Resistência à penetração de um solo em recuperação sob sistemas agrosilvopastoris

In the Research and Teaching Farm of the State University of São Paulo (UNESP) - Campus of Ilha Solteira, located in Selviria, in Mato Grosso do Sul State, a study was conducted with the objective of investigating the resistance to penetration of a highly degraded soil due to construction of a Hydroelectric Power Plant. The experimental design was a completely randomized, with five treatments and five replications. The treatments were constituted of the following uses and managements: area in advanced state of degradation; area under regeneration cultivated 13 years with Pinus; area under regeneration cultivated 11 years with green manure and pasture; degraded area with natural regeneration; and area with natural vegetation (savanna). The system where the area was under regeneration with Pinus cultivation and the niches with natural regeneration were the closest to natural condition (savanna). Except for the natural area (savanna), all others presented a higher resistance to penetration in the layer of 0.20-0.40 m, which represents serious limitations for growth of plant roots.

Correlação da produtividade do feijão com a resistência à penetração do solo sob plantio direto

The soil mechanical resistance to penetration (PR) has great influence on vegetative development as the root growth and the crop productivity change in inverse proportion. Thus, the objective of this research was to study correlation between the bean grain productivity and the PR in an Oxisol cultivated for four years in no-tillage system at FEIS/UNESP. The attributes PR and yield were determined in a regular grid with 119 sample points. The PR was determined in the layers of 0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20 and 0.25-0.30 m. The results were submitted to procedures of descriptive statistics, linear correlation and geostatistic analysis. The linear correlation between the yield and PR was practically null, as in all soil layers investigated it showed determination coefficients (R2) smaller than 0.03 and not significant. The geostatistic analysis showed moderate structure of spatial dependency for PR in the layers of 0.05-0.10 and 0.10-0.15 m, and strong for yield; however, the conjugate spatial analysis of such attributes showed no correlation, therefore, the spatial variability of PR did not influence the yield.

Crescimento inicial do cafeeiro irrigado com água salina e salinização do solo

The coffee crop is expanding to new areas with not enough studies about its response to saline irrigation water. The initial growth of coffee plant was evaluated, in greenhouse at the Engineering Department of the Federal University of Lavras (UFLA), under different levels of irrigation water salinity. The completely randomized design was used with 6 treatments (S0 = 0.0 dS m -1, S1 = 0.6 dS m -1, S2 = 1.2 dS m -1, S3 = 1.8 dS m -1, S4 = 2.4 dS m -1 and S5 = 3.0 dS m -1) and 4 replications. The irrigation was accomplished according to soil water retention curve and resistance block reading, restoring the soil water content to its field capacity. It was verified that water salinity affected the plants characteristics significantly. The water salinity above 1.2 dS m -1 caused damage to plant development resulting, in some cases, in death of plants. The leaf area of plant was the variable most affected by salinity of irrigation water. By the end of the experiment, the soil was classified as saline-sodic.

Comportamento fisiológico e morfológico de clones de Eucalyptus urograndis submetidos a diferentes níveis de água no solo

The present study had as its objective the assessment of the possible effects of hydric stress on the growth, physiological characteristics of two different genetic materials from Eucalyptus urograndis. The experiment was carried out in a greenhouse at Faculdade de Ciências Agronômicas of UNESP, campus Botucatu from March to July, 2005. The hydric management was established based on the soil water potential. Two water levels were established, doing the evapotranspired water replacement by pot weighing. Two clones were used, Eucalyptus urograndis 105 and 433, being the first one more resistant to the hydric deficit and the 433 more sensitive to stress. The study was made from a 2×2 factorial (two levels of water × two genetic materials). For the hydric management, the plants were irrigated when they reached a soil water potential of -0.03 MPa or -1.5 MPa. The assessments made were: diffusive water vapor of stomato, transpiration, leaf temperature and leaf water potential. The physiological evaluations throughout the day, in the end of the experiment. Treatments without hydric stress had a higher performance in all studied characteristics, but the clones had no influence. The stomatic resistance followed the potentials, showing higher values in the treatments submitted to hydric deficiency, more intensely for clone 433, being that this also happened with the leaf water potential. The transpiration also followed the leaf water potential and the stomatic resistance more intensely for clone 105 both comparing stressed plants and non-stressed plants. Consequently, the leaf temperatures had higher values for clone 433 on the stressed treatment. Thus, it can be concluded that there was a better performance in plants kept on a soil water potential of -0.03 MPa and a higher resistance to hydric stress for clone 105.

