Mineralogy and forms of potassium in red yellow latosol of a guava (Psidium guajava) tree orchard

A trial was conducted during 1994-95 to study the effect of potassium fertilization on a guava (Psidium guajava L.) culture for 3 years. The control plots (without K) showed fruit production and potassium exportation that did not agree with the levels obtained by chemical analysis of the soil. Physical, chemical, mineralogic and morphologic analyses were performed on the red yellow latosol to identify minerals able to supply potassium, with emphasis on the fact that guava trees have a considerably widespread root system. The results obtained confirmed the presence of minerals in this soil that can supply potassium to the trees through weathering. Feldspars were identified in the silt fraction and micas in the clay fraction by X-ray diffractometry. The determination of total potassium revealed that the silt fraction of the soil had the largest absolute amounts of potassium, followed by clay. However, in view of its greater content, clay was the fraction that contributed most to the total amounts of potassium detected.

An evaluation into the potential of biological processing for the removal of metals from sewage sludges

The use of sewage sludge in agricultural land as a means of sludge disposal and recycling has been shown to be economical and suitable because of the presence of nutrients such as nitrogen and phosphorus. However, municipal sludges often contain high quantities of toxic metals and other compounds that must be removed for its safe use in agricultural soils. The biological leaching of metals from sewage sludges has been shown to be a promising technique for metal detoxifying in such complex matrix. The process efficiency is dependent on several physico-chemical parameters, such as total solids concentration, metal forms, pH-ORP, and temperature. Scale-up of the process has not yet been defined and is still pursuing the correct operational design. Current research involving the bioleaching of metals from sewage sludge and its application to land, which affects soil physical properties, are presented and discussed.

Sistemas agroflorestais e seus efeitos sobre os atributos químicos em Argissolo Vermelho-Amarelo do Cerrado piauiense

This study aimed to quantify the effects of agroforestry systems (AFS), with different periods of adoption, and slash and burn agriculture (SB) on the chemical attributes of an Ultisol in the 'Cerrado' of Piaui State, Brazil. In two distinct climatic seasons (dry and rainy) four systems were studied: AFS with six (AFS6) and thirteen years (AFS13) of adoption, an area under SB and a native forest (NF), as a reference. In the AFS, in all depths, higher reduction in the Al3+ and H+ + Al3+ contents were observed as well as an increase of pH value and contents of nutrients (N, P, Ca, Mg and K) and organic carbon in soil. In the soil under SB, only in superficial layers, the ash deposited on the soil caused an increase in contents of nutrients, except for P, which was higher in all the depths. There was significant seasonal effect in the contents of nutrients, reducing in the rainy season. Agroforestry systems promoted increase in the nutrient contents of an Ultisol and can be considered useful to improve soil chemical quality in areas of 'Cerrado' of Piau State, Brazil.

Efeitos dos danos mecânicos e fisiológicos na colheita e beneficiamento de sementes de soja

The objective of this study was to evaluate the effect of mechanical damage and physiological events in harvesting and processing of soybean cv. Mosoy RR 8000. The samples were taken during harvest manual, mechanical harvesting and during processing (receipt, pre-cleaning, cleaning, spiral separator, classification and gravity table). The physiological and physical quality was analized through the purity, germination, vigor (first germination count, seedling dry matter, accelerated aging, electrical conductivity, tetrazolium, mechanical damages and seedling field emergence) tests. The statistical design used was a entirely randomized with nine treatments (9 sampling points) with 4 replications, being the means compared by the Tuckey test at 5% probability. In the purity and seedling field emergence were observed highly significative difference between the sampling process, also this differences were obtained the first germination count, seedling dry weight matter, accelerated aging and electrical conductivity which showed smaller results for the mechanical harvesting when compared with the manual harvesting. The germination was obtained differences at 5% for the manual harvesting in relation to the mechanical harvesting were obtained smaller results, being the main cause of reducing the soybean seed quality, when compared with the manual harvesting.

Distribuição de poros e densidade de latossolos submetidos a diferentes sistemas de uso e manejo

Man cultivates the soil for centuries, but the intensive business and use of the soils under Cerrado vegetation for agricultural production grew out of the seventies. The objective of this study was to evaluate soil physical characteristics as a function of sampling time and the soil uses in a Cerrado area in Uberlandia City - MG, Brazil. The managements were adopted: degraded pasture (M-1), conventional tillage (M-2), minimum tillage (M-3), tillage absence (M-4), no-tillage (NT) for three years (M-5); NT for nine years (M-6), NT for three years after Pinus (M-7), PD for one year after Pinus (M-8) and Pinus forest (M-9) with 25 years old. The evaluations were conducted in 2002/03 growing season, in two areas. The soils were: area 1, an Oxisol (Red Latosol - LV-1, M-1 through M-5) and area 2, two Oxisols (Red Latosol and Red-Yellow Latosol - LVA and LV-2, M-6 through M-9). The physical attributes studied changed depending of the soil class, sampling time and management systems, with emphasis on the area 2 soils, which, in general, better preserved its main physical attributes. Managements with intense tillage, such as the M-2, are the most soil physically degrade, presenting mostly negative changes to soil bulk density, total porosity, microporosity and macroporosity. Since the systems which promote less tillage, in short term, to preserve desirable physical attributes. The M-9 system had the lowest attributes range, compared to the others.

