Produtividade e características biométricas do capim-braquiária em sistema silvipastoril

Abstract

Resumo -O objetivo deste trabalho foi avaliar a produtividade e as características biométricas do capimbraquiária (Urochloa decumbens) sob pastejo, em sistema silvipastoril. Avaliou-se um sistema com árvores nativas de interesse comercial, plantadas em renques, no sentido norte-sul, espaçados por 17 m. Utilizou-se o delineamento experimental de blocos ao acaso, com quatro repetições e parcelas subdivididas, tendo-se avaliado o ciclo de rebrota da forragem nas parcelas, e a distância desta em relação aos renques, nas subparcelas. Sete ciclos de rebrota foram avaliados, em quatro distâncias dos renques: a 2 e a 6 m do renque leste, e a 2 e a 6 m do renque oeste. Quantificou-se a produtividade de matéria seca, o índice de área foliar (IAF), a área foliar específica (AFE) e a altura das plantas. A produtividade de forragem, nos dois primeiros ciclos, e o IAF, no segundo e no terceiro ciclo, diminuiram com níveis de sombra acima de 39 e 40%, respectivamente. Já a altura de plantas aumentou com sombreamentos superiores a 53%, nos quatro primeiros ciclos; o que também ocorreu com a AFE, com sombreamento superior a 66%, nos três primeiros ciclos.Termos para indexação: Urochloa decumbens, árvores nativas, deficit hídrico, radiação solar, sistemas agroflorestais, sombreamento. Productivity and biometric characteristics of signal grass in a silvopastural systemAbstract -The objective of this work was to evaluate the productivity and biometric characteristics of signal grass (Urochloa decumbens) under grazing, in a silvopastural system. A system with native trees of commercial interest, planted in a set of rows with north-south orientation, with 17 m spacing was evaluated. A randomized complete block design with four replicates was carried out in a split-plot arrangement, with forage grass regrowth cycles evaluated in the plots and distances from trees in the subplots. Seven regrowth cycles were evaluated at four distances of the set of tree rows: at 2 and 6 m from trees at east, and at 2 and 6 m from trees at west. Dry matter productivity, leaf area index (LAI), specific leaf area (SLA), and plant height were measured. Forage productivity in the first two cycles and LAI in the second and third cycles reduced with shading levels higher than 39 and 40%, respectively. However, plant height increased with shadings greater than 53%, in the first four cycles, and SLA with shadings greater than 66%, in the first three cycles.

Plant growth, radiation use efficiency and yield of sugarcane cultivated in agroforestry systems: An alternative for threatened ecosystems

“…This confirmed the influence of the canopy trees on the interception of incident radiation. Our findings are in line with a study carried out by Pezzopane et al (2015) and Bosi et al (2014) who reported the strong relation between levels of incident solar radiation, and its effect on microclimate, growth characteristics of plants, and soil moisture. The growth of sugarcane was correlated to an increase in k values (Table II), coinciding with an increase in LAI.…”

Productivity and nutritive value of Brachiaria decumbens and performance of dairy heifers in a long‐term silvopastoral system

“…These results followed a similar pattern of response to tiller population and emphasized the negative effect of severe shading on pasture in the SPS, especially in the summer. Decreases in the forage productions in shaded systems were observed by other authors (Bosi, Pezzopane, Sentelhas, Santos, & Nicodemo, 2014;Neel & Belesky, 2017;Santos et al, 2016). The strong restriction of PAR compromises the photosynthetic capacity of the plants, reducing the production of the components of the forage mass (Santiago-Hernández et al, 2016).…”

Productive, morphological and qualitative characteristics of sugarcane in the understory tree species in agroforestry systems

“…The evaluation of dynamic radiation of forestry species and systems is not a widespread practice in scientific circles yet. Another study was carried out by Pezzopane et al (2015) and Bosi et al (2014) who reported on high relation between levels of incident solar radiation, and its effect on microclimate, growth characteristics of plants and soil moisture in areas with high rations During crop cycles, there is an increase in the overall radiation interception, followed by an increase in leaf area index (LAI), but only up to a certain value when full canopy closure is reached, due to leaf self-shadowing (Posada et al, 2012). At this point, the issue of new leaves does not result in an increased amount of light interception.…”