Influência de diferentes sistemas de cultivo nos atributos físicos e no carbono orgânico do solo

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

Atributos físicos do solo em diferentes condições de cobertura vegetal em área de plantio direto

The use of cover crops in the soil causes changes in soil attributes influencing in a series of hydro-physical processes, which also modify the ability of soil to support the many activities that it is intended. Thus, the objective of this study was to evaluate the effect of cover crops on physical attributes of the soil. For this, an experiment was carried out on a Typic Hapludox, Jaboticabal State, Brazil, using cover crops of millet, sunn hemp, jack bean, lab-lab and black velvet bean in no-tillage and fallow area (spontaneous vegetation). The characteristics evaluated were the bulk density, macroporosity, microporosity, total porosity, aggregate stability, penetration resistance and organic matter. The incorporation of cover crops has proved to be a beneficial practice for the physical attributes of the soil, allowing a greater aggregate stability compared to fallow in the depth of 0-0.05 m. All cover crops presented values of soil penetration resistance below the critical value of 2 MPa.

produção de mudas de maracujazeiro amarelo submetidas à salinidade em solo com biofertilizante bovino

The experiment was conducted in a greenhouse from May 1 to July 31, 2008, in Areia county, Paraiba State, PB, Brazil, in order to evaluate the effects of irrigation water salinity on initial growth of the passionfruit seedlings in non-saline substrate with and without bovine biofertilizer. The treatments were distributed in a completely randomized design, with three replications and twelve plants per plots, in a factorial arrangement 5 × 2 × 2, corresponding the former to the levels of salinity in the irrigation water: 0.5; 1.0; 2.0; 3.0 and 4.0 dS m-1, in soils with and without bovine biofertilizer applied at two moments (25 and 65 days after seedling emergence). The growth of the seedlings and the soil electrical conductivity were evaluated at the end of the experiment. The biofertilizer was diluted in a low saline water at a 1:1 ratio and was applied once two days before sowing, corresponding to 10% of the substrates volume. The increase in water salinity inhibited the growth in height of plants, leaf area and root length, but always to a lesser extent in the treatments with bovine biofertilizer. The increase in electrical conductivity of the irrigation water elevated the soil salinity, independently of the addition of biofertilizer.

Uso de Dois Espaçamentos Entre Gotejadores na Mesma Linha Lateral e Seus Efeitos Sobre a Formação do Bulbo Molhado no Solo e Parâmetros Físicos de Rabanete

The use of irrigation systems that consume lower water and energy in agriculture is important to supply the growing global demand for food. In this way, it's important to develop techniques that will increase the uniformity of water application on drip irrigation systems. The aim of the work was to compare the provision of lateral lines in drip irrigation, through the formation of wet bulbs in soil and physical parameters of radish, composed of single spacing between drippers in relation to lateral lines composed of two segments, each one composed by different spacing between emitters. Two distributions of evaluation were carried out: 1) conventional drip lateral lines with 20 cm emitter spacing were compared to proposed drip lines, with 24 emitter spacing in the initial section and 20 cm emitter spacing in the final section; 2) conventional drip lateral lines with 30 cm emitter spacing were compared to proposed drip lines, with 36 emitter spacing in the initial section and 30 cm emitter spacing in the final section. The experiment was carried out in a greenhouse of the Sao Manuel Experimental Farm, located at Sao Manuel, SP. The experimental design was entirely randomized, with six treatments and four replications. Results showed no difference among treatments for the most of the evaluated variables. So it is possible to conclude that the use of different spacing between emitters in the same lateral line can be used to increase the line length.

Porosidade e infiltração de água do solo sob diferentes sistemas de manejo

Management systems affect soil structure, causing changes in porosity that can influence water infiltration into the soil. This study aimed to evaluate the effect of different management systems on the porosity and water infiltration in Distroferric Red Nitosol with clay texture. The management systems were: conventional with disc plow + two soft harrowing, conventional with heavy disc harrow + two soft harrowing, no tillage and fallow. The following attributes: porosity, pore shape and water infiltration velocity into the soil were determined. Management systems such as no-tillage, conventional with disc plow and heavy disc harrow, and fallow modify the porosity and the shape of pores of a Distroferric Red Nitosol, influencing water infiltration, which was favored in no-tillage for the greater presence of elongated pores.

Propriedades físico-hídricas, desenvolvimento radicular e produtividade da soja em dois tipos de manejos de solo

The soybean culture is part of crop rotation used by irrigators from the southwestern region of São Paulo State that perform no-tillage soil management as a form of sustainable soil use. The objective of this work was to evaluate the effect of this conservationist practice on physicalhydric properties, soil compaction, root development, and soybean culture production components in relation to the conventional management. The experiment was conducted at the Buriti-Mirim Farm, Angatuba, SP, in Brazil, using an area irrigated by a center pivot system divided into two types of soil management: conventional and no-tillage. Although the no-tillage management presented higher soil density, lower water available and lower soil resistance to penetration, both soil managements showed no difference in relation to root development.

