Douglas Marcelo Pinheiro Silva

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.

Variabilidade espacial da estabilidade de agregados e estoque de carbono em Cambissolo e Argissolo

The advancement of agricultural activities without considering the soil structural conditions ceases at the expense of those environments. This study aimed at evaluating the spatial variability of aggregate stability, bulk density, total organic carbon (TOC) and carbon stock in areas of natural grassland and forest, in the region of Humaita, Amazonas State, Brazil. The soils were sampled at the crossing points of a grid with 70 m x 70 m, at regular intervals of 10 m, at the depths of 0.0-0.05 m, 0.05-0.10 m and 0.10-0.20 m, totaling 64 samples per depth. The results of the geostatistical analysis showed spatial dependence of attributes. The smaller ranges resulted from the constant variations in the relief of the natural grassland area. The mean values for mean weight diameter (MWD) and TOC were respectively around 3.0 mm and 29.0 g kg -1 of the surface layer, similarly to natural grassland and forest areas, confirming the proportional correlation between TOC and MWD. However, the bulk density greater than 1.40 kg dm -3 expresses the inefficiency of soil structural functions in the natural grassland area. The carbon stock contents at the different depths were more favored by TOC than by the different densification levels of the soils evaluated.

CRESCIMENTO DAS MUDAS DE CUPUAÇU (Theobroma grandiflorum) SOB EFEITO DE DIFERENTES COMPOSIÇÕES DE BIOFERTILIZANTES DOI: http://dx.doi.org/10.5892/ruvrd.v15i2.3299

1 Engenheira Agrônoma da Universidade Federal do AmazonasUFAM, ediana.agronomia@gmail.com * 2 Engenheiro Agrônomo, Professor Dr. Adjunto IV, Bolsista de Produtividade do CNPq Universidade Federal do Amazonas – UFAM – Campus de Humaitá, e-mail: mcesarsolos@gmail.com; 3 Mestre em Agronomia Tropical. Docente do Instituto Federal de Ciência, Inovação e Tecnologia do Amazonas-IFAM, leandro_alho@yahoo.com 4 Academico de Engenheira Agrônoma da Universidade Federal do AmazonasUFAM, felipec.weckner@gmail.com 5 Engenheiro Agrônomo, Mestrando pelo Programa de Pós Graduação em Ciência do Solo da Universidade Federal Rural de Pernambuco – UFRPE – Recife, e-mail: brunomantovanelli21@gmail.com. 6 Bacharel em Física, Professor Doutorando do Programa de Pós Graduação em Física Ambiental Adjunto I Universidade Federal do Amazonas – UFAM – Campus de Humaitá, e-mail: maujmc@gmail.com.

Growth of cowpea cultivars in upland and lowland soils

O feijao caupi apresenta grande importância na alimentacao especialmente das populacoes das regioes norte e nordeste brasileiro, sendo uma das principais fontes de energia e proteina nestas localidades. Entretanto, as produtividades obtidas geralmente sao baixas, o que poderia ser contornado utilizando-se solos de maior fertilidade natural. Assim, o objetivo neste trabalho foi avaliar o crescimento de tres cultivares de feijao caupi cultivado em solo de terra firme e de varzea, na regiao de Humaita, Amazonas. O experimento foi conduzido em casa de vegetacao, utilizando-se sacos de polietileno de aproximadamente 2 litros. Como substrato, foram coletadas amostras de solos na profundidade 0,0 a 0,20 m, de Argissolo Vermelho (terra firme) e Neossolo Fluvico (varzea). Foram utilizadas na semeadura as cultivares: Barrigudinho, Manteiguinha e Felipinho. O delineamento estatistico utilizado foi em blocos completos casualizados, em esquema fatorial 2x3, com quatro repeticoes. Foram avaliadas as seguintes caracteristicas: altura da planta, diâmetro do coleto, biomassa seca e verde da parte aerea e radicular. Verificou-se que o solo de varzea e mais propicio ao cultivo do feijao caupi, devido a sua fertilidade natural. Nao ha diferenca no crescimento vegetativo das cultivares de feijao estudadas, independentemente do cultivo em solo de varzea ou terra firme. Abstract The cowpea is important especially in feeding the populations of northern and northeastern Brazil, it is a main source of energy and protein in these places However, the yields are low generally, which could be overcome using higher natural fertility soils. The aim was to evaluate the growth of three cultivars of cowpea grown in soil “terra firme” and “ varzea ” in the region of Humaita , AM . The experiment was performed in a greenhouse, using polyethylene bags of about 2 liters. Soil samples were collected at a depth from 0.0 to 0.20 m, Typic Hapludalf (terra firme) and Fluvic Neosol (varzea), the cultivars used for varieties: Barrigudinho , Manteiguinha and Felipinho . The statistical design was randomized blocks in factorial 2x5, with four replications. The parameters used in assessing the growth of plants were: plant height, stem diameter and dry biomass of green shoots and roots. It was found that the meadow soil is more conducive to the cultivation of cowpea, due to its natural fertility. There is no difference in vegetative growth of bean varieties studied, regardless of the crop in “ varzea ” or “ terra firme ”.