Vermiculite

About: Vermiculite is a research topic. Over the lifetime, 2320 publications have been published within this topic receiving 37142 citations.

Effect of Neotyphodium endophyte-tall fescue symbiosis on mineralogical changes in clay-sized phlogopite and muscovite

Abstract: Numerous studies have been conducted to determine the positive effects of Neotyphodium endophye-tall fescue symbiosis on plant resistance to different stresses. However, its effects on the uptake of potassium (K) and transformation of K-bearing minerals are not yet known. The objective of this research was to investigate the possible effects of such symbiosis on the transformation of clay-sized micaceous minerals. Tall fescue genotype 75B, both infected and non-infected with natural Neotyphodium endophyte, was cultivated in a mixture of quartz sand and phlogopite or muscovite. Pots were irrigated with distilled water and complete or K-free nutrient solutions for a period of 140 days. K concentrations in shoot and root were determined using a flame photometer and the clay-sized particles in each pot were analyzed using an X-ray diffractometer. Results revealed vermiculitization of phlogopite under both nutrient solutions. In addition to vermiculite, smectite was detected as a newly formed mineral in phlogopite-amended pots. In contrast, a very weak rate of vermiculitization was observed in muscovite-treated media. The rate of phlogopite transformation was significantly higher under the endophyte-infected plants, particularly when the K-free nutrient solution had been applied. Also, the significant decrease in pH value in the rhizosphere of infected plants confirmed the positive effect of endophyte-tall fescue symbiosis on mineral transformation.

Changes in mineral composition and bioavailable potassium under long-term fertilizer use in cotton-wheat system

Abstract: Changes in soil bioavailable potassium (K) and mineral composition determines long-term sustainability of a cropping system. After 5-year fertilizer treatments to cotton-wheat rotation, changes in soil mineralogy and the Kavailability indices were investigated to help devise optimum fertilization plan. The soil contained mica, quartz, and feldspars in the sand and silt fractions; mica and kaolinite with small amount of quartz, smectite and vermiculite in the coarse clay; and mainly smectite and some vermiculite and mica in the fine clay fraction as determined by X-ray diffraction and total K and Ca/Mg and K/NH4 CEC properties. The sand and silt from AB (14-27 cm) horizon of NPK treatment had stronger mica peak than that of NP. Treatment effect on mica in Ap (014 cm) and Bwk (27-43 cm) horizons was limited probably due to sedimentation of fresh minerals entering the field with canal irrigation and less root activity in Bwk horizon. Boiling HNO3-extractable K varied from 196 to 432 mg 100 g -1 sand and from 181 to 197 mg 100 g -1 silt from the fallow profile. The NPK treatment contained greater boiling HNO3-extractable K in the sand and silt fractions as well as the soil NH4OAc-extractable K than the NP. The soil NH4OAc-extractable K ranged from 75 to 124 mg kg -1 soil and K-fixation ranged from 27.0 to 42.5 mg 100 g -1 soil. There was no long-term fertilizer treatment effect on soil K-fixation. The study conclude only marginal changes in soil bio-available K and in the mineral composition due to K-less fertilization in the canal irrigated cotton-wheat system in Southern Pakistan (Sindh).

Sandstone‐derived soils of a catena at iperu, nigeria

Abstract: Summary Chemical and mineralogical properties of five soil profiles of a catena in Iperu, Western State of Nigeria, are reported. The pH values of the subsoils are extremely acid. Acidity decreases with improved drainage in the subsoils (pH 4.0–5.8). The cation exchange capacity (C.E.C.) of the soils range from 3.0 to 16.2 me/100g of soil. The silt: silt+clay ratio, calcium: magnesium ratio and Fe2O3:Al2O3 ratio are used as weathering indices. The low values of the silt: silt + clay index indicate that the soils must have undergone advanced weathering. The magnitude of the Ca: Mg ratio indicates that more calcium than magnesium is available in the soils. The values for sodium and potassium are extremely low. More iron than aluminium was extracted from the soils by the dithionite-citrate method. Kaolinite is the most abundant clay mineral. Halloysite, interstratified clay materials, vermiculite, quartz, and mica are present in considerable amounts. The silt fraction in which quartz is the most abundant mineral, also contain some kaolinite and mica.

Substratos alternativos para produção de mudas de alface e couve em sistema orgânico

Abstract: This work aimed to evaluate the effect of different alternative substrates in the production of lettuce and cabbage seedlings in an organic system. The work was conducted in the experimental area of Universidade Estadual de Mato Grosso do Sul, city of Gloria de Dourados, Mato Grosso do Sul state, in plastic greenhouse. The experimental outline used was entirely randomized, with four repetitions. The evaluated treatments were: T1: commercial substrate (Bioplant®), T2: compost of cattle manure, T3: vermiculite, T4: coffee straw, T5: compost of cattle manure (50%)+vermiculite (50%), T6: compost of cattle manure (75%)+vermiculite (25%), T7: compost of cattle manure (25%)+vermiculite (75%), T8: compost of cattle manure (50%)+coffee straw (50%), T9: compost of cattle manure (75%)+coffee straw (25%), T10: compost of cattle manure (25%)+coffee straw (75%), T11: vermiculite (50%)+coffee straw (50%), T12: vermiculite (75%)+coffee straw (25%), T13: vermiculite (25%)+coffee straw (75%), T14: compost of cattle manure (50%)+vermiculite (25%)+coffee straw (25%), T16: compost of cattle manure (25%)+vermiculite (25%)+coffee straw (50%). By the results got, the utilization of substrate made with cattle manure mixed in proportions with the vermiculite introduces itself as an alternative in commercial substrate in production of lettuce and cabbage seedlings in trays system.

Vermiculite processing machine

Abstract: This invention relates to a vermiculite process,ing machine. This invention is particularly concerned with an apparatus for expanding or exfoliating fragments of vermiculite, for separating the stones from the exfoliated vermiculite, for separating the smaller fragments of exfoliated vermiculite...