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This paper describes a study about the quantitative separation of cations and anions of the aqueous solution contain ing ferric iron, calcium, magnesium, potassium, sulfate and phosphate, employing a column formed by a resin bed (Dowex 50 -X8). The cation retention was studied by using solutions of pH 1.85; 1.00; 0.60 and 0.20. The retention was good for the pH 1.85 to 0.60 for all the cations studied. The elution of the cations with three five mililiters portions of 4 N HCl solution showed good results. Sulfate and phosphate were recuperated after the solution was passed through the column of resin, washing the resin with two mililiters of water. The results obtained allow to conclude that the technique is satisfactory for the separation of cations and anions of the plant materials extracts.

Five genera of mites and one hypopus of Acaridae are reported as to occur associated with the fungi cultivated by the leaf cutting ant Atta sexdens rubropilosa (Hymenoptera, Formicidae).

Rhaphignathoid genera Cryptognathus, Noephyllobius, Eupalopsellus, Raphignathus, Ledermuelleria, Microstigmaeus, Zetzellia and Agistemus, and the species Agistemus longisetus Gonzalez, 1963, are recorded from the State of São Paulo, Brasil.

Eggplants(Solanum melongena L. var. Hibrida F1 Piracicaba nº 100) were grown in pots containing 7 kg of pure quartz. Twice a day they were irrigated by percolation with complete nutrient solution. Every ten days from the 35th day, plants were harvested, divided into aerial part and fruits and analysed for N, P, K, Ca, Hg and S. Data obtained allowed for the following main conclusion: a) The initial rate of growth of the eggplant during the first 66 days is rather slow. b) The uptake of macronutrients is samll until the 66 days increasing with the age of the plant. c) The maximum absorption rate according to the element in decrease order is: K, N, Ca, Mg, P and S. d) The following amounts of element in kg/ha were absorved by a population of 20.000 plants with 20.000 kg harvested:

The present work reports a study of the chelatometric method (by EDTA titration) for determination of sulfate in plant materials. A preliminary study about the indicator, conditions for the good precipitation of barium sulfate, and other influences on the method were performed. The presence of cations in the plant extracts did not cause interferences because they were separated using a cation exchange resin. The phosphate interferes and this ion can be removed by precipitation as ferric phosphate, adding ferric iron, acetate and ammonium hydroxide. Sulfate was determined in aqueous solutions, containing several ions, with good results. In order to compare the chelatometric (based in the proposed technique) and the gravimetric methods, in the determination of total sulfur in plants, five replications of different plant materials were analysed by both methods. The data obtained allowed to conclude that the technique proposed is good and the accuracy satisfactory. The determination of sulfur-sulfate was performed by the proposed method with satisfactory results.

Onion plants (Allium cepa L. var. Baia Piriforme Precoce de Piracicaba) were grown in pots containing 1 kg of pure quartz. Twice a day they were irrigated by percolation with nutrient solution. The treatments were: complete solution, -N, -P, -K, -Ca, -Mg and -S. The plants showed deficiencies symptoms in the following order: N, Ca, P, K, Mg and S. The deficiencies were comproved by chemical analysis of the different parts of the plant. The percentage of macronutrients in dry matter are expressed on the Table 3 in Portuguese text. "Levels" found in percentage of dry matter were: The amount of nutrients exported per plant, in mag, were: N-657.7; P-84.1; K-992.4; Ca-102.2; Mg-72.9; S-167.7.

Cocumber (Cucumis sativus, L.) and wheat (Avena sativa L.) were used a test plants for determination of DIURON in two soils: sandy soil (Arenito Bocucatu) and clay loam (série "Luiz de Queiroz". The rates of herbicide applied for 400 g of the soils were: 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.5, 10.0, 15.0 and 20.0 mg. Cucumber is very sensible to DIURON and may be used for determination up to 1.0 mg/400 g of soil; and wheat from 1.0 to 20.0 mg.

Due to the great economic importance of the cotton crop to Brazil, a systematic series of research work has been carried out in recent years dealing with its mineral nutrition an fertilization. A summary of recent finding is given in the following sections.

No summary/description provided

This experiment was conducted to compare percent hatch ability, hatching weight and feasability of raising chicks from three grades of eggs (special, A and B) of the New Hampshire breed. This experiment consisted of 12 incubations of 300 eggs each (100 eggs from each grade). Chicks from the last two incubations were raised to 8 weeks of age. Interpretation of results showed: 1 - no difference in percent hatchability between the egg grades studied; 2 - significant relation between weight of egg and weight of egg and weight of chick at hatching; 3 - chicks from larger eggs developed better had higher weight-gain, an lower mortality index.

