Application of directly brewed compost extract improves yield and quality in baby leaf lettuce grown hydroponically

The aim of this work was to study whether the application of a directly brewed compost extract (added in the nutrient solution or by microsprinkler) could be used to improve the yield and quality of baby leaf red lettuce growing in a floating system, and to control the incidence of Pythium irregulare. Its e_ect on the quality of fresh-cut red lettuce was also studied. For this, two experiments were carried out over two growing cycles (winter–spring and autumn). The results showed that the use of compost extract added to the nutrient solution improved baby leaf lettuce growth and quality, reducing the nitrate content and enhancing the content of potentially health-promoting compounds such as phenols and flavonoids and the antioxidant capacity. Microbial quality was maintained during storage and the compost extract had no negative e_ect on the microbial load of the final product. In addition, application of the compost decreased the population of P. irregulare in the water. It is concluded that the application of directly brewed compost extract is of potential use in a sustainable soilless production system for baby leaf red lettuce, since it improves the yield and quality of the product and is able to control the incidence of P. irregulare.This work was supported by projects AGL2017-84085-C3-3-R and AGL2017-84085-C3-1-R from the Ministerio de Economía y Competitividad of Spain

Estudio de lixiviación de nitratos en suelos de invernaderos de pimiento biosolarizados

La biosolarización del suelo en invernaderos de pimiento (Capsicum annuum L.) supone una estrategia de control de enfermedades telúricas (Phytophthora capsici y/o parasítica y Meloidogyne incognita), de vegetación adventicia y de fenómenos de fatiga muy adecuada para mantener buenos niveles productivos en sistemas de monocultivo prolongado. Este trabajo pretende evaluar las repercusiones de la aplicación de cantidades importantes de materia orgánica, hasta 100 t/ha, en estos agrosistemas sobre la calidad del suelo y en el medio ambiente. El ensayo de lixiviación de nitratos en condiciones controladas se realizó sobre columnas de suelo inalterado los cuales habían sido sometidos a biosolarización de primer año (100 t/ha de enmiendas) comparándose con el efecto sobre un suelo de referencia tratado con bromuro de metilo (BM) en la dosis de 30 g/m2 + plástico VIF, sin la aplicación de enmiendas orgánicas. El contenido en agua lixiviada en las muestras biosolarizadas fue de 5,3 L/columna, mientras que la columna desinfectada con bromuro de metilo lixivió 9,9 litros, de un total de 29,7 litros aplicados en ambos casos. El total de nitrato lixiviado para cada uno de los tratamiento fue de 10,0 g NO3 ‐/columna para el tratamiento con la enmienda y 25,7 g NO3 ‐/columna para el tratamiento con ausencia de enmendantes orgánicos. La actividad biológica medida en el suelo biosolarizado fue superior a la del suelo tratado con BM, sobre todo en los dos primeros perfiles de la columna (hasta 20 cm de profundidad)

Promising composts as growing media for the production of baby leaf lettuce in a floating system

The floating system is a successful strategy for producing baby leaf vegetables. Moreover, compost from agricultural and agri-food industry wastes is an alternative to peat that can be used as a component of growing media in this cultivation system. In this study, we experimented with three composts containing tomato (Solanum lycopersicum L.), leek (Allium porrum L.), grape (Vitis vinifera L.), and/or olive (Olea europaea L.) mill cake residues, which were used as the main component (75/25 volume/volume) of three growing media (GM1, GM2 and GM3) to evaluate their e_ect on the growth and quality of red baby leaf lettuce (Lactuca sativa L.). We used a commercial peat substrate as a control treatment (100% volume) and in mixtures (25% volume) with the composts. The plants were cultivated over two growing cycles, in spring and summer, and harvested twice in each cycle when the plants had four to five leaves. We found that the percentage of seed germination was significantly higher in plants grown in peat than in those grown in compost growing media. The yield was a_ected by the growing media in the summer cycle, and we obtained the highest value with GM1. Furthermore, the second cut was more productive than the first one for all the growing media in both cycles. The lettuce quality was also a_ected by the growing media. In general, the total phenolic content and antioxidant capacity in the leaves was higher in plants grown in the compost growing media, particularly in the second cut, but the nitrate content in the leaves was greater in some of the compost treatments compared with the peat treatment. In addition, an in vitro suppressive activity study demonstrated that the interaction between di_erent fungi and bacteria observed through metagenomics analysis could contribute to the e_ectiveness of the compost in controlling Pythium irregulare. The use of compost as a component of the growing media in the production of baby leaf vegetables in a floating system does not only favor the crop yield and producto quality, but also shows suppressive e_ects against P. irregulare.This research was funded by the Spanish Ministry of Economy and Competitiveness: Reference project: AGL2017-84085-C3-1-R, AGL2017-84085-C3-2-R, AGL2017-84085-C3-3-R

