Condicionadores do solo e sua influência na colonização micorrízica arbuscular e na fertilidade do solo em reflorestamento no semiárido

Abstract

Exploratory actions have caused injury in the Caatinga biome, leading to environmental degradation process. Practices such as reforestation with native plants and the use of soil conditioners have been widespread as recovery measures of degraded areas. This research was developed to evaluate the colonization of mycorrhizal fungi (AMF) on the roots of Tamboril plants [Enterolobium contortisilliquum (Vell.) Morong] under the influence of hydrogel use and carnauba straw as soil conditioners, and its ability to improve the process of absorption of soil nutrients, especially phosphorus (P). The experiment was conducted in a degraded area in the county of Ibaretama-CE, BR. The experimental design was made in a randomized block with factorial 4x2 and five replications, totaling 40 experimental units. In the evaluated treatments it was repeated four different doses of hydrogel (0, 4, 5, and 6 g L-1) and the absence and presence of carnauba straw. The conditioners were placed in the soil when planting, the hydrogel was added into the dug hole and carnauba straw on the topsoil. Chemical analysis of soil were made, plant tissue and microbiological analysis to assess the percentage of colonization by AMF. The presence of carnauba straw along with increasing doses of hydrogel influenced positively in calcium, potassium and zinc dosage on soil. In plant tissue, treatments containing carnauba straw had lower levels of the nutrients calcium and magnesium dosage. Concerning AMF, both simultaneous and isolated action of this conditioner influenced by increasing the percentage of colonization on Tamboril roots, with the highest percentage of colonization in response to the presence of carnauba straw and increasing doses of hydrogel 5,0 and 6,0 g L-1. The presence of AMF did not improve absorption of nutrients present in the soil by the Tamboril roots. There was no response at P absorption due to the colonization by AMF.