Impact of dimethylpyrazole-based nitrification inhibitors on soil-borne bacteria

[EN] Nitrogen (N) input from fertilizers modifies the properties of agricultural soils as well as bacterial community diversity, composition and relationships. This can lead to negative impacts such as the deterioration of system multifunctionality, whose maintenance is critical to normal nutrient cycling. Synthetic nitrification inhibitors (NIs) can be combined with fertilizers to improve the efficiency of N use by reducing N losses. However, analysis of their effects on non-target bacteria are scarce. This study aimed to analyze the effect of applying the NIs DMPP and DMPSA on the whole bacterial community. Through 16S rRNA amplicon sequencing we determined the differences between samples in terms of microbial diversity, composition and co-occurrence networks. The application ofDMPP and DMPSA exerted little impact on the abundance of the dominant phyla. Nevertheless, several significant shifts were detected in bacterial diversity, co-occurrence networks, and the abundance of particular taxa, where soil water content played a key role. For instance, the application of NIs intensified the negative impact of N fertilization on bacterial diversity under high water-filled pore spaces (WFPS) (>64%), reducing community diversity, whereas alpha-diversity was not affected at low WFPS (<55%). Interestingly, despite NIs are known to inhibit ammonia monooxygenase (AMO) enzyme, both NIs almost exclusively inhibited Nitrosomonas genera among AMO holding nitrifiers. Thus, Nitrosomonas showed abundance reductions of up to 47% (DMPP) and 66% (DMPSA). Nonetheless, non-target bacterial abundances also shifted with NI application. Notably,DMPSA application partially alleviated the negative effect of fertilization on soil multifunctionality. A remarkable increase in populations related to system multifunctionality, such as Armatimonadetes (up to+21%), Cyanobacteria (up to +30%) and Fibrobacteres (up to+25%) was observed when DMPSA was applied. NI application substantially influenced microbial associations by decreasing the complexity of co-occurrence networks, decreasing the total edges and node connectivity, and increasing path distances.This project was funded by the Spanish Government (RTI2018- 094623-B-C21 MCIU/AEI/FEDER, UE), the Basque Government (EJ/GV, IT-932-16 and IT-1213-19) and by EuroChem Agro Iberia S.L.-UPV/ EHU 2018.0612. Mario Corrochano-Monsalve holds a grant from the Ministry of Science and Innovation of the Spanish Government (BES- 2016-076725)

Response of Wheat Storage Proteins and Breadmaking Quality to Dimethylpyrazole-Based Nitrification Inhibitors under Different Nitrogen Fertilization Splitting Strategies

Improving fertilizer nitrogen (N) use efficiency is essential to increase crop productivity and avoid environmental damage. This study was conducted during four crop cycles of winter wheat under humid Mediterranean conditions (Araba, northern Spain). The effects of N-fertilization splitting and the application of the nitrification inhibitors (NIs) 3,4-dimethylpyrazole phosphate (DMPP) and 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinic acid isomeric mixture (DMPSA) as strategies to improve grain quality were examined. The hypothesis of this study was to test if the partial ammonium nutrition and the reduction of fertilizer losses presumably induced by the application of NIs can modify the grain gliadin and glutenin protein contents and the breadmaking quality (dough rheological properties). Among both NIs assayed, only DMPP showed a slight effect of decreasing the omega gliadin fraction, following splitting either two or three times, although this effect was dependent on the year and was not reflected in terms of dough extensibility. The slight decreases observed in grain quality in terms of dough strength and glutenin content induced by DMPP suggest that DMPSA is more promising in terms of maintaining grain quality. Nonetheless, these poor effects exerted by NI application on grain quality parameters did not lead to changes in the quality parameters defining the flour aptitudes for breadmaking.This research was funded by the Basque Government (IT 932-16), by the Spanish Government (RTA2009 00028 C03 03, AGL2012 37815 C05 02 and AGL2015 64582 C3 2 R MINECO/FEDER) and by EuroChem Agro Iberia S.L.–UPV/EHU 2011.0051, 2012.0007, 2013.0001 and 2014.0002, Ximena Huérfano received a specialization fellowship for PhD researchers from the UPV/EHU

Dimethylpyrazole-based nitrification inhibitors have a dual role in N2O emissions mitigation in forage systems under Atlantic climate conditions

