SOIL ATTRIBUTES UNDER DIFFERENT WATER MANAGEMENT SYSTEMS OF RICE PADDIES IN THE AMAZONIAN SAVANNA OF BRAZIL1

ABSTRACT The rational use of water while considering the increases in food production is a great challenge for agriculture currently. aim present study was to evaluate soil properties rice paddy areas under different management systems. For this, cultivars BRS Tropical and IRGA 424 were grown following treatments: M1: Intermittent flooding; M2: flooding, followed by continuous M3: Continuous intermittent M4: flooding entire plant cycle. As control, non-cultivated area, adjacent experimental plots also evaluated. variables analyzed P, K+, Ca2+, Mg2+ Al3+ contents, pH, organic carbon (SOC), total nitrogen (TN) Carbon Stock (C-Stock), stock (N-Stock), Cation-exchange capacity (CEC), C/N ratio; CO2 emission, microbial biomass (SMB), metabolic coefficient (qMic) acid phosphatase urease activities. There not difference among systems Mg2+, CEC ratio. SMB activities lower treatments when compared control. emission system influenced phenological phase crop. SOC, C-Stock, SMB, ratio, usease are those most sensitive attributes observed during cultivation. Water changing its quality.