cassava (Manihot esculenta crantz) is a highly mycotrophic crop, and prior soil cover may affect the density of arbuscular mycorrhizal fungi (aMfs), as well as the composition of the aMfs community in the soil. the aim of this study was to evaluate the occurrence and the structure of aMfs communities in cassava grown after different cover crops, and the effect of the cover crop on mineral nutrition and cassava yield under an organic farming system. the occurrence and structure of the aMfs community was evaluated through polymerase chain reaction (pcr) and denaturing gradient gel electrophoresis (dgge). a randomized block

The objective of this work was to evaluate the potential of olivine melilitite rock powder, in two particle sizes and in increasing rates, to improve the chemical properties of the soil and the growth and nutrient accumulation of soybean (Glycine max) and sorghum (Sorghum bicolor) plants. The treatments consisted of three rates of the rock powder, equivalent to 2.5, 5.0, and 10 Mg ha-1, in the powder and filler particle sizes of the commercial product. Physicochemical and mineralogical analyses were carried out using, as a basis, the Brazilian normative ruling on rock powder as a soil remineralizer. The soybean and sorghum plants were cultivated for 60 and 45 days, respectively, in a greenhouse on a Humic Dystrudept and a Typic Hapludult. The olivine melilitite rock powder applied in the tested increasing rates and two particle sizes improved soil chemical properties and promoted plant growth. However, the filler particle size is more efficient than that of the powder to improve soil chemical properties and plant growth and nutrient accumulation.

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