Condutividade hidráulica e resistência à penetraçao do solo influenciada por diferentes sistemas de manejo

Soil management measures that increase the efficiency of organic matter cycling and maintain favorable soil structure are needed for improving soil quality. On the other hand, soil structure degradation due to inadequate soil management systems is widespread. Among the indicators of soil physical quality, saturated hydraulic conductivity and penetration resistance are thought to be sensitive to soil management system. The aim of this work was to study the influence of soil tillage system and organic fertilization on selected soil physical properties after the first year of treatment. The field work was conducted in Selviria, MS, Brazil on an Oxisol. The experimental design was randomized complete blocks with split-plots, with 12 treatments and 4 repetitions. Tillage treatments included conventional ploughing (CT) and direct drilling (DD). Fertilizer treatments were: 1) manure, 2) manure plus mineral, 3) traditional mineral 4) plant residues of Crotalaria juncea, 5) plant residues of Pennisetum americanum and 6) control plot. The plots were cropped to bean in winter and to cotton in summer, and both cultures were irrigated. After one year no significant differences between treatments in mechanical resistance and porosity were found. However, saturated hydraulic conductivity and infiltration were higher in the conventional tillage treatment at the 0.00-0.10 m depth. Moreover, an improvement in soil physical condition by organic fertilizers was shown.

Comportamento contrátil de barreiras selantes de solo estabilizado para base de lagoas de tratamento

Liners were proposed as subsoil contamination protection devices for waste disposal sites. In the rural environment, they can be used to construct pond bottoms for liquid waste treatment, but the construction needs to be quick and cheap. A good technical solution for these situations is the use of local soil compacted with low quantities of cement or lime, obtaining good properties for this purpose. These barriers need special care about their contraction behavior which may compromise its use. This work shows the results of contraction tests in sandy soil specimens and others stabilized with lime and with cement. Soil structure changes during cure time were checked using electronic scan microscopy. Results show maximum soil contraction of 0.648% for specimen with 14 days cure process. After twenty eight days of cure the contraction values were lower than 0.5%, which classifies the material as of low contraction. Electronic scan image shows significant material structure alteration up to seven days cure. Results show that studied mixtures had appropriate contraction behavior for liner usage.

Análise da incerteza na representação de classes de cobertura do solo urbano resultantes da aplicação de uma rede neural artificial

The great diversity of materials that characterizes the urban environment determines a structure of mixed classes in a classification of multiespectral images. In that sense, it is important to define an appropriate classification system using a non parametric classifier, that allows incorporating non spectral (such as texture) data to the process. They also allow analyzing the uncertainty associated to each class from the output alues of the network calculated in relation to each class. Considering these properties, an experiment was carried out. This experiment consisted in the application of an Artificial Neural Network aiming at the classification of the urban land cover of Presidente Prudente and the analysis of the uncertainty in the representation of the mapped thematic classes. The results showed that it is possible to discriminate the variations in the urban land cover through the application of an Artificial Neural Network. It was also possible to visualize the spatial variation of the uncertainty in the attribution of classes of urban land cover from the generated representations. The class characterized by a defined pattern as intermediary related to the impermeability of the urban soil presented larger ambiguity degree and, therefore, larger mixture.

Efeitos de níveis de cobertura do solo sobre a produtividade e crescimento do feijoeiro irrigado, em sistema de plantio direto

The objective of this research was to study the effects of five different treatments of grass (Brachiaria decumbens) straw mulch on common beans (Phaseolus vulgaris L.): 0% (0 t.ha-1), 25% (2,25 t.ha-1), 50% (4,5 t.ha-1), 75% (6,75 t. ha-1) and 100% (9,0 t/ha) designed by randomized blocks, with four replicates. The irrigation was applied when minimum soil water potential were reached about - 30kPa. The water management based on tensiometers and soil water characteristic curve. A microsprinkler irrigation system was used. The experiment was set up at the Experimental Station of Embrapa Rice and Bean (Empresa Brasileira de Pesquisa Agropecuária Arroz e Feijão) at Santo Antonio de Goiás, Brazil, in a Dark - Red Latosol soil. The results showed: the bean yield and his components were not affected by treatments, except grain number/pod,. The mulch increased the water use efficiency and, consequently, decreased the number of irrigations when the mulch reached more than 50% straw mulch. The treatment with 100% of mulching presented the largest leaf area index and dry matter accumulation was not affected by mulching.

