Produtividade e características fisiológicas do consórcio milho-braquiária / Productivity and physiological characteristics of Corn-Brachiaria Intercrop

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

08/07/2011

RESUMO

Three experiments were installed between the years of 2007 and 2009, two of them made in the field and one held in a greenhouse. Our aims were: experiment 1 - evaluate the effects of emergence time in brachiaria and in the application of atrazine herbicide mixture + nicosulfuron at two levels of fertilization, in photosynthesis, stomatal conductance, transpiration and water use efficiency in corn and brachiaria. experiment 2 - evaluate the effects of planting arrangements of brachiaria in the activity of reductase nitrate, in leaf area index of corn and in the productivity of the system with four corn hybrids and experiment 3 - evaluate the effects of spacing between rows of corn and ways of planting of brachiaria in the productivity of corn-brachiaria-eucalyptus intertroping, The first experiment was conducted in the greenhouse of the Corn Program (from October to December 2009) in the Universidade Federal de Viçosa. The test was conducted in 20 dm3 pots, where the soil has been previously fixed. In each pot three plants of corn were planted and one of brachiaria. The experimental lineation adopted was randomized blocks with four replications in a factorial arrangement. The treatments consisted of three periods of emergence of brachiaria in relation of corn (tendays prior, concurrent and ten days later), two levels of fertilization (fertilization of reference forthis vessel and half one), with and without the application of mixture of atrazine herbicide + nicosulfuron. The application of the herbicide mixture trazine+ nicosulfuron + (sub-dose) induced the reduction in photosynthesis, transpiration and stomatal conductance of brachiaria plants and promoted the growth of these characteristics in corn plants. The germination of brachiaria before the corn promoted a decrease in photosynthesis, stomatal conductance, transpiration and water use efficiency in corn plants. Younger brachiaria plants were more sensitive to the application of herbicides. The second experiment was conducted at the Experimental Station of Coimbra (November 2008), an area belonging to UFV. The experimental lineation adopted was randomized block in factorial arrangement, with four repetitions. Four hybrids corn were used with different cycles and leaf architecture (AGN30A00, BM2202, AG2060 and BM2202) and three arrangements of planting of brachiaria. In the first arrangement, the corn was planted at a spacing of 0.9 m and two rows of brachiaria in between the corn rows, 30 cm distant-row corn. In the second arrangement, the corn was planted in a spacing of 0.9 m and one brachiaria linein the rows of corn and another in the inter-row. The reduction of the spacing promoted the increased leaf area index of corn hybrids, the increased productivity and the reduced of the growth of brachiaria plants. The planting of two lines of brachiaria in between the corn was what resulted in the higher growth of the grass, and caused reduction in activity of reduce tasenitrate in corn hybrids And in the third arrangement, was carried in Viçosa (November 2007), in an area of degraded pasture. The experimental lineation used was a factorial arrangement with four repetitions. We evaluated the corn hybrids AS1575 (simple hybrid) and DKB 747 (double hybrid) under three spacings. The hybrids were planted in spacing of 0.5 m, 0.75 m and 1m in direct system tillage. Corn was sown in rows of the eucalyptus in intertroping with Brachiaria brizantha. The variations in spacing did not influence statistically the productivity of corn, however, higher productivity values were found at the spacing of 0.75 m in the best use of the area between rows of eucalyptus trees. The reduction in spacing between the rows promoted less dry product of brachiaria in the corn harvest, however, 390 days after planting there was no difference between treatments. There was no difference in the production of eucalyptus wood, in order to use of different corn hybrids and used spacing.

ASSUNTO(S)

fitotecnia milho-braquiária consórcio fotossíntese corn-brachiaria intercrop photosynthesis

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