Anderson Cristian Bergamin

Erosão em entre sulcos em área cultivada com cana crua e queimada sob colheita manual e mecanizada

Although a number of studies related to environmental issues address air pollution, the increased use of biotechnology and mechanical harvesting of sugar cane, less attention has been paid to the negative environmental impacts caused by laminar erosion. This study aimed to determine the levels of organic matter (OM) and nutrients (P, K, Ca and Mg) in sediment and runoff water from interrill erosion from different sugarcane harvest systems (green and burnt cane), on a loamy Dystrophic Red Latosol (Oxisol). The treatments consisted of burnt cane harvested by hand, mechanical harvesting of green cane and mechanical harvesting of burnt cane. A portable rainfall simulator was calibrated to apply rainfall of 60 mm h-1, for 50 min. The sediment concentration in runoff resulting from interrill erosion, as well as OM, P, K, Ca and Mg were higher in the system with mechanical harvesting of burnt cane, while losses were lowest from the system with mechanized harvesting of green cane. The soil physical quality is negatively influenced by the management system with mechanical harvesting of burnt cane, due to the pressure exerted by the harvest machine traffic. However, crop residues distributed across the soil surface at mechanical harvesting of green cane reduce losses of soil, nutrients and OM in the sediment, and increase the soil resistance against physical degradation caused by machinery traffic for mechanical harvesting of sugarcane.

Caracterização de terras pretas arqueológicas no sul do estado do Amazonas

The Archaeological Dark Earth (ADE) soils are characterized by its high fertility, dark color, and presence of pottery fragments. Regarding the formation of ADE, the most widely accepted hypothesis is that anthropogenic processes involving pre-Columbian populations made them. The purpose of this study is to characterize ADE units located in the Southern Amazon Region, in the cities of Apui and Manicore. Seven ADE sites were selected, trenches opened and the soil profiles characterized morphologically. Then, samples of each horizon were collected for analyses of the following physical and chemical properties: particle size, water-dispersible clay, flocculation, soil bulk density, particle density, total porosity, pH in water and KCl solutions, Ca2+, Mg2+, K+, Al3+, available P, H+Al, and organic C. Also, total oxides, free oxides and amorphous forms were analyzed. The texture of the anthropic A horizon ranged from sandy loam to clay loam. The pottery fragments and lithic material were found in similar quantities and at similar depths in the A horizons of the studied soil profiles, suggesting some similarity between the anthropogenic factors of formation. The anthropic horizons of profiles P3, P4, and P7 had a eutrophic character and high to very high levels of available phosphorus, compared to P1, P2, P5, and P6, indicating the heterogeneity of the ADEs.

Anatomia radicular de milho em solo compactado

O objetivo deste trabalho foi avaliar a relacao entre a estrutura anatomica das raizes de milho e os atributos fisicos de solo submetido a diferentes graus de compactacao. O estudo foi realizado em campo, no Municipio de Dourados, MS, em Latossolo Vermelho distroferrico, textura muito argilosa. O delineamento experimental foi o de blocos ao acaso, com cinco repeticoes. O solo utilizado apresentava historico de oito anos com plantio direto. A compactacao adicional do solo foi realizada por meio de trafego com trator, com uma (PDc1), duas (PDc2), quatro (PDc4) e seis passadas (PDc6) sucessivas, sobre toda a area da parcela. Houve aumento na razao entre o cortex e o cilindro vascular da raiz com o aumento na compactacao do solo. Essa razao correlacionou-se negativamente com a macroporosidade e positivamente com a densidade do solo e com a resistencia do solo a penetracao. O grau de compactacao afeta a anatomia radicular do milho, e a resistencia do solo a penetracao e o indicador fisico que melhor expressa esse efeito.

Relationship of soil physical quality parameters and maize yield in a Brazilian Oxisol

In Brazilian agriculture, maize (Tea mays L.) is prominent because of its magnitude of grain production. However, soil compaction changes negatively the soil physical attributes, limiting the crop growth. This study aimed to evaluate physical attributes of a clayey Oxisol (Rhodic Hapludox) under no-tillage, and the relationships between these attributes with maize yield in the Midwest region of Brazil. Besides this, indicators of soil physical quality when subjected to levels of compaction were determined. A randomized complete block design was applied with five replicates. Treatments were induced levels of compaction: a reference condition that reflects 8 yr of no-tillage (NT); no-tillage with additional compaction by tractor traffic in one (NT-1), two (NT-2), four (NT-4), and six passes (NT-6). There was significant correlation (P < 0.01) between all physical attributes of the studied soil. Maize yield was positively correlated to macroporosity (r = 0.41*), and negatively to penetration resistance (r = -0.42*), geometric mean diameter (r = -0.51*), and mean weighted diameter (r = -0.53*). The index of emergence speed, stem diameter, plant height, grain mass, and grain yield decreased as soil compaction increased. The physical attributes evaluated, especially the resistance to penetration and soil macroporosity, reveal the level of soil compaction and can be used as soil physical quality indicators.