Abstract
Description of the subject. In crop-weed competition, some periods are critical because they may interfere with the crop production capacity. Therefore, knowing these periods is crucial when deciding on the best time for control and preparation of the Integrated Management Program. Objectives. To determine the Period Prior to Interference, Total Period for Interference Prevention, and the Critical Interference Period in pineapple cultivation. Method. The experimental design consisted of randomized blocks in 2 x 15 factorial arrangement, four replications, and two management systems: weeds control and crop-weeds coexistence; 15 increasing periods of 30 days each after planting: 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, 360, 390, 420. In the control treatments, since planting, manual weeding (with hoe) and mechanical weeding (with brush cutter) were done during increasing periods of time, and in the coexistence treatments, the weeds lived together with pineapple plants and, at the end of each period, weeds control was made with mechanical and chemical weeding. Results. The best yields were achieved in the periods of less coexistence with weeds. The critical periods for interference prevention with 5 and 10% of yield losses were 259 and 204 days, respectively. Conclusions. The critical period for interference prevention lasted 14-259 days after planting of the pineapple offsets.
Highlights
Brazil is the third largest global producer of pineapple, a species of the family Bromeliaceae grown worldwide in the tropics (FAO, 2018)
Numerous factors determine the degree of interference of weeds with a crop and these are related to the environment and cultural practices (Ramos & Pitelli, 1994)
Some periods during competition between weeds and crops are critical because they may affect yields. These periods were identified by Pitelli et al (2013) as Period Prior to Interference (PPI) – during which, after emergence, the crop can coexist with weeds without reductions in production; Total Period for Interference Prevention (TPIP), - during which, after emergence, the weeds must be controlled to allow crops to manifest their full productive potential; and the Critical Interference Period (CIP), which is the time interval between the previous periods of the crop growth cycle, during which the weeds must be controlled to avoid unacceptable yield losses
Summary
Brazil is the third largest global producer of pineapple, a species of the family Bromeliaceae grown worldwide in the tropics (FAO, 2018). Because it is a slowgrowing plant and has surface roots, pineapple plants suffer greatly from competition with weeds, which contributes to delay the crop development and reduce yields (Reinhardt & Cunha, 1984). It is crucial to identify the species present in the cropping areas and determine the periods of interference, which indicate the time when control is no longer needed due to inexistent negative interactions between weeds and crops and the appropriate time to carry out weeds control (Marques et al, 2017) These periods were identified by Pitelli et al (2013) as Period Prior to Interference (PPI) – during which, after emergence, the crop can coexist with weeds without reductions in production; Total Period for Interference Prevention (TPIP), - during which, after emergence, the weeds must be controlled to allow crops to manifest their full productive potential; and the Critical Interference Period (CIP), which is the time interval between the previous periods of the crop growth cycle, during which the weeds must be controlled to avoid unacceptable yield losses.
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