Moisture determination in fertilizers by the application of Archimedes Principle drive the author to the following equation were u = moisture in percentage d = fertilizer density x1= difference between the sample dry weight and the buoyed up by a force equal to the weight of the displaced fluid (saturated solution of the fertilizer) y= sample weight d1= density of the fluid. For seeds the following equation was obtained were u = moisture in percentage v - seeds volume d = seeds density y'= seeds weight The application of both formulas showed straight correlation with the usually method in store at 100-105°C.

No summary/description provided

This paper describes the determination of the nitrate, ammonium and urea nitrogen content in fertilizers. The ammonium and urea nitrogen were determined directrly in the water extract of the fertilizer. The nitrate nitrogen was separated by a column of resin DOWEX-1-X8, strongly basic. Nitrate was determined after the elution with 20% NaCl solution. The procedure described requires less working time than the classical method and yelds accurate results.

Aluminum and hydrogen ions extracted from soils with 1 N KC1 solution are considered the most active forms of acidity. In fact, the displacement of those ions by continuous percolation with 250 ml of 1 N KC1 solution increased the pH of seven soils samples studied, determined in soil: water proportion 1 : 2,5. However, the pH of five soils samples remained 6.25, 6.05, 5.80, 5.45 and 5.05 after the extraction with 1 N KC1 solution, pointing out the presence of other active forms of acidity. Those samples wich were treated with KC1 solution and then with 1 N calcium acetate solution(pH=7,0) presented other components of soil acidity, determined by titration with standardized 0,02 N NaOH solution.

The determination of boron in vegetables by the curcumin colorimetric method is based on the formation of the rosocianin complex in acetic-sulphuric media. In this procedure the reaction takes place in solution at room temperature, needing not to control the temperature at 55 3°C, as with the common method in which the rubrocurcumin complex is formed. An aliquot of the vegetable extract is rendered alkiline by adding a solution of NaOH and then dried over a vapor bath. To the residue is added a 0,125% curcumin acetic solution and a (1 + 1) acetic-sulphuric solution. The reaction is completed in 15 minutes. In the application of the method to plant materials analysis, several aspects were studied: interferents and their elimination, the recovery of boron from the ashed samples, the contamination due to filtration through paper filter, and the precision and accuracy of the method. Among the normally found elements in vegetable aske, the one interfering were: Ca2+, Mg2+, Fe3+, Mn2+ and Co2+. They were separated by passing the extract through cation exchange resin. The method, as described, may be considered efficient for the boron determination in vegetables, since it showed good precision and accuracy, coupled with high sensitivity, allowing the determination of as low as 2 ppm of boron in vegetables, within the limits of the least erros.

Nitrate in soils and plants can be determined by the method of ultraviolet absorption of nitrowyl chloride. The extracts of plants need to be treated with hydrogen peroxide before the determination in order to exidize the organic matter. For the soil extracts the blank is obtained by eliminating nitrates with hydrazine sulfate wich server to correct the absorption of the soil solutions. The determination is carried on adding perchloric, sulfuric and hudrochloric acids to the solutions obtained from vegetable and soil materials to form nitrowyl chloride. The absorbances of solutions are read at 230 miliraicrons.

This paper reports the ammonium determination in soils, by the colorimetric method of Nessler. Several aspects were studied, like the absorption spectra of the color compound and the Nessler's reactive, the action of the time of standing and the temperature on the development of the color and the interference of some ions which are normaly in the soils extracts. The ammonium determination wasmade in soil extracts obtained with KC1 1 N solution and distilled, in order to prevent the interference of manganous ion, which gives a precipitated with the Nessler's reactive. The results were compared with the those obtained by the tritrimetric method.

Êste trabalho apresenta um estudo sobre o método espectrofotométrico do metiltimol azul para a determinação do magnésio trocável dos solos. São apresentados dados relativos à curva de absorção e à estabilidade do composto magnésio-metiltimol azul e do metiltimol azul. No estudo dos interferentes, foram considerados diversos íons, verificando-se que o principal deles é o íon cálcio, o qual é eliminado da solução através da precipitação com solução saturada de oxalato de amônio. Para a extração do magnésio trocável dos solos usou-se uma solução de KC1 1 N.

This paper presents a little knew method for determining soil moisture supported on the famous Archimedes principle. It is suggested also a modification to the original method for making it convenient to the use in relation to soluble fertilizers. Finally, this paper presents a simplification to the original method in order to make it useful to the determination of moisture in granular fertilizers, seeds and soils without immersion of them.

This paper describes the data obtained concerning the chloride concentration in coffee leaves. The application of potassium chloride furnished the following means: 843,3 ± 134,3; 4476,0 ± 356,4; 4812,0 ± 67 0,7 and 5149,0 ± 570,7 ppm of chloride, respectively, for the treatments K0 (no KC1 applied); K1(167 grams of KC1 or 100 grams of K2O); K2(335 grams of KC1 or 200 grams of K2O); and K3 (670 grams of KC1 or 400 grams of K2O). Symptoms of excess of chloride were not observed in this experiment.