Recuperação de área degradada no Semiárido Brasileiro utilizando água residuária num sistema agroflorestal.

Abstract

The establishment of an agroforestry system based on the cultivation of aroeira, sabiá and forage palm is a form of land use or management and when associated with wastewater can recover degraded areas and provide socioeconomic and environmental benefits. The present work was developed with the objective of evaluating the potential of an agroforestry system irrigated with treated wastewater in the recovery of a degraded area in the northeastern semiarid. The research was conducted at the administrative headquarters of the National Institute of Semiarid, Campina Grande, PB, Brazil, in a degraded area by the removal of horizons A and B, whose physiographic region and Cariris Velhos have geographical coordinates of latitude 07º 27 'S, longitude 35 ° 95 'W and average altitude of 550 m, from 2015 to 2018. To determine the chemical characteristics of the soil, the treatments were randomized blocks, and three treatments (0.5 L of water) were evaluated. 0.5 and 1.0 L wastewater supplied in drip irrigation), in two seasons (before and after two years of application of water treatments), with two depths (015 and 1530 cm) and repetitions. Regarding growth and yield evaluation of forage palm var. Mexican Elephant ear irrigated with treated wastewater, the irrigated water factor was repeated as a function of three seasons (240, 300 and 360 days after planting). This same design was evaluated in the second year of cultivation of the experiment after cutting the plants. In the first and second year, the total plant height, length, width, perimeter and average thickness of the cladode were evaluated and the production variables: plant dry mass, moisture content, plant productivity and irrigated water productivity. The initial growth evaluation of the sabiá and aroeira tree species was based on a factorial scheme with two factors (wastewater and plant age with ten blocks), each experimental unit consisting of three plants. The irrigation water factor was constituted by three levels weekly application in native plants of Caatinga (0,5 L of supply water; 0,5 and 1,0 L wastewater). The age factor consisted of six levels (300, 420, 540, 660, 780 and 900 days after transplantation). The growth variables were evaluated: stem diameter and plant height. It was found that the increase of the domestic effluent blade provided reduction in Na, Ca and Mg content in the soil. Both 1.0 L and 0.5 L volume of wastewater reduce soil carbon. The weekly drip of 0.5 L of wastewater per plant provided gains in the biometric variables of the plants in relation to the application of water supply. There was an increase in dry mass, water content, fresh mass and water yield in the second cut. The weekly drip of 0.5 L of domestic effluent provided greater height and stem diameter in the thrush and aroeira compared to the drip of 0.5 L with water supply. The height and diameter of the stem plants of the thrush and mastic plants grew linearly during the evaluated period.