ALTERA??ES EM ALGUNS ATRIBUTOS QUíMICOS DO SOLO DECORRENTES DA IRRIGA??O E ADUBA??O NITROGENADA E POTáSSICA EM BANANEIRA APóS DOIS CICLOS DE CULTIVO

摘要

Soil samples were analyzed with the objective of investigating changes on some soil chemical properties due to nitrogen and potassium fertilization and irrigation in a banana plantation. The samples were collected in a field experiment carried out on an Eutrustox (Latossolo Vermelho Eutroférrico típico) in S?o Paulo State, Brazil, during two crop seasons. A split-plot design was used with irrigation (micro-sprinkler) and no irrigation applied to main plots and a combination of four rates of N (0, 200, 400 and 800kgNha-1year -1) and K (0, 300, 600 and 900kgK2Oha-1 year-1) as the sub-plots treatments. Soil pH, base saturation and exchangeable Mg decreased with increasing in N rates. Exchangeable K was significantly reduced after two crop cycles with a greater K depletion in irrigated than in nonirrigated plots. The effects of cropping on soil properties strengthened the importance of checking fertility (especially acidity, exchangeable Mg and K) periodically in order to keep the sustainability of banana plantations.