Evaluation of phosphorus and nitrogen dosages in strawberry pear (Hylocereus undatus) cultivation.

Abstract

An experiment with strawberry pear was carried out in the Bluefields experimental center in an inseptisol soil. The experiment started in 1992, and lasted four years. The treatments studied consisted of four Nitrogen levels (0; 40; 80; and 120 kg/ha), and three Phosphorus levels (0; 20; and 40 kg P205/ha), combined in a factorial arrangement (4x3). Two exploratory treatments were included: Potasium (10 kg. 20 kg/ha) , and rnicronutrients (5 kg B/ha, 10 kg Cu/ha, 10 Zn/ha, and 5 kg Mn/ha), combined in a single mix with the highest levels of N and P. In total, there were 14 treatments, which were distributed in complete blocks at random, with four repetitions. Nitrogen had a significant effect on the amount of fruit per plant, as well as on the total yield in the three crops (1994, 1995, and 1996); Phosphorus was significant only in the first and second crops; while the effect of Potasium and the micronutrients was significant only in the third crop. Basedon the response of yield to nitrogen, the three crops showed a significant effect compared to the control (0 kg/ha) at levels of 40 and 80 kg/ha in the first and second crops, and 40 kg/ha in the third crop. Concerning Phosphorus, in 20 and 40 kg P205/ha as compared to the control, in the third crop all the levels were equal. In economic terms, the leve1 of 80 kg/ha of Nitrogen turned out to be more cost-effective for the first crop, with 41.78% and 143.43% marginal return rates, respectively. As for Phosphorus, the greatest return was obtained at 20 kg P205/ha for the three crops: 10.31 %; 22.19%; and 73.23%. The rate of return for Potasium and rnicronutrients was negative in the first two crops; however, in the third crop the return rates were 333.76% and 129.71 % for Potasium and micronutrients, respectively.