Micronutrient contents of a revegetated saprolite exposed by excavation of an oxisol

Soils of the Brazilian Cerrado biome have been found to be deficient in copper (Cu) and zinc (Zn). In this area, an Oxisol was deeply excavated in 1962 during the construction of a hydroelectrical plant, and the exposed saprolite material was abandoned, without any reclamation measures. The abandoned land was a harsh environment for plant growth, and the secondary vegetation has not recovered. A field trial was established in 1992 to assess the effects of different grass species and lime amendments on soil reclamation at the degraded site. In 2011 soil samples were collected at three depths (0-10, 10-20, and 20-40cm) from vegetated and bare plots over tilled saprolite, from an untreated area of the saprolite, and from an Oxisol under native forest, used as external reference. Nineteen years after the reclamation effort was begun, the organic carbon (OC) content of the restored saprolite still was much lower than that of the Oxisol under natural vegetation. The undisturbed Oxisol was deficient in extractable Cu (0.16-0.10mgkg(-1)) and Zn (0.10-0.02mgkg(-1)) and exhibited rather low concentrations of extractable iron (Fe; 5.24-1.47mgkg(-1)) and manganese (Mn; 3.21-0.77mgkg(-1)). However, the saprolite under reclamation showed even lower levels of these elements compared to the native forest soil. In the natural soil, OC, N, extractable Fe, Mn, and Cu showed stratification, but this was not the case for extractable Zn. Although the reclaimed saprolite still was far from predisturbance conditions, the revegetation treatments promoted recovery of OC, N, Fe, Mn, and Cu at the surface layers, which resulted in incipient stratification. Extractable Fe, Mn, and Cu were correlated to OC, whereas no association between Zn and OC was detected. Our results also suggest that reclamation of the excavated saprolite may be constrained by micronutrient deficiencies and mostly by the extremely low levels of Zn and Cu.

Frugivores at higher risk of extinction are the key elements of a mutualistic network

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

Acúmulo de cádmio, crômio e níquel e isolamento de micro-organismos potenciais para biorremediação em área agrícola

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Variação bioacústica das vocalizações do complexo Taraba major (Vieillot, 1816) (Aves: Passeriformes: Thamnophilidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Diversidade e prospecção de fungos endofíticos de Begonia spp. encontradas na Mata Atlântica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Control of Brachiaria decumbens and Panicum maximum by S-metolachlor as influenced by the occurrence of rain and amount of sugarcane straw on the soil

Com o objetivo de estudar o controle em pré-emergência de Brachiaria decumbens e Panicum maximum pelo herbicida S-metolachlor em função do intervalo de tempo entre a aplicação e a ocorrência de chuva e da quantidade de palha de cana-de-açúcar na superfície do solo, dois experimentos foram desenvolvidos em vasos mantidos em casa de vegetação. No primeiro, foram estudadas cinco quantidades de palha sobre o solo (0, 3, 6, 10 e 15 t ha-1) e cinco dosagens de S-metolachlor (0; 0,96; 1,44; 1,92 e 2,40 kg ha-1). No outro, foram avaliadas duas quantidades de palha sobre o solo (0 e 10 t ha-1) e sete intervalos de tempo entre a aplicação de S-metolachlor e a simulação de chuva (1 dia antes; logo após; 4, 8, 12, 16 e 20 dias após a aplicação). As dosagens de S-metolachlor não foram afetadas pelos níveis de palha na superfície do solo. Além disso, sem a manutenção de palha sobre o solo, o controle das plantas daninhas pelo herbicida S-metolachlor não foi influenciado pelos intervalos de tempo entre a aplicação e a simulação de chuva, até 20 dias. Com 10 t ha-1 de palha, o controle de B. decumbens e P. maximum pelo S-metolachlor não foi prejudicado quando choveu até 12 dias da sua aplicação ou um dia antes, mas, nesse caso apenas para P. maximum.