Vulnerabilidade à erosão do solo da Região do Alto Rio Pardo, Pardinho, SP

This study aimed at the elaboration of a database with information and a map of erosion vulnerability for ecological zoning for the upper Pardo River, Botucatu, SP, by using the Geographical Information System - SPRING. The map of erosion vulnerability was made from spectrally homogeneous regions, producing a grid of zone averages, which was then subdivided, resulting in a vulnerability map to erosion. The results allowed us to conclude that digital imaging produced valuable information for mapping of soil use and database formation. The GIS - SPRING was efficient at identifying soil and vulnerability erosion classes and 95% of the basin presents a moderately stable vulnerability degree, through the presence of medium young soils in gently waring reliefs and covered by 49.27% of pasture and 29.88% crops.

Tijolos prensados de solo-cimento confeccionados com resíduos de concreto

In this work results are presented of laboratory tests aiming to evaluate the possibility of using concrete wastes in manufactured soil-cement pressed bricks. Tests of characterization of used soil of the composite of this soil with concrete wastes and of the mixtures of soil cement made with this composite were evaluated. According to results of tests carried out with cylindrical specimens and with soil cement pressed bricks, it was verified that the addition of the concrete wastes improved soil cement mechanical properties, favoring the a reduction of the cement consumption, obtaining pressed bricks with a better quality.

Compactação do solo e intervalo hídrico ótimo no crescimento da parte aérea e produtividade da cultura do milho

The aim of this work was to evaluate the effect of soil compaction caused by tractor wheel traffic on the limiting water range (LLWR), shoot growth and levels of compaction and four replications in a completely randomized experimental design. Soil samples with preserved structure were collected in the layers: 0.02-0.05; 0.08-0.11; 0.15-0.18 and 0.22-0.25m to determine macroporosity, microporosity, total porosity, bulk density, resistance to penetration and LLWR. The evaluated corn parameters were: plant and first spike height, steam diameter, number of spikes per plant, plant dry matter, dry matter of 1000 seeds and seed productivity. The soil compaction restricted all corn parameters except the number of spikes per plant and dry matter of 1000 seeds. The LLWR was reduced by the soil resistance to penetration, even in the tilled soil with bulk density of 1.12 Mg m-3. Only the treatment with 11 Mg tractor, repeated four times on the area, demonstrated bulk density above critical bulk density in the LLWR that was 1.37 Mg m-3, where the seed productivity was significantly smaller.

Atributos químicos e físicos de um solo tratado com biossólido industrial e cultivado com milho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Produção de cebola em solo salinizado

The use of water or soil with a high salt concentration has been the main cause of failure in the yield of many crops. Consequently, this work aimed at evaluating the effects of different salinity levels and soil moisture on onion yield (cultivar Baia periforme). An experiment was conducted in a greenhouse of the Soil Science Department - FCA - UNESP, Botucatu, SP, in pots of 10 L. The soil was salinized with NaCl in order to increase the electrical condutivity of saturation extract of soil from 0.13 to 2; 4; 6 and 8 dS m-1. In each experimental unit 15.2 g of thermophosphate enriched by micronutrients and 1.5 L of organic matter were incorporated. The moisture treatments kept the soil within the limits of 25-50, 50-75 and 75-100 % of field capacity. The plant height the pseudostem diameter and yield of bulbs were evaluated. The results lead to the conclusion that the salinity reduced the vegetative growth and the yield of onion bulbs. Moisture treatment influenced both the diameter and weight of bulbs. The water consumption of the plants decreased with increassing soil salt concentration.

Avaliação de interpoladores estatísticos e determinísticos na estimativa de atributos do solo em agricultura de precisão

The obtaining of the correct space distribution for attributes of the soil is relevant in the agricultural planning, in what concerns to the installation and maintenance of the cultures. The objective of that work was to compare statistical interpolation methods (ordinary krigagem) and deterministic methods (inverse square distance) in the estimate of CTC and V% in a distrophic yellow-red Latossolo. The study was accomplished in the State of Experimental Hands on of the Instituto Capixaba de Pesquisa, Assistência Técnica e Extensão Rural (INCAPER), in an irregular grading with 109 points. The data were collected in the layer of 0 - 0,20 m in the projection of the cup of the plants, in the superior part of the slope. The performance of the interpolators was obtained and compared using the criterion of the medium mistake. The observations are dependent in space until a maximum reach of 14,1 m, considering the isotropy. IDW presented larger mistake in the estimate of the data; however its difference in relation to KRIG was small for both variables.