Biodiversity of Soil Microorganisms

In organic farming, homemade organic fertilizer such as compost or enriched organic material had become one of crucial factors for nutrient management. Other than the limited source of N for organic fertilizer as the key factor for growthlimiting nutrients in organic farming, the cost of fertilization is also affected by different organic fertilizer application rates. Therefore, the objectives of this study were (i) to determine the effect of these organic fertilizers on the soil properties (chemical and biological properties) and (ii) to evaluate the efficiency and growth performance of Kailan (Brassica alboglabra) as influence by the application of different organic fertilizer in the field. A study was conducted at an integrated organic farming research area in the Malaysian Agricultural Research and Development Institute (MARDI) at Serdang, Selangor for two consecutive cycles. The experimental treatments were focused on the different rates of organic fertilizer inputs (3-33 t/ha from organic sources) with soil alone as a control. The treatments were applied 14 days after transplanting using Brassica alboglabgra as a test crop. The study result found that a BIOC at 2 tonne kg/ha give significant different in nutrient use efficiency (NUE), however NC at 33 tonne kg/ha rate of organic input had improved most of soil properties NF showed a great yield as well as their growth performances. Study findings have shown that the range of application rate of organic input depends on applicability of the organic fertilizer whether it can promotes nutrient uptake in plants and or can be scaled up to farm level to sustain organic system productivity.

Impact of anthropisation and revegetation on soil microbial diversity was studied by characterizing bacterial community structure in a sandpit located in Terga (Algeria). Soil samples were collected from several sites: an undisturbed forest area with pristine vegetation, a site revegetated by the National Forest Services in 1998, a newly revegetated site by the introduction of two tree species (Tetraclinis articulata and Schinus terebinthifolius) associated, or not, with two legume species (Retama monosperma and Lotus creticus). Samples were collected from bulk and rhizospheric soil compartments during an18 month-period. Soil bacterial community structure was characterized by rRNA Intergenic Spacer Analysis (RISA) and statistical analysis. Concerning revegetated sites, soil physicochemical analysis was performed just after plantation and after 18 months. The plant effects on bacterial community structure differed among sites and plant species. In pristine forest, bacterial community...

Agricultural extension is an essential strength in agricultural development and social innovation factor. It is a key that can capacitate sugarcane farmers to accelerate the adoption of technology in farm production. Furthermore, agricultural extension services are instrumental in bridging the gap between agricultural research and practical farming. This study aims to determine the influence of extension services on the production of sugarcane in the Philippines. Descriptive method of research was employed in the study. The respondents were 320 sugarcane farmers that were randomly identified from seven locations in the Visayas. The instrument used was the validated survey questionnaire used by Oñal, et al (2021). Results show that there is a significant difference in the production of sugarcane among location with a mean of 2.28 or an average of 50-64 TC/ha (ɑ=0.05). The advocacy on planting of high yielding varieties (HYVs) that are adaptable to sugarcane farms (m=3.87, ɑ=0.05) and the dissemination of different projects to the farmers (m=3.98, ɑ=0.05) had a significant impact on sugarcane production at >65 Tons/ha. Furthermore, the two agricultural extension services mentioned are moderately correlated with the production. The study recommends that the advocacy for planting of HYVs suitable to farms should be further prioritize including the strong dissemination of various agricultural development to bolster the sugarcane production in the area.

Se evaluó la efectividad de la coinoculación micorrizarizobacterias en el crecimiento, rendimiento y colonización del chile jalapeño Capsicum annuum L. El presente estudio se realizó de septiembre de 2013 a mayo de 2014. Se utilizó suelo Andosolmólico al cual se agregó arena de rio lavada y tamizada, en proporción 1:1 (V/V) y al mismo se le adicionó 30% de gallinaza (v/v). Los tratamientos consistieron en la inoculación y la coinoculación de micorriza y rizobacterias y el testigo. En total, ocho tratamientos con cinco repeticiones distribuidas en un diseño completamente al azar. Se consideró una planta como repetición. Se realizaron tres muestreos destructivos cada 28 días. Los resultados mostraron un efecto positivo de la coinoculación en el crecimiento de las plántas, con variaciones iniciales y finales contrastantes en interacción con los diversos microorganismos. La inoculación individual de los microorganismos Pseudomonas fluorescens, Azospirillum brasilense y la coinoculación ...

