Microbial biomass plays an important role in phosphorus cycling in tropical and subtropical soils. The purpose of this research is to quantify the content of phosphorus stored in the microbial biomass in soils under different tillage and cropping systems. Four long term experiments were then used, involving no-tillage and conventional tillage and different crop rotations, installed in different soils (Heavy clay Rhodic Hapludox, Clay Rhodic Hapludox and fine-loamy Rhodic Paleudult) in the state of Rio Grande do Sul – Brazil. […]

The existence of soil exchangeable Al in toxic levels inhibits root growth and elongation, with negative effects on water and nutrient uptake, especially of P. Thus, as soil P increases, plants become less dependent on a large root system, that may decrease crop response to liming. This study was carried out to evaluate the effect of liming and phosphorus fertilization on corn yield. The experiment was conducted in Lages, Southern Brazil, from 1994 to 1998, in a clayed Oxisol (Hapludox) […]

Microorganisms were isolated from phenolic sands resulting from metallurgic activities, using Minimal Medium for fungi containing pentachlorophenol (PCP) as the only carbon source. After four successive subcultures every 15 incubation days, the final culture was plated on Martin Medium Agar. Three different fungi were isolated and subsequently identified as Acremonium sp., Paecilomyces sp. and Penicillium sp.; which were tested for their ability to degrade: PCP, indigo dye and Remazol Brilliant Blue R (RBBR). The decolouration of indigo dye was 99% […]

An experiment was carried out under greenhouse conditions at the Soil Science Department of the Universidade Federal de Lavras, Minas Gerais, Brazil, to determine critical levels of different phophorus fractions and acid phosphatase activity in bean plants (Phaseolus vulgaris L. cv. Carioca-MG); the relationship between these fractions and the acid phosphatase activity and grain production, and the relationship between acid phosphatase activity determined “in vivo” and “in vitro“. The plants were cultivated on four lowland soils of southern Minas Gerais, […]

Morphological, physical and chemical data of 58 soil profiles of Ferralsols and low activity clay Cambisols, Lixisols, Acrisols and Nitisols and of Alisols of the International Soil Reference and Information Centre (ISRIC) collection, described and sampled in eighteen different countries of tropical and subtropical regions, were selected to analyse their consistency and, or, variability and to search for properties to better describe and differentiate them. The soil profile descriptions were based on the guidelines of FAO and the FAO endorsed […]

Imazaquin herbicide is an organic molecule presenting ionizable functional groups, with its sorption depending on soil pH and electrical charges. In this research, sorption of imazaquin was evaluated on an Anionic Acrudox at different soil depths and pH values. Radiolabelled (14C) molecules were employed to study imazaquin sorption, which was estimated by the difference between applied concentration and that remaining in solution. The sorption data were fitted to Freundlich equation to determine the sorption coefficient values (Kf), which were, overall, […]

The aim of this work was to evaluate the influence of seed pelleting with lime and with ‘Magnesian Thermophosphate’ on ionic absorption of three sorghum genotypes (Sorghum bicolor (L.) Moench), cv BRS 701, BRS 304 e BRS 601. Pelletized and non-pelletized seeds were germinated during eight days at room temperature. After this period, eight plants with uniform root and shoot development, from each treatment, were transferred to a Hoagland solution. Phosphorus and potassium absorption parameters were determined after 20 days. […]

Root system growth of the common bean, variety IAC-Carioca, under center pivot irrigation in rotation with fallow; corn; black oat; sunn hemp (Crotalaria juncea L.); pigeon pea [Cajanus cajan (L.) Millsp.] and velvet bean (Mucuna aterrima) was evaluated during a non-conventional (Autumn – Winter) cultivation period, from 1993 to 1995, on a typic Haplorthox soil, at an experimental area of the Instituto Agronômico, in Ribeirão Preto, São Paulo, Brazil. The crop sequences of common bean with corn and green manure […]

Soybean [Glycine max (L.) Merrill] plants establish a symbiosis with bacteria belonging to the genus Bradyrhizobium, realizing the biological N2 fixation process. The inoculation with selected rhizobial strains guarantees the maximization of the biological process. In Brazil, almost 13 million doses of inoculants, mainly peat based, are commercialized annually. However, the peat adhesion to the soybean seeds is low, requiring the use of adhesives. The current recommendation is the use of a water sugar cane solution at 25%, but this […]

In order to be used in a program of inoculation, efficient arbuscular mycorrhizal fungi (AMF) must be able to cope with the indigeneous fungal population. An experiment was conducted under greenhouse conditions at the Embrapa Cassava and Fruit Crops in Cruz das Almas (BA), Brazil, with the objective to evaluate the competitive capability of selected fungi, using natural soil with Tainung no. 1 variety. A Yellow Oxisol with 3 mg dm-3 of available P was used. Three exotic and three […]