Effect of long-term potassium fertilization on the chemical composition of Oriental tobacco

The effects of the different potassium rates (0, 75 and 450 kg K2O ha-1) on nutrient concentrations in the above-ground biomass and chemical characteristics of sun-cured tobacco have been studied in a stationary field trial. Annual fertilization with 75 kg K2O ha-1 was adequate to maintain soil K concentration near the initial value. It was found that yield of cured leaves was not significantly affected by rate of K application when oriental tobacco was grown on soils with high available soil K. With the increase of K fertilization rate the content of the potassium in leaves increased from 0.65 to 4.49%. The concentration of Ca and Mg in the leaves ranged from 2.03 to 5.23% and from 0.52 to 0.71%, respectively and decreased with increases in added potassium. No effect of K rates on nicotine and protein content was noted. Only the reducing sugars’ content tended to increase to 11.42% at the highest K rate. Fertilization with moderate potassium rates (75 kg K2O ha-1) on soils high in available K is necessary to maintain the good potassium reserves. When oriental tobacco was grown on alkaline soils with high available K and Ca, potassium fertilization improves K nutrition and therefore may favorably affect burning properties of tobacco

Soil Fertility in Response to Long-Term Fertilization under the Tobacco Monoculture System on Rendzic Leptosol in Bulgaria

The effect of long-term mineral and organic-mineral fertilization on selected soil properties (pH, total humus and N, available phosphorus, potassium, calcium, magnesium, iron and manganese content) was studied in a stationary trail with tobacco monocropping system. The trial was established on Rendzic Leptosols in 1966. Five treatments were selected for this study, including control without fertilization (Check), nitrogen + phosphorus (NP), nitrogen + potassium (NK), nitrogen + phosphorus + potassium (NPK) and nitrogen + phosphorus + potassium + manure (NPK + manure). Soil samples at a depth of 0–25 cm were collected from all studied plots every year (2014, 2015 and 2016). The results indicated that maintaining humus content at the initial level is not possible through yearly mineral fertilizer application. Long-term mineral phosphorus fertilization increased 5.5–5.7 times available P2O5 in the soil compared to the initial level. The soil available K2O content in NK and NPK treatments increased, respectively, by 41.1% and 44.9% over the initial level. A remarkable increase in available phosphorus (25.5 times) and potassium (2.5 times) content in the soil compared with the initial level was found due to longterm NPK + manure fertilization. The NPK + manure treatment was found to be the most efficient management system in accumulating of total humus and N, available P2O5, K2O, Fe and Mn in a long-term fertilized Rendzic Leposol, under a tobacco monocropping system

Accumulation of heavy metals in soil and tobacco after long-term mineral and organic-mineral fertilization

The effect of long-term mineral and organic-mineral fertilization on accumulation of heavy metals in soil and plants was studied in stationary field experiment with continuous tobacco cropping system. Five treatments were selected in this study, including CK (control without fertilization), NP (nitrogen+phosphorus), NK (nitrogen+potassium), NPK (nitrogen+phosphorus+potassium) and NPK+FYM (nitrogen+phosphorus+potassium+manure). Total and available Pb, Cd, Ni, Mn, Zn and Cu content in soil, as well as concentration of the elements in tobacco leaves were determined. The application of mineral fertilizers did not significantly increase the total Pb, Cd, Ni, Zn and Cu content in the soil as compared to unfertilized control. The addition of manure (NPK+FYM treatment) decreased total Ni. There was significant increase of available Ni and Mn in treatment receiving NPK+FYM. A comparison of unfertilized treatment indicated that long-term mineral fertilization had no significant effect on studied metals in oriental tobacco leaves. A considerable decrease in Cd (2.2-2.8 times), Zn (1.7-3.3 times) and Cu (2.2-3.8 times) concentrations in the leaves compared with control without fertilization was detected due to long-term NPK+FYM fertilization. This study demonstrated that the risk of heavy metals’ accumulation in tobacco leaves associated with long-term mineral and organic-mineral fertilization was low

КОЕФИЦИЕНТИ ЗА ОПРЕДЕЛЯНЕ НА ЛИСТНАТА ПЛОЩ ПРИ ТРИ СОРТА ТЮТЮН ТИП БЪРЛЕЙ

In relation to determination of leaf area through linear measurements of leaf blade and mathematical coeffi cients in Burley tobacco individual values of correction coeffi cients have been determined by variety and in dependence of the leaf position.Във връзка с определянето на площта на листата чрез линейните параметри на листната петура и математически коефициенти при тютюн тип Бърлей, са изчислени индивидуалните стойности на коригиращите коефициенти както по сортове, така и в зависимост от вертикалното положение на листата спрямо стъблото

COEFFICIENTS FOR DETERMINATION OF THE LEAF AREA IN THREE BURLEY TOBACCO VARIETIES

In relation to determination of leaf area through linear measurements of leaf blade and mathematical coeffi cients in Burley tobacco individual values of correction coeffi cients have been determined by variety and in dependence of the leaf position