EnglishMicrobial parameters are considered to be potential indicators of soil quality since soil microorganisms can respond rapidly to agricultural management systems. The effect of long-term fertilizer applications on soil, especially nitrogen (N), phosphorus (P), sulphur (S), and micronutrients (m) can alter soil chemistry, microbial community structure and function. The purposes of this study were to analyse the long-term effect of chemical fertilizers on soil properties, microbiological communities and function in relation to grain yields in two growing seasons (2012-2013 and 2013-2014). All fertilization treatments were applied to a maize-wheat/soybean rotation under no-till farming system. Six fertilization treatments were evaluated: PS, NS, NP, NPS, NPSm, and CK (unfertilized control). Application of N, P, and S, with several exceptions, tended to increase both total and available nutrient in comparison with nutrient-deficient treatments. In both growing seasons, CK treatment...

En vista de la escasez creciente de tierras, se vuelve impostergable la necesidad de conocer mejor los procesos de degradación y mejoramiento de suelos. Pese a que en el ámbito científico -técnico, se cuenta con parámetros para evaluar la condición física, química y biológica de los suelos, es necesario contar con indicadores locales para que sean los mismos agricultores quienes evalúen la calidad de los mismos. El objetivo de estudio fue evaluar el estado de los suelos de la planicie y laderas de Nandaime, mediante el uso de indicadores técnicos y locales de calidad de suelos. La metodología incluyó la selección de 17 fincas, en cada una las cuales se seleccionaron parcelas con cultivo, pasto y bosque. Se definieron los indicadores infiltración, estabilidad estructural, compactabilidad, organismos, profundidad, mediante métodos sencillos; además, se tomaron muestras de suelos para determinar en laboratorio densidad aparente, porosidad, pH, CIC, N, K, P. Se hicieron entrevistas y un taller con los propietarios, para identificar los indicadores utilizados para designar la calidad de los suelos. Los resultados indican que los suelos bajo agricultura han perdido el horizonte superficial, están compactados, tienen baja infiltración, CIC baja y niveles bajos de P y K. Se ha reducido la fertilidad natural y capacidad productiva de los suelos producto de prácticas inadecuadas tales como la deforestación, quemas, agricultura migratoria, sobrepastoreo, labranza inadecuada. Entre los indicadores usados por los agricultores se encuentran el color, profundidad, rendimiento, soltura, así como la presencia y abundancia de ciertas plantas.

Earthworms transform organo-mineral associations in soil, especially by incorporating fresh residues inside casts where the microbial abundance and activity are enhanced. The heterogeneous distribution of organic carbon in these structures influences decomposition levels at the microscale. The incorporation of 13 C labelled plant residues by Lumbricus terrestris inside cast was investigated, through the innovative combination of two fine scale imaging techniques: transmission electron microscopy and nanoscale secondary ion mass spectrometry (NanoSIMS). The association of these methods sheds new lights on organo-mineral structures. Different types of organic matter (plant residues, microbial remains) were identified in the casts and the freshly incorporated residues could be differentiated from the indigenous organic matter thanks to d 13 C NanoSIMS mapping. 13 C labelled bacteria and fungi abundance and diversity highlight their preeminent role in litter decomposition within casts. Labelled plant residues observed at various stages of decomposition and microorganisms presented highly variable d 13 C values, emphasizing the complexity of organic matter dynamics and the importance of microscale analyses to describe this variability. Thus, the combination of NanoSIMS and TEM shows great potential to relate organic matter stages of decomposition with their 13 C signature.

The plastic film mulching system has a significant role in increasing crop grain yields by changing the microenvironment of the plant. On the other hand, plastic mulching materials pollute the land and water because they are not degraded or disposed of properly. Biodegradable plastic mulches (BPM) may be used as a substitute for conventional low-density polyethylene (LDPE) to protect soil health. In this review, the effect of micro(nano)plastics on soil health and function has been discussed in light of their distribution in soil, changes in soil biochemistry, interactions between microplastics with soil microbes and plants, and their growth patterns. The nano-plastics are now incorporated into the food chain from the soil through plants and finally harm the whole ecosystem, including humans. The use of BPM has been practiced recently, but only 1% of the world’s total plastic production is from biodegradable materials. In the second part of the review, the confusing terms "bio-...

