INFLUÊNCIA DA ADUBAÇÃO MINERAL SOBRE TRÊS CULTIVARES DE CANA-DE-AÇÚCAR NA MICRORREGIÃO DE GUARABIRA NA PARAÍBA 1

This research assessed the effect of mineral fertilization on the amount of daughter plants, sucrose level and sugarcane stem yield in three cultivars of sugarcane. A randomized block design was used with three repetitions, and four fertilization doses as treatments: 1 – control NPK (0-0-0 kg ha-1 ); 2 – NPK (0-80-50 kg ha -1 ); 3 – NPK (45-80-50 kg ha -1 ); 4 – NPK (90-80-50 kg ha -1 ). Three sugarcane cultivars were evaluated in portions of 5 x 4 m: NA 56-79, SP 79-1011 and CB 45-3. Nitrogen fertilization was made using ammonium sulphate. It was used 1/3 base fertilization with phosphorus (simple superphosphate) and potassium (potassium chloride), and 2/3 covering fertilization, 30 days after the first fertilization. It was observed that the fertilization did not contribute to alter the number of daughter plants and the yield of the three sugarcane cultivars. Sucrose levels were high, but showed no interaction with mineral fertilization. From the three cultivars that were tested, NA 56-79 and SP 79-1011 presented better yield in the experimental conditions.