Historia de uso del suelo y contenido de micronutrientes en Argiudoles del centro de la provincia de Santa Fe (Argentina)

67-73The studies related to the concentration and bioavailability of soil micronutrients are very limited for the central region of Santa Fe province, reason for which the objectives of the current research were: a) to determine the decrease of the micronutrient contents in Argiudolls of Santa Fe as a consequence of soil use, and b) to correlate the micronutrient bioavailability with soil properties that were affected by the intensification of productive systems (organic matter, pH). The study was carried out in Argiudolls of Las Colonias county (Santa Fe). Composite soil samples were collected from 20 fields under pristine conditions (CP), 22 fields under milk production history (G), 24 fields under agricultural-livestock history (AG) and 20 fields under a long agricultural history (A). These samples were used to determine: pH, organic carbon (OC), boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn). The results indicate that the pH did not vary among the studied situations; the values of OC diminished 40 percent with the intensification of agriculture; the concentration of B and Zn in fields with a long agricultural history decreased 50 percent with respect to the pristine condition; the Cu concentration was not altered; Fe and Mn did not show a clear tendency to change as a function of the soil use. Zinc deficiencies could occur in some cases, therefore, its concentration should be routinely controlled, especially in intensive systems, to assure an appropriate supply of nutrients according to the crop demand

Eficiencia agronómica del azufre elemental relativa a una fuente azufrada soluble en trigo en la Región Pampeana

67-77Agronomic efficiency of elemental sulphur (AE) compared with soluble and S-sulphate sulphur sources depends on reactivity of AE (e.g. particle size) and environmental conditions (soil and climate). Although there is published information suggesting that elemental sulphur has similar effectiveness than soluble sulphur sources, the information is not conclusive. We hypothesized that agronomic efficiency of AE and soluble S sources are similar under the Pampas Region conditions. The objectives of the study were to: i. Evaluate S grain response to a reactive source of AE compared to a soluble S source under different S rates and soil and climate conditions. ii. Compare, for the group of experiments, agronomic S efficiency between S sources. iii: Relate S responses with soil and climatic variables. Eight field experiments were conducted during two successive years on cropping systems in the Pampas Region. The experimental design was a randomized complete block with four or six replicates and a factorial treatment arrangement (factor 1: S source, factor 2: S rate). The treatments were: check (without S application), fertilization with a micronized source of AE (95 percent of S) and a fertilization treatment with ammonium sulphate (SA, 24 percent). Both sulphur sources were applied at two S rates. Sulphur rates were 10 and 30 kg ha-1 (year 1) and 15 and 30 kg ha-1 (year 2). In the first year, wheat responded significantly to S in four of five sites (p less than 0.05) with yield increases of 231 to 857 kg ha-1. Significant yield increases were observed in all sites in the second year, ranging from 702 to 2,119 kg ha-1. There were no significant differences in grain yield among S sources, rates or interaction source x S rates (p greater than 0.05) in most sites. When all sites were combined, sulphur sources presented similar agronomic S efficiencies (p greater than 0.05). The lower S rate (10 or 15 kg ha-1) was enough to provide S to the crop under the Pampas Region conditions. Grain yield responses to S were positively correlated with organic matter content and rainfall (during tillering or the whole crop cycle) and inversely associated with SO4 2- at planting, although with a poor adjustment. No correlation was detected between S response and temperatures during tillering or the whole crop cycle

Historia de uso del suelo y contenido de micronutrientes en Argiudoles del centro de la provincia de Santa Fe (Argentina)

67-73The studies related to the concentration and bioavailability of soil micronutrients are very limited for the central region of Santa Fe province, reason for which the objectives of the current research were: a) to determine the decrease of the micronutrient contents in Argiudolls of Santa Fe as a consequence of soil use, and b) to correlate the micronutrient bioavailability with soil properties that were affected by the intensification of productive systems (organic matter, pH). The study was carried out in Argiudolls of Las Colonias county (Santa Fe). Composite soil samples were collected from 20 fields under pristine conditions (CP), 22 fields under milk production history (G), 24 fields under agricultural-livestock history (AG) and 20 fields under a long agricultural history (A). These samples were used to determine: pH, organic carbon (OC), boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn). The results indicate that the pH did not vary among the studied situations; the values of OC diminished 40 percent with the intensification of agriculture; the concentration of B and Zn in fields with a long agricultural history decreased 50 percent with respect to the pristine condition; the Cu concentration was not altered; Fe and Mn did not show a clear tendency to change as a function of the soil use. Zinc deficiencies could occur in some cases, therefore, its concentration should be routinely controlled, especially in intensive systems, to assure an appropriate supply of nutrients according to the crop demand