Effects of Different Periods of Clomazone plus Hexazinona Permanence in Soil and Sugarcane Mulch before the Occurrence of Rain on Weed Control Efficacy

The objective of this work was to evaluate the efficacy of the formulated mixture clomazone and hexazinone applied in soil or combined with sugarcane mulch, after different periods of permanence without the occurrence of rain. The experiment was carried out in vases under greenhouse conditions in Botucatu, São Paulo, Brazil. The weeds Brachiaria decumbens, Ipomoea grandifolia, Ipomoea hederifolia and Euphorbia heterophylla were sown and covered or not with sugarcane mulch. The experiment was arranged in a complete randomized design with four repetitions. The treatments were displaced in a 3x6 factorial scheme, with the factors being six periods without rain (0, 3, 7, 15, 30, and 60 days) and three modes of herbicide application(on the soil without sugarcane mulch, on and under sugarcane mulch). Control evaluations were carried out at 10, 21, 35 and 42 days after the occurrence of rain. The clomazone + hexazinone mixture promoted an excellent weed control for all the species studied when applied on, under, or without sugarcane mulch. However, the control levels tended to reduce for periods over 60 days without rain.

Seed rain and seed limitation in a planted gallery forest in Brazil

With seeds collected monthly during one year from 53 1-m(2) seed traps, we investigated the seed rain and seed limitation in a gallery forest planted in 1994 in SE Brazil. Contrasting animal- (zoochorous) and wind-dispersed (anemochorous) plants we investigated (1) which aspects of the composition and structure of the vegetation influence the abundance and species richness of the seed rain; (2) if such influences differ between zoochorous and anemochorous seeds; (3) if the abundance and richness of the seed rain sampled under zoochorous and nonzoochorous plant species differ; and (4) if seed limitation (given by the proportion of sites to which seeds were not dispersed) differs between zoochorous and anemochorous plant species, and also between species that have been planted and those that further colonized the area (colonists). Seed rain was intense and dominated by anemochorous species. The overall seed rain was not influenced by the vegetation parameters we analyzed (canopy height and cover, plant size, abundance, and richness) or by the plant species above the seed trap. The abundance and richness of zoochorous seeds in a given spot was influenced by the abundance and richness of zoochorous plants in its immediate vicinity. Seed limitation was higher for anemochorous than zoochorous species and higher for planted than for colonist species. We concluded with recommendations for the initial establishment of a planted forest, including the homogeneous distribution of zoochorous plants to permit a spatially homogeneous zoochorous seedfall, which will likely enhance the chances of survival and successful establishment of seeds.

Different responses in bulk density and saturated hydraulic conductivity to soil deformation by logging machinery on a Ferralsol under native forest

Ferralsols have high structural stability, although structural degradation has been observed to result from forest to tillage or pasture conversion. An experimental series of forest skidder passes in an east Amazonian natural forest was performed for testing the effects of mechanical stress during selective logging operations on a clay-rich Ferralsol under both dry and wet soil conditions. Distinct ruts formed up to 25 cm depth only under wet conditions. After nine passes the initially very low surface bulk density of between 0.69 and 0.80 g cm(-3) increased to 1.05 g cm(-3) in the wet soil and 0.92 g cm(-3) in the dry soil. Saturated hydraulic conductivities, initially > 250 mm h(-1), declined to a minimum of around 10 mm h(-1) in the wet soil after the first pass, and in the dry soil more gradually after nine passes. The contrasting response of bulk density and saturated hydraulic conductivity is explained by exposure of subsoil material at the base of the ruts where macrostructure rapidly deteriorated under wet conditions. We attribute the resultant moderately high hydraulic conductivities to the formation of stable microaggregates with fine sand to coarse silt textures. We conclude that the topsoil macrostructure of Ferralsols is subject to similar deterioration to that of Luvisols in temperate zones. The stable microstructure prevents marked compaction and decrease in hydraulic conductivity under wetter and more plastic soil conditions. However, typical tropical storms may regularly exceed the infiltration capacity of the deformed soils. In the deeper ruts water may concentrate and cause surface run-off, even in gently sloping areas. To avoid soil erosion, logging operations in sloping areas should therefore be restricted to dry soil conditions when rut formation is minimal.

Estimation of water transit time in soils under Amazon forest cover using variations in sigma18O values.

