Caracterização de plantas de sabiá (Mimosa caesalpiniifolia Benth.), submetidas à fertilização fosfatada, Itambé-PE

Abstract

The research aimed to evaluate the effect of phosphate fertilization on morphological components, chemical composition, and root system of Mimosa caesalpiniifolia Benth on different seasons. The experiment was conducted at Itambé Experimental Station – IPA, with three P fertilization levels equivalent to: 0, 100, and 200 kg P2O5/ha on a randomized block design with six replicates in Block I and seven replicates on Block II. Morphological evaluations were conducted six times with 60 days intervals.Harvest of leaves and twigs up to 5 mm diameter were conducted in the months of September and November 2005 and February 2006 corresponding to the dry season and April, June and August 2005 referring to the rainy season. Soil samplings were collected before and after aerial part pruning. Phosphorus fertilization effect was observed only for branch length, with average of 189,9 cm. For the remaining variables, there was an effect of evaluation season, but no phosphorus effect, with average values of 195,3 cm; 24,6; 8,9 mm and 3,8 for height, number of sprout, branch thickness, and thorn number, respectively.There were no effects of the studied factors for graze able forage, with an average of 152 kg DM/ha/60 days. There was high variability between plant fractions, independent of theevaluation period, with better chemical composition of leaves and on the rainy season. There was no significant effect of phosphorus fertilization on root length and root mass, nodule dry mass, and litter mass before the pruning. Root length averages ranged from 431 to 655 cm before pruning and from 409 to 454 cm after pruning. Phosphorus fertilization did not affect most morphological and chemical characteristics of Sabiá plants. Aerial partpruning significantly affected nodule development.