Veronildo S. Oliveira

Estabilidade de agregados de um latossolo amarelo distrocoeso de tabuleiro costeiro sob diferentes aportes de resíduos orgânicos da cana-de-açúcar

The potential yield of sugarcane depends on factors related to climate, soil and the plant variety. Management systems that provide the addition of organic waste to the soil can cause changes in physical attributes of the soil, enhancing the growth of the root system and sugarcane yield. The objective of this study was to evaluate the effects of different management systems at several levels of organic residue addition on the distribution and indices of aggregate stability of dystrophic cohesive Yellow Latosol of coastal plains, in the State of Alagoas. Plots were selected in the following sugarcane-growing areas: area under irrigation management system, area fertigated with vinasse, and an area under application of vinasse + filter cake. These management systems were compared to each other and to a control (native forest). To evaluate the distribution and stability indices of soil aggregates, soil samples were randomly collected in the different areas, at the depths 0-0.20; 0.20-0.40 and 0.40-0.60 m, at points between two neighboring sugarcane rows. The results were subjected to analysis of variance and the mean compared by the Tukey test at 5 % significance. Simple correlation analysis was performed between some measured variables. Results showed that the different management systems induced changes in the aggregate distribution and that the stabilization of soil aggregates in the surface layer dependeds on the organic matter content and the action of successive cycles of soil wetting and drying. The studies of simple correlations showed that total organic C and aggregate stability indices were significantly and positively correlated.

Avaliação de solos sob diferentes períodos de aplicação com vinhaça

The objective of this study was to evaluate physico-chemical alterations associated to soil depth and respective correlations in soils under periods of different stillage fertigation. Therefore, four areas were selected at Usina Santa Tereza: Area 1), irrigated with stillage for 3 years; Area 2), for 7 years; Area 3), 10 years; Area 4), without stillage application. In each area 20 points were demarcated and georeferenced, forming a mesh. Soil samples were collected at depths of 0 - 10, 10 - 20 and 20 - 40 cm. After sampling, the soil was air dried, prepared and passed through sieves for analysis of particle size: sand, silt, clay, and for the physico-chemical properties: exchangeahle Ca, Mg, K, Na; pH (1:2.5 soil: water); and electrical conductivity of saturated paste extract. Simple linear correlation coefficients of Pearson between pairs of data were obtained. The results pointed out relation between depth and other variables in all areas, indicating stillage application alters cation concentration depending on soil characteristics and management of each area.

Compressibilidade de um Argissolo Amarelo distrocoeso submetido a diferentes manejos

The objective of this paper was to evaluate the compressibility of an Ultisol submitted to different managements of sugarcane cultivation. The investigation was carried out at Triunfo Mill, in the State of Alagoas, Brazil. The testing area was composed by four distinct sub-areas: a preserved forest (NF), an area without irrigation (MWOI), an irrigated area (MWI), and an area with vinasse (MWV). All investigated areas, except the forest, were prepared using conventional equipment for soil preparation. Soil samples were collected within depths ranging from 0 to 20 cm, 20 to 40 cm, and 40 to 60 cm. A trench was dug in the four selected areas and four undeformed samples were collected in each depth. The samples were collected with metallic rings with dimensions of 6.4 cm in diameter and 2.5 cm in height. In the laboratory, the samples were previously saturated and submitted to soil suctions raging from 0.1 to 1500 kPa in order to build the soil-water characteristic curves. Confined compression tests were performed with saturated samples. The results obtained from the compression tests were used for the determination of the void ratio (e) and the pre-consolidation stress (σp) of the tested samples. Data were submitted to regression analysis and the differences among the obtained means were compared using the test of Tukey at 5% of probability. Regression analysis for pre-consolidation stress in function of water content (Ug) and correlations among the several variables were carried out at 5-% significance. Within all investigated areas, the depth range from 0 to 20 cm showed to be more susceptible to compaction in relation to the depth range from 20 to 40 cm. Management MWV was found to modify the compressive behavior of the soil in both depth ranges. In all investigated areas, the soil bearing capacity was higher in the depth range of 20 to 40 cm.

