Phosphorous distribution in the drip bulb, applied by fertigation with phosphoric acid

The phosphorous distribution, pH and the water content in the wet bulb of a Latosol without vegetation fertigated along one month, were investigated. The experiment, with randomised blocks design was carried out in UNESP - São Paulo State University, Jaboticabal - Brazil. The treatments (0; 30; 60; 90 and 120 kg ha-1 of P2O5) were divided in four weekly applications, by fertigation, using phosphoric acid. After the last application, trenches in the bulbs were opened, and samples of the soil were collected in 100 cm² areas. The phosphoric acid increased the acidity and provoked high phosphorus contents in the fertigated bulbs, until 30 cm of lateral distance and until 40 cm of depth, in relation to the drip point. Increasing the rate of the phosphoric acid (90 and 120 kg ha-1 of P2O5) resulted in higher phosphorus concentration and soil acidity until 30 cm of lateral distance and until 40 cm of depth. The phosphorous distribution and its effect in the pH did not follow the moisture distribution in the bulb.

wet bulb; trickle irrigation; soil acidity

Associação Brasileira de Engenharia Agrícola SBEA - Associação Brasileira de Engenharia Agrícola, Departamento de Engenharia e Ciências Exatas FCAV/UNESP, Prof. Paulo Donato Castellane, km 5, 14884.900 | Jaboticabal - SP, Tel./Fax: +55 16 3209 7619 - Jaboticabal - SP - Brazil