In the last years, different biotechnological approaches were developed to
reduce the indiscriminate use of chemical fertilizers and pesticides and enhance plant growth and health. The most attractive, safe, and environmentally friendly alternatives include those based on plant beneficial microorganisms. After a long period of studies on isolation, selection, and characterisation of plant-beneficial microorganisms, the main lines of research have been oriented to optimising the fermentation processes to produce high-quality and large volumes of biomass/spores and their further formulation. However, further well-structured schemes for improvement of all main steps of the production of formulations should be developed following the ideas based on “healthy soil-healthy plantshealthy humans”. This brief review highlights the strengths and weaknesses of the techniques applied in the biotechnological production of plant beneficial microorganisms.

La región pampeana argentina padece acidificación acelerada de sus suelos por su historia productiva y tecnología aplicada en las últimas décadas, derivando en consecuencias sobre los cultivos de cosecha. Experiencias de encalado en Buenos Aires y Santa Fe mostraron efectos variados sobre el aumento de pH y saturación de bases, mejorando propiedades físicas y rendimiento. El objetivo del presente trabajo fue evaluar la incidencia de diferentes dosis de enmiendas básicas sobre el pH, carbono orgánico, dinámica del agua, densidad aparente, resistencia a la penetración, rendimiento de soja y sus componentes. Los ensayos se realizaron en dos suelos de la Pampa Ondulada, un Argiudol con pH 5,66 y un Paleudol con pH 5,44, en bloques completamente al azar con 3 repeticiones. Los tratamientos fueron 0 (TCY), 1000(D1CY) y 4000(D4CY) kg ha-1 de dolomita todos con 200 kg ha-1 de yeso. Se sembró soja 3 meses y 1 mes posteriores al encalado en el Argiudol y Paleudol respectivamente. Las variables evaluadas fueron pH, carbono orgánico (COT), infiltración básica (Ib), densidad aparente (Dap), resistencia a la penetración (RP), rendimiento (R) y sus componentes: plantas/ hectárea (PL ha-1), vainas/planta (V PL-1), granos/vaina (G V-1), granos/planta (G PL-1) y peso de 1000 granos (P 1000G). En el Argiudol y Paleudol, el tratamiento D4CY produjo aumento del pH respecto a TCY. El COT no presentó diferencias entre los tratamientos. La Ib aumentó para los dos suelos con D4Y respecto a TCY. La Dap disminuyó con D4CY en el Argiudol. La adición de dolomita produjo disminución de PL ha-1 e incremento del resto de los componentes, lo que produjo incremento del rendimiento del 45% con D4CY en el Paleudol.

La región pampeana argentina padece acidificación acelerada de sus suelos por su historia productiva y tecnología aplicada en las últimas décadas, derivando en consecuencias sobre los cultivos de cosecha. Experiencias de encalado en Buenos Aires y Santa Fe mostraron efectos variados sobre el aumento de pH y saturación de bases, mejorando propiedades físicas y rendimiento. El objetivo del presente trabajo fue evaluar la incidencia de diferentes dosis de enmiendas básicas sobre el pH, carbono orgánico, dinámica del agua, densidad aparente, resistencia a la penetración, rendimiento de soja y sus componentes. Los ensayos se realizaron en dos suelos de la Pampa Ondulada, un Argiudol con pH 5,66 y un Paleudol con pH 5,44, en bloques completamente al azar con 3 repeticiones. Los tratamientos fueron 0 (TCY), 1000(D1CY) y 4000(D4CY) kg ha-1 de dolomita todos con 200 kg ha-1 de yeso. Se sembró soja 3 meses y 1 mes posteriores al encalado en el Argiudol y Paleudol respectivamente. Las variables evaluadas fueron pH, carbono orgánico (COT), infiltración básica (Ib), densidad aparente (Dap), resistencia a la penetración (RP), rendimiento (R) y sus componentes: plantas/ hectárea (PL ha-1), vainas/planta (V PL-1), granos/vaina (G V-1), granos/planta (G PL-1) y peso de 1000 granos (P 1000G). En el Argiudol y Paleudol, el tratamiento D4CY produjo aumento del pH respecto a TCY. El COT no presentó diferencias entre los tratamientos. La Ib aumentó para los dos suelos con D4Y respecto a TCY. La Dap disminuyó con D4CY en el Argiudol. La adición de dolomita produjo disminución de PL ha-1 e incremento del resto de los componentes, lo que produjo incremento del rendimiento del 45% con D4CY en el Paleudol.

