Fontes e épocas de aplicação de nitrogênio em cenoura

Abstract

The carrot is a vegetable of global importance, the acreage extension and provide socio economic development of farmers. The work was carried out between April and July 2014 at the Federal University of Paraíba, in order to assess the carrot behavior submitted to sources and nitrogen application times. The design experiments performed was randomized blocks in a factorial 2 x 7, with three replicates. The treatments were represented by the following nitrogen installments (100% in planting; 100% at 30 days after sowing (DAS), 100% at 60 DAS, 50% at sowing and 50% at 30 DAP, 50% at planting and 50 % at 60 DAS, 50% at 30 and 50% at 60 DAS;. 33% in planting 33% at 30 and 33% at 60 DAS and two nitrogen sources (urea and ammonium sulfate) Plots measured 2.0 . mx 1.0 m and consisted of 160 plants, spaced 25 x 5.0 cm, with all plants considered useful We evaluated the following variables: length, diameter, average weight, work number, total, commercial, nitrogen, phosphorus and potassium leaf. The root length was changed by the treatments and the diameter showed lower value (27.91 mm), supply urea provided 100% in planting. The average root mass was higher in installments 33% in planting 33% at 30 and 33% at 60 DAS, 166 and 189 g respectively in supplies of ammonium sulfate and urea. For commercial root number was no significant effect only for the source of ammonium sulfate, bringing the number when the installment was 100% at 30 DAS and 100% at 60 DAS. The 33% installment in planting 33% at 30 and 33% at 60 DAS provided the highest commercial yields of roots 89.83 t ha-1 and 100% application at planting roots highest total productivity 110 t ha-1. The leaf N content showed higher accumulation when nitrogen was divided 50% to 30 DAS and 50% at 60 DAS for ammonium sulfate 41.12 g kg-1 for urea obtained the highest value when applied 100% to 60 DAS, 42 00 g kg-1. The application of 100% to 30 DAS provided higher phosphorus foliar 3.40 and 2.90 g kg-1. The potassium content in carrot leaves obtained no significant effect when used source was ammonium sulfate when the source was urea was obtained greater value by applying 100% in planting.