Produtividade, índices fisiológicos e nitrogenados avaliados na planta em tempo real, influenciados pelo manejo do nitrogênio, época de cultivo e cultivar de batata

• Autor(a) principal: Braun, Heder
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1189
• topic: Nitrogênio; Solanum tuberosum; Efeito do Nitrogênio; Diagnóstico; Prognóstico; Nutrição Mineral; Nitrogen; Solanum tuberosum; Effect of Nitrogen; Diagnosis; Prognosis; Mineral Nutrition; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

The objectives of the thesis were: a) to determine the effect of nitrogen (N) management, rates and application time of the N, on physiological and N indexes realtime evaluated both in the fourth leaf from the apex (FL) and in the plant; b) to estimate the critical values (CV) of those indexes in two potato cultivars at two growing season; c) to determine the value of morphological and physiological characteristics associated with plant growth and leaf N productivity in potato cultivars; d) to determine the optimum N fertilization rate associated with the maximum tuber physical and economic yield of potato cultivars. It was also evaluated the possibility to indirectly estimate the leaf N concentration of potato cultivars with Dualex® equipment (chlorophyll index, flavonol index and N balance index) as well the soluble phenol and carbohydrates (total soluble sugars, reducing sugars and starch) in potato leaf and tuber at the harvest time. In FL, the N indexes were: reading SPAD, total leaf chlorophyll concentration, leaf chlorophyll a and b ratio, N efficiency use, N concentration in per area; N concentration in FL, stem, and leaf, N content in FL and N accumulated amount by shoots. The physiological indexes were: FL and plant leaf area, °h, L , C, °h/(L *C) ratio; leaf, stem, FL, shoot and total dry matter; FL and plant specific leaf area and leaf area ratio. The experiments were established in the field, at the Federal University of Viçosa (UFV), Viçosa, Minas Gerais State, the years 2009, 2010 and 2011. In different experiment were evaluated: a) five N fertilization rates applied in furrow at pre-planting (0, 50, 100, 200 and 300 kg ha-1) and two potato cultivars (Asterix and Atlantic) during July-November 2009, in a randomized block design with four replications. At 21 days after emergence (DAE), were harvested representative plants in each plot. The physiologic and N indexes were evaluated after harvest plant; b) between March to June, 2010 it were simultaneously installed and conducted two field experiments. Each experiment was one potato cultivars (Ágata and Asterix) and three N fertilization rates (0; 300 and 600 kg ha-1) pre-planting applied in the furrow which were characterized as limiting, adequate and excessive conditions. The experiments were arranged in a split-plot design with four repetitions in randomized complete blocks. The plots were constituted by N fertilization rates and subplots by five plant sampling time, 14; 28; 42; 56 and 70 DAE. In each sampling time it was harvested representative plant in each subplot and calculated alometrics ratio and accomplished the plant growth analysis and leaf N productivity; c) in experiment during the dry season (May to September 2010), but irrigated, and wet season (December 2010 to March 2011) it were evaluated five N fertilization rates (0; 50; 100; 200 and 300 kg ha-1) applied in the furrow at pre-planting and four N fertilization rates (0; 100; 200 and 300 kg ha-1) applied in the furrow at sidedress in two potato cultivars (Ágata and Atlantic). The physiological and N indexes were evaluated after harvest plant at 42 DAE; d) in the rainy season, immediately before the N fertilizer sidedressing, at 21 DAE, and at 42 DAE, Dualex® readings were taken in plants representative by plot. It was also determined at 21, 42 DAE and at tuber harvest, the carbohydrates (total soluble sugars, reducing sugars and starch) and soluble phenol concentration. It is concluded the N fertilization rates affect positively all physiological and N indexes evaluated at 21 DAE. N fertilization rate for maximum physical efficiency (MFE) is 180.33 and 205.24 kg ha-1 de N, associated with maximum marketable tuber yield of the 38.60 and 37.90 t ha-1, for Asterix and Atlantic, respectively. The marketable yield tuber of potato cultivars is prognosticated by SPAD index and explained by a quadratic model contained physiological and N indexes as dependent variable. The sampling time influence the values of the morphological and physiological characteristics at limiting, adequate and excessive conditions. The leaf specific area and leaf mass ratio are the variable with the highest correlation with the plant relative growth rate. The physiological and N indexes determined at 42 DAE are appropriate to determine the N availability pre-planting and sidedress applied. In wet season it is not necessary to split N fertilizer application. In this season, the N fertilization rates by the maximum economic efficiency is 189.8 kg ha-1 of the N in preplanting and 174.8 kg ha-1 of the N in sidedressing, for Ágata cultivar; 183.3 kg ha-1 of the N in pre-planting and 214.4 kg ha-1 of the N in sidedressing, for Atlantic cultivar. In the rainy season it is necessary to split the N fertilizer application. In this season, the N fertilization rates for the maximum economic efficiency is 189.8 kg ha-1 of the N at preplanting and 174.8 kg ha-1 of the N in sidedress, for Ágata cultivar; 183.3 kg ha-1 of the N in pre-planting and 214.4 kg ha-1 of the N in sidedress, for Atlantic cultivar. At 21 DAE there were positive effects of N fertilization rates pre-planting applied on chlorophyll index, N balance index and N concentration; and negative effects on flavonol, soluble phenol and starch concentration and on the starch/ANR ratio, as determined in FL. The N concentration in potato FL is indirectly estimated with Dualex®. At 42 DAE there were positive effects of N fertilization rates pre-planting and sidedress applied on chlorophyll index and N balance index; and negative effects of N fertilization rates preplanting and sidedress applied on flavonol index, soluble phenol and starch concentration, as determined in FL. It was observed a negative effect of N fertilization rates at pre-planting and sidedress applied on soluble phenol and starch concentrations; and a positive effect on the total soluble sugars and reducing sugars, as determined in the tuber at the harvest time.