After the accident of Fukushima Daiichi Nuclear Power Plant (FDNPP), we screened Japanese soybean mini-core collections to select cultivars with low 137Cs accumulation in seeds. Field tests at Fukushima Prefecture resulted in two groups of soybeans: one with low and the other with high Cs accumulation in seeds. We continued investigations to find the reasons. A reconfirmation field test and two pot experiments were conducted to evaluate the 137Cs activity concentrations in various organs of soybean cultivars, focusing on the root nodules affected by single/co-inoculation with Bradyrhizobium and arbuscular mycorrhizal (AM) fungi in two types of soils. Oni hadaka with low, and Kuromame and Kurakake with high 137Cs accumulation properties in seeds were the test cultivars. These cultivars had similar biomass and root surface area. Total 137Cs inventory was greater in cultivars Kuromame and Kurakake. Average 137Cs concentrations were in the order: root nodules > plant root > leaf &...

Organic fertilizers are naturally available mineral sources that contain moderate amount of plant essential nutrients. They are capable of mitigating problems associated with synthetic fertilizers. They reduce the necessity of repeated application of synthetic fertilizers to maintain soil fertility. They gradually release nutrients into the soil solution and maintain nutrient balance for healthy growth of crop plants. They also act as an effective energy source of soil microbes which in turn improve soil structure and crop growth. Organic fertilizers are generally thought to be slow releasing fertilizers and they contain many trace elements. They are safer alternatives to chemical fertilizers. However, the improper use of organic fertilizers leads to overfertilization or nutrient deficiency in the soil. Hence, controlled release of organic fertilizers is an effective and advanced way to overcome these impacts and maintain sustainable agriculture yield.[a]

There is considerable uncertainty about how rates of soil carbon (C) and nitrogen (N) cycling will change as CO2 accumulates in the Earth's atmosphere. We summarized data from 47 published reports on soil C and N cycling under elevated CO2 in an attempt to generalize whether rates will increase, decrease, or not change. Our synthesis centres on changes in soil respiration, microbial respiration, microbial biomass, gross N mineralization, microbial immobilization and net N mineralization, because these pools and processes represent important control points for the below‐ground flow of C and N. To determine whether differences in C allocation between plant life forms influence soil C and N cycling in a predictable manner, we summarized responses beneath graminoid, herbaceous and woody plants grown under ambient and elevated atmospheric CO2. The below‐ground pools and processes that we summarized are characterized by a high degree of variability (coefficient of variation 80–800%), ...

EnglishMicrobial parameters are considered to be potential indicators of soil quality since soil microorganisms can respond rapidly to agricultural management systems. The effect of long-term fertilizer applications on soil, especially nitrogen (N), phosphorus (P), sulphur (S), and micronutrients (m) can alter soil chemistry, microbial community structure and function. The purposes of this study were to analyse the long-term effect of chemical fertilizers on soil properties, microbiological communities and function in relation to grain yields in two growing seasons (2012-2013 and 2013-2014). All fertilization treatments were applied to a maize-wheat/soybean rotation under no-till farming system. Six fertilization treatments were evaluated: PS, NS, NP, NPS, NPSm, and CK (unfertilized control). Application of N, P, and S, with several exceptions, tended to increase both total and available nutrient in comparison with nutrient-deficient treatments. In both growing seasons, CK treatment...

Tomato (Lycopersicon esculentum) is a worldwide edible vegetable whose cultivation demands agricultural inputs such as fertilization, resulting in high economic and ecological costs. Alternate agricultural practices like biofertilization, are proposed for diminishing production costs in accordance to sustainable agriculture. This research evaluated the effects of Azospirillum strains (Cd, C4, VS1, VS7, or VS9) as biofertilizers on growth and production of tomato plants, by setting three experimental stages. First experiment was conducted under hydroponic conditions in which plants were inoculated with the Azospirillum strains (Cd, C4, VS1, VS7, and VS9) in a randomly experimental design, during 190 days. The five strains significantly increased root length and stem diameter. Experiment 2 considered treatments, parameters and duration as described for experiment 1, but established at greenhouse conditions using pots with soil. Strain VS9 significantly promoted plant growth in compari...