[EN]Nitrogen fertilization is the most important factor increasing nitrous oxide (N2O) emissions from agriculture, which is a powerful greenhouse gas. These emissions are mainly produced by the soil microbial processes of nitrification and denitrification, and the application of nitrification inhibitors (NIs) together with an ammonium-based fertilizer has been proved as an efficient way to decrease them. In this work the NIs dimethylpyrazole phosphate (DMPP) and dimethylpyrazole succinic acid (DMPSA) were evaluated in a temperate grassland under environmental changing field conditions in terms of their efficiency reducing N2O emissions and their effect on the amount of nitrifying and denitrifying bacterial populations responsible of these emissions. The stimulation of nitrifying bacteria induced by the application of ammonium sulphate as fertilizer was efficiently avoided by the application of both DMPP and DMPSA whatever the soil water content. The denitrifying bacteria population capable of reducing N2O up to N-2 was also enhanced by both NIs provided that sufficiently high soil water conditions and low nitrate content were occurring. Therefore, both NIs showed the capacity to promote the denitrification process up to N-2 as a mechanism to mitigate N2O emissions. DMPSA proved to be a promising NI, since it showed a more significant effect than DMPP in decreasing N2O emissions and increasing ryegrass yield.This work was funded by the Spanish Government (AGL2015-64582-C3-2-R MINECO/FEDER and RTI2018-094623-B-C21 MCIU/AEI/FEDER, UE) , by the Basque Government (IT-932-16) and by EuroChem Agro Iberia S.L.-UPV/EHU 2015.0248 and 2016.0339. Ximena Huerfano was recipient of a specialization fellowship from the UPV/EHU for Ph.D. researchers

Mealworm Frass as a Potential Organic Fertilizer in Synergy with PGP-Based Biostimulant for Lettuce Plants

This study explores the potential use of frass, the larval excrement residue obtained from mealworm rearing, as organic fertilizer for crops. Its high organic matter content means that its joint application with a biostimulant based on efficient microorganisms, favoring its mineralization, is of interest. An experiment with lettuce plants (Lactuca sativa L.) was conducted with two factors and six replicates under greenhouse conditions. The first factor was frass amendment at 0%, 1%, 2.5%, and 5% of the peat substrate, and the second factor was a Bacillus-based BS at two levels, with and without efficient microorganism application. The results reveal that frass shows great potential as an organic fertilizer, providing macronutrients and increasing lettuce aerial biomass, although its effect is mediated by the application rate. Rates of 2.5% or higher proved negative for lettuce plant growth, especially root development, probably due to an increased incidence of potentially pathogenic fungi. The negative effect of medium–high frass rates was counteracted by the addition of a PGP-based biostimulant, enhancing lettuce plant nutrient uptake, aerial biomass, and quality in terms of succulence, but also favoring microbial diversity in the rhizosphere, increasing the incidence of beneficial microorganisms, and decreasing potentially pathogenic fungi. This positive synergy observed between frass and the PGP-based biostimulant is of interest for the design of new organic fertilization strategies.This work was funded by Grant PID2021-128273OB-100 funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, and by the Basque Government (IT1560-22)

Compost and PGP-Based Biostimulant as Alternative to Peat and NPK Fertilization in Chestnut (Castanea Sativa Mill.) Nursery Production

In forest nurseries, intensive use of non-renewable substrates such as peat and high application rates of chemical synthesis fertilizers lead to environmental problems and high susceptibility to biotic and abiotic stresses. This work aims to seek more sustainable crop management to help mitigate these problems, combining the substitution of peat by compost and the use of growth-promoting microorganisms (PGPs) as a fertilization tool. For this purpose, a trial was carried out to test the effectiveness of an agricultural waste compost and a biostimulant based on PGP microorganisms in the production of Castanea sativa plants in a forest nursery. This trial assessed the growth of plants, with both inputs separately and combined, and then studied the tolerance of chestnut seedlings to water deficit. The results showed that partial substitution of peat by compost is possible, but not complete, as the high levels of conductivity and pH generated by a high proportion of compost negatively affected plant growth. It was also noted that the application of the biostimulant enables the complete substitution of mineral fertilization. Moreover, at the end of the nursery phase, chestnut seedlings treated with the biostimulant showed the same or even better quality than chestnut seedlings obtained with conventional fertilization, also resulting in greater resistance to water deficit, based on the increase in root volume and the improvement of the physiological status. Changes observed in both quantity and composition of microbiota associated with chestnut rhizosphere after inoculation with PGPs were related to the improvement observed. In relation to water deficit resistance, a positive synergy was also observed with the combination of both inputs, since plants with full substitution of peat by compost combined with PGP-based fertilization showed the greatest drought resistance.This work was funded by the Spanish Government (RTI2018-094623-B-C21 MCIU/AEI/FEDER, UE), and by the Basque Government (IT-932-16)

