Effect of the environment inside and outside the cage on the activity and behaviour test performance of silver foxes

Selostus: Kasvatushäkin ympäristön vaikutus hopeakettujen käyttäytymiseen

Nitrate and ammonium in soil solution in tobacco management systems

Tobacco farmers of southern Brazil use high levels of fertilizers, without considering soil and environmental attributes, posing great risk to water resources degradation. The objective of this study was to monitor nitrate and ammonium concentrations in the soil solution of an Entisol in and below the root zone of tobacco under conventional tillage (CT), minimum tillage (MT) and no-tillage (NT). The study was conducted in the small-watershed Arroio Lino, in Agudo, State of Rio Grande do Sul, Brazil. A base fertilization of 850 kg ha-1 of 10-18-24 and topdressing of 400 kg ha-1 of 14-0-14 NPK fertilizer were applied. The soil solution was sampled during the crop cycle with a tension lysimeter equipped with a porous ceramic cup. Ammonium and nitrate concentrations were analyzed by the distillation and titration method. Nitrate concentrations, ranging from 8 to 226 mg L-1, were highest after initial fertilization and decreased during the crop cycle. The average nitrate (N-NO3-) concentration in the root zone was 75 in NT, 95 in MT, and 49 mg L-1 in CT. Below the root zone, the average nitrate concentration was 58 under NT, 108 under MT and 36 mg L-1 under CT. The nitrate and ammonium concentrations did not differ significantly in the management systems. However, the nitrate concentrations measured represent a contamination risk to groundwater of the watershed. The ammonium concentration (N-NH4+) decreased over time in all management systems, possibly as a result of the nitrification process and root uptake of part of the ammonium by the growing plants.

Nitrate reductase activity and spad readings in leaf tissues of guinea grass submitted to nitrogen and potassium rates

Nitrogen and K deficiency are among the most yield limiting factors in Brazilian pastures. The lack of these nutrients can hamper the chlorophyll biosynthesis and N content in plant tissues. A greenhouse experiment was carried out to evaluate the relationship among N and K concentrations, the indirect determination of chlorophyll content (SPAD readings), nitrate reductase activity (RNO3-) in newly expanded leaf lamina (NL) and the dry matter yield for plant tops of Mombaça grass (Panicum maximum Jacq.). A fractionated 5² factorial design was used, with 13 combinations of N and K rates in the nutrient solution. The experimental units were arranged in a randomized block design, with four replications. Plants were harvested twice. The first harvest occurred 36 days after seedling transplanting and the second 29 days after the first. Significance occurred for the interaction between the N and K rates to SPAD readings and to RNO3- assessment taken on the NL during the first growth. Besides, RNO3- and SPAD readings increased only with the NL N concentration, reaching the highest values of both variables up to about 25 g kg-1, but were ratively constant at higher leaf N. Significant relationships either between SPAD readings or RNO3- activity and shoot dry mass weight were also observed. The critical levels of N concentration in the NL were, respectively, 22 and 17g kg-1 in the first and second harvest. Thus, SPAD instrument and RNO3- assessment can be used as complementary tools to evaluate the N status in forage grass.

Nitrate role in basic cation leaching under no-till

Especially under no-tillage, subsuface soil acidity has been a problem, because it depends on base leaching, which has been associated with the presence of low molecular weigth organic acids and companion anions. The objective of this study was to evaluate exchangeable base cation leaching as affected by surface liming along with annual urea side-dressing of maize and upland rice. Treatments consisted of four lime rates (0, 1500, 3000, and 6000 kg ha-1) combined with four nitrogen rates (0, 50, 100, and 150 kg ha-1) applied to maize (Zea mays) and upland rice (Oryza sativa), in two consecutive years. Maize was planted in December, three months after liming. In September of the following year, pearl millet (Pennisetum glaucum) was planted without fertilization and desiccated 86 days after plant emergence. Afterwards, upland rice was grown. Immediately after upland rice harvest, 18 months after surface liming, pH and N-NO3-, N-NH4+, K, Ca, and Mg levels were evaluated in soil samples taken from the layers 0-5, 5-10, 10-20 and 20-40 cm. Higher maize yields were obtained at higher N rates and 3000 kg ha-1 lime. Better results for upland rice and pearl millet yields were also obtained with this lime rate, irrespective of N levels. The vertical mobility of K, Ca and Mg was higher in the soil profiles with N fertilization. Surface liming increased pH in the upper soil layers causing intense nitrate production, which was leached along with the base cations.

Seasonal changes in platform use by adult farmbred silver foxes (Vulpes vulpes)

Selostus: Aikuisten hopeakettujen hyllynkäytön vuodenaikaisvaihtelut

Estimating subsoil resistance to nitrate leaching from easily measurable pedological properties

Leaching of nitrate (NO3-) can increase the groundwater concentration of this anion and reduce the agronomical effectiveness of nitrogen fertilizers. The main soil property inversely related to NO3- leaching is the anion exchange capacity (AEC), whose determination is however too time-consuming for being carried out in soil testing laboratories. For this reason, this study evaluated if more easily measurable soil properties could be used to estimate the resistance of subsoils to NO3- leaching. Samples from the subsurface layer (20-40 cm) of 24 representative soils of São Paulo State were characterized for particle-size distribution and for chemical and electrochemical properties. The subsoil content of adsorbed NO3- was calculated from the difference between the NO3- contents extracted with 1 mol L-1 KCl and with water; furthermore, NO3- leaching was studied in miscible displacement experiments. The results of both adsorption and leaching experiments were consistent with the well-known role exerted by AEC on the nitrate behavior in weathered soils. Multiple regression analysis indicated that in subsoils with (i) low values of remaining phosphorus (Prem), (ii) low soil pH values measured in water (pH H2O), and (iii) high pH values measured in 1 moL L-1 KCl (pH KCl), the amounts of surface positive charges tend to be greater. For this reason, NO3- leaching tends to be slower in these subsoils, even under saturated flow condition.