Effect of long-term potassium fertilization on the chemical composition of Oriental tobacco

The effects of the different potassium rates (0, 75 and 450 kg K2O ha-1) on nutrient concentrations in the above-ground biomass and chemical characteristics of sun-cured tobacco have been studied in a stationary field trial. Annual fertilization with 75 kg K2O ha-1 was adequate to maintain soil K concentration near the initial value. It was found that yield of cured leaves was not significantly affected by rate of K application when oriental tobacco was grown on soils with high available soil K. With the increase of K fertilization rate the content of the potassium in leaves increased from 0.65 to 4.49%. The concentration of Ca and Mg in the leaves ranged from 2.03 to 5.23% and from 0.52 to 0.71%, respectively and decreased with increases in added potassium. No effect of K rates on nicotine and protein content was noted. Only the reducing sugars’ content tended to increase to 11.42% at the highest K rate. Fertilization with moderate potassium rates (75 kg K2O ha-1) on soils high in available K is necessary to maintain the good potassium reserves. When oriental tobacco was grown on alkaline soils with high available K and Ca, potassium fertilization improves K nutrition and therefore may favorably affect burning properties of tobacco

Effect of long-term potassium fertilization on the chemical composition of Oriental tobacco

The effects of the different potassium rates (0, 75 and 450 kg K2O ha-1) on nutrient concentrations in the above-ground biomass and chemical characteristics of sun-cured tobacco have been studied in a stationary field trial. Annual fertilization with 75 kg K2O ha-1 was adequate to maintain soil K concentration near the initial value. It was found that yield of cured leaves was not significantly affected by rate of K application when oriental tobacco was grown on soils with high available soil K. With the increase of K fertilization rate the content of the potassium in leaves increased from 0.65 to 4.49%. The concentration of Ca and Mg in the leaves ranged from 2.03 to 5.23% and from 0.52 to 0.71%, respectively and decreased with increases in added potassium. No effect of K rates on nicotine and protein content was noted. Only the reducing sugars’ content tended to increase to 11.42% at the highest K rate. Fertilization with moderate potassium rates (75 kg K2O ha-1) on soils high in available K is necessary to maintain the good potassium reserves. When oriental tobacco was grown on alkaline soils with high available K and Ca, potassium fertilization improves K nutrition and therefore may favorably affect burning properties of tobacco

Population Response of Rhizosphere Microbiota of Garden Pea Genotypes to Inoculation with Arbuscular Mycorrhizal Fungi

This study of a legume’s rhizosphere in tripartite symbiosis focused on the relationships between the symbionts and less on the overall rhizosphere microbiome. We used an experimental model with different garden pea genotypes inoculated with AM fungi (Rhizophagus irregularis and with a mix of AM species) to study their influence on the population levels of main trophic groups of soil microorganisms as well as their structure and functional relationships in the rhizosphere microbial community. The experiments were carried out at two phenological cycles of the plants. Analyzes were performed according to classical methods: microbial population density defined as CUF/g a.d.s. and root colonization rate with AMF (%). We found a proven dominant effect of AMF on the densities of micromycetes and actinomycetes in the direction of reduction, suggesting antagonism, and on ammonifying, phosphate-solubilizing and free-living diazotrophic Azotobacter bacteria in the direction of stimulation, an indicator of mutualistic relationships. We determined that the genotype was decisive for the formation of populations of bacteria immobilizing mineral NH4+-N and bacteria Rhizobium. We reported significant two-way relationships between trophic groups related associated with soil nitrogen and phosphorus ions availability. The preserved proportions between trophic groups in the microbial communities were indicative of structural and functional stability

Impact of KCNQ2 mutations in Bulgarian patients with electroclinical syndromes with onset in the first year of life

Mutations in KCNQ2 are associated with a range of electroclinical syndromes with dominant inheritance that are differentiated by the age at onset of the seizures and are associated with good prognosis. These are benign familial neonatal seizures (BFNS), benign familial neonatal--infantile seizures (BFNIS) and benign familial infantile seizures. Herein, we report the results of a systematic screening of KCNQ2 in 27 unrelated Bulgarian patients with compatible clinical diagnoses. Two pathogenic point mutations were identified: a novel splice-site c.1526-2A>G variation causing BFNS and a missense c.998G>A alteration in a patient with BFNIS, who subsequently developed benign epilepsy with centro-temporal spikes. Additionally, multiplex ligation-dependent probe amplification analysis and array comparative genomic hybridization assay detected a de novo deletion on 20q13.3 encompassing 0.41 Mb genomic region and covering 11 genes, including KCNQ2 and CHRNA4. This large-scale rearrangement was found in a patient with typical BFNS and no additional developmental abnormalities. Overall, KCNQ2 genetic defects were found in 11% of the patients in our cohort. These findings enrich the genetic epidemiology and mutation spectrum of KCNQ2 and allow adequate genetic counselling in the affected families