Abstract:
The objective of this work was to evaluate the effects of combined phosphorus and nitrogen fertilization and of harvesting frequency on the chemical composition of 'Gigante' cactus pear (Opuntia ficus-indica) cladodes. The experiment was carried out in two municipalities, Quixadá and Tejuçuoca, in the state of Ceará, Brazil. Fertilization with nitrogen (urea) and phosphorus (single superphosphate) was done with nine doses, respectively: 10 and 70, 70 and 10, 70 and 70, 70 and 130, 100 and 100, 130 and 70, 130 and 130, 130 and 190, and 190 and 130 kg ha-1 per year, besides 100 kg ha-1 N and P2O5 per year as the control. The harvesting frequencies evaluated were annual and biannual. A randomized complete block design was adopted, in split plot, with four replicates. The effect of fertilization on the contents of total dry matter, crude protein, neutral detergent fiber, organic matter, and total carbohydrates in the cladodes varies with harvesting frequency and site. Regarding harvesting frequency, there were higher contents of organic matter, total carbohydrates, and neutral detergent fiber, but lower contents of crude protein for the biannual harvesting in both municipalities. Annual harvesting improves the nutritional quality of primary and secondary cladodes in the municipality of Quixadá and of secondary and tertiary cladodes in Tejuçuoca.
Index terms:
Opuntia ficus-indica; harvesting frequency; nitrogen; phosphorus