Comparison of two breeding systems for timing of whelpings in farmed silver foxes

Selostus: Vertaileva tutkimus kahden paritusjärjestelmän vaikutuksista tarhattujen hopeakettujen penikoimisten ajoittumiseen

EFFECT OF RICE STRAW AND NITRATE LEVELS IN SOIL SOLUTION ON NITROUS OXIDE EMISSION

Among the greenhouse gases, nitrous oxide (N2O) is considered important, in view of a global warming potential 296 times greater than that of carbon dioxide (CO2) and its dynamics strongly depend on the availability of C and mineral N in the soil. The understanding of the factors that define emissions is essential to develop mitigation strategies. This study evaluated the dynamics of N2O emissions after the application of different rice straw amounts and nitrate levels in soil solution. Pots containing soil treated with sodium nitrate rates (0, 50 and 100 g kg-1 of NO−3-N) and rice straw levels (0, 5 and 10 Mg ha-1), i.e., nine treatments, were subjected to anaerobic conditions. The results showed that N2O emissions were increased by the addition of greater NO−3 amounts and reduced by large straw quantities applied to the soil. On the 1st day after flooding (DAF), significantly different N2O emissions were observed between the treatments with and without NO−3 addition, when straw had no significant influence on N2O levels. Emissions peaked on the 4th DAF in the treatments with highest NO−3-N addition. At this moment, straw application negatively affected N2O emissions, probably due to NO−3 immobilization. There were also alterations in other soil electrochemical characteristics, e.g., higher straw levels raised the Fe, Mn and dissolved C contents. These results indicate that a lowering of NO−3 concentration in the soil and the increase of straw incorporation can decrease N2O emissions.

Organic and Nitrogen Fertilization of Soil under ‘Syrah’ Grapevine: Effects on Soil Chemical Properties and Nitrate Concentration

ABSTRACT Viticulture is an activity of great social and economic importance in the lower-middle region of the São Francisco River valley in northeastern Brazil. In this region, the fertility of soils under vineyards is generally poor. To assess the effects of organic and nitrogen fertilization on chemical properties and nitrate concentrations in an Argissolo Vermelho-Amarelo (Typic Plinthustalf), a field experiment was carried out in Petrolina, Pernambuco, on Syrah grapevines. Treatments consisted of two rates of organic fertilizer (0 and 30 m3 ha-1) and five N rates (0, 10, 20, 40, and 80 kg ha-1), in a randomized block design arranged in split plots, with five replications. The organic fertilizer levels represented the main plots and the N levels, the subplots. The source of N was urea and the source of organic fertilizer was goat manure. Irrigation was applied through a drip system and N by fertigation. At the end of the third growing season, soil chemical properties were determined and nitrate concentration in the soil solution (extracted by porous cups) was determined. Organic fertilization increased organic matter, pH, EC, P, K, Ca, Mg, Mn, sum of bases, base saturation, and CEC, but decreased exchangeable Cu concentration in the soil by complexation of Cu in the organic matter. Organic fertilization raised the nitrate concentration in the 0.20-0.40 m soil layer, making it leachable. Nitrate concentration in the soil increased as N rates increased, up to more than 300 mg kg-1 in soil and nearly 800 mg L-1 in the soil solution, becoming prone to leaching losses.

Estimation of soil nitrate in the spring as a basis for adjustment of nitrogen fertiliser rates

Selostus: Maassa olevan nitraattitypen arviointi simulointimallin avulla

No evidence for mutations of CTCFL/BORIS in Silver-Russell syndrome patients with IGF2/H19 imprinting control region 1 hypomethylation.

BACKGROUND: Silver-Russell syndrome (SRS) is a genetically and clinically heterogeneous disease. Although no protein coding gene defects have been reported in SRS patients, approximately 50% of SRS patients carry epimutations (hypomethylation) at the IGF2/H19 imprinting control region 1 (ICR1). Proper methylation at ICR1 is crucial for the imprinted expression of IGF2, a fetal growth factor. CTCFL, a testis-specific protein, has recently been proposed to play a role in the establishment of DNA methylation at the murine equivalent of ICR1. A screen was undertaken to assess whether CTCFL is mutated in SRS patients with hypomethylation, to explore a link between the observed epimutations and a genetic cause of the disease. METHODOLOGY/PRINCIPAL FINDINGS: DNA was obtained from 36 SRS patients with hypomethylation at ICR1. All CTCFL coding exons were sequenced and analyzed for duplications/deletions using both multiplex ligation-dependent probe amplification, with a custom CTCFL probe set, and genomic qPCR. Novel SNP alleles were analyzed for potential differential splicing in vitro utilizing a splicing assay. Neither mutations of CTCFL nor duplications/deletions were observed. Five novel SNPs were identified and have been submitted to dbSNP. In silico splice prediction suggested one novel SNP, IVS2-66A>C, activated a cryptic splice site, resulting in aberrant splicing and premature termination. In vitro splicing assays did not confirm predicted aberrant splicing. CONCLUSIONS/SIGNIFICANCE: As no mutations were detected at CTCFL in the patients examined, we conclude that genetic alterations of CTCFL are not responsible for the SRS hypomethylation. We suggest that analysis of other genes involved in the establishment of DNA methylation at imprinted genes, such as DNMT3A and DNMT3L, may provide insight into the genetic cause of hypomethylation in SRS patients.