Effect of substrates on germination and seedling emergence of sunflower (Helianthus annuus L.) at the Yongka Western Highlands Research/Garden Park, Bamenda-Cameroon

A study was carried out at the Yongka Western Highlands Research Garden Park, Nkwen­Bamenda in Cameroon to evaluate the effect of substrates on the germination and seedling emergence of sunflower (Helianthus annuus L.). Seeds of African Giant variety were used with six substrate media (sawdust, sand, soil, sawdust­sand, sawdust­soil and sand­soil). The experiment was laid out in a Randomized Complete Block Design in three replications. Germinated seeds were counted daily for a 15 days period. To estimate seedling emergence from two Weeks After Sowing (WAS) up to four WAS, data on seedling height and number of leaves were recorded. The results showed that germination started 8 days after sowing for all substrates. Germination rate was significantly affected by the substrates but the rates were less than 80%. The highest germination rate was recorded on the soil substrate (75%) while the lowest rate (25%) was recorded on the sawdust substrate. Seedlings on the sawdust substrate were also less vigorous and had less leaves (12.67 cm height and 4.7 leaves) than those on other substrates at four WAS (50–63 cm and 12.6–15.3 leaves). Based on the results, it is recommendable to use the soil substrate to nurse African Giant seeds

Properties and Utilisation of Andisols in Indonesia

Soils formed on volcanic ash parent materials and classified as Andisols are widespread in the Indonesian archipelago, covering an area about 3 million hectares. Soils are developed from mostly andesitic to basaltic rocks on Upper Pleistocene to Holocene surfaces. Weathering gradually increases downslope and with the prevailing high precipitation and high temperature produces deep soils. The Indonesian Andisols mostly have dark epipedons with high content of organic carbon and low bulk densities (). soil reaction is slightly acid with negative A pH values with CEC ranges from 22 to 30 cmol(+) kg^. Major minerals in the sand fraction are quartz, plagioclase, hornblende, augite, hypersthene, olivine and volcanic glass. Short-range-order minerals like allophane, imogolite and/or ferrihydrite dominate the clay fraction, whilst halloysite, gibbsite, cristobalite are also detected in lesser amount. The surface charge of Indonesian Andisols containing allophane and imogolite is pH dependent (variable charge) resulting high phosphate fixation. The Langmuir phosphorus sorption maxima ranged from 300 to 2, 500 mg P kg^. Most of the Indonesian Andisols are among the most productive soils. These soils are intensively cultivated with both annual and perennial of upland crops like tea, coffee, cocoa with quite high productivity. The areas in the vicinity of volcanoes are also well-known as the horticultural centre and support more than 50% of the Indonesian people. The tea and Arabica coffee plantations occupied hundreds hectares of land from lower to medium slopes of volcanoes both in Sutmatra and Java islands while secondary and primary forests formed in the upper slopes of volcano

Charge characteristics in relation to free iron and organic matter of soils from Bambouto Mountains, Western Cameroon

We have examined the charge characteristics, with special emphasis on the role of free Fe and organic matter, of humid tropical soils from Bambouto Mountains, Western Cameroon. The soils, which are formed from tuff, basalt and trachyte, are dominated by kaolinite and sesquioxides. The mounts of Fe oxides in them increase somewhat with depth. Open 2:1 phyllosilicates are present in trace amounts. The point of zero charge of the variable charge components, pH0, is around 4 in the topsoil (0-20 cm) and around 6 at 100-150 cm depth. In the subsoils, pH0 exceeds soil pH presumably because of large quantities of Fe oxides. Deferration increases both soil pH and pH0, but diminishes the anion exchange capacity. Oxides and oxyhydrates of Fe have positive surface charge, so their removal from the soils would result in overall loss of positive charge. Increases in soil pH would bring about an increase in the cation exchange capacity of the soils. Hence, management practices that reduce soil acidity should reduce loss of essential basic cations via leaching

Changes in the chemical and mineralogical properties of Mt. Talang volcanic ash in West Sumatra during the initail weathering phase.