Adubação verde em Citrus: Influência na porosidade e retenção de água de um latossolo vermelho-escuro do noroeste do estado de São Paulo

The objective of this research was to study the porosity, bulk density and retention of water of an Oxisol, located in the Northwestern region of Sn̄o Paulo state, Brazil. The soil was cultivated with Citrus sp., to which green manure was applied between rows for three years. Each of six species of green manure crops (Crotalaria juncea L., Mucuna deeringiana Steph. & Bart., Canavalia ensiformis L. DC., Cajanus cajan L., Lablab purpureum L. and Ricinus communis L.) were seeded for three years (1995, 1996 and 1997) between Citrus rows, plus a treatment with a mix of all six species and a control (natural regrowth af vegetation). The experimental design was a randomized complete block design, with four replications for each of the eight treatments. Water retention, microporosity, macroporosity, total porosity and bulk density were analyzed in the beginning (1995) and end (1997) of the experiment, at three depth ranges (0-0.10; 0.10-0.20 and 0.20-0.40m). We concluded that there were statistically significant differences for bulk density, macroporosity, total porosity and retention of water among the different soil depth ranges; there were no significant differences among treatments though.

Propriedades físicas e infiltração de água de um Latossolo Vermelho Amarelo (Oxisol) do noroeste do estado de São Paulo, Brasil, sob três condições de uso e manejo

This study presents the results obtained in a field experiment carried out at Glicério, Northwest of São Paulo state, Brazil, whose objective was to analyze changes of selected soil physical properties and water infiltration rates on a Yellow-Red Latosol, under three different management conditions. The experimental design was arranged as completely randomized split-block with twelve treatments, which corresponded to four depths (0-0.05 m; 0.05-0.10 m; 0.10-0.20 m and 0.20-0.40 m) and three conditions of soil use and management with four replications. The soil surface conditions were: conventional tillage (one disking with moulboard plus two levelling passes with harrow), nine months before starting filed experiences; recent conventional tillage (also one disking with moulboard plus two levelling passes with harrow) and native forest. The conventional tillage areas were cropped for about fifteen years with annual cultures. The considered soil general physical properties were: macroporosity, microporosity, total porosity, bulk density, soil moisture and penetration resistance and, in addition; soil water infiltration rates were also recorded. According to our results, differences on general soil physical properties and infiltration rates appeared when both tilled sub-treatments and native forest were compared. Both, plots recently prepared by conventional tillage and those prepared by tillage but left nine months in rest, presented a statistically significant decrease of constant (final) water infiltration rates of 92.72% and 91.91% when compared with native forest plots.

Propriedades físicas de um latossolo vermelho cultivado no sistema plantio direto

The pressure caused by agricultural machinery traffic many result in soil compactation in no-tillage system. The aim of this work was to evaluate no-tillage system onset,time on some physical properties, index S and organic matter (OM) of an oxysol located in Jaboticabal, Sao Paulo State, Brazil. The experiment had completely randomized split-splot design. The treatments consisted of four no-tillage systems: no-tillage for 2 years, no-tillage for 4 years, no-tillage for 6 years and one natural wooded area. The evaluated layers were: Q-0.10m, 0.10-0.20m and 0.20-030m. The following were determined: soil porosity, soil aggregates, bulk density, index S and organic matter. The results were submitted to variance analysis and when there was a difference between averages, Tukey's test was used to compare them. The natural wooded area showed higher organic matter, macroporosity, hydraulic conductivity and Index S. There was no difference between the studied parameters, showing that the no-tillage system for six years was not enough to change the soil physical property.

