Interferência de Ipomoea grandifolia na cultura do milho
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Data
2019-03-26
Autores
Barreto, Lívia Felicio
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Universidade Estadual Paulista (Unesp)
Resumo
Entre as plantas daninhas importantes na cultura do milho, destacam-se as cordas-de-viola, sendo que a ocorrência crescente de espécies de Ipomoea tem causado preocupação e, dentre elas, tem-se Ipomoea grandifolia. Sendo assim, os objetivos deste estudo foram verificar a interferência de I. grandifolia no crescimento, acúmulo de massa seca, nutrição mineral e na produtividade do milho; determinar o período necessário de controle das plantas daninhas para evitar perdas significativas na produtividade; averiguar se essa comunidade interfere nas características biométricas e de pós colheita, verificar se a interferência decorre de efeitos negativos no processo de colheita mecanizada bem como determinar o impacto econômico sobre a cultura. Foram realizados dois experimentos simultâneos por dois anos agrícola, sendo um composto por 14 tratamentos denominado “Experimentos para períodos de interferência” e, outro paralelo composto por seis tratamentos denominado “Experimentos para interferência na colheita mecanizada”. Para o experimento de períodos, a cultura foi submetida a períodos crescentes de convivência e controle da comunidade infestante sendo estes: V2, V4, V6, V8, V10 e V12 e mais duas testemunhas; já para os experimentos de colheita mecanizada os tratamentos constituíram-se dos estádios crescentes de controle: V2, V4, V6, V8 e também duas testemunhas, ambos em delineamento em blocos casualizados. Os experimentos foram realizados a campo, recebendo semeadura de I. grandifolia. Para evitar interferência de outras espécies de plantas daninhas foram realizadas capinas seletivas. As plantas de I. grandifolia não interferiram no crescimento inicial da cultura do milho, mas, interferiram no acúmulo de massa seca e macronutrientes, porém não alterando os parâmetros biométricos da cultura, nem as características quantitativas das espigas. O período crítico de prevenção à interferência - PCPI compreendeu os períodos dos estádios V4 ao V12, considerando um nível de perda aceitável de 5%. As plantas de milho que permaneceram por um maior período convivendo com plantas de I. grandifolia, nos tratamentos no Mato, V2 e V4 no ano de 2016/17, foram afetadas negativamente, com menor produtividade, e prejudicaram a eficiência mecânica da colheita, aumentando o fluxo de alimentação, demorando um tempo maior para realização da operação nestes tratamentos; aumentaram também as impurezas (grandes números de sementes e restos vegetais de I. grandifolia), e as perdas foram significativamente maiores quando comparadas com os demais tratamentos. Economicamente, a manutenção da cultura no limpo facilitou a viabilidade da colheita, resultando em maiores ganhos econômicos para o produtor quando comparado com os tratamentos com menores ou nenhum período de controle.
Among the important weeds in the corn crop, we highlight the morning glory, and the increasing occurrence of Ipomoea species has caused concern, among which Ipomoea grandifolia stands out. Therefore, the objectives of this study were to verify the interference of I. grandifolia on growth, accumulation of dry mass, mineral nutrition and corn yield; determine the necessary period of weed control to avoid significant losses in productivity; to verify if this community interferes in the biometric and post-harvest characteristics, to verify if the interference stems from negative effects in the mechanized harvesting process as well as to determine the economic impact on the crop. Two simultaneous experiments were carried out per agricultural year in two consecutive years, being a compound of 14 treatments denominated "Experiments for interference periods" and another parallel composed by six treatments denominated "Experiments for interference in the mechanized harvesting". For the experiment of periods, the crop was submitted to increasing periods of coexistence and control of the infesting community, being these: V2, V4, V6, V8, V10 and V12 and two checks. For the mechanized harvesting experiments, the treatments consisted of increasing control stages: V2, V4, V6, V8 and also two checks, both in a randomized block design. The experiments were carried out in the field, receiving sowing of I. grandifolia. To avoid interference from other weed species, selective weeds were used. The plants of I. grandifolia did not interfere in the initial growth of maize, but, interfered in the accumulation of dry mass and macronutrients in the aerial part of the corn plant, but did not alter the biometric parameters of the crop, as well as the quantitative characteristics of the ears. Weed interference critical period was between V4 and V12 phenological stages of growth considering an acceptable loss level of 5%. The maize plants that stayed for a longer period living with I. grandifolia plants, in the treatments in the grass, V2 and V4 in the year 2016/17, were negatively affected as they decreased the corn productivity and impaired the mechanical efficiency of the harvest increasing the feed flow, taking more time to perform the operation in these treatments, also increased the impurities (large numbers of seeds and vegetable remains of I. grandifolia), and losses were significantly higher when compared to the other treatments. Economically, maintaining the crop in the clean facilitated the viability of the harvest, resulting in greater economic gains for the producer when compared to the treatments with smaller or no control period.
Among the important weeds in the corn crop, we highlight the morning glory, and the increasing occurrence of Ipomoea species has caused concern, among which Ipomoea grandifolia stands out. Therefore, the objectives of this study were to verify the interference of I. grandifolia on growth, accumulation of dry mass, mineral nutrition and corn yield; determine the necessary period of weed control to avoid significant losses in productivity; to verify if this community interferes in the biometric and post-harvest characteristics, to verify if the interference stems from negative effects in the mechanized harvesting process as well as to determine the economic impact on the crop. Two simultaneous experiments were carried out per agricultural year in two consecutive years, being a compound of 14 treatments denominated "Experiments for interference periods" and another parallel composed by six treatments denominated "Experiments for interference in the mechanized harvesting". For the experiment of periods, the crop was submitted to increasing periods of coexistence and control of the infesting community, being these: V2, V4, V6, V8, V10 and V12 and two checks. For the mechanized harvesting experiments, the treatments consisted of increasing control stages: V2, V4, V6, V8 and also two checks, both in a randomized block design. The experiments were carried out in the field, receiving sowing of I. grandifolia. To avoid interference from other weed species, selective weeds were used. The plants of I. grandifolia did not interfere in the initial growth of maize, but, interfered in the accumulation of dry mass and macronutrients in the aerial part of the corn plant, but did not alter the biometric parameters of the crop, as well as the quantitative characteristics of the ears. Weed interference critical period was between V4 and V12 phenological stages of growth considering an acceptable loss level of 5%. The maize plants that stayed for a longer period living with I. grandifolia plants, in the treatments in the grass, V2 and V4 in the year 2016/17, were negatively affected as they decreased the corn productivity and impaired the mechanical efficiency of the harvest increasing the feed flow, taking more time to perform the operation in these treatments, also increased the impurities (large numbers of seeds and vegetable remains of I. grandifolia), and losses were significantly higher when compared to the other treatments. Economically, maintaining the crop in the clean facilitated the viability of the harvest, resulting in greater economic gains for the producer when compared to the treatments with smaller or no control period.
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Palavras-chave
Colheita mecanizada, Zea mays, Convolvulaceae, Macronutrientes, Perdas, Períodos de interferência