Spraying agro-industrial compost tea on baby spinach crops: Evaluation of yield, plant quality and soil health in field experiments

Compost tea is a liquid fraction extracted from composts, and it is of great interest in sustainable agriculture because it reduces the unsustainable use of chemical-based pesticides and fertilizers. In this study, during two spinach field cycles, we evaluated the potential beneficial e_ect of the foliar application of a compost tea made from onion and vineyard composts either by itself (CT) or implemented with the beneficial microorganism Trichoderma harzianum T78 (CT + Th) on the “healthy quality” and yield of baby spinach. Results showed that both the CT and CT + Th treatments produced a higher spinach yield than the control, but these treatments did not result in an increase in soil dehydrogenase activity (DHA) or soil nutrient content. Furthermore, CT + Th treatment showed the highest yield, phenolic content, antioxidant capacity and flavonoid levels. Nitrate levels were below legal amounts, and they were significantly (p _ 0.05) lower in the CT and CT + Th treatments than in the control. Data suggest that compost tea extracts from onion waste and vineyard compost and/or enriched with T. harzianum can be used in a sustainable agriculture to increase yield and quality of baby spinach.This work was supported by projects AGL-2014-52732-C2–1-R and AGL-2014-52732-C2-2-R from the Ministry of Economy and Competitiveness of Spain

Effects of solarisation combined with compost on soil pathogens and the microbial community in a spinach cropping system

This study compares the effects of solarization combined with compost (72% vineyard prunings and 28% leek residues) (CAS) versus solarization (NAS) in soils used for intensive spinach cultivation in the Mediterranean area. The objective was to study the beneficial effects of the compost on the soil microbial community, soil fertility and soil functionality related to C and N cycling during solarization, during the spinach crop growth period and after harvesting. CAS did increase soil fertility and microbial activity, in addition, CAS increased the microbial alpha diversity in the soil to a greater extent than NAS, and the Principal Coordinate Analysis (PCoA) of the beta diversity in the soil revealed changes in the bacterial and fungal community at the different sampling times, except after the plastic was lifted. During solarization and after harvesting, different beneficial bacteria and fungi related to C and N cycling were more abundant in CAS than in NAS, in the same way as the genera involved in plant defense and plant growth (Pseudomonas, Sphingomonas, Bacillus, Thermomyces, Streptomyces, NMD1 or Nitrospira). CAS also had a notable effect on the abundance of predictive genes involved in the C and N cycles. The functional genes showed their lowest activity level a week after covering the soil with plastic, but they increased after lifting the plastic and after harvesting. Compared to NAS, CAS also showed higher N2-fixation and greater conversion of N2O to N2. Moreover, the abundance of several predictive genes involved in hemicellulose, lignin and cellulose degradation suggested that CAS produced an increase in nutritional availability. From this study, it can be concluded that the combination of solarization and compost increased soil fertility, microbial activity, microbial diversity and functionality. Compost could provide added value by stimulating the microbiological community in the soil until harvest.This work was supported by the Spanish Ministry of Economy and Competitiveness and with European Regional Development Funds (ERDF, “Una manera de hacer Europa”) in the framework of the project “Compoleaf” (Compost as biofertilizer, resistance inductor against plant pathogens and healthy property promoter under a crop intensive sustainable production). Project (AGL2017–84085-C3–1-R, C3–2-R and C3–3-R) and grant (PRE2018–085802). Thanks to Ansley Evans for having made the corrections of this work in English

