Nutrição nitrogenada na cultura do pimentão fertirrigado, em função de tensões de água no solo.

Abstract

Considering lhe lack of technical information on lhe water blade and fertilization with nitrogen via fertigation in protected cultivation and economic analysis that provides lhe producer with management data for the production of sweet pepper in the northern region of Brazil, with this, this work hopes to contributo this knowledge to the producers, producing information and technologies for the society. The experiment was conducted in a greenhouse at the experimental farm of Igarapé Açu, UFRA. The hybrid used was DAHRA RX in spacing 1.0 m by 0.50 m, using the experimental design of blocks organized in a 5x4 factorial scheme, with three replicates. The treatments was made of five soil water tensions (15, 25, 35, 45 and 65 kPa) as indicativo of the moment of irrigation and by four nitrogen doses (0, 135, 265 and 395 kg ha"1). The evaluated characteristics were: plant height, fresh shoot mass, shoot dry mass, number of fruits, fruit length, fruit diameter, fresh fruit mass, SPAD index, productivity, water use efficiency, nitrogen use efficiency and hydric potential. There was interaction between soil water tension factors and nitrogen doses for only for nitrogen efficiency, obtaining a better index of the combination of 15 kPa of water in the soil and 135 kg ha'1 de nitrogen. The leveis of nitrogen in the bell pepper leaves were within the range suitable for the crop, with the exception of the third harvest, in which the treatments with the highest soil water tensions presented lower values than the adequate ones. The economic analysis showed us that variable costs had greater participation in total costs, especially the labor force. The maximum profit found in the cultivation was R $ 130,903.80, in combination of 15 kPa of water in the soil and 265 kg ha-1 of nitrogen. At the front of the conditions in which this work was developed and the results obtained in the evaluated variables for the culture of the pepper in a protected environment, a good productive and economic yield was verified in the tension 15 kPa of water in the soil and dose of 265 kg ha'1 of nitrogen.