Estudio de la compactación de un Ferralsol manejado con un sistema de no laboreo en Selvíria (MS, Brasil)

No tillage management is widely used by the Brazilian farmers and technicians like a soil conservation system, which reduces the soil losses by water erosion, increasing the infiltrated and stored water in soil, warranting environmental sustainability. No-tillage system does not invert the soil; it causes the creation of a compacted layer. The samples were taken in the agricultural year 2005/2006 in an Oxisoil at Selviria (MS/Brazil). The tillage management in the last 15 years was no-tillage system with crop rotation (maize -Zea mays L./bean - Phaseolus vulgaris L.). The analyzed soil physical properties were bulk density (BS), gravimetric water content (U) and mechanical resistance to penetration (RP) at three depths: 0-0.10 m, 0.10-0.20 m and 0.20-0.30 m. The samples were taken in a mesh with 117 sampled points covering an area of 0.16 ha. It was investigated the existence of compacted soil layer, using the mechanical resistance to penetration to 0.60 m depth with soil water content at field capacity. The data shows low coefficient of variation, except the resistance penetration data. Bulk density and gravimetric water content has a normal distribution. Only resistance to penetration at 0.10-0.20 m depth layer has a normal distribution. The correlation between different properties was low. The bulk density increases with depth; the increase of the values of soil bulk density are consistent with data in other papers, indicating there are not compaction problems for the crop development at the study area. Most of the values of resistance to penetration are lower than 2 MPa, being this value restrictive for root development. The analysis of resistance to penetration profile 0 to 0.60 m shows a compacted layer between 0.20-0.30 m. This compacted layer was caused by the conventional tillage system used at this area before the use of no-tillage system. The soil bulk density has higher values at the upper area, that it shows higher values of soil compaction. Although the values of bulk density and resistance to penetration are high, the area does not show great problems of soil compaction.

Relação do meio físico com o manejo sustentável de plantio de eucalipto em áreas de terrenos acidentados - A Fazenda Santa Edwirges, Vale do Paraíba, Sudeste do Brasil

This study intends to evaluate the effects of landscape physical elements (rocks and relief) associated with silviculture activities. The study was carried out on a small farm (Fazenda Santa Edwirges) covered by Eucalyptus forested situated in the Paraiba do Sul Basin, Southeast Brazil. The methodology consisted of detailed geological and geomorphological studies at 1:10,000 scale, and laboratory analysis of soil physical properties. The results showed three geologic-geomorphologic associations (ridge escarpment with granitic rocks, steep and gentle hills cut by shear zones and gentle hill with alluvial sediments) present high vulnerability for the development of the physical processes such as accelerated erosion landslides and flooding. In contrast, mountains associated with gneissic rocks present smaller vulnerability and high resilience for the development of the physical processes. The results have showed the importance of considering the interactions among landscape physical for the eucalyptus forest management contributing to a better selection area for eucalyptus cultivation and minimize adverse environment impact in road design.

Variabilidade espacial dos atributos físicos em um Argissolo Vermelho sob floresta

This study aim to evaluate the spatial variability of soil physical attributes in of Alfissol forest in Manicoré region, AM. The mapping of an agroforestry growing area of 70×70m was made using a regular grid sampling of 10 × 10m. In each grid, soil samples were collected at 0.0-0.2 and 0,40-0,60 m depth, with a total of 128 sample points. Physical analyses were made (texture, soil bulk and particles density, macro and microporosity, total porosity and aggregates stability in water). With the exception of DMG, DMP and class aggregates <1.00 mm had all the physical attributes spatial dependence structure ranging from moderate to weak. Values were above the range established in the mesh (12.00 to 45.56 m), enabling to make a basis for future studies in forest area. The physical attributes presented in kriging maps different spatial behavior, however there are relationships between these attributes shown by geostatistics proving that this is effective tool for studies in forest area.

Sugarcane vinasse: Environmental implications of its use

The inadequate and indiscriminate disposal of sugarcane vinasse in soils and water bodies has received much attention since decades ago, due to environmental problems associated to this practice. Vinasse is the final by-product of the biomass distillation, mainly for the production of ethanol, from sugar crops (beet and sugarcane), starch crops (corn, wheat, rice, and cassava), or cellulosic material (harvesting crop residues, sugarcane bagasse, and wood). Because of the large quantities of vinasse produced, alternative treatments and uses have been developed, such as recycling of vinasse in fermentation, fertirrigation, concentration by evaporation, and yeast and energy production. This review was aimed at examining the available data on the subject as a contribution to update the information on sugarcane vinasse, from its characteristics and chemical composition to alternatives uses in Brazil: fertirrigation, concentration by evaporation, energy production; the effects on soil physical, chemical and biological properties; its influence on seed germination, its use as biostimulant and environmental contaminant. The low pH, electric conductivity, and chemical elements present in sugarcane vinasse may cause changes in the chemical and physical-chemical properties of soils, rivers, and lakes with frequent discharges over a long period of time, and also have adverse effects on agricultural soils and biota in general. Thus, new studies and green methods need to be developed aiming at sugarcane vinasse recycling and disposal. © 2013 Elsevier Ltd. All rights reserved.

Propriedades físicas de um latossolo vermelho manejado com material orgânico e submetido à compactação

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Morfo-anatomia de raízes tuberosas de mandioca (Manihot esculenta Crantz) cultivar IAC 576-70 em diferentes preparos do solo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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)