Impactos do estresse salino e da cobertura morta nas características químicas do solo e no desenvolvimento do amaranto

Availability of good quality water has been reduced vertiginously, over the last decade, in the world. In some regions, the water resources have high concentration of the dissolved salts, these characteristics of the water make it s use impossible. Water quality can be a limitation for irrigated agriculture, principally in regions of arid or semiarid climate where the water resources are generally saline and are exposed at high evaporation ratio. For that reason, precipitation of the salts occurs near the soil surface and those salts themselves cumulate in the vegetal tissue, reducing the soil fertility and crop production. The adoption of tolerant crop to the water salinity and soil salinity, adaptable to the climatic conditions is other emergent necessity. This work had the goal of studying the effects of four salinity levels of the irrigation water salinity and use of mulch, dried leaves of Forest mangrove (Acacia mangiumWilld), in cultivated soil with amaranth (Amaranthus cruentus, BRS Alegria variety), in greenhouse. It was utilized the transplant of plants to PVC columns, containing 30 kg of silty loam soil, 10 days after emerging, with space of 50 x 50 cm between lines. Treatments were composed by combination of four levels of salinity (0.147; 1.500; 3.000 e 4.500 dS m-1), obtained by addition NaCl (commercial) to irrigation water and soil with and without protection, by mulch. A factorial system 4 x 2 was used with four repetitions, totalizing 32 parcels. The concentrations of nutrients in soil solution have been evaluated, in the dry matter of the vegetal tissue (roots, stem, leaves and raceme residue), at the end of the vegetative cycle. The use of soil protection reduced time for the beginning inflorescence of plants, at the same time, the increase of the salinity delayed this phase of amaranth development. The use of the mulch effectively increased the height, stem diameter, area of the larger leaf, humidity and dry matter content and amaranth grain production. The vegetal species showed salinity tolerance to experimented levels. The adopted treatments did not affect the pH values, exchangeable cation contents, electrical conductivity of soil solution (EC1:5) and saturated extract (ECSE), and Ca+2, Mg+, Fe+2 and Mn+2 contents, in the soil solution. The increase of the salinity concentration in the irrigation water inhibited the mineralization process of the organic matter (OM) and, consequently, the efficiency in the it´s utilization by plants, at the same time, produced increase in the values of the exchangeable sodium percentage (ESP), sodium adsorption ratio (SAR) and potassium adsorption ratio (PAR), in the soil solution. Therefore, the use of the mulch did not affect the first three parameters. The protein and nutrient contents: K+, Ca+2, P, Mg+2 e Cu+2, in amaranth grains, were improved by tillage condition. The raceme residues showed chemical/nutritional composition that makes advantageous its application in animal ration. In this context, it follows that amaranth tolerate the saline stress, of the irrigation water, until 4.500 dS m-1, temperature and relative humidity of the air predominant in the experimental environment

Características químicas de solo e rendimento de fitomassa de adubos verdes e de grãos de milho, decorrente do cultivo consorciado

A adubação verde é uma das formas de aporte de matéria orgânica ao solo. O sistema de cultivo consorciado de culturas pode ser uma alternativa para aumentar a reciclagem de nutrientes e melhorar a produtividade. Para avaliar o sistema consorciado de adubos verdes com o milho, foram estudadas as características químicas do solo, a produção de matéria seca, a composição mineral de adubos verdes e o rendimento de grãos de milho, num experimento realizado em campo, entre 1995 e 1997, em solo classificado como Nitossolo Vermelho eutrófico. O milho foi semeado no espaçamento de 90 cm nas entrelinhas, perfazendo, aproximadamente, 50.000 plantas por hectare. Os tratamentos constaram de quatro espécies de adubos verdes: mucuna anã [Mucuna deeringiana (Bort.) Merr], guandu anão (Cajanus cajan L.), crotalária (Crotalaria spectabilis Roth) e feijão-de-porco (Canavalia ensiformis L.) e um tratamento-testemunha, sem cultivo consorciado. Essas espécies foram semeadas sem adubação, no meio da entrelinha, em duas épocas: simultânea ao milho e 30 dias após. O delineamento experimental foi o de blocos ao acaso em parcelas subdivididas, com quatro repetições. O feijão-de-porco apresentou maior produção de fitomassa e acúmulo de N, P, K, Ca, Mg e S. No primeiro ano de cultivo, o rendimento de grãos de milho não foi influenciado pelo cultivo consorciado com adubos verdes; no entanto, no segundo, a produção foi beneficiada pelo consórcio com feijão-de-porco.