Eficiencia agronómica del azufre elemental relativa a una fuente azufrada soluble en trigo en la Región Pampeana

67-77Agronomic efficiency of elemental sulphur (AE) compared with soluble and S-sulphate sulphur sources depends on reactivity of AE (e.g. particle size) and environmental conditions (soil and climate). Although there is published information suggesting that elemental sulphur has similar effectiveness than soluble sulphur sources, the information is not conclusive. We hypothesized that agronomic efficiency of AE and soluble S sources are similar under the Pampas Region conditions. The objectives of the study were to: i. Evaluate S grain response to a reactive source of AE compared to a soluble S source under different S rates and soil and climate conditions. ii. Compare, for the group of experiments, agronomic S efficiency between S sources. iii: Relate S responses with soil and climatic variables. Eight field experiments were conducted during two successive years on cropping systems in the Pampas Region. The experimental design was a randomized complete block with four or six replicates and a factorial treatment arrangement (factor 1: S source, factor 2: S rate). The treatments were: check (without S application), fertilization with a micronized source of AE (95 percent of S) and a fertilization treatment with ammonium sulphate (SA, 24 percent). Both sulphur sources were applied at two S rates. Sulphur rates were 10 and 30 kg ha-1 (year 1) and 15 and 30 kg ha-1 (year 2). In the first year, wheat responded significantly to S in four of five sites (p less than 0.05) with yield increases of 231 to 857 kg ha-1. Significant yield increases were observed in all sites in the second year, ranging from 702 to 2,119 kg ha-1. There were no significant differences in grain yield among S sources, rates or interaction source x S rates (p greater than 0.05) in most sites. When all sites were combined, sulphur sources presented similar agronomic S efficiencies (p greater than 0.05). The lower S rate (10 or 15 kg ha-1) was enough to provide S to the crop under the Pampas Region conditions. Grain yield responses to S were positively correlated with organic matter content and rainfall (during tillering or the whole crop cycle) and inversely associated with SO4 2- at planting, although with a poor adjustment. No correlation was detected between S response and temperatures during tillering or the whole crop cycle

Orthogonally bifunctionalised polyacrylamide nanoparticles: a support for the assembly of multifunctional nanodevices

Polyacrylamide nanoparticles bearing two orthogonal reactive functionalities were prepared by reverse microemulsion polymerisation. Water-soluble photosensitisers and peptide or carbohydrate moieties were sequentially attached to the new nanospecies by orthogonal conjugations based on copper- catalysed azide-alkyne cycloaddition and isothiocyanate chemistry

Prox1 Is Required for Granule Cell Maturation and Intermediate Progenitor Maintenance During Brain Neurogenesis

The transcription factor Prox1 plays a crucial role in intermediate progenitor maintenance and hippocampal neuron differentiation during adult neurogenesis in the dentate gyrus region of the hippocampus

North Tropical Atlantic influence on western Amazon fire season variability

The prevailing wet climate in the western Amazon is not favorable to the natural occurrence of fires. Nevertheless, the current process of clearing of humid forests for agriculture and cattle ranching has increased the vulnerability of the region to the spread of fires. Using meteorological stations precipitation and the Moderate Resolution Spectroradiometer (MODIS) Active-Fires (AF) during 2000-2009, we show that fire anomalies vary closely with July-August-September (JAS) precipitation variability as measured by the Standardized Precipitation Index (SPI). The precipitation variability is, in turn, greatly determined by sea surface temperature (SST) anomalies in the North Tropical Atlantic (NTA). We develop a linear regression model to relate local fire activity to an index of the NTA-SST. By using seasonal forecasts of SST from a coupled model, we are able to predict anomalous JAS fire activity as early as April. We applied the method to predict the severe 2010 JAS season, which indicated strongly positive seasonal fire anomalies within the 95% prediction confidence intervals in most western Amazon. The spatial distribution of predicted SPI was also in accordance with observed precipitation anomalies. This three months lead time precipitation and fire prediction product in the western Amazon could help local decision makers to establish an early warning systems or other appropriate course of action before the fire season begins

Prox1 Regulates the Notch1-Mediated Inhibition of Neurogenesis

During development of the spinal cord, Prox1 controls the balance between proliferation and differentiation of neural progenitor cells via suppression of Notch1 gene expression