-rich mineral phase of this soil can explain at least partially this observation. We conclude that irrigation can contribute to effectively increase SOC storage in themid-term, but its effectmight be dependent upon the type of crops and soil.
Open Access
A fertilisation strategy combining mineral fertiliser and biosolid improves long-term yield and carbon storage in a calcareous soil
(MDPI, 2023) Zaragüeta, Armelle; Enrique Martín, Alberto; Portell Canal, Xavier; Antón Sobejano, Rodrigo; Virto Quecedo, Íñigo; Orcaray Echeverría, Luis; Ciencias; Zientziak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD
At a strategic moment for agricultural soils, which are expected to contribute to climate change mitigation through carbon storage while safely feeding a growing world population, the fertiliser strategies used will be key. In a calcareous soil with extensive rainfed agricultural use and straw removal, different fertiliser strategies were evaluated with the aim of determining their effects on crop yield, nitrogen agronomic efficiency, and the storage of organic carbon and total nitrogen in the soil. Different doses of mineral fertiliser, expressed as kg of mineral nitrogen ha−1 year−1 (0, 60, 120, 180, and 240 nitrogen fertilising units (NFUs)), were applied to plots with and without biosolid amendment. The biosolid, applied at a rate of 40 Mg ha−1 every 3 years for 18 years, complied with national and European regulations to be applied on agricultural soil. The use of combined fertilisation reduced the amount of mineral fertiliser applied between 33 and 67% and the total fertiliser units between 7 and 40%, while maintaining similar yields to the reference mineral fertilisation (180 NFUs). These results could be related to a higher nitrogen agronomic efficiency in the combined fertilisation treatments that do not exceed the total NFUs required by the crop. Combined fertilisation was also an effective fertiliser technique to store total nitrogen and organic carbon in the soil. However, compared to the reference mineral fertilisation (180 NFUs), no significant changes in the soil organic carbon were observed, probably due to the crop management method in which the straw is removed and to higher gas emissions. Our results support the need to assess the efficacy of each agricultural technique at local scales in order not to overestimate or underestimate the potential of each agricultural technique to store soil organic carbon.
Open Access
Effect of the long-term application of sewage sludge to a calcareous soil on its total and bioavailable content in trace elements, and their transfer to the crop
(MDPI, 2021-03-30) Zaragüeta, Armelle; Enrique Martín, Alberto; Virto Quecedo, Íñigo; Antón Sobejano, Rodrigo; Urmeneta Martín-Calero, Henar; Orcaray Echeverría, Luis; Ciencias; Zientziak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Estadística, Informática y Matemáticas; Estatistika, Informatika eta Matematika
Sewage sludge (SS) can be used as an organic amendment in agricultural soils, provided they comply with the relevant legislation. This use can incorporate traces of metals into the soil, which can cause environmental or human health problems. In the study period between 1992 and 2018 (26 years), it was observed that the use of SS as an organic fertilizer significantly increased the total concentration of Zn, Cu, Cr, Ni and Hg of this study between 55.6% (Hg) and 7.0% (Ni). The concentration of Zn, Cu, Pb, Ni and Cd extracted with DTPA, also increased between 122.2% (Zn) and 11.3% (Cd). In contrast, the Mn concentrations extracted with Diethylene Triamine Pentaacetic Acid (DTPA)were 6.5% higher in the treatments without SS. These changes in the soil had an impact on the crop, which showed a significant increase in the concentration of Zn, Cu and Cr in the grain, between 15.0% (Cr) and 4.4% (Cu), and a decrease in the concentration of Mn, Cr and Ni in the barley straw when SS was added to the soil between 32.2% (Mn) and 29.6% (Ni). However, the limits established by current legislation on soil protection and food were not exceeded. This limited transfer to the crop, is likely due to the high content of carbonates and organic matter in the soil, which limit the bioavailability of most of the trace metals (TM) in the soil. As a conclusion, we observe that the use of SS as an organic amendment increased the concentration of some TM in the soil, in its bioavailable forms, and in the crop.