Relationship between tillage management and DMPSA nitrification inhibitor efficiency

Agricultural sustainability is compromised by nitrogen (N) losses caused by soil microbial activity. Nitrous oxide (N2O) is a potent greenhouse gas (GHG) produced as consequence of nitrification and denitrification processes in soils. Nitrification inhibitors (NI) as 3,4-dimethylpyrazole-succinic acid (DMPSA) are useful tools to reduce these N losses from fertilization. The objective of this work was to test the efficiency of DMPSA in two different tillage management systems, conventional tillage (CT) and no-tillage (NT), in a winter wheat crop under Humid Mediterranean conditions. N fertilizer was applied as ammonium sulphate (AS) with or without DMPSA in a single or split application, including an unfertilized treatment. GHG fluxes N2O, CO2 and CH4) were measured by the closed chamber method. amoA and nosZl genes were quantified by qPCR as indicators of nitrifying and denitrifying populations. Nitrification was inhibited by DMPSA in both CT and NT, while the higher water filled pore space (WFPS) in NT promoted a better efficiency of DMPSA in this system. This higher efficiency might be due to a greater N2O reduction to N-2 as result of the nosZl gene induction. Consequently, DMPSA was able to reduce N2O emissions down to the unfertilized levels in NT. Provided that NT reduced CO2 emissions and maintained crop yield compared to CT, the application DMPSA under NT management is a promising strategy to increase agro-systems sustainability under Humid Mediterranean conditions. (C) 2019 The Author(s). Published by Elsevier B.V.This project was funded by de Spanish Government (AGL2015-64582-C3-2-R MINECO/FEDER and RTI2018-094623-B-C21 MCIU/AEI/FEDER, UE), by the Basque Government (IT-932-16) and by EuroChem Agro Iberia S.L.-UPV/EHU 2017.0016. Mario Corrochano-Monsalve held a grant from the Ministry of Economy and Business of the Spanish Government and Ximena Huerfano received a specialization fellowship for PhD researches from the UPV/EHU

15N Natural Abundance Evidences a Better Use of N Sources by Late Nitrogen Application in Bread Wheat

This work explores whether the natural abundance of N isotopes technique could be used to understand the movement of N within the plant during vegetative and grain filling phases in wheat crop (Triticum aestivum L) under different fertilizer management strategies. We focus on the effect of splitting the same N dose through a third late amendment at flag leaf stage (GS37) under humid Mediterranean conditions, where high spring precipitations can guarantee the incorporation of the lately applied N to the soil-plant system in an efficient way. The results are discussed in the context of agronomic parameters as N content, grain yield and quality, and show that further splitting the same N dose improves the wheat quality and induces a better nitrogen use efficiency. The nitrogen isotopic natural abundance technique shows that N remobilization is a discriminating process that leads to an impoverishment in N-15 of senescent leaves and grain itself. This technique also reflects the more efficient use of N resources (fertilizer and native soil-N) when plants receive a late N amendment.This research was supported by IT-932-16, RTA2005-00219-CO3-02 and RTA2013-00057-CO5-02

A Multi-Species Analysis Defines Anaplerotic Enzymes and Amides as Metabolic Markers for Ammonium Nutrition

