Weed Interference Periods in Pre-Sprouted Sugarcane Seedlings

• Published in: Advances in Weed Science 2019, Vol.37
• Main Authors: AMARAL, F.C.R., NEPOMUCENO, M.P., CHAVES, A.R.C.S., CARLIN, S.D., AZANIA, C.A.M.
• Format: Article
• Language: English
• Subjects: Agricultural production; Coexistence; critical periods; Crop diseases; Crop yield; Crops; Cultivars; Flowers & plants; Merremia aegyptia; PLANT SCIENCES; Prevention; PSS; Regression analysis; Saccharum spp; Seedlings; Sugarcane; Urochloa decumbens; weed competition; Weeds
• ISSN: 0100-8358; 1806-9681; 1806-9681; 2675-9462
• DOI: 10.1590/s0100-83582019370100105

The aim of this research was to determine weed interference periods in sugarcane cultivated under the system of pre-sprouted seedlings, taking into account the impact on the final plant stand, and bud yield and stalk yield. In the field, this study used a randomized block design with 14 treatments and four replications. The treatments consisted of periods of control and weed coexistence with the sugarcane crop (cultivar IACSP95-5000): 30, 60, 90, 120, 150, 180, 210 and 240 days after planting. A phytosociological survey was carried out in the experimental area, and the species Merremia aegyptia, Urochloa decumbens and Nicandra physaloides were found to be predominant. At the end of 240 days, regression analysis was performed according to Boltzmann’s sigmoidal model and considering loss tolerance of 5% in the evaluated variables. For final plant stand, the period prior to interference was 31 days and the total period of interference prevention was 187 days. For bud yield, the period prior to interference was 23 days and the total period of interference prevention was 178 days. For stalk yield, the period prior to interference was 19 days and the total period of interference prevention was 195 days. Weed interference was detrimental to all evaluated variables, with losses of up to 100% of the sugarcane plants after 120 days of weed coexistence. RESUMO: Esta pesquisa objetivou estudar a determinação dos períodos de interferência de plantas daninhas na cultura da cana-de-açúcar cultivada sob o sistema de mudas pré-brotadas, levando-se em conta os impactos no estande final de plantas e na produtividade de gemas e de colmos. No campo, utilizou-se o delineamento em blocos casualizados com 14 tratamentos e quatro repetições. Os tratamentos foram constituídos por períodos de controle e convivência de plantas daninhas com a cultura da cana-de-açúcar, cultivar IACSP95-5000: 30, 60, 90, 120, 150, 180, 210 e 240 dias após plantio. Realizou-se o levantamento fitossociológico da área experimental, determinando-se o predomínio das espécies Merremia aegyptia, Urochloa decumbens e Nicandra physaloides. Ao final dos 240 dias, utilizando-se da análise de regressão conforme o modelo sigmoidal de Boltzmann e considerando a tolerância de perda de 5% nas variáveis consideradas, para estande final de plantas, determinou-se o Período Anterior à Interferência de 31 dias e o Período Total de Prevenção a Interferência de 187 dias. Para produtividade de gemas, determinou-se o Período A