Compaction of a Ultisol submitted to different managements.

The objective of this work was to evaluate the susceptibility to compaction of an utisoil under different soil managements and use. Evaluations were based on both maximum density (MD) and critical humidity (CH) through Standard Proctor compaction tests, and the degree of compaction in different soil managements and use. The study was carried out at the Triunfo Mill, State of Alagoas in Brazil. The testing area consisted of four distinct sub-areas: a preserved forest (MA), an area without irrigation (MSI), an irrigated area (MCI), and an area with vinasse (MCV). Undeformed soil samples were collected for soil density and the deformed ones for organic matter and Standard Proctor tests in order to obtain MD, CH and the compaction grade (CG). Plots (50 × 50 m) were randomized within the four areas at depths of 0-20, 20-40 and 40-60 cm, with three replications. Data were submitted to variance analyses, and means compared through the Tukey test at 5% of probability. MD data followed the grade MSI > MCI > MCV > MA, in contrast to CH which presented the inverse sequence. Therefore MSI and MCI can cause soil degradation, even at lower CH. Only MCI presented CG higher than 4.3%, the critical value reference, at 0-20 cm.

Distribution of aggregates and organic carbon in an Ultisol submitted to different managements

The main objective of this study was to evaluate the stability and aggregate distribution of an Ultisol submitted to different management systems under sugarcane cultivation. Evaluated areas consisted of native forest (MA) and sugarcane managed areas with irrigation (MCI), vinasse irrigation (MCV) and without irrigation (MSI). Management of the areas followed the same conventional preparation: heavy and light harrowing and subsoiling. Undeformed soil samples were collected along the lines of the crop and in native forest to determine aggregate stability, expressed by the average weighted diameter (DMP), aggregate stability index (IEA), module of thinness (MF), percentage of stable aggregate in water larger than 2.0 mm (AGRI) and total organic carbon. The distinct kinds of soil management on sugarcane promoted decrease in aggregate stability as soil depth increased. In relation to native forest, aggregate stability reduced in the sequence MA > MCV > MCI > MSI. MSI showed the lowest aggregation indexes, in contrast to MCV data which closely linked with MA data and presented the best aggregate stability index in water. Significant and positive correlations were obtained between total organic carbon and stability indexes studied (DMP > AGRI > MF > IEA) under different management situations.

Development and mineral composition of corn as a function of soil compaction and application of organic compost

The objective of the this study was to evaluate the effect of organic compost and compaction levels of two soils on shoot dry weight and macronutrient contents of corn (Zea mays), cultivar Itapoa 700. In 54 pots, three doses of the processed organic compost residue from Recife Central Market were applied in two soils, one being a dark red Argissoil (DRA) and the other a yellow red Argissoil (YRA), collected in Ap horizon (0 to 0.20 m depth) and under three compaction levels in a factorial arrangement 2 × 3 × 3 with three replications. Shoot dry matter and N, P, K, Ca and Mg contents were evaluated. The results indicate that soil compaction does not affect corn growth. The organic compost application increased K and Ca but decreased Mg content in shoots. Calcium content in corn shoot increased with the organic compost in DRA soil, but was found to decrease in YRA soil.

Produção e nutrientes minerais de milheto forrageiro e sorgo sudão adubado com soro de leite