Response of microbial community to soil disinfection with compost

[SPA] Evaluamos una enmienda de compost incorporada a un proceso de solarización en comparación con la solarización de suelos agrícolas para determinar si produce algún efecto beneficioso sobre la comunidad microbiana, la fertilidad y la funcionalidad del suelo relacionado con el ciclo del N y C. Se tomaron muestras al inicio (T1), una semana después de añadir los tratamientos (T2) y justo al terminar los tratamientos (T3). La solarización del suelo con enmienda de compost (SEC) enriqueció el suelo con diferentes bacterias y hongos, que se caracterizaron por estar involucradas en diferentes funciones relacionadas con el ciclo del N y C; promotores del crecimiento de las plantas o defensa contra patógenos en comparación con el suelo no modificado (SNM). El compost dio un valor agregado al suelo al aumentar la actividad microbiana, la diversidad microbiana y la composición de la comunidad, aumentando la fertilidad funcional del suelo manteniendo el ciclo del C y N del suelo. [ENG] We evaluated a compost amendment incorporated into a solarization process compared to solarization of agricultural soils to determine if it produced any enhanced effects on the microbial community, fertility, and soil functionality related to N and C cycling. at the beginning (T1), one week after adding the treatments (T2) and just after finishing the treatments (T3). Soil solarization with compost amendment (CAS) enriched the soil with different bacteria and fungi, which were characterized by being involved in different functions related to the N and C cycle; plant growth promoters or defense against pathogens compared to unmodified soil (NAS). CAS brought added value to the soil by increasing microbial activity, microbial diversity, and community composition, increasing functional soil fertility maintaining the soil C and N cycle.Al Ministerio de Economía, Industria y Competitividad por la financiación recibida para llevar a cabo el proyecto AGL 2017-84085-C3-1-R

Bacterial and fungal community dynamics during different stages of agro-industrial waste composting and its relationship with compost suppressiveness

Composting is an advantageous and efficient process for recycling organic waste and producing organic fertilizers, and many kinds of microorganisms are involved in obtaining quality compost with suppressive activity against soil-borne pathogens. The aim of this work was to evaluate the main differences in the effects of three composting piles on the whole bacterial and fungal communities of baby-leaf lettuce crops and to determine the specific communities by high-throughput sequencing related to suppressiveness against the soil-borne plant pathogen Pythium irregulare- (P. irregulare). Compost pile A was composed of 47% vineyard pruning waste, 34% tomato waste and 19% leek waste; pile B was composed of 54% vineyard pruning waste and 46% tomato waste; and pile C was composed of 42% vineyard pruning waste, 25% tomato waste and 33% olive mill cake. The temperature and the chemical properties of the piles were monitored throughout the composting process. In addition, the potential suppressive capacity of the three composts (C_A, C_B and C_C) against P. irregulare in baby-leaf lettuce was assessed. We found that the bacterial community changed according to the composting phases and composting pile and was sensitive to chemical changes throughout the composting process. The fungal community, on the other hand, did not change between the composting piles and proved to be less influenced by chemical properties, but it did change, principally, according to the composting phases. All composts obtained were considered stable and mature, while compost C_C showed higher maturity than composts C_A and C_B. During composting, the three piles contained a greater relative abundance of Bacterioidetes, Proteobacterias and Actinobacterias related to the suppression of soil-borne pathogens such as Pythium irregulare. Composts C_A and C_B, however, showed higher suppressiveness against P. irregulare than compost C_C. Deeper study showed that this observed suppressiveness was favored by a higher abundance of genera that have been described as potential suppressive against P. irregulare, such as Aspergillus, Penicillium, Truepera and Luteimonas.This study was supported by the Spanish Ministry of Economy and Competitiveness and by European Regional Development Funds (ERDF, “Una manera de hacer Europa”) in the framework of the project “Compoleaf” (Compost as biofertilizer, resistance inductor against plant pathogens and healthy property promoter under a crop intensive sustainable production) (Project AGL2017-84085-C3-1-R, C3-2-R and C3- 3-R). Alicia Hernández-Lara acknowledges the financial support she has received from the Spanish Ministry of Science, Innovation and Universities through the "FPI" Program [PRE2018-085802] for the training of research personne

Changes in bacterial and fungal soil communities in long-term organic cropping systems