Tropical sandy soils (or upper sandy horizons of tropical soils) have diverse physical and chemical constraints: poor structural stability (making soils sensitive to crusting, and compaction), poor nutrient holding capacity and low cation exchange capacity. In these soils, in which the clay content is low (3 to 15% by mass), organic matter is the main determinant of fertility, nutrient storage, aggregate stability, microbial and enzymatic activities. However, cultural practices or land uses aimed at increasing organic matter stocks have a minor impact if compared with the potential storage of organic matter in clayey soils. Nevertheless, this stock increase is possible in sandy soils and is mainly linked with the increase of the "vegetal debris" functional pool. Like organic matter, the abundance, activity, and diversity of soil biota are largely dependent upon land management. In these soils, biotic interactions such as termites-microorganisms or nematodesmicroorganisms modify nutrient fluxes, N mineralization being higher in soil-feeding termite mounds or in the presence of bacterial feeding nematodes. Moreover, the management of organic residues represents a means to control the activity of soil microorganisms and the structure of nematode and other fauna populations. An adequate management of organic matter (through fallows, improved fallows, pastures, external organic inputs) through its consequences on soil biofunctioning, largely determines the agronomic (plant production) and environmental (carbon sequestration) potentials of sandy soils. In the present paper, we provide information on the biofunctioning in sandy soils, i.e., interactions existing between organic matter, biological activities (termites, earthworms, nematodes, microorganisms) and physical soil properties, in natural and cropped ecosystems. Data mainly originate from experiments and measurements from West (Senegal, Burkina Faso, Ivory Coast) and East (Kenya) Africa.

For more than twenty years, nanotechnologies have arisen a huge interest and are used in numerous fields. Carbon nanotubes (CNTs) are one of the most used nanomaterials thanks to their excellent optical, mechanical, electrical and thermal properties. All along their lifecycle, CNTs may be spread in the environment during production, use, destruction, reuse or potential accidents in production units or during transportation. For this reason, it is essential to evaluate their behaviour and potential impacts on ecosystems and particularly on the terrestrial ecosystem. After a brief summary of CNT properties, synthesis methods, and applications as well as detection and characterisation techniques, this review will focus on impacts of CNTs on the terrestrial ecosystem, discussing their behaviour in soil, plants and interactions with other pollutants as well as their impacts on soil microbiota, macrobiota and plants.

After the accident of Fukushima Daiichi Nuclear Power Plant (FDNPP), we screened Japanese soybean mini-core collections to select cultivars with low 137Cs accumulation in seeds. Field tests at Fukushima Prefecture resulted in two groups of soybeans: one with low and the other with high Cs accumulation in seeds. We continued investigations to find the reasons. A reconfirmation field test and two pot experiments were conducted to evaluate the 137Cs activity concentrations in various organs of soybean cultivars, focusing on the root nodules affected by single/co-inoculation with Bradyrhizobium and arbuscular mycorrhizal (AM) fungi in two types of soils. Oni hadaka with low, and Kuromame and Kurakake with high 137Cs accumulation properties in seeds were the test cultivars. These cultivars had similar biomass and root surface area. Total 137Cs inventory was greater in cultivars Kuromame and Kurakake. Average 137Cs concentrations were in the order: root nodules > plant root > leaf &...

The plastic film mulching system has a significant role in increasing crop grain yields by changing the microenvironment of the plant. On the other hand, plastic mulching materials pollute the land and water because they are not degraded or disposed of properly. Biodegradable plastic mulches (BPM) may be used as a substitute for conventional low-density polyethylene (LDPE) to protect soil health. In this review, the effect of micro(nano)plastics on soil health and function has been discussed in light of their distribution in soil, changes in soil biochemistry, interactions between microplastics with soil microbes and plants, and their growth patterns. The nano-plastics are now incorporated into the food chain from the soil through plants and finally harm the whole ecosystem, including humans. The use of BPM has been practiced recently, but only 1% of the world’s total plastic production is from biodegradable materials. In the second part of the review, the confusing terms "bio-...