Características químicas de solo cultivado com soja e irrigado com água residuária da suinocultura

In this work the distribution was evaluated "in situ" of phosphorus (P), organic matter (MO), potassium (K), calcium (Ca), magnesium (Mg), cation exchange capacity (CEC), aluminum (Al), sum of bases (S), base saturation (V) and pH of a soil cultivated with soybean and irrigated with swine wastewater in the 0, 25, 50 and 75% levels. The factorial scheme was constituted by the 20, 40 and 60 cm soil depths and four wastewater levels with five repetitions. The results showed that significant difference occurred only for P, K and CEC in the soil profile. However, in all parameters, the 60 cm soil depth showed that the concentrations levels are similar to before the aplication of treatments.

Culturas de cobertura, doses de nitrogênio e residual da aplicação de calcário: características químicas do solo, estado nutricional e características agronômicas do milho

Pós-graduação em Agronomia - FEIS

Efeito da incorporação de macrófitas aquáticas sobre características químicas de solo degradado

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Características químicas do solo e produção de biomassa de alface adubada com compostos orgânicos

The objective of the present study was to evaluate changes in chemical characteristics of soil and yield response of lettuce fertilized with organic compounds from waste and/or raw materials. Treatments were arranged in a randomized block design in a 5 x 4 factorial scheme, with five types and four doses of organic compounds, with four replications, applied to plants grown in pots for 35 days under greenhouse conditions. In the soil, the evaluated variables were: organic matter content, nutrient content -P, K+, Na+, Ca2+ and Mg+2, potential acidity (H+ + Al3+), sum of bases (S value), cation exchange capacity (CEC), base saturation (V%) and pH. In plants, dry matter yield of shoot was assessed. The addition of organic compounds increased the dry matter yield of the lettuce and organic matter content in soil, favoring the increase of phosphorus and exchangeable sodium in soil, also, increase in calcium and potassium were observed, with use of some compounds. Compounds 3 (domestic, urban and industrial residues) and 4 (Commercial Composto - Greenworld), mainly, improve the chemical characteristics of soil and reduce potential acidity.

Características químicas do solo e desempenho de culturas após quatro anos de aplicações de cama de aviário em diferentes épocas e níveis

Due to the high supply and its attractive cost, the poultry litter has been used in the southwestern region of Parana to the improvement of soil fertility seeking greater production of grains and pastures. However, the use without technical knowledge can minimize the benefits of poultry litter or even cause undesirable effects on soil, environmental pollution and also productivity losses in the used crops. The objective of this study was to evaluate the influence of different times of poultry litter application, predating the winter crop, associated with increasing levels, about soil chemical properties, release of nutrients and crop performances in four consecutive years (2011-2014). In the first three years the experimental design was randomized blocks with a split plot system and four replications. In the main plots were tested four poultry litter application times preceding the wheat production: 0, 15, 30 and 45 days before sowing (DAS); in the subplots were applied four poultry litter levels (wet basis): 0, 4, 8 and 12 Mg ha-1. Last year one more subdivision of plots was done, evaluating the use or not of nitrogen in coverage in wheat, at a dose of 100 kg N ha-1. The wheat cultivar used in the four years was the BRS 220. In three years it was evaluated the residual effect on soybean production (cultivar - BMX Turbo RR) and in one year on the beans. The chemical soil attributes were evaluated at four depths 0-2,5cm, 2,5-5cm, 5-10cm and 10-20cm, and also the rate of decomposition and nutrient release of poultry litter and the crop productivity. The different times of application concerning the poultry litter had little influence on the studied variables, demonstrating that the producer does not need to have a specific date (before planting) to the application of poultry litter. Potassium was fully released 60 days after the allocation of litter bags into the field; for nitrogen and phosphorus the release was slower. The use of increasing levels of poultry litter increased the levels of various soil elements, highlighting the potassium which reached 20 cm deep in the second year of evaluation. The increase in pH and in the base saturation occurred only in the upper layers, while the phosphorus reached 10 cm deep in the third year of the study. It was observed increased pH and base saturation. The use of increasing doses of poultry litter contributed to the wheat plant nutrition, significantly increasing the weight of a thousand grains, and the grain yield of wheat in all the evaluated years; the nitrogen fertilization in coverage also had significant effect for the fourth evaluated year. Also there was a significant response from the residual effect of poultry litter for crops planted in summer for both soybeans and beans.

