Alterações físicas do solo em cultivos fertirrigados com água residuária tratada

Abstract

The treated wastewater is an important alternative to minimize agricultural water resources demand, especially in semi-arid and arid regions. However, there are concerns that irrigation with treated wastewater may lead to degradation of soil physical properties. The soil fertigation changes with treated sanitary wastewater from the Janaúba Wastewater Treatment Plant was studied in two field experiment: after the sequential cropping of cotton, maize, cotton, beans, and pineapple, and after 'Prata-Anã' banana cropping. Soil sampling was made after five years of cropping, in 2017, in the depths of 0-0.2; 0.2-0.4; 0.4-0.6 and 0.6-0.8 m. It was used the randomized block design with four replications. The attributes evaluated were soil bulk density, particle density, tota/l porosity, macroporosity, microporosity, mean weight diameter, geometric mean diameter, macro and microaggregates, sand, silt and total clay, water-dispersible clay, and clay flocculation index. The treated wastewater fertigation after five years with sequential cropping changes soil physical properties in the 0-0.2 m depth but did not modify the soil structure in the deeper layers. In the banana area, wastewater fertigation changes soil aggregation in the 0-0.2 m depth, without modify soil physical properties in the deeper layers. The wastewater fertigation based on chemicals concentration criteria for five years improvessoil physical quality comparing to pasture.