Quality of green fruits of 'an?o verde' coconut in relation to doses of nitrogen and potassium via fertigation

摘要

The objective of this study was to evatuate the effects of doses of N and K applied via fertigation on quality of green fruits of coconut (Cocos nucifera L.) cultivar Anão Verde of Jiqui, 7 years old in a Quartzarenic Neosol of Coastal Table Lands. The study was carried out in the municipality of Parnamirim, in the State of Rio Grande do Norte - Brazil, during April, 2003 to March, 2004. The experiment was conducted in a randomized block, using for the combination of treatments the Plan Puebla III experimental matrix, consisting of 10 combinations of doses of nitrogen and potassium supplied through urea and potassium chloride, respectively. The doses of N varied from 256 to 4874 g plant-1 year-1 and that of K2O from 258 to 4872 g plant-1 year-1 applied via fertigation by micro-sprinkler irrigation system. The quality of green fruits was evaluated on the basis of mean weight of fruit, volume of water, ?oBrix, pH and salinity (electrical conductivity) of the coconut water. The mean weight of fruit was not influenced by the application of N and K in fertigation. The increase in dose of N decreased the volume and ?oBrix and increased pH of the coconut water, while increase in dose of K decreased the salinity and increased ?oBrix of coconut water.