Uso do solo e monitoramento dos recursos hídricos no córrego do Ipê, Ilha Solteira, SP

Brazil has great potential of water resources, however, with deficiency in terms of qualitative and quantitative monitoring and knowledge of the influences of land use. So, this study had the purpose of presenting the qualitative and quantitative monitoring of water for irrigation and the influences caused by the use and occupation of land in the watershed of Ipê stream, in the municipality of Ilha Solteira, São Paulo. The qualitative monitoring was conducted from 2006 to 2011 and the quantitative monitoring from 2009 to 2011. In order to evaluate the influences, the Pearson correlation analysis was used. It was found that the watershed is mostly made up by the crop of sugar cane and the use in conflict with areas of permanent preservation are the fallow areas and pasture. The watershed is characterized with high concentrations of iron and coliforms, originating from degraded pastures and irregular use of urban and rural occupation. The small permanent preservation areas, bad soil conservation and expansion of urban areas imply in the deterioration of the quality and availability of water, generating socio-economic and environmental impact in the area.

Análise da compacidade do solo na área urbana de Bauru/ Estado de São Paulo utilizando Ensaios de Penetração Padronizado e sísmica de refração

This study was done to determine compactness of soil strata in the urban area of Bauru, central São Paulo State using standard penetration test (SPT) and seismic refraction methods. Frequency distribution within boreholes was measured every meter to a depth of 30 meters. The geometric mean of standard penetration test values was computed every meter. A biplot graph showing the relationship of SPT with depth indicates soil stratification. In addition, five sections of seismic refraction values, which also indicate the compactness of soil strata, were obtained. A comparison of the two methods shows significant correlation between the results obtained from each.

Estimativa Da Água No Solo Em Floresta de Eucalyptus Grandis

The study aimed to assess the moisture and density of the soil, the amount of water stored in the profile, and the average soil's porosity with Eucalyptus grandis reforestation, compared to bare soil. The study areas are located in the Paulista region, in São Paulo, Brazil. The samples were collected in layers of 0, 20, 40, 60, 100 and 300 cm, in the months of April, June, August and October 2008. The results show that the density is lower and the porosity is higher in Eucalyptus forest soil compared to bare soil, due to the higher content of organic matter in forest leaf litter. Furthermore, the forest soil has a lower amount of water stored in profile than the bare soil without vegetation.

Posicionamento de Extratores de Cápsula Porosa em Solo Arenoso Na Citricultura Fertirrigada Por Gotejamento

The efficiency of monitoring fertigation by means of porous capsule extractors is directly related to its correct placement, since the nutrients applied through fertigation have different mobility throughout the soil profile. The objective of this study was to evaluate the distributions of NO3, P, and K in the soil solution, when applied in citrus in sandy soil through drip fertigation systems, aiming to define the proper placement of the solution extractors. In order to measure the concentration of ions in the soil solution, the extractors were installed at four different distances (5, 15, 25, and 35 cm) and depths (15, 30, 60, and 90 cm) with an emitter located under the projection of the tree canopy. The experiment was conducted in a Valencia orange orchard on citrumelo Swingle rootstock, in Reginópolis/SP. The experimental design was randomized blocks and the treatment arrangement was a 4 x 4 factorial design with five repetitions. Sixteen soil solution extractors were installed per block, with a total of 80 extractors in the experiment. According to the obtained results, to determine P and K, it is recommended to install the solution extractor at 15 cm horizontal and 30 cm depth from the emitter. For NO3, the extractor recommended placement is 25 cm horizontal and 30 cm depth. The soil solution extractor proved to be a sensitive tool, capable of determining the ions mobility in the wet bulb.

Superfícies geomórficas e atributos do solo em uma toposseqüência de transição várzea-terra firme

Soil attributes reflect influence of the geomorphic surfaces. Therefore, the objective of this work was to investigate the influence of the geomorphic surfaces on soil attributes in a topossequence from low lands to high lands in the Humaitá region, AM. A transect of 4.5 km, from the top of the slope towards the low lands was established and the geomorphic surfaces were identified and limited according to topographic and estratigraphic criteria, based on detailed field investigation. Twenty soil samples were collected in each one of the slope segments within the geomorphic surfaces (G.S.), at the following depths: G.S. I: LAa (0.0-0.16 and 0.48-0.79 m); G.S. II: Lad1 (0.0-0.13 and 0.44-0.70) and Lad2 (0.0-0.10 and 0.30-0.55 m); G.S. III: RYve1 (0.0-0.18 and 0.51-0.89) and RYve2 (0.0-0.23 and 0.58-0.91 m). The sampling depths were determined by the surface and subsurface horizon depths, defined during the soil morphological description. Physical analysis involved particle size distribution, disperse clay, soil and particle density and total porosity. The chemical analysis involved determinations of pH in water and KCl, exchangeable cations, exchangeable Al, total acidity (H+Al), available P, organic carbon. The relief variations contributed to the presence of dystrophic soils in the geomorphic surface I and eutrophic soils in the geomorphic surface III. The multivariate statistical techniques were able to separate three heterogeneous groups, equivalent to the mapped geomorphic surfaces.