Long-term organic farming aims to reduce synthetic fertilizer and pesticide use in order to sustainably produce and improve soil quality. To do this, there is a need for more information about the soil microbial community, which plays a key role in a sustainable agriculture. In this paper, we assessed the long-term effects of two organic and one conventional cropping systems on the soil microbial community structure using high-throughput sequencing analysis, as well as the link between these communities and the changes in the soil properties and crop yield. The results showed that the crop yield was similar among the three cropping systems. The microbial community changed according to cropping system. Organic cultivation with manure compost and compost tea (Org_C) showed a change in the bacterial community associated with an improved soil carbon and nutrient content. A linear discriminant analysis effect size showed different bacteria and fungi as key microorganisms for each of the three different cropping systems, for conventional systems (Conv), different microorganisms such as Nesterenkonia, Galbibacter, Gramella, Limnobacter, Pseudoalteromonas, Pantoe, and Sporobolomyces were associated with pesticides, while for Org_C and organic cultivation with manure (Org_M), other types of microorganisms were associated with organic amendments with different functions, which, in some cases, reduce soil borne pathogens. However, further investigations such as functional approaches or network analyses are need to better understand the mechanisms behind this behavior.Raúl Zornoza acknowledges the financial support received from the Spanish Ministry of Science, Innovation and Universities through the “Ramón y Cajal” Program (RYC-2015-18758). We would like to thank Ansley Evans for providing English corrections

Osterix and RUNX2 are Transcriptional Regulators of Sclerostin in Human Bone

Sclerostin, encoded by the SOST gene, works as an inhibitor of the Wnt pathway and therefore is an important regulator of bone homeostasis. Due to its potent action as an inhibitor of bone formation, blocking sclerostin activity is the purpose of recently developed antiosteoporotic treatments. Two bone-specific transcription factors, RUNX2 and OSX, have been shown to interact and co-ordinately regulate the expression of bone-specific genes. Although it has been recently shown that sclerostin is targeted by OSX in mice, there is currently no information of whether this is also the case in human cells. We have identified SP-protein family and AML1 consensus binding sequences at the human SOST promoter and have shown that OSX, together with RUNX2, binds to a specific region close to the transcription start site. Furthermore, we show that OSX and RUNX2 activate SOST expression in a co-ordinated manner in vitro and that SOST expression levels show a significant positive correlation with OSX/ RUNX2 expression levels in human bone. We also confirmed previous results showing an association of several SOST/RUNX2 polymorphisms with bone mineral density

A first-year melon/cowpea intercropping system improves soil nutrients and changes the soil microbial community

[SPA] La asociación de cultivos podría ser una alternativa al monocultivo tradicional capaz de optimizar la producción reduciendo a su vez la aplicación de fertilizantes, pesticidas y herbicidas, promoviendo cambios en la comunidad bacteriana del suelo que podrían contribuir a la salud del suelo. Para estudiar estos cambios, se realizó un estudio de las propiedades del suelo, así como de las comunidades bacterianas a través de la secuenciación del gen 16S. Los resultados mostraron como se produjo un cambio tanto en las propiedades del suelo como en las comunidades bacterianas mostrando un aumento de TOC, TN y P en los cultivos asociados, además algunos géneros como Pseudomonas y Bacillus estuvieron significativamente aumentados en los cultivos asociados, por lo que podrían haber contribuido a aumentar la cantidad de P en los suelos. Por otro lado, LEfSe reveló algunos biomarcadores resistentes a las sequías en M lo que podría deberse a las peores condiciones de agua cuando se realiza el monocultivo. En este sentido, una aplicación a largo plazo de estos cultivos asociados podría favorecer a la calidad del suelo.[ENG] Intercropping could be an alternative to traditional monocropping, capable of optimizing yield reducing the fertilizers, pesticides, and herbicides application promoting changes on soil bacterial community which could contribute to soil health. To study these changes, a soil properties and bacterial community through 16S gene amplification was performed. The results showed how soil properties and bacterial community changed under the different cropping systems showing and increase of TOC, TN, and P in the intercropping system, in addition, some genus like Pseudomonas or Bacillus, were significantly increased in intercropping system as well, so they could have contributed to this higher availability of P on soils. On the other hand, LEfSe revealed some biomarkers drought-resistant in M which could be due to worse conditions of water where monocrop was made. In this sense, long-term intercropping system could favor to soils quality.Este estudio se ha apoyado por el proyecto AsociaHortus [AGL2017-83975-R] del Ministerio de Ciencia e Innovación, también ha sido apoyado por el proyecto Diverfarming [grant agreement 728003] de la Comisión Europea Horizon 2020 y por último ha recibido financiación del Ministerio de Ciencia e Innovación a través del programa Ramón y Cajal [RYC-2015-18758]