Análise de crescimento do capim-elefante 'Napier' adubado e irrigado

• Main Author: Andrade, Alex Carvalho
• Publication Date: 2005
• Other Authors: Fonseca, Dilermando Miranda da, Lopes, Rogério dos Santos, Nascimento Júnior, Domício do, Cecon, Paulo Roberto, Queiroz, Domingos Sávio, Pereira, Dalton Henrique, Reis, Sidnei Tavares
• Format: Article
• Language: por
• Source: Repositório Institucional da UFLA
• Download full: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542005000200020; http://repositorio.ufla.br/jspui/handle/1/6050
• topic: Coeficiente de extinção; Índice de área foliar; Interceptação luminosa; Pennisetum purpureum; Taxa assimilatória líquida; Taxa de crescimento relativo; Razão de área foliar; Extinction coeficient; Interception of light; Net assimilation rate; Leaf area index; Leaf area ratio; Relative growth rate

The growth indexes were evaluated: relative to growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), leaf area index (LAI) and the luminous interception of the 'Napier' elephant grass after graze. The work consisted of two experiments for the study of four manuring treatments of N and K, in kg/ha (T1: 100 kg of N and 80 kg of K, T2: 200 kg of N and 160 kg of K, T3: 300 kg of N and 240 kg of K and T4: 400 kg of N and 320 kg of K), being an irrigated and other without irrigation, according to the randomized block desing, with three replicates. The statistical analysis was donne in outline of split plot, tends in the portions the doses of N and K, and in the sub-portions the regrowth ages after graze (2, 8, 15, 45 and 123 days) for LAI and interception of light. The LAI in the irrigated area increased from 0.28 to 8.27, average of the four treatments of N and K, between the smaller and larger regrowth ages. In the not irrigated area also was verified an increase in LAI, although in smaller magnitude that in the irrigated area, of 0.16 for 7.76. The medium values of RGR, NAR and LAR were 0.0083 g/g.day, 3.57 g/cm2.day and 0.0021 m2/g, respectively. The light interception increased with the increase of the LAI, stabilizing in the 51.5th day. therefore, the light penetration inside the dossel reduced asymptotically in function of LAI. The extinction coefficient varied of 0.29 in the largest combination of N and K for 0.53 in the doses of 200 kg/ha of N and 160 kg/ha of K.