Ocorrência de Macroptilium SPP e diversidade rizobiana em neossolos litólicos do semiárido de PE

Abstract

The Northeast is formed by a large proportion of semiarid region, with the Caatinga as predominant native vegetation. In this region, people survive mainly by means of economic activities mostly related to agriculture and livestock. The genus Macroptilium spp. includes 20 species from tropical and subtropical America, with seven species occurring in the Brazilian semiarid region. This study aimed to identify the occurrence of plants of the genus Macroptilium spp. present in eleven counties in the semiarid region of Pernambuco State. And also an experiment was conducted to study of Macroptillium lathyiroides rhizobium diversity in the semiarid of Pernambuco State. Descriptive analyses of the samples were used for the explanation of the rhizobium occurrence. Correlations of chi-square test and decision tree were also used. Variables that most influenced the occurrence of Macroptilium spp. accesses were rainfall and average temperature, with much accessions collected in silty sandy soils. It was observed that the municipalities of Sertânia and Parnamirim were those who had higher plants Macroptilium with plants of Bom Jardim, Caetes and Tupanatinga shown higher survival rates. For assess the diversity of rhizobium in Entisols located in the semiarid of Pernambuco State, an experiment aiming to study rhizobium diversity was carried out using random blocks, with four replications. Treatments consisted of seven “Entisols Lithicc soils” (inoculum) collected from the municipalities of Santa Cruz do Capibaribe, Tupanatinga, Jataúba, Caetés, Santa Cruz, Petrolina, and Floresta. Two additional treatments, with and without nitrogen, were used as the control, totaling nine treatments. Analysis of shoot and root, relative efficiency, dry matter accumulation, weight and number of nodules were performed. Morphological characteristics of bacterial isolates were also assessed. It was observed that the soils of the counties of Santa Cruz do Capibaribe, Tupanatinga, and Jataúba were the bacterial isolates with higher nodule weight, nodule number, and relative efficiency. It was also observed that most bacterial isolates were fast growing.