In an attempt to estimate the soil-water transit time using the variation in 18O values, a statistical model was used. This model is based on linear regression analysis applied to the values observed for soil water and rain water. The time obtained from these correlations represents the mean time necessary for the water to run from one collecting point to the next.-from Authors

Evaluation of soil management and use in an Ultisol in a guava orchard in comparison with a sugarcane field and native forest area

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

SIMULATION OF USE AND MANAGEMENT EFFECTS ON THE SOIL ORGANIC MATTER POOLS OF THE ATLANTIC FOREST BIOME, BRAZIL

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Soil erodibility assessment in a pasture and forest remnant using the Indrbitzen device

Brazil has the largest cattle herd in the world with approximately 200 million head. An important feature of the Brazilian cattle industry is that most of its herd is raised on pasture, which constitutes one of the most economical and practical ways to produce and provide food for cattle. However, this production model is mishandled and can lead to soil degradation. Maintaining soil quality is essential for the conservation of natural ecosystems and the areas of production, thus soil quality improves the conditions for biogeochemical cycles. In this context, the objective of this study was to develop a device for testing the Inderbitzen way of assessing soil erodibility in two situations of usage and occupation. Therefore, one area was used as a sample collection occupied by grazing and the other as a forest fragment; both located in the city of Sorocaba in Sao Paulo State, Brazil. Thus, we concluded that the proposed device – the Inderbitzen – proved capable of assessing soil erodibility of the pasture and remnant forest. Accordingly, there was a tendency for a smaller loss of forest soils in the remnant when compared to the degraded pasture. The greatest resistance of the soil erosion in the forest remnant may be associated with the amount of organic matter released by the forest litter in all its diversity, influencing the quality of the structure of aggregates. Keywords: erosion, forest remnant, degraded pasture, Inderbitzen test.

Soil water evaporation under densities of coverage with vegetable residue

O presente estudo foi realizado no Instituto Agronômico do Paraná (IAPAR), em Londrina, Estado do Paraná (latitude de 23º18'S, longitude de 51º09'W e altitude média de 585 m). O clima local, segundo a classificação do Köppen, é do tipo Cfa, ou seja, subtropical úmido, com chuvas em todas as estações, podendo ocorrer secas no período de inverno. Determinou-se a evaporação (E) da água do solo sob diferentes densidades de cobertura com resíduo da cultura de trigo. Os tratamentos foram instalados em lisímetros de pesagem de 2,66 m² e 1,3 m de profundidade, que permitem determinar E por diferença de massa com precisão equivalente a 0,1 mm em intervalos de uma hora. Os tratamentos consistiram em 0; 2,5; 5 e 10 t ha-1 de resíduos da cultura do trigo, colocadas de forma homogênea em cada lisímetro. No primeiro ciclo (22/09 a 20/10/2008), a redução de E em relação ao solo descoberto foi de 4; 15 e 24%, enquanto no segundo ciclo (01/12 a 30/12/2008), a redução foi de 15; 22 e 25%, respectivamente, para os tratamentos 2,5; 5 e 10 t ha-1.

Chemical attributes of a degraded soil after application of water treatment sludges

Mining is an activity that tends to degrade the environment. The restoration of mining areas, aims to accelerate and improve the succession process according to its future use. The objective of this work was to rehabilitate a soil degraded by tin mining activities in the Amazon Basin (Jamari National Forest, State of Rondonia) with the application of water treatment sludge (WTS), and verify the effect of Sludge on Values of pH (CaCl2 0.01 mol L-1), organic matter, P, Ca, Mg, K, H+Al, and soil micronutrient contents when Cultivated with native plants, legumes, and grass species. A factorial (3 x 5) experimental design was used to optimize the rehabilitation of these areas including three N rates (100, 200, and 300 mg N ka(-1) soil supplied by WTS), five plant species (grasses, legumes, and native plants), and two controls (degraded soil with no fertilizer and degraded soil fertilized with mineral fertilizers), with four replications. WTS increased pH values. The chemical products used to treat the water contributed, in greater extension, to increase soil Ca and Fe contents. The use of WTS as fertilizer proved viable, since it contains nutrients for plants; however, nitrogen Should not be used as a criterion to define the rate of Sludge application, because it is present at small amounts in the WTS.