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Determinação do período de tempo para amonificação e nitrificação de diversos fertilizantes nitrogenados

In this paper results obtained with the phenomenon of ammonification and nitrification in several nitrogen fertilizers are presented. The objective was the determination of the intensity and evolution of these phenomena. For this purpose an experiment was set up including the following nitrogenous fertilizers: ammonium sulfate, urea, castor bean cake, blood meal, horn and hoof...

Zinco em solos do estado de São Paulo I: zinco total

Determinations of total zinc, extracted with HF-HClO4, were carried out in 227 samples of 28 profiles of 14 soil units of the State of São Paulo, using the atomic absorption spectrophotometry. The amount of zinc found in the different soils was mainly determined by the zinc content of the soil forming material. In soils derived from basic igneous rocks, those richest in zinc, the...

A separação do Cálcio de Estroncio mediante o emprego de Resina Trocadora de Íons e de Estroncio Radioativo Sr-89

A simple, rapid and efficient method of separation of strontion from calcium can be perfomed by using a solution of 2.5% NH4- EDTA, with pH adjusted to 4.80 to dissolve those cations. After, the solution is passed through a 25-28 ml column of the Amberlite 1R-120 (4+) cation exchange resin. Strontinum is quantitatively retained on the resin, while calcium passes through. After...

A precipitação do estrôncio na forma de cromato em meio amoniacal e hidroalcoolico

This paper describes the data obtained concerning qualitative and quantitative analyses of the precipitate formed when to a solution containing strontium ion are added potassium dichromate, ammonium hydroxide and 95 per cent alcohol. Three replications of standard solution containing 1.8, 4..4, 8.8, 13.7, 27.5, 41.2, and 50.5 mg of strontium were treated with potassium dichromate...

Método do EDTA na determinação do cálcio e magnésio "trocável

This paper describes the determination of exchangeable calcium and magnesium in soil by using ethylenediamine tetracetic acid, after the separation of the principals interferents (iron, aluminum, manganese and phosphate) by using both ammonium hidroxide and ammonium sulfide in only one operation. In order to compare the chelometric and the permanganometric methods for determining...

Determinação de cálcio e magnésio em plantas, pelo método do EDTA

The present work reports a study of the chelatometric method (by EDTA titration) for determining calcium and magnesium in plant materials. A preliminary study about the influence of severals íons (Fe3 +, PO43 -, Al3 +, SO42 - and Mn2+) was performed. The presence of sulfate and aluminum did not cause interference in the method. Manganese (200 micrograms) interferes by causing the...

Avaliação da exigência de calcário do solo através de soluções tampão

- Testing soils for lime requirements by means of a buffered solution and the glass electrode. Soil Sci., 66:53-63.         [ Links ] ZUNIGA, A. A. T. & R. A. CATANI, 1967 - Extração de diversos íons do

Amostragem de solo para estudos de fertilidade

The following methods of collecting soil samples for fertility studies were compared : 1) thirty individual samples covering the whole area ; 2) ten composite samples, each consisting of five individual samples, covering the whole area ; 3) five composite samples, each consisting of 20 individual samples, covering the whole area. The three types of samples were collected in each...

A absorção de nitrogênio, fósforo, potássio, cálcio, magnésio, enxôfre e silício pela cana de açúcar, Co 419, e o seu crescimento em função da idade

This paper describes the data obtained for the growth of sugar cane, Variety Co 419, and the amount and rate of absorption of nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, and silicon, according to the age of the plant, in the soil and climate conditions of the state of S. Paulo, Brazil. An experiment was installed in the Estação Experimental de Cana de Açúcar "Dr...