Maria Anita Gonçalves da Silva

Características químicas de um latossolo adubado com uréia e cloreto de potássio em ambiente protegido

The production of healthy, high quality vegetables and the development of technologies for continuous supply to the market are important factors determining the adaption of protected cultivation systems by an increasing number of growers. Due to the little knowledge on soil management practices under these conditions, high fertilizer rates are normally applied, causing salinity problems and nutricional unbalances. The objective of this paper was to evaluate the effects of urea and potassium chloride applications on the chemical characteristics of an Eutrorthox, mainly on its acidity and potassium saturation. The N was applied in rates of 13.3 and 39.9g m-2 and the K in rates 5.5 and 16.6 g m-2, in a fatorial (2X2+1) design, including a control. Pepper plants (Capsicum annuum, Mayata cultivar) were grown under protected condition, during 34 weeks. After seedling rooting, the nutrients were applied at the rate of one sixth of the total at ten day intervals, up to 60 days. It was observed that urea did not acidify the soil probabily due to its high buffering capacity. The nitric and ammoniacal forms of N were directly effeted by the N rates applied in relation to the soil. In the treatment with N, the roots showed better development compared to the control. However, the highest K rate, applied as KCl, decreased root growth, probably due to the high soil K concentration and possible salinity effects, resulting in more than 5.0 mmolc dm-3 of K and more than 5.3% of K saturation in the exchange complex.

Efeito do nitrogênio e potássio na nutrição do pimentão cultivado em ambiente protegido

Avaliou-se a influencia do N e K na concentracao e acumulo de nutrientes no pimentao, cultivar Mayata, irrigado por gotejamento. O experimento foi instalado em cultivo protegido telado, em Latossolo Vermelho mesoferrico, entre o periodo de novembro de 1996 a agosto de 1997, durante 34 semanas. Os tratamentos constaram de tres doses de N (13,3; 26,6 e 39,9 g m-2), como ureia, e tres doses de K (5,5; 11,0 e 16,6 g m-2), como KCl, distribuidas em esquema fatorial, utilizando o delineamento em blocos casualizados. Todas as plantas foram irrigadas por gotejamento tendo sido a ureia e o cloreto de potassio aplicados logo abaixo dos gotejadores. As doses de N nao afetaram a concentracao dos nutrientes em folhas recem-maduras, no inicio do florescimento e inicio da frutificacao, enquanto o K diminuiu a concentracao de P e S, no inicio da frutificacao, exceto na dose de 5,5 g m-2 de K. O N aumentou o acumulo de nutrientes na parte aerea, ao final do ciclo de cultivo, quando aplicado na dose de 26,6 g m-2, porem nao influenciou a producao de frutos. O K contribuiu para a absorcao de nutrientes e producao de frutos, somente quando presente em baixas concentracoes no solo. Doses de K de 16,6 g m-2, relacionaram-se com a alta condutividade eletrica (1.400 µS cm-1), ate a camada de 40 cm, e com a alta concentracao de cloreto na parte aerea e frutos de pimentao.

Rendimento e qualidade de frutos de pimentão cultivado em ambiente protegido em função do nitrogênio e potássio aplicados em cobertura

The objective of this work was to evaluate the effect N and K2O on the production and yield of sweet pepper plants, related to the characteristics of growth (weight, lenght and diameter) and total number of fruits per plant, per area. Nitrogen (urea) and potassium (KCl) fertilizers were side dressed in six applications to sweet pepper cultivar Mayata, cultivated in a protected environment. The experiment was conducted from November/96 to August/97, with the following treatments: control and combination of three rates of N (13.3, 26.6, and 39.9 g m-2) and three rates of K2O (13.3, 26.6 and 39.9 g m-2). The experimental design consisted of randomized blocks, in a factorial scheme (3 x 3 + 1), with four replications with a total of 40 plots. Each plot comprised 11 plants, totalizing of 444 plants. Plants were grown with drip irrigation along the entire cycle of the crop. Fruits were harvest when ripe, ready for consumption. Nitrogen fertilizer increased the maximun dry matter of the stem, leaves and roots, but not of fruit dry matter production. The optimal rate for maximum dry matter accumulation of N was 27.0 g m-2. Nitrogen did not affect the growth characteristics of the commercial fruits, such as weight, length, and diameter. Therefore did not affect the yield of commercial fruits. The favorable effect of the nitrogen on the production of total dry matter and yield occurred only at low concentrations of potassium in the soil (13.3 gm-2) and a minimum development of sweet pepper with 33,0 g m-2 de K2O in the soil.