Nitrate and ammonium are the main nitrogen sources in agricultural soils. In the last decade, ammonium (NH4+), a double-sided metabolite, has attracted considerable attention by researchers. Its ubiquitous presence in plant metabolism and its metabolic energy economy for being assimilated contrast with its toxicity when present in high amounts in the external medium. Plant species can adopt different strategies to maintain NH4+ homeostasis, as the maximization of its compartmentalization and assimilation in organic compounds, primarily as amino acids and proteins. In the present study, we report an integrative metabolic response to ammonium nutrition of seven plant species, belonging to four different families: Gramineae (ryegrass, wheat, Brachypodium distachyon), Leguminosae (clover), Solanaceae (tomato), and Brassicaceae (oilseed rape, Arabidopsis thaliana). We use principal component analysis (PCA) and correlations among metabolic and biochemical data from 40 experimental conditions to understand the whole-plant response. The nature of main amino acids is analyzed among species, under the hypothesis that those Asn-accumulating species will show a better response to ammonium nutrition. Given the provision of carbon (C) skeletons is crucial for promotion of the nitrogen assimilation, the role of different anaplerotic enzymes is discussed in relation to ammonium nutrition at a whole-plant level. Among these enzymes, isocitrate dehydrogenase (ICDH) shows to be a good candidate to increase nitrogen assimilation in plants. Overall, metabolic adaptation of different carbon anaplerotic activities is linked with the preference to synthesize Asn or Gln in their organs. Lastly, glutamate dehydrogenase (GDH) reveals as an important enzyme to surpass C limitation during ammonium assimilation in roots, with a disparate collaboration of glutamine synthetase (GS).The design of the study, analysis, and interpretation of data and writing of the manuscript was supported by the Basque Government [IT932-16] or GIC15/179, the Spanish Ministry of Economy and Competitiveness [AGL2015-64582-C3-2-R] and [BIO2017-84035-R]. IVM held a postdoctoral grant from the Basque Government (conv. 2018) and MDLP held a PhD grant by COLCIENCIAS (conv. 672)

El nuevo seguro de ingresos de la patata: Una evaluación preliminar

[EN] In 2003 and 2004, an insurance product that protects against market risks of agricultural commodities was offered in Spain. It consists on a revenue insurance product which has been launched as a pilot program for mid-season and late potato in five Spanish provinces (Álava, Burgos, La Rioja, León and Valladolid). The objective of this article is to describe the characteristics of this insurance product and to perform a preliminary evaluation of the seasons it was marketed. We start from a conceptual approach to the market risk management instruments, that constitute the context for the current program. Later, we explain the price model used to define market reference prices and the premia, checking the quality of the statistical price model against the potato farm-gate prices. Finally, the article ends with a preliminary valuation/ assessment of this first pilot experience in Spain, stressing those aspects which are liable/prone to be improved and reckoning the possible extensions of this insurance line to other potato varieties, provinces and also to other agricultural commodities.[ES] En 2003 y 2004, se ofreció por primera vez en España un seguro que protege contra la caída de precios en origen de un producto agrícola. Se trata de un seguro de rentas lanzado con carácter piloto para las producciones de patata de media estación y patata tardía en cinco provincias españolas (Álava, Burgos, La Rioja, León y Valladolid). El objetivo de este trabajo es describir las características del seguro y realizar una evaluación preliminar de las campañas en que ha funcionado. Se parte de una aproximación conceptual a los instrumentos de gestión de riesgos de mercado, en cuyo contexto se enmarca el presente seguro. Posteriormente se explica el modelo de precios empleado para definir los precios de referencia del mercado y las primas, contrastando la calidad estadística del modelo con los precios en origen de la patata. Finalmente el trabajo concluye con una valoración preliminar de esta primera experiencia piloto en España, incidiendo en los aspectos que pueden ir mejorándose y reflexionando sobre posibles ampliaciones de esta línea de aseguramiento a otras variedades y provincias de patata y también a otras producciones.Estavillo Dorado, J.; Aguado Manzanares, S.; Bielza Díaz-Caneja, M.; Garrido Colmenero, A.; Sumpsi Viñas, JM. (2005). The new potato revenue insurance: A preliminary evaluation. Economía Agraria y Recursos Naturales - Agricultural and Resource Economics. 5(9):139-163. doi:10.7201/earn.2005.09.06SWORD1391635

Tutorías colaborativas: aprendizaje colaborativo y adquisición de competencias transversales

Memoria de Proyecto de Innova Docentia sobre una experiencia de implantación de tutorías colaborativas en tres facultades de la UCM (Comercio y Turismo, Ciencias Económicas y Empresariales y Ciencias de la Información), basadas en la mentorización por alumnos de cursos superiores en diferentes asignaturas de Análisis Económico, Estadística empresarial y Sociología, supervisada y dirigida por los profesores de la asignatura. Los objetivos del proyecto son la mejora de resultados académicos, el fomento del aprendizaje colaborativo entre pares y la adquisición de competencias transversales