Adubação orgânica e mineral na cultura da melancieira no semiárido Paraibano.

Abstract

To produce in quantity and quality without harming the environment and without placing a burden the production costs, is the main aim of small and medium farms. Therefore, new technologies are needed to decrease the market dependence on input products industrialized, prioritizing the use of renewable resources acquired on the itself farm. Thus, we aimed to evaluate the effect of combined and isolated use of mineral and organic fertilizers on the watermelon culture. The experiment was taken place in an area located at the Federal University of Campina Grande (UFCG), Campus Pombal - PB (6 º 48 '16'' Sand 37º 49'15''W), during the period from June to September 2013.The design was a randomized block with four repetitions in a factorial 3x5 where the factor (A) were allocated different concentrations of nutrients N, P and K (50, 100 and 150 % of recommended NPK to watermelon) and the factor (B) five proportions of mineral and organic (100/0, 75/25, 50/50, 25/75 and 0/100) fertilizer. The rate of NPK corresponding to 100% was 120 kg ha-1 respectively for N, P e K. Were evaluated: gas exchange, leaf dry weight, stem, fruit, total dry matter, leaf area, nutrient accumulation in leaves, stem, fruit and total, total yield, titratable acidity, total soluble solids and ratio soluble solids and titratable acidity. The concentration of 150% of the recommended NPK to the culture of watermelon was the most effective in the physiological characteristics increasing, and dry matter accumulation in stem, leaf, fruit, and total; concentration of 100% of the recommended NPK does not supply adequately the nutritional needed requirements of the culture of watermelon 'Olympia' in Paraiba interior; the combination of mineral and organic fertilizer application provides equivalent photosynthetic rate isolated application of mineral fertilizer with an 50/50 ratio the most effective for this variable; The manure use alone does not contribute to the increase of dry mass in the vegetative part, when compared to combined use with mineral fertilizers, the proportions being 75/25 and 50/50, the most effective in dry matter accumulation in watermelon; the concentration of 150% of the recommended dose was the most effective in NPK accumulation in leaves, stems and fruits of watermelon; the proportions of mineral and organic fertilizer 50/50 and 75/25 were more effective in the accumulation of N and P and 0/100 in the K in leaves of watermelon; NPK accumulation in fruits and vegetative parts showed the following order of magnitude: K>N>P; fruits were preferred drains NPK vis-à-vis vegetative part; 150% of the nutrients concentration was more effective in increasing yield in the proportions of mineral and organic fertilizer of 0/100, 75/25 and 25/75; the concentration of 100 and 150% were more effective in the accumulation of soluble solids when combined with proportions of mineral and organic fertilizer 75/25 and 50/50.