Interferência de plantas daninhas na cultura do abacaxizeiro cv pérola em função do espaçamento

Abstract

The degree of weed interference depends on factors linked to the crop itself, the weed community, the environment, the period in which they live and the available resources (water, nutrients and light). This work aimed to evaluate phytosociology and weed interference on pineapple productivity, as well as the growth and development of culture in two spacing. The experiment was carried out from June 2016 to December 2017, in the experimental area of the Agricultural Sciences Center of the Federal University of Alagoas (CECA-UFAL). Using a randomized block design in a 2 x 20 factorial scheme with 4 blocks, with 2 spacings (Single Row and Double Row) and 20 interference periods with weeds. The periods consisted of 10 control seasons after which weeds were controlled (30, 60, 90, 120, 150, 180, 240, 300, 360 and 420 days after planting - DAP) and 10 control seasons. coexistence between pineapple and weeds, where these weeds emerged after these intervals were no longer controlled (30, 60, 90, 120, 150, 180, 240, 300, 360 and 420 days after planting - DAP). The families that stood out the most were: Asteraceae with 6 species and Poaceae with 5 species, being the most expressive families, followed by Fabaceae and Euphorbiaceae, with two species each and the others: Cyperaceae, Molluginaceae, Commelinaceae, Rubiaceae, Solanaceae, Turneraceae, Cleomaceae, Malvaceae and Amarantaceae, with only 1 species. The species: Digitaria insularis, Richardia grandiflora and Panicum maximum presented the highest Importance Value Indices (IVI) in the 2 studied spacing. The Pre-Interference Period (PAI) was 35 days, the Total Interference Prevention Period (PTPI) was 35 days at 365 days and the Critical Interference Prevention Period (PCPI) was 330 days. There was an 80% reduction in productivity when the pineapple was kept in coexistence with weeds throughout the cycle. The results showed that all the growth variables of the pineapple culture suffered reductions when they lived with the periods of weed interference due to the spacing used (single rows and double rows). Throughout the experimental period, the pineapple plants that lived with the weed community showed a reduction of 30 to 80% of their growth variables in relation to the pineapple plants that grew free from the interference of these weeds.