Conocer los procesos que ocurren asociados al manejo de suelos y cultivos resulta fundamental para entender los efectos que la actividad agropecuaria causa sobre el ambiente. Los ensayos de larga duración nos ayudan a comprender los cambios que pueden ocurrir sobre el sistema de producción.EEA BarrowFil: Forjan, Horacio Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Barrow; ArgentinaFil: Manso, Marina Lucrecia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Barrow; Argentin

cause these plant tissues are the primary substrates for microbial metabolism in soil. Soil microorganisms are limited by the amount and type of plant-Ozone is a greenhouse gas that is accumulating in the derived substrates entering soil, and we reasoned that changes in the production and biochemical constituents of plant litter produced lower atmosphere, and elevated O 3 has the potential to under elevated CO 2 and O 3 would elicit physiological changes in soil alter soil microbial communities through its influence microbial communities. To test this idea, we studied microbial activity on plant litter production. Elevated O 3 can decrease beneath trembling aspen (Populus tremuloides Michx.), paper birch photosynthesis (Pye, 1988; Coleman et al., 1995a) and (Betula papyrifera Marsh.), and sugar maple (Acer saccharum Marsh.) net C gain (Skä rby et al., 1987; Reich et al., 1990) in growing under experimental atmospheric CO 2 (ambient and 522.7 L many woody plants, which should modify litter produc-L Ϫ1) and O 3 (ambient and 54.5 nL L Ϫ1). To assess changes in microbial tion. For example, high levels of O 3 often decrease root community function, we measured microbial biomass, respiration, and growth to a greater extent than foliage or stem growth the metabolism of root-derived substrates using BIOLOG GN micro-(Manning et al., 1971; Blum and Tingey, 1977; Hogsett et plates. We also measured the activity of phosphatase, leucine aminoal., 1985). Elevated O 3 also can modify the biochemical peptidase, ␣-glucosidase, N-acetylglucosaminidase, cellobiohydrolase, phenol oxidase, and peroxidase enzymes, which are involved in plant composition of fine roots, wherein starch and soluble and fungal litter decomposition. Microbial biomass and respiration sugar concentrations can decline following exposure to were not significantly altered by elevated CO 2 and O 3. Cellobiohydroelevated O 3 (Andersen et al., 1991). It is possible that delase activity significantly increased under elevated CO 2 ; however, this creased growth and biochemical changes under elevated response was eliminated by elevated O 3. N-acetylglucosaminidase activ-O 3 could potentially mitigate increases in plant growth ity also increased under elevated CO 2 , but elevated O 3 did not signifiand changes in tissue biochemistry resulting from elecantly alter this response. We found no difference in the metabolism vated atmospheric CO 2. However, we do not understand of amino acids, organic acids, and simple carbohydrates, suggesting how these atmospheric gases will interact to alter the our experimental treatments did not alter the use of these substrates input of organic substrates to soil, which could potenby soil microorganisms. Our analysis indicates that changes in plant tially modify microbial activity in soil. growth in response to elevated CO 2 and O 3 alters microbial metabolism in soil.

Soil microorganisms are limited by the amount and type of plant‐derived substrates entering soil, and we reasoned that changes in the production and biochemical constituents of plant litter produced under elevated CO2 and O3 would elicit physiological changes in soil microbial communities. To test this idea, we studied microbial activity beneath trembling aspen (Populus tremuloides Michx.), paper birch (Betula papyrifera Marsh.), and sugar maple (Acer saccharum Marsh.) growing under experimental atmospheric CO2 (ambient and 522.7 μL L−1) and O3 (ambient and 54.5 nL L−1). To assess changes in microbial community function, we measured microbial biomass, respiration, and the metabolism of root‐derived substrates using BIOLOG GN microplates. We also measured the activity of phosphatase, leucine aminopeptidase, α‐glucosidase, N‐acetylglucosaminidase, cellobiohydrolase, phenol oxidase, and peroxidase enzymes, which are involved in plant and fungal litter decomposition. Microbial biomass a...

Chemical interactions in forested ecosystems play a role in driving biodiversity and ecosystem dynamics. Plant phenolics released by leaching can influence surrounding plants and soil organisms such as bacteria, fungi or arthropods. However, our knowledge about such chemically-mediated biotic interactions in Mediterranean oak forests is still limited, in particular whether they play a role in the limited forest regeneration. In this study, we analyzed how phenolics of Cotinus coggygria, a dominant shrub of Mediterranean downy oak (Quercus pubescens) forests, influence understory herbaceous plant species, downy oak regeneration and soil organisms in order to obtain a more integrative view of possible direct and indirect interactions triggered by this shrub species. We performed a series of experiments testing the effect of aqueous extracts of C. coggygria, mimicking natural leachates, on these organisms. Cotinus coggygria contained a high quantity of phenolics in green and senescent leaves but much less in leaf litter. Extracts from C. coggygria leaves stimulated bacterial communities, exhibited few effects on both saprophytic and symbiotic fungi, and negatively affected Collembola. Herbaceous species growth was particularly impaired by extracts from green and senescent leaves, although these effects were alleviated in the presence of soil microorganisms. In both greenhouse and field experiments, C. coggygria affected early oak seedling establishment in particular through a reduced root growth, but exhibited no effect on later seedling and sapling growth. We discussed the implication of these results for the balance between competition and facilitation in oak forests and concluded that C. coggygria has the potential to strongly alter biotic interactions, understory plant diversity and oak forest dynamics.

