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Mechanical actions exerted by diverse categories of machines are used to take the soil to the most desirable physical state. The mechanical operations are carried out in the soil with or without the plant and on the plant for harvesting with high yields. All these actions can affect the soil microstructure, its density and content of organic matter, as well as its capacity of cation exchange, its fertility and productivity. To value the behavior of these properties, Lixiviated Red Ferrallitic soils were studied in areas without cultivating, cultivated with sugar cane (Saccharum officinarum L.) during twelve and seventy-five years, cultivated with medicinal plants for twenty years and cultivated with varied crops for eighteen years, with irrigation. It was found that the pH (H2O and KCl) and the hydrolytic acidity increased as years of sugar cane cultivation increased, which did not happen in the areas without cultivating and in soils dedicated to medicinal plants. In the Red Ferrallitic Lixiviated fields with several cultivations and irrigation, the pH reached values above seven due to the high content of calcium in irrigation waters derived from karst region, effect generated by the climate change. [ABSTRACT FROM AUTHOR]

The production of tomato under greenhouse system in Cuba is subjected to a high use of mineral fertilizers that resulted to high yield but it affects the nutritional quality of tomato fruits and this has brought great concern at a national level to obtain productions with a high ecological quality. In line with this, two experiments were carried out at the "Los 3 Picos" farm, in Managua Cuba, on a Feralitic Yellow Glay soil, under a protected cultivating system, with the objective to determine the effects of the arbuscular mycorrhizal fungi (AMF) of Cubense strain and earth worm´s humus, used individually or combined, as substitute to the mineral fertilizers at different dosages in tomato crop hybrid (HA 3108 Hazera). The beneficial effects of the AMF applied in the commercial biofertilizer Ecomic®, produced by the National Institute of Agricultural Sciences (INCA) and the earth worm's humus were evaluated in the plant, using the variables: height, dry matter content of leaves, final yield and internal fruit quality of fruits. The results shown that the application of AMF, was more efficient than the earth worm's humus at a 25 % dose of the mineral fertilizer and without any relevant effects when applied in combination with earth worm´s humus but with no significant influences on its biological parameters. Nevertheless, when increasing the mineral fertilizer by 50 %, could appreciate a synergy effects between the two products, being most efficient when applied in combination than applied separately, obtaining a higher production to that brought by the dosage of the mineral fertilizer considered to be optimum. The combination of the AMF and earth worm's humus improves the internal quality of tomato fruits with respect to the parameters of soluble total solids and vitamin C. [ABSTRACT FROM AUTHOR]

The objective of this research work was to evaluate the effect of applying different doses of mineral fertilization, organic fertilization (worm humus) or arbuscular mycorrhizal fungi (Glomus hoi-like) separately or in combination on the establishment of the strain IMI SD 187 of P. chlamydosporia var. catenulata. The experiment was carried out using the tomato (Solanum lycopersicum L.) hybrid HA-3108 in a greenhouse at «Los 3 Picos» farm in Havana, Cuba. Colonization of the soil and roots by the selected strain was assessed in each treatment. The number of P. chlamydosporia colony forming units in soil and roots was directly related to the application of arbuscular micorrhizal fungi and worm humus according to the Principal Component analysis and the biplot graph used. A direct relationship between the mineral fertilization and P. chlamydosporia colonization of roots was found, while it was inverse respect the soil colonization. These results indicated that the nutritional treatments favored P. chlamydosporia (IMI SD 187) growth, with more significant effects when the arbuscular mycorrhizal fungi were used combined with the worm humus. [ABSTRACT FROM AUTHOR]