Management of straw influencing effectiveness of emergency control of weeds flows for emerging pre herbicides, and the initial selectivity of these treatments on cane sugar with pre- sprouted seedlings

• Grant number: 15/14833-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): October 01, 2015
• Effective date (End): September 30, 2016
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Pedro Jacob Christoffoleti
• Grantee: Henrique Rodrigues Milagres Viana
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Two new technologies are being introduced in the culture of sugarcane and in them we need studies of management adaptations of weeds. One is the economic viability of using crop residues for the production of bioelectricity that promote full withdrawal and / or part of this straw on the soil surface after mechanical harvesting of sugarcane, resulting in changes in weed species, and dynamics of pre-emergent herbicides. The other is planting with pre-sprouted seedlings of sugarcane, which significantly improves the planting system currently used, however, there are no studies on the selectivity of herbicides in this system. Therefore, this project aims to study the efficacy of herbicide treatments on weed control in systems with straw gathering, and evaluate the selectivity of these treatments in plantations with pre- sprouted sugarcane. For this, two experiments will be developed in greenhouse, with the application of the following herbicide treatments in the pre- emergency condition : amicarbazone (1400 g ha- 1 ), metribuzin (1920 g ha- 1 ), indaziflan (200 g ha- 1 ), isoxaflutole ( 105 g ha- 1 ), amicarbazone + indaziflan ( 1005 + 150 g ha- 1 ) + metribuzin indaziflan ( 960 + 150 g ha -1) and isoxaflutole + indaziflan (75 + 150 g ha- 1). The first experiment followed a factorial 3 x 5 x 4 with three weed species (Sorghum halepense (L. ) Pers.; Rottboellia exaltata L. and Mucuna aterrima Piper & Tracy. ), five amounts of straw ( 0, 1, 2, 3 and 5 t ha -1) and four emergency flows ( 0, 45, 60 and 90 DAT ). The herbicides will be applied to different quantities of straw and in the sequence will be simulated 30 mm of rain,, when the straw is dry it will be removed. At 0, 45, 60 and 90 DAT, will be held sowing weed species. 7, 14, 21, 28 and 35 days after sowing (DAS ) will be carried out visual assessments of percent control. At 35 DAS, will determine the dry mass of the plants and the assessment of the root system. The second experiment will be on the selectivity and followed the factorial 2 x 2, two varieties of sugarcane ( RB835054 and RB867515 ) and two planting systems ( individual gems and pre- sprouted seedlings). At 7, 15, 30, 45 and 60 days after treatments ( DAT ), will be carried out visual assessments of fitoxicidade. At 7, 30 and 60 DAT leaf area analysis, stem diameter and chlorophyll content. At 60 DAT, the dry mass and root system of plants analyzes will be performed. Biometric data and fitoxicidade percentages will be statistically analyzed.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DA SILVA, PAULO VINICIUS; MILAGRES VIANA, HENRIQUE RODRIGUES; MONQUERO, PATRICIA ANDREA; RIBEIRO, NAGILA MORAES; PEREIRA NETO, WILSON; INACIO, ESTELA MARIS; CHRISTOFFOLETI, PEDRO JACOB; DIAS, ROQUE DE CARVALHO. Influence of sugarcane (Saccharum officinarum) straw on weed germination control. REVISTA DE LA FACULTAD DE CIENCIAS AGRARIAS, v. 53, n. 1, p. 220-233, JUN 2021. (15/14833-0)