Alexandre Behling

Interceptação da radiação luminosa pelo dossel de espécies florestais e sua relação com o manejo das plantas daninhas

The energy of solar radiation absorbed by the plants is a decisive factor of the photosynthesis tax and it can limit the production, the biomass accumulation and the development of the plants. The objective of the research was to evaluate the interception of the luminous radiation and her relationship with the need of handling undesirable plants through crowning and mowing, in the forest species: Acacia mearnsii De Wild, Eucalyptus grandis W. Hill ex Maiden, Mimosa scabrella Benth e Ateleia glazioviana Baill, submitted at levels spacing: 2,0x1,0m; 2,0x1,5m; 3,0x1,0m and 3,0x1,5m. The measurement of the luminous radiation was accomplished monthly during the period from 0 to 360 days after the planting. The points of samplings were among the plants in the line and in the planting among-line. The crowning and mowing were not necessary when the levels of interception of radiation photosynthesis activate were larger than 60%. However, they became necessary starting from the second month after the planting and with a frequency of 60 days for all the species until the first 180 days. The crowning was spared for the species E. grandis starting from the 210 days and for A. mearnsii and M. scabrella after the 240 days after the transplant. Cleared was given only for the species E. grandis in the spacings 2,0x1,0m and 2,0x1,5m starting from the 210 and 240 days after the planting, respectively.

Eficiência de conversão da radiação fotossinteticamente ativa interceptada em fitomassa de mudas de eucalipto

The biomass production is function of the conversion efficiency of the photosynthetically active radiation intercepted (PARi), varying according to the conditions in which plants are cultivated. Therefore the objective of this work was to quantify the function of the efficiency of conversion of the photosynthetically active radiation intercepted (PARi) in dry biomass - eb - , of seedlings of Eucalyptus grandis W. Hill ex Maiden (eucalyptus) when submitted to different sizes of tubes and densities of plants. Therefore, an experiment was conducted in randomized blocks to study seedlings production in two sizes of tubes (small and medium) and two densities of plants in the tray (high with 100% of occupation of the tray and average with 50% of occupation), where PARi, the index of foliar area and the total dry biomass of the seedlings were evaluated. The volume of the tube did not interfere in the efficiency values, but, the density of plants did because the index of foliar area is the one which determines such value. The ab was of 7.33 g.MJ-1 for medium and small tube in high density and of 3.26 g.MJ-1 for medium and small tube in medium density.

Crescimento em viveiro de mudas de Schizolobium parahyba (Vell.) S. F. Blake. submetidas a níveis de sombreamento

The study of the growth and development of a plant under different environmental conditions offers the researcher a good clue as to which are the best conditions to grow a particular species. The main objective was to evaluate the initial growth, for up to 80 days, for of Schizolobium parahyba (guapuruvu) seedlings submitted to the shading levels: 0% (full sunshine), 30%, 50% and 70% shading. The results demonstrate that the shading interfered positively in the growth in height of the seedlings, even at the greatest levels, and did not cause damage to the plants, which was proven by the lack of differences in the variables: dry matter, lap diameter and number of pairs of leaves. The production of quality seedlings is favorable up to the 45th day of submission to shading, after which seedlings should be transplanted.

Resistência de espécies arbóreas submetidas a extremos climáticos de geada em diferentes sistemas agroflorestais

The present research had the aim to evaluate the answers of the arboreal species Schizolobium parahyba (Vell.) Blake (guapuruvu), Mimosa scabrella Benth. (bracatinga), Peltophorum dubium (Spr.) Taubert (canafistula), Parapiptadenia rigida (Benth.) Brenan (angico-vermelho) and the hybrid Eucalyptus urophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden (eucalipto) in consortium with sugar cane (Saccharum spp.) in two agroforestry arrangement systems (strip - 3x3m + 12m and line - 6x1,5m) submitted to climatic extreme frost conditions, in the Northwest of Rio Grande do Sul. The damages (resistance to frost) were appraised according to the system of notes used by HIGA et al. (2000) in which a note from 0 to 10 was attributed according to the intensity of the damage to the plant. For the resistance degrees to frost, it was adapted the methodology used by CARVALHO (1981), which is also in function of the intensity of the damage to the plant. Upon the frost condition studied, it was observed that the results demonstrated that different of agroforest system arrangements damaged the resistance of the guapuruvu specie, being sensitive in the agroforest system strip and moderatelly tolerant in the system line. In both systems, the species angico-vermelho, bracatinga e eucalipto showed resistance, while the canafistula demonstrated to be tolerant.

Growth of tree species and sugarcane production in agroforestry systems

The appropriate choice of tree species and planting arrangement for use in agroforestry systems is very important in order to maximize productivity and sustainability. The aim of this study was to evaluate the growth of five tree species and its effect on sugarcane yields in different planting arrays in agroforestry systems. The study was conducted from 2007 to 2011 in the city of Frederico Westphalen, RS, Brazil. The five studied tree species were: guapuruvu (Schizolobium parahybae), bracatinga (Mimosa scabrella), canafístula (Peltophorum dubium), angico-vermelho (Parapiptadenia rigida) and eucalypt (Eucalyptus urophylla S.T. Blake x Eucalyptus grandis Hill ex Maiden). Root collar diameter, diameter at breast height, plant height and mean diameter of crown were evaluated for four years with an interval of 90 days between assessments. Yield data for sugarcane were collected in June 2009, 2010, and 2011. Eucalypt presented the greatest root collar diameter values, diameter at breast height, crown development, and plant height. Angico-vermelho, canafístula and eucalypt presented a higher growth in the strip system, while guapuruvu presented the greater growth in the line system. Bracatinga was not influenced by an arrangement in the agroforestry systems. Sugarcane presented greater production in the understory of angico and bracatinga.

ANÁLISE DE TRILHA PARA AVALIAÇÃO DOS EFEITOS DA GRANULOMETRIA DO SOLO SOBRE O ÍNDICE DE SÍTIO PARA Acacia mearnsii De Wild.

The knowledge about the productive potential of a site is extreme important, mainly from the the decision maker of the handler. In this sense, an influence of the physical environment on this potential must be understood and considered in analyzes. The aim of this study was the construction of site index curves, starting from de age and height growth, and evaluating the contribution of soil texture to site index quality, considering the population of black wattle, located in the municipality of Cristal, Rio ENCICLOPÉDIA BIOSFERA, Centro Científico Conhecer Goiânia, v.14 n.25; p. 2017 58 Grande do Sul State. For that, population informations between 9 and 11 years old, located in Ouro Verde farm were used. The results obtained to dominant height classes to the site population rate studied were 18.75 m to site class III, 21.25 m to site class II and 23.75 m to site class I. As for the granulometry soil analysis, the sand content decrease allied to the depth increase was noted, while for the clay content an increase was verified, the textural class of the soils was characterized as clay loam for the superficial and subsurface layers. After the track analysis, it was observed that particle size fractions do not influence the quality of black wattle population site, with all the coefficients being lower than the residual variable rate.