Open Access
Effects of long-term sewage sludge addition to a calcareous soil on soil organic C fractions and soil functions
(Elsevier, 2024) Simoes da Mota, Ana Claudia; Barré, Pierre; Baudin, François; Poch, Rosa María; Bruni, Elisa; Antón Sobejano, Rodrigo; Enrique Martín, Alberto; Virto Quecedo, Íñigo; Ciencias; Zientziak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD
Soil organic matter (SOM) is a recognized carbon reservoir and paramount in soil functioning and agrosystems productivity. Different management strategies have been established to enhance SOM in arable soils, and one is the application of exogenous organic matter (EOM). Despite significant efforts in recent years, the consequences of EOM addition on increasing soil organic C (SOC) storage and stability in different pedoclimatic contexts remain incompletely understood. In this study, we evaluated the effect of long-term (28 y) sewage sludge (SS) addition to a calcareous soil supporting rainfed extensive crops in a Mediterranean sub-humid area in terms of SOC stabilization and distribution among functional fractions. To that end, we studied total SOM storage and soil fractions in a long-term experiment comparing 4 different doses of SS with mineral fertilization and no-fertilization controls. We compared the concentration, storage and distribution of C using two different fractionation methods (particulate vs. mineral-associated, defined by granulodensimetric fractionation, and active C vs. stable C defined by Rock-Eval® thermal analysis coupled to the machine learning PARTYsoc v2.0 model) on the tilled layer (0–30 cm). Three soil functioning indicators (crops yield, soil microbial biomass C and aggregate stability) were also quantified. We found that SS application, which slightly increased SOC concentration when SS was added, resulted in a net SOC stock gain only with the highest dose used (80 tons/ha), compared to mineral fertilization, suggesting that most of the C added was mineralized. An uneven response of soil fractions was however detected. The coarsest heavy physical fractions > 250 μm and 50–250 μm in size were the most enriched in their C concentration with SS addition, whereas SOC was mostly accumulated as mineral-associated C in the silt-size (2–50 μm) and the 50–250 μm fractions. Regarding thermal fractionation, SS treatments showed C gains between 57 % and 35 % in the active C pool, compared to mineral fertilization. This can be explained considering that the accumulated SOM in mineral-associated fractions corresponded to mean-residence times in the order of 20–40 years. The consequences on soil functioning indicators were not directly related to the amount of SOC stored in the soil, as the highest SOC gains corresponded to the highest dose, but not the highest yields, and some negative correlations were observed between SOC fractions and soil structural stability and microbial biomass. This can be related to some deleterious effects of excessive SS application reducing yields, the soil biological activity and soil structure, and represents an example of the need to decouple the assessment of soil health from that of SOC storage for certain soil management practices. The overall evaluation of the net consequences of long-term SS application indicated that low doses (10 tons/ha) seem a better choice, as they resulted in the highest efficiency in C incorporation, and in a slightly greater increase in SOC concentration than intermediate doses, and equal yields than mineral fertilization, but did not have the negative effects observed in soil functioning with higher doses.
Open Access
Soil organic carbon monitoring to assess agricultural climate change adaptation practices in Navarre, Spain
(Springer, 2021) Antón Sobejano, Rodrigo; Arricibita Bidegáin, Francisco Javier; Ruiz Sagaseta de Ilurdoz, Alberto; Enrique Martín, Alberto; De Soto García, Isabel Sonsoles; Orcaray Echeverría, Luis; Zaragüeta, Armelle; Virto Quecedo, Íñigo; Zientziak; Institute on Innovation and Sustainable Development in Food Chain - ISFOOD; Ciencias; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Climate change adaptation strategies are needed for agriculture, one of the most vulnerable human activities. In Navarre, North of Spain, ongoing adaptive management practices were identified and promoted in the framework of a regional adaptation strategy. Most include practices aiming to increase topsoil organic carbon (SOC) in agricultural land. In this work, the effectiveness of these practices (conservation agriculture, crop rotations, additions of organic matter, irrigation, and controlled grazing management) was assessed by means of monitoring SOC in a network of 159 agricultural fields across the region. These fields were selected across bioclimatic zones, where soil vulnerabilities and land-uses were previously assessed, to represent the most widespread conditions in the region. A sampling protocol designed to compare SOC stocks in plots with equal soil conditions within each zone, and with or without adaptive practices, allowed the determination of their effect size (measured as response ratios, RR). Exogenous organic matter addition was the most effective practice for SOC storage (RR 95% confidence interval (CI) [1.25–1.37]) across the region. Controlled grazing also resulted in net SOC gains (RR CI [1.13–1.42]) in temperate and semiarid grasslands. Conservation agriculture seemed to be more effective in the driest zone (RR CI [1.30–1.53]) than in the more humid ones (RR CI [0.98–1.21]). Irrigation also displayed a net positive effect (RR CI [1.17–1.34]), modulated by irrigated crop management, whereas crop rotations had an overall negative impact vs. monoculture (RR CI [0.84–0.96]), likely by their interaction with irrigation. These results confirm the variability in SOC responses to changes in management, and SOC as an indicator for assessing regional adaptation practices, although other biophysical, agronomic, and socio-economic factors also need to be accounted for.