Eruptions from Talang volcano on 12 April 2005 distributed volcanic ash over portions of the Solok District of West Sumatra, Indonesia. Unleached and leached pristine volcanic ash were collected immediately after the eruption, and the third sample was collected after 2 years. The mineralogy and chemical properties of pristine volcanic ash and volcanic ash deposits that were weathered for 2 years from the 2005 eruption of Mt. Talang, Sumatra, were studied to characterize the volcanic ash, identify the primary minerals present, and determine its chemical properties. Results showed that the volcanic ash contained 30% noncrystalline minerals (or volcanic glass); the remaining ash is composed of crystalline minerals such as labradorite, hypersthene, augite, hornblende, olivine, opaque ferromagnetic minerals, and rock fragments. Notable differences in pH values were observed as the pH tended to become more acidic from the unleached, leached, and weathered volcanic ash, but the ash did not give much response to the sodium fluoride (NaF) test. Total sulfur gradually decreased from 3.28% in unleached ash to 1.93% after 2 years. Available phosphorus (P) in the unleached volcanic ash was 68 mg kg−1, and this value was decreased by 15 % after 2 years of being exposed to the atmosphere, while phosphate retention ranged between 52.8% and 66.8%. Cation exchange capacity (CEC) was low with the value of 10 cmolc kg−1 although base saturation was high, exceeding 75%. The low acid oxalate–extractable silicon (Si), aluminum (Al), and iron (Fe) values of 0.07%, 0.25% and 1.17%, respectively, show the scarcity of secondary amorphous compounds in the ash. Total elemental analysis indicated that no differences were found in total silica oxide (SiO2) content of all samples, with a value about 56%, and this volcanic ash can be classified as basaltic andesite. We observed that removal of chemical elements by leaching was large for calcium oxide (CaO), magnesium oxide (MgO), and sodium oxide (Na2O) as the values decreased in time. Solid-state 29Si and 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) studies indicated that Al occurred in both tetrahedral and octahedral forms. Silicon was not present in the tetrahedral layer. An intense peak at −92 ppm was indicative of the presence of aluminosilicates

SARS-CoV2 (COVID-19) infection: is fetal surgery in times of national disasters reasonable?

Even though the global COVID‐19 pandemic may affect how medical care is delivered in general, most countries try to maintain steady access for women to routine pregnancy care, including fetal anomaly screening. This means that, also during this pandemic, fetal anomalies will be detected, and that discussions regarding invasive genetic testing and possibly fetal therapy will need to take place. For patients, concerns about Severe Acute Respiratory Syndrome‐Corona Virus 2 will add to the anxiety caused by the diagnosis of a serious fetal anomaly. Yet, also for fetal medicine teams the situation gets more complex as they must weigh up the risks and benefits to the fetus as well as the mother, while managing a changing evidence base and logistic challenges in their healthcare system

Organic Matter in Clay Density Fractions from Sandy Cropland Soils with Differing Land-Use History

Land-use history is oft en overlooked when assessing soil fertility of intensive cropland production systems. Th e unusually high organic carbon (OC) content of many sandy cropland soils in Northwestern Europe is unexpected given their general low clay content (3–8%) and organic matter (OM) input typical of cropland, but appears to be related to historical heathland land-use. Clay fraction OM composition was compared between two groups of sandy cropland soils with (HC) or without (CC) a history of heathland/forest land-use. Light (1.6–2.2 g cm−3) and heavy (>2.2 g cm−3) clay fractions in HC soils were nearly twice as rich in OC (on average 199 g kg−1) compared with those of CC soils (on average 109 g kg−1). Th e hypothesized preferential presence of stable heathland derived OM in light soil fractions, was not supported by our data. Pyrolysis-fi eld ionization mass spectrometry of the clay fractions revealed a more decomposed character of OM in the CC soils and lasting long-term infl uence of land-use history on SOM composition. Th is could be concluded from higher proportions of lipids and sterols, a lower thermostability in the HC compared with the CC soils, and enrichment of alkylaromatics and heterocyclic N-containing compounds in the latter. Th e density fractionation methodology separated organic-mineral particles with similar OM loadings but lower proportions of sterols and medium to long-chained lipids in the heavy compared with the light clay fraction. Given the very high clay OC loadings (6–16 mg C m−2) and low binding capacity of the quartz/kaolinite/mica dominated clays, we hypothesize that OM–OM interactions are involved as an OM stabilization mechanism. However, contrary to our hypothesis high clay OC loading (and hence thick OM layering) were found in all sandy croplands regardless of land-use history or density fraction

High rotarix™ vaccine effectiveness against different rotavirus genotypes: modest relative increase in the prevalence of G2P[4] in remaining RVGE cases

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