Boron extraction and vertical mobility in Paraná State oxisol, Brazil

The deficiency or excess of micronutrients has been determined by analyses of soil and plant tissue. In Brazil, the lack of studies that would define and standardize extraction and determination methods, as well as lack of correlation and calibration studies, makes it difficult to establish limits of concentration classes for analysis interpretation and fertilizer recommendations for crops. A specific extractor for soil analysis is sometimes chosen due to the ease of use in the laboratory and not in view of its efficiency in determining a bioavailable nutrient. The objectives of this study were to: (a) evaluate B concentrations in the soil as related to the fertilizer rate, soil depth and extractor; (b) verify the nutrient movement in the soil profile; (c) evaluate efficiency of Hot Water, Mehlich-1 and Mehlich-3 as available B extractors, using sunflower as test plant. The experimental design consisted of complete randomized blocks with four replications and treatments of five B rates (0, 2, 4, 6, and 8 kg ha -1 ) applied to the soil surface and evaluated at six depths (0–0.05, 0.05–0.10, 0.10–0.15, 0.15–0.20, 0.20–0.30, and 0.30–0.40 m). Boron concentrations in the soil extracted by Hot Water, Mehlich-1 and Mehlich-3 extractors increased linearly in relation to B rates at all depths evaluated, indicating B mobility in the profile. The extractors had different B extraction capacities, but were all efficient to evaluate bioavailability of the nutrient to sunflower. Mehlich1 and Mehlich-3 can therefore be used to analyze B as well as Hot Water.

Mineral Composition and Dry Mass Production of Corn Plants Affected by Different Phosphate Sources and Different Soil Aluminum Saturation Levels

Abstract The effects of different commercial phosphate fertilizers [Triple superphosphate (TSP), Tricalcium phosphate (TCP), and ARAD rock phosphate) and soil aluminum (Al) saturation (86, 29, and 0%) on the mineral composition and dry mass production of corn (Zea mays) plants were studied. As soil Al saturation values decreased, pH, calcium (Ca), and magnesium (Mg) levels in the soil increased. High Ca values in the shoot resulted in the reduction in potassium (K) concentrations. The high values of P availability in the soil for the ARAD source of P did not correspond to the high values of dry mass production of corn plants. The high values of corn mass production were noticed for the TSP phosphate source, and the mass productions values were reduced as the soil Al saturation values increased.

Use of Agro-industrial Organic Compound : Yield and Nutrient Absorption in Wheat

Abstract This study, focusing on the cultivation of wheat, consisted of applying an organic compound to the soil for a period of 2 years. The organic compound was made from a mixture of organic residues from a jelly industry (bovine chips and sharings) and other residues from a sugar‐alcohol industry. The mixture was applied at random into the intergrowth lines in a top‐dressing process, without incorporation, and in cumulative increasing doses. In the first year, the applications ranged from 2 to 25 t ha; in the second year, the applications ranged from 8 to 75, in wheat plants. Comparing the results of the chemical treatment to the organic application, it was observed that the organic compound increased the yield of wheat during the 2 years. Furthermore, the organic compound did not contaminate the plants, such as in the absorption of nutrients by the grains, once they have presented normal patterns of nutrient concentrations.