Este estudo objetivou avaliar o desenvolvimento e teores de macronutrientes presentes no milheto e no sorgo Sudao, em resposta a aplicacao de doses de soro de leite ao solo. O experimento foi conduzido com solo em vasos com capacidade de 8 dm3 em ambiente protegido utilizando-se delineamento inteiramente casualizado em arranjo fatorial 2 (aplicacao unica e parcelada) x 5 (doses de soro) com quatro repeticoes. As doses foram equivalentes a: 0, 167, 333, 667 e 1000 m3 ha-1 de soro de leite, determinadas com base no teor de K. O soro foi aplicado em dose unica, 10 dias antes da semeadura e em dose parcelada (50% 10 dias antes da semeadura e 50% 20 dias apos a emergencia das plantas). Apos 42 dias realizou-se a colheita e se determinaram altura e massa seca da parte aerea. A trituracao da massa seca foi realizada para o preparo de extratos, com vista as determinacoes analiticas dos nutrientes, P, Na, K, Ca e Mg. Os resultados mostraram que para producao de massa seca no manejo de aplicacao dose unica ocorreu, a partir da dose equivalente a 667 m3 ha-1 de soro de leite, diminuicao na producao, em ambas as culturas, enquanto para a aplicacao parcelada a reducao se deu a partir da dose 167 m3 ha-1.

Relações de atributos do solo e estabilidade de agregados em canaviais com e sem vinhaça

Realizou-se este estudo com o objetivo de se avaliar o efeito da aplicacao da vinhaca na estabilidade dos agregados e nos indices de agregacao do solo e nas correlacoes das propriedades fisicas do solo em areas cultivadas com cana-de-acucar no litoral sul do estado de Pernambuco. As amostras de solo foram coletadas nas camadas de 0-0,20 e 0,20-0,40 m, em 12 areas com e sem aplicacao de vinhaca. Analises foram realizadas para caracterizacao do solo e tambem para determinacao da argila dispersa em agua, grau de floculacao das argilas, carbono orgânico total e materia orgânica do solo. A estabilidade dos agregados estaveis em agua foi calculada por meio dos indices de agregacao: diâmetro medio ponderado (DMP), modulo de finura (MF) e percentagem de agregados >2,00 mm (AGRI) que apresentaram diferenca significativa na avaliacao das areas com e sem aplicacao de vinhaca. Nas areas com vinhaca o carbono orgânico total apresentou melhores correlacoes com os indicadores DMP, AGRI e MF e as maiores percentagens de agregados estaveis em agua > 2,00 mm ocorreram na profundidade de 0-0,20 m, nas areas com vinhaca.

Efeito do composto orgânico e compactação do solo no milho e nutrientes do solo

When well utilized, organic residues lead to great benefits making organic matter and nutrients available in soils. In this context, the present study had the objective to evaluate the effect of organic compost doses on two soils submitted to different compactions and on corn biomass. Thus, in 54 pots were added three doses 0, 40 or 80 g dm-3 of organic compost in a Dark Red Argisoil or Red Yellowish Argisoil, collected from the Ap horizon (depth of 0 to 0.20 m), submitted to three compaction degrees (1.3, 1.5 and 1.7 kg dm-3), with three replications. The crop used in the experiment was corn (Zea mays), cultivar Itapua 700. The plant growth, and content of N, P, K, Ca, Mg and organic carbon (TOC) in soil were evaluated. The results point out that the organic compost application significantly affected soil OC and macronutrients, but little effect was induced by the soil compaction on these variables.

Evaluation of soils under different periods of stillage aplication

The objective of this study was to evaluate physico-chemical alterations associated to soil depth and respective correlations in soils under periods of different stillage fertigation. Therefore, four areas were selected at Usina Santa Tereza: Area 1), irrigated with stillage for 3 years; Area 2), for 7 years; Area 3), 10 years; Area 4), without stillage application. In each area 20 points were demarcated and georeferenced, forming a mesh. Soil samples were collected at depths of 0 - 10, 10 - 20 and 20 - 40 cm. After sampling, the soil was air dried, prepared and passed through sieves for analysis of particle size: sand, silt, clay, and for the physico-chemical properties: exchangeahle Ca, Mg, K, Na; pH (1:2.5 soil: water); and electrical conductivity of saturated paste extract. Simple linear correlation coefficients of Pearson between pairs of data were obtained. The results pointed out relation between depth and other variables in all areas, indicating stillage application alters cation concentration depending on soil characteristics and management of each area.