Variations in the Chemical Composition of Soils of Various Types

Nitrogen, phosphorus, potassium, silica, iron, alumina, and base-exchange capacity were determined on nine Iowa soils and correlations made in an attempt to devise a system of soil mapping to be used when these constituents of the soil and soil extract were known. The results secured indicate a definite relationship between these constituents in each of the soils studied. However, no apparent relationship existed between the variations and soil type. The P2O3 content of all soils was found to vary directly with the base-exchange capacity of the soil

The Importance of Soil Colloids to Soil Microorganisms

The significance of soil colloids with respect to microorganisms in the soil has received little attention by soils investigators. Results secured here indicate that the soil colloid is the principal habitat for both aerobes and anaerobes in the soil

The Effect of Lime on the Availability of Phosphate in Tama Silt Loam

Calcium limestone and dolomitic limestone were applied to Tama silt loam in pots in the greenhouse. The soil had a lime requirement of 3 tons per acre ancl the pH was 5.30. Rock phosphate was applied at the rate of 250 pounds per acre alone and in combination with calcium limestone and with dolomitic limestone. Samples of the variously treated soils were taken after 4, 8, 12, and 18 weeks for the determination of pH and available phosphate

Soil Survey of Iowa, Report No. 76—Hancock County Soils

Hancock County is located in north central Iowa in the second tier of counties south of the Minnesota state line and in the middle tier of counties from east to west in the state. It lies entirely in the Wisconsin drift soil area, and hence its soils are all of drift or glacial origin

Experiments with Dry Dust Cultures for the Inoculation of Legume Seeds

Within the past few years a number of commercial concerns have produced a dry dust type of culture for the inoculation of legume seeds. Field experiments have been conducted to test the value of these cultures for the inoculation of soybeans. The results showed that the dry dust cultures did not give satisfactory inoculation. Greenhouse experiments have also shown that the inoculation of legume seeds sometime in advance of the planting date, as is recommended by the producers of the dry dust manufacturers, is undesirable

Deposizione di rivestimenti in Al2O3 mediante High Velocity Suspension Flame Spraying (HVSFS): caratteristiche dei riporti ed effetto dei parametri operativi

La tecnica denominata HVSFS (High Velocity Suspension Flame Spraying) è un processo di termospruzzaturainnovativo che, alimentando la torcia con una sospensione di particelle finissime (micro- o nano-metriche)disperse in una fase liquida, permette la deposizione di rivestimenti ceramici ad alta densità e basso spessore(<100 ?m). Per approfondire la relazione fra caratteristiche dei riporti e proprietà della sospensione, varirivestimenti a base di Al2O3 sono stati depositati utilizzando sospensioni di particelle sia micrometriche, siananometriche. Indipendentemente dai parametri di processo selezionati, una sospensione di particellemicrometriche sufficientemente disperse garantisce maggior efficienza di deposizione (>50%) e producerivestimenti costituiti da un’ottima sovrapposizione di lamelle fortemente coese, con maggior durezza(?1200 HV0.05) e minor rugosità (Ra ? 1.3 ?m) rispetto ai rivestimenti ottenibili con sospensioni dinanoparticelle. Sebbene i rivestimenti ottenuti da sospensioni di particelle micrometriche siano anche soggettia tensioni residue trattive più elevate (fra 50 MPa e 100 MPa), la loro eccellente densità e ottima coesione lirendono molto più resistenti all’usura per strisciamento (studiata con test “ball on disk”) rispetto a riporti diAl2O3 prodotti sia con sospensioni di nanoparticelle, sia con tecniche di termospruzzatura convenzionali

A novel satellite mission concept for upper air water vapour, aerosol and cloud observations using integrated path differential absorption LiDAR limb sounding

We propose a new satellite mission to deliver high quality measurements of upper air water vapour. The concept centres around a LiDAR in limb sounding by occultation geometry, designed to operate as a very long path system for differential absorption measurements. We present a preliminary performance analysis with a system sized to send 75 mJ pulses at 25 Hz at four wavelengths close to 935 nm, to up to 5 microsatellites in a counter-rotating orbit, carrying retroreflectors characterized by a reflected beam divergence of roughly twice the emitted laser beam divergence of 15 µrad. This provides water vapour profiles with a vertical sampling of 110 m; preliminary calculations suggest that the system could detect concentrations of less than 5 ppm. A secondary payload of a fairly conventional medium resolution multispectral radiometer allows wide-swath cloud and aerosol imaging. The total weight and power of the system are estimated at 3 tons and 2,700 W respectively. This novel concept presents significant challenges, including the performance of the lasers in space, the tracking between the main spacecraft and the retroreflectors, the refractive effects of turbulence, and the design of the telescopes to achieve a high signal-to-noise ratio for the high precision measurements. The mission concept was conceived at the Alpbach Summer School 2010