The expansion of the soybean crop has evidenced a high host specificity, indicating the requirement of new strains with capacity of nodulating soybean and competition capacity with the natural soil rhizobial population. The purpose of this study was to evaluate the host specificity of mutants isolated from Bradyrhizobium spp strains in relation to nodulation and relative N2 fixation effectiveness in soybean (cultivars Peking and Clark), cowpea and pigeon pea. The experiment was carried out under controlled conditions in a growth […]

Despite of Luvisols and Planosols being ubiquitous in the semiarid region of Northeastern Brazil there are very few studies on the micromorphology and genesis of these soils. The purpose of this study was to investigate the soil micromorphology of four toposequences of Luvisols to understand and identify the main soil formation processes. Profiles of 12 soils (10 Luvisols and 2 Planosols) arranged in four toposequences were selected in the semiarid region of the states of Pernambuco and Paraíba. Undisturbed samples […]

There is no information about the diversity of springtails associated with Araucaria angustifolia (Bert.) O. Kuntze forests in Brazil. This study was carried out to evaluate the potential of springtail family diversity as a soil quality indicator and to separate different Araucaria areas, using soil chemical and microbiological attributes as explanatory variables. The study was conducted in four areas of: 1. native forest with predominance of Araucaria (NF); 2. Araucaria reforestation (R); 3. Araucaria reforestation burnt by an accidental fire […]

The long-term residual effect of the herbicide picloram poses risks of leaching and phytotoxicity to successive crops. Phytoremediation can abbreviate the long carryover effect. This research was carried out from September 2006 to February 2007, under green house conditions, in Rio Verde, Goiás, Brazil, to study the influence of Eleusine coracana population density on phytoremediation of soil contaminated with picloram. The treatments consisted of the combination of four Eleusine coracana population densities (0, 7, 14 and 21 plants per pot, […]

The experiment was conducted with the sugar cane variety SP81 3250, in a commercial area of the sugar mill São Martinho (Pradópolis-SP), on a clay-texture Rhodic eutrustox. The experimental had a randomized block design with four replications. Bags containing straw enriched with 15N (1.07 % 15N atoms) equivalent to 9 t ha-1 dry matter were placed on the soil surface between the sugar cane plant rows in all treatments (0, 40, 80 and 120 kg ha-1 of N). After 14 […]

In the watershed Água Fria, in Barra do Choça (BA), native vegetation and environmentally protected areas have been replaced by coffee and pasture cultivation. This study evaluated the physical characteristics, particle size distribution, water dispersible clay, flocculation, mean weight diameter and aggregate stability index and organic C concentration of soils under different land uses, in the area surroundings the above watershed. Soil samples were collected from six different fields: two coffee plantations (manual and mechanical cultivation), two pastures and two […]

In Brazil, the species Pinus elliottii and Terminalia ivorensis are being recommended for reforestation. However, little is known about the ecological characteristics of such forests, the nutrient cycle and possible consequences on yields and sustainability under tropical conditions. For a better understanding of the C dynamic in these ecosystems, this study aimed to evaluate the microbial activity of soil, litter, and the mixture of soil + litter in forest stands of P. elliottii and T. ivorensis. Samples of soil, litter […]

Soils in the region of Campos de Cima da Serra, RS, have high organic matter contents (SOM) and high levels of exchangeable Al. This study aimed to investigate the SOM quality of surface samples (0-10 cm) of eight representative soils from the region (two Neossols, two Gleissols, three Cambissols, one Latosol) under native pasture. The objectives were to evaluate the sample behaviour under demineralization with HF solution, to determine the chemical composition and the influence of exchangeable Al and iron […]

Soil compaction limits grain yields. Among others factors, soil amendment with agricultural lime can contribute to micro-aggregate dispersion and the formation of compacted layers. The objective of this study was to evaluate the effect of lime on soil physical attributes related to soil compaction. The experiment was carried out in PVC columns, in a glass house, during 18 months. Sterilized and non-sterilized samples of a dystrophic Red Latosol (Hapludox) were incubated with 0, 1.9, 3.8, 5.7, 7.6 and 15.2 Mg […]

The ribossomal deoxyribonucleic acid (rDNA) represents an important tool in the characterization of fungi polymorphism. There are many copies of rDNA arranged in non encoded spaces. These copies are highly preserved in fungus species. The purpose of this study was to investigate the Internal Transcribed Spacer (ITS) region and to analyze the differences in the sequence polymorphism of the ITS region in the fungus Scleroderma UFSMSc1 with sequences of Scleroderma and Pisolithus isolates from the GenBank database. The DNA of […]