Soil fertilization with organic fertilizers condition the soil for efficient proliferation and interactions of phages and its bacterial hosts. • Soil dwelling Phages are suitable and sustainable agents in the biocontrol of plant bacterial pathogens. • Phages survival in the soil are affected by both biotic and abiotic properties of the soil.

The diversity of mycorrhizal fungi in the rhizosphere of the carob tree (Ceratonia siliqua) was studied in five regions of Morocco: Taroudant, Khénifra, Afourar, Nador and Ksiba. Microscopic examination of the carob tree soil, collected from the studied areas, revealed the presence of 31 AM fungal species belonging to six genera Glomus (16 species), Acaulospora (7 species), Scutellospora (4 species), Gigaspora (2 species), Entrophospora and Pacispora (one species each). The genus Glomus is the most abundant with a distribution percentage of 93%. Species richness varies between 13 and 18 species. All the encountered species were morphologically characterized basing on: shape, color, average size of the spore and its wall, spore surface and size of the hyphae. The diversity of AM fungi in different ecological studied zones varies from one site to another, it is higher in Taroudant site, the Shannon-Wiener index H ' is in the order of 2.78 and the index of Margalef IM 3.6. Furthermore, the similarity index of Jaccard shows a strong similarity between the Taroudant site and that of Afourar.

El objetivo fue evaluar el efecto de la aplicación de estiércol de ovino (EO) en el rendimiento de papa (Solanum tuberosum), para determinar la dosis adecuada a aplicar en el cultivo de papa variedad “canchan” en Acobamba, Huancavelica. Ante la problemática de que no se tiene una dosis óptima para cubrir la demanda de nutrientes para una mejor producción de papa en la aplicación de enmiendas orgánicas de EO, toda vez que la papa requiere alta cantidad de nutrientes, ya que absorbe 20, 240, 220, 60 y 20 Kg ha-1 de P, K, N, Ca y Mg, respectivamente, se trabajó en cinco tratamientos con tres repeticiones mediante el diseño DBCA, realizando el ANVA con la prueba de Duncan. Los tratamientos: T1 = 0 kg EO/planta, T2 = 0, 25 kg EO/planta, T3 = 0,50 kg EO/planta, T4 = 1 kg EO/planta y T5 = 1, 5 kg EO/planta, correspondiendo el mayor rendimiento al T5 con 20, 31 ton/ha, no hay diferencia estadística entre el T4 con 18,29 ton/ha con el T3 con 17, 06 ton/ha, con el T2 se obtuvo 14, 40 ton/ha, ...

In this study, we provide experimental evidences that in calcareous soils microbial degradation/decomposition of citrate can promote Al-(hydr)oxide precipitation concurrently decreasing copper (Cu) solubility by a coprecipitation process. Citrate is an organic acid anion commonly released by roots to increase nutrient availability or to limit Al toxicity. However, under specific environmental conditions (i.e. high microbial activity of Al-citrate-degrading bacteria, alkaline pH), this organic acid may become ineffective in mobilizing Cu for the plant acquisition process. To demonstrate this, a calcareous soil and an artificial soil system have been treated with citrate solutions; then, changes in Al and Cu solubility and the formation of Cu-containing Al-(hydr)oxides were monitored. Both in experiments with the artificial soil and in those where the soil was inoculated with microbial strains, the formation of Cu-Al coprecipitates not only occurred but was also concurrent with the decrease of Cu and Al solubility. The role of bacteria in metal-citrate complex degradation has been assessed, and the 16S rDNA of bacteria related with these processes has been sequenced for genus identification. Bacteria belonging to Pseudomonas, Sphingomonas, Bradyrhizobium and Sphingopixis have been identified as possible candidates to degrade Al-and Cu-citrate complexes thus triggering the metal precipitation phenomena.