Avaliação da comunidade de macrófitas aquáticas no reservatório de Aimorés, composição química das principais espécies e influência da incorporação nas características químicas de um solo degradado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Características químicas e fisiológicas de sementes de feijão em função do teor de fósforo na semente e doses de fósforo no solo

Para avaliar o efeito da combinação de teores de fósforo na semente com doses de fósforo aplicadas via solo sobre as características químicas e fisiológicas de semente de feijão, foram avaliadas sementes das cultivares Carioca Precoce e IAC-Carioca Tybatã, produzidas em cultivo da seca. Na produção das sementes utilizou-se o delineamento experimental em blocos casualizados em esquema fatorial 3x3, correspondente a três teores de fósforo na semente (baixo, médio e alto) e três doses de fósforo, na forma de superfosfato triplo, aplicadas no sulco de semeadura (zero, 90 e 150 kg P2O5 . ha-1), totalizando nove tratamentos para cada cultivar, com cinco repetições. Foram determinados o teor de água e as características químicas (teores de proteína, açúcares total, N, P, K, Ca, Mg, S, Cu, Fe, Mn e Zn) e fisiológicas da semente (germinação e vigor). Os dados obtidos foram submetidos à análise de variância e as médias comparadas pelo teste Tukey, a 5% de probabilidade. A qualidade fisiológica da semente não é favorecida pelos teores de fósforo na semente e no solo, embora esses ocasionem algumas alterações nos teores de nutrientes da semente.

Vinhaça in natura e biodigerida concentrada: efeitos nas características químicas e bioquímicas do solo e no crescimento inicial da cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Adubação nitrogenada em videiras na Campanha do Rio Grande do Sul: avaliação do rendimento e das características químicas do mosto da uva.

2007

Alterações físicas e químicas do solo em função do sistema de produção e da aplicação superficial de silicato e calcário

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Desempenho das redes neurais artificiais na estimativa das variáveis físicas e químicas do solo

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Efeitos da fosfatagem em pré-plantio nas condições químicas do solo e no desenvolvimento da cultura da cana-de-açúcar

Pós-graduação em Ciência e Tecnologia Animal - FEIS

Fibras naturais: características químicas e potenciais aplicações

This study has as objective determining the chemical properties that serve as the basis for potential scientific and technological applications of seven species of fibrous plants cultivated in Brazil, which are: Banana” (Musa spp.), “Coco” (Cocos nucifera), Curauá (Ananas erectifolius), Fique (Furcraea andina), Piteira” (Furcraea gigantea), Sisal(Agave sisalana) and “Taboa” (Typha domingensis). The tests for determining the percent dry completely, extractives soluble in cold water, in hot water, in sodium hydroxide 1% and in ethanol-toluene, and the percentages of ash, hydrophobicity, lignin, holocellulose and cellulose were performed at the Department of Environmental Sciences, Agronomy College (FCA) of UNESP – Botucatu, São Paulo State. It also presents a literature review about these fibers and their potential applications. Differences between the results obtained and those found by other authors are possibly explained by variations on the origin of plant material, the harvest season, the climate and soil where they were grown. However, the results and the methodology used, serve as a basis for further studies with natural fibers