A influência do uso e ocupação do solo na qualidade e genotoxicidade da água no reservatório de itupararanga, São Paulo, Brasil

The Brazilian reservoirs have been under great anthropogenic pressure due to continued population growth, which in turn places great pressures on the environment. Given this issue, this study aimed to analyze the influence of land use on the quality and genotoxicity of water in the Itupararanga reservoir, São Paulo, Brazil. Water and sediment samples were analyzed for their quality, genotoxicity and benthic diversity, as well as their interrelationship with the landscape. The reservoir was found to be eutrophic in most sampling stations, and genetic al terations were found in radicular cells of exposed Allium cepa in some sampling stations, besides a low diversity of benthic organisms. Among the variables that most contributed to the genetic alterations and water quality are the presence of riparian vegetation, the bare soil and urban occupation. With the results obtained in this study it was concluded that the quality of water and sediment at the Itupararanga reservoir is compromised, requiring emergency managements to ensure the sustainability of water resources.

Emergência de Rottboellia exaltata influenciada pela profundidade de semeadura, quantidade de palha de cana sobre o solo e aplicação de herbicidas residuais

Mechanical sugarcane harvest without burning and continuous straw on the soil surface may affect the Rottboellia exaltata infestation dynamics in sugarcane fields. Three greenhouse experiments were conducted with the aim of studying the effects of sowing depth (0, 2.5, 5, 7.5, and 10 cm), amount of sugarcane straw on the soil surface (0, 5, 10, and 15 ton ha-1), and residual herbicide (clomazone, flumioxazin, imazapyr, isoxaflutole, and s-metolachlor) on the emergence of Rottboellia exaltata. For each experiment, a completely randomized design with four replicates was applied. The combination of mulch on soil surface (especially with larger amounts of straw) with deeper sowing depths provides less emergence and mass accumulation of R. exaltata. In bare soil, the sowing depth did not affect the weed dynamics. Clomazone and imazapyr were effective herbicides controlling R. exaltata regardless of the amount of straw on the soil surface. Flumioxazin was also effective in controlling R. exaltata but only under bare soil conditions. Even with 60 mm of accumulated rainfall over the 4 day period after application, the amount of flumioxazin leached to the soil was not enough to ensure the same control observed when applying the herbicide on bare soil.

Efeito do manejo e de níveis de lodo de esgoto na fertilidade do solo após tres aplicações

The agricultural use of sewage sludge as organic fertilizer is considered nowadays as on alternative of disposal, in the end of the residue in addition to possible environmental problems, it's using can decrease the mineral fertilizers and avoid provide organic matter to the soil. The objective of this study it was to evaluate the parameters of soil fertility under different managements and doses of sewage sludge after the third application of the residue. The experiment was carried out in São Manuel - SP, with the cultivation of sunflower in two consecutives cycles, followed by wheat and triticale without application of the residual, and in the following year with the application of sewage sludge and cultivated the black oats. It was adopted a randomized complete block design, consisting of six treatments and five repetitions defined as follows: T0 - without fertilization; T1 - mineral fertilizer nitrogen according to crop need, T2 - 50% of N from sewage sludge and 50% in mineral form, T3 - 100% of N from sewage sludge, T4 - 150% of N from sewage sludge, T5 - 200% of N derived from sewage sludge. Soil samples were collected in the end of the trial of oats. There were an increase in the levels of P, H + Al, CEC and OM, B, Cu, Fe, Mn, Zn as a function of increasing dose of sewage sludge. To V% and pH were decreased the values in the proportional soil to the increase of sludge dose until 24 and 22 t ha-1, respectively and after increasing the pH and V%.

Análise das tensões de água no solo cultivado com morangueiro sob poda

Strawberry yield and quality was evaluated after drastic pruning (second cycle), under different soil water tensions, drip irrigation. The experiment was conducted on beds at a greenhouse, located at Engineering Department, Federal University of Lavras (UFLA), from April to December of 2010. An experimental design was in randomized blocks with three replicates. The treatments were composed of six different soil water tension, 15, 25, 35, 45, 55 e 70 kPa. Results obtained allowed to verify that to higher values of: total and commercial fresh weight of fruits per plant, total and commercial number fruits per plant and total and commercial yield, it is necessary to irrigate when soil water tension gets approximately to 15 kPa, at 0.15 m deep. Commercial average fruit mass and noncommercial fresh weight of fruits per plant, were not reduced under different soil water tensions applied.