Sewage sludge has been used in agriculture in many crops as an alternative to reduce environmental impacts and water pollution. Nonetheless there is a need to adjust rates and timing for each crop. Therefore, the effects of sludge application on earliness and heart-of-palm yield were studied in peach palm in a field experiment carried out in Ubatuba, SP, Brazil. Four annual nitrogen rates, (0, 0.5, 1.0 and 2.0 times the recommended amounts for the crop) were tested in a complete block design. The first application was incorporated at planting (6 replications), whereas the others were performed annually, as top dressing or incorporated between plant rows (3 replications). Potassium chloride and boric acid were applied as complementary fertilization every three months to correct plant deficiencies. Ten-month-old seedlings were used in a planting density of 5,000 plants ha-1. The plant response to sewage sludge doses was evaluated monthly, through traits directly correlated to peach palm yield, for 40 months. Statistical differences in response to the doses were detected for all variables. An anticipation of the harvest of over three months could be detected when the highest and lowest doses were compared. No differences resulted from the application forms. There was an increase in yield proportional to the sludge rates, varying from 0.82 to 1.65 t ha-1 year-1 of heart-of-palm and from 0.87 to 1.39 t ha-1 year-1 of basal stem. It was concluded that sewage sludge application is suitable for peach palm and meets, partly, the fertilization needs of the crop.
Bactris gasipaes; biosolids; harvest; heart-of-palm; pejibaye