Diagnosis and Recommendation Integrated System (DRIS) to Assess the Nutritional State of Plants

© 2013 Serra et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Diagnosis and Recommendation Integrated System (DRIS) to Assess the Nutritional State of Plants

Ammonium sulphate on maize crops under no tillage

The objectives of this work were to evaluate the management of N and S (as ammonium sulphate) fertilization under no-tillage system on the components of maize productivity and on N and S accumulation in the crop, as well as to evaluate the minimum value of the Nitrogen Sufficiency Index (NSI 0.95) as an indicator for side dressing requirements. The experiment had a completely randomized block design with six treatments and four replications carried out in Red Latosol dystrophic soil (Hapludox), in Campo Mourao, Parana State, where the following treatments in summer growth maize were applied: T1- 120 kg ha-1 N in seeding; T2- 120 kg ha-1 N in side dressing; T3- 40 kg ha-1 N in seeding and 80 kg ha-1 N in side dressing; T4- 30 kg ha-1 N in seeding and 90 kg ha-1 N in side dressing, monitored by a chlorophyll meter using the Nitrogen Sufficiency Index (NSI); T5- 120 kg ha-1 N anticipated in wheat seeding; T6- without nitrogen fertilization. NSI was determined by the relationship between the leaf chlorophyll index (ICF) average of T4 plants and that one in the plot fertilized with 120 kg ha-1 N at the maize seed sowing (T1). During two years, ammonium sulphate was applied to the maize crop after wheat under no tillage system. In the first year, with adequate rainfall, the maize yield was similar to the one in which the complete ammonium sulphate dose application was done in maize seeding and side dressing. The anticipated fertilization to wheat seed sowing resulted in maize yield without difference from the parceled form. In the second year, with irregular rainfall, all treatments with N were similar and they increased maize yield compared to that without N fertilization. NSI of 0.95 was not efficient to evaluate maize N requirements in side dressing, and resulted in lower maize yield. N was accumulated mainly in the grains unlike S that accumulated in the plant shoots; both were highly correlated to maize productivity.

Nutrient Availability in the Soil and Its Absorption, Transport, and Redistribution in Vines

Abstract This study was to determine the concentration, accumulation, redistribution, and export of nutrients by Rubi grape. Ten branches with leaves and fruit were collected; the vegetable matter (stem, leaf, and fruit) was washed, dried, weighed, and analyzed so as to determine the concentration of nutrients in the plant. The nutrients most absorbed were nitrogen (N), potassium (K), and calcium (Ca), and the best absorption time started after the berry ripening. Phosphorus (P), magnesium (Mg), and sulfur (S) were less demanded by the grape although they had the same behavior in relation to the period of greater absorption. The best absorbed nutrient was manganese (Mn), and its absorption increased gradually and steadily, according to the plant growing phases. The absorption of copper (Cu), zinc (Zn), and boron (B) was minimal up to the ripening of berries, but increased from then on. The greatest absorption and accumulation of nutrients occurred during the ripening of the fruits. The leaves had greater absorption of Ca, Mg, S, Mn, and Cu, whereas the fruit absorbed more K (61%), P (56%), N (38%), and B (56%). The stem presented similarly in the proportion of all macronutrients, and it accumulated more Zn.

ALUMINUM TOXICITY IN CORN PLANTS CULTIVATED WITH LOW AND HIGH IONIC STRENGTH NUTRIENT SOLUTIONS

The objective of the present study was to evaluate the phytotoxic effect of aluminum (Al) in corn plants in nutrient solution under high ionic strength (0.0094 uM) and low ionic strength (0.00001 uM). Regarding the low ionic strengths, nutrient solution was added daily until the end of the experimental period. The findings showed that the pH of the nutrient solution reduced with the increase in Al concentration, under both high and low ionic strengths solutions. Electrical conductivity of the nutrient solution increased with Al concentrations only in the solution with low ionic strength, demonstrating that the plant was more sensible to the element toxicity, thus reducing its growth and absorption of nutrients. The production of the total dry mass of corn was affected by the increase of Al concentration in the solution only under low ionic strengths, which reinforces the greater activity and absorption of the element under such condition.