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To assess the impacts of Cu and Zn on fungi, we tested the growth of 18 taxonomically different saprotrophic (basidiomycete, ascomycete and zygomycete) fungi and their production of extracellular oxidative enzymes on Cu-(0, 100, 200, 400 mg kg-1) or Zn-(0, 100, 200, 400 mg kg-1) containing ABTS (2,2´-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) agar plates. Coniothyrium sp. was the most tolerant ascomycete and Sordaria sp. the most sensitive to both Zn and Cu. The growth of 8 basidiomyceteous fungi was reduced by 22%-100% on ABTS plates with 200 mg Cu kg-1. Bioluminescent Saccharomyces cerevisiae yeast tests showed that Cu was 7-fold more toxic than Zn. Dose responses with respect to enzyme production varied among ascomycetous, zygomycetous and basidiomycetous fungi. Cu was more toxic than Zn for all tested fungi with all methods indicating that microbial functioning of soil is more vulnerable to Cu than Zn in the soil.

Revista Ciencias Técnicas Agropecuarias Universidad Agraria de La Habana paneque@isch.edu.cu ISSN (Versión impresa): 1010-2760 CUBA ... 2007 Francisco Higinio Ruiz Espinoza / Pablo Marrero Labrador / Orestes Cruz La Paz / Sergio Zamora Salgado / ...

Resumen Se plantaron estacas apicales e internodales de dos variedades en tubetes de 400 cm 3 sobre una mezcla de turba y perlita (1:1), y un testigo con compost. Los PGPR evaluados fueron A. brasilense Az39, P. fluorescens ZME4 y P. putida LSR1. Las estacas se inocularon en forma de riego en la base del tallo con una dosis de 5 mL/planta. Luego de 15 días, se evaluó la longitud del brote, peso fresco y seco de los brotes y peso fresco y seco de la raíz. Si bien, en la parte aérea los efectos de la inoculación no fueron significativos, los tratamientos inoculados no se diferenciaron estadísticamente de los esquejes crecidos en compost, que fueron los que mayor crecimiento aéreo presentaron. El crecimiento radicular, en cambio, no se vio favorecido con el compost, en donde se pudo observar plantas con raíces más livianas y más débiles que aquellas inoculadas. Un buen sistema radicular, obtenido con algunos de los tratamientos con PGPR es imprescindible para lograr plantines viables.

Las caracteristicas microbiologicas y quimicas del suelo cambian por la aplicacion de abonos organicos y pueden resultar indicadores sensibles al impacto producido. El objetivo de este estudio fue evaluar los cambios a corto plazo en variables microbiologicas y quimicas en respuesta a la aplicacion de abonos organicos bajo condiciones de incubacion. Fracciones de suelo sin (testigo) y con agregado de compost y vermicompost fueron incubadas por 90 dias a 28o C y 60 % del agua disponible remanente . Cada 10 dias se midio actividad microbiana total (AMT), abundancia de bacterias y hongos totales, microorganismos celuloliticos, fijadores de N, amonificadores y nitrificadores, N-NO 3 , N total, P-H 2 CO 3 , K intercambiable y materia organica. La AMT y los microorganismos amonificadores y celuloliticos fueron sensibles a la optimizacion de temperatura y humedad del suelo, y no frente al abonado organico. Los microorganismos celuloliticos incrementaron durante la incubacion, mientras que ...

In Baracoa, municipality of the Guantanamo province the coconut seedling nurseries are being affected by the index low of germination and the little vigor of the seedling. The worm casting and the bacteria of the genus Azotobacter has been of those more employees in the seedling production, since promote the vegetable growth. The investigation over Randomized Block Design the combination of three levels of the substrates S:HL:FC (10:1:1), (4:1:1), (2:1:1) was studied with the inoculation of three strain of A. chroococcum (INIFAT-8, CDM-1, CDM-2) on the obtaining of seedling coconut belonging to the domesticated ecotipo "Indio Verde-1" in two soil, Haplic Arenosol (ARh) and Haplic Fluvic Gleysol (GFLh). As development indicators they were evaluated the index of speed germination of the seeds, the plant height (cm), the diameter in the stem base (cm) and the population of Azotobacter (UFC g -1 of soil). The possibility to diminish the organic mature levels employed in 50 % b...