Qualidade da semeadura das culturas do algodão, milho e soja sob a ação de forças descendentes em linha
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Data
2021-04-16
Autores
Oliveira, Luan P. de [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
O sistema de força descendente em linha (downforce) é um sistema acoplado às unidades de semeadura individuais com o intuito de auxiliar a manutenção das rodas calibradoras na profundidade de semeadura regulada, garantindo um contato constante com o solo. Atualmente, três sistemas de força descendente predominam no mercado: hidráulico, mecânico e pneumatico. O sistema hidráulico pode ser configurado em dois modos de operação: ativo (automático) ou fixo (manual). A força descendente pré-configurada é automaticamente regulada de acordo com a variabilidade do terreno no modo automático. Em contraste, o modo manual mantém a força alvo previamente definida, não considerando a variabilidade do terreno, o que pode causar alteração nas forças aplicadas, bem como o sistema mecânico (molas). Objetivou-se verificar se a qualidade da distribuição de forças verticais em dois modos de operação possui influência sobre características do solo, profundidade de semeadura, emergência e crescimento de plantas na semeadura do algodão, milho e soja. Os estudos com as culturas do algodão e milho foram conduzidos nos anos de 2019 e 2020 na Estação Experimental de E.V. Smith em Shorter, AL, EUA em áreas com solos de predominância Franco-arenosa, Franco-argilosa e Franco-argilo-arenosa. Para a cultura da soja, os estudos foram realizados em áreas comerciais próximas às cidades de Itapeva, SP, Brasil e Rondonópolis, MT, Brasil no ano de 2020 em solos com textura predominantemente argilosa. Uma semeadora John Deere Max Emerge Plus com seis unidades de semeadura foi equipada com um sistema de força descendente hidráulico comercial para os experimentos com algodão e milho, e, para a cultura da soja, utilizou-se semeadora MF 73 HF com 12 unidades de semeadura, equipada nas seis linhas do lado esquerdo da máquina com mecanismo de força descendente mecânico (molas), bem como do lado direito com mecanismo hidráulico comercial. As variáveis analisadas nos experimentos foram nível de força vertical, resistência mecânica do solo à penetração (RMSP), densidade do solo, profundidade de semeadura, índice de velocidade de emergência e altura de plantas. O delineamento experimental foi em blocos casualizados com quatro repetições para os experimentos com algodão e milho, porém, para a cultura da soja o delineamento seguiu o esquema fatorial 5x3 (5 forças verticais e três ferramentas sulcadoras) em três repetições. Os dados foram coletados ao longo do tempo, de acordo com as especificações do Controle Estatístico de Processos (CEP). Os tratamentos para as culturas do algodão e milho para cada modo operacional (Manual e Automático), foram níveis de forças verticais: Sem força descendente; Muito Baixo; Baixo; Médio; Alto e Muito Alto tanto para o modo manual, quanto para o automático de operação totalizando onze tratamentos. Para a cultura da soja, dois níveis: Muito Baixo e Baixo em modo automático e manual utilizando-se de duas fontes de forças verticais (mecânico e hidráulico), bem como dois tipos de ferramentas sulcadoras (haste e disco duplo). A variabilidade do processo de semeadura foi avaliada pelas cartas de controle I-MR e Xbar-S. Foi efetuada análise de variância e, quando significativo, as médias foram comparadas pelo teste de Tukey a 5% de probabilidade. A variabilidade da distribuição de forças verticais foi maior sem aplicação de forças (0 N). Não houve diferença entre as qualidades operacionais ao comparar os modos ativo ou fixo. O processo de semeadura relacionado à profundidade foi considerado uniforme com forças verticais altas ou muito altas. A RMSP e a densidade do solo, não foram influenciadas pelas forças verticais aplicadas. A profundidade de semeadura foi incrementada com o aumento das forças descendentes aplicadas independente do tipo de solo. A emergência do milho foi incrementada em solo franco-argiloso com o aumento das forças. Para a cultura da soja verificou-se incremento na emergência de plântulas utilizando-se sistema hidráulico juntamente às ferramentas sulcadoras. De maneira geral, a utilização de um sistema hidráulico de força descendente em linha de semeadura, proporciona melhor distribuição de sementes, quando da utilização de força vertical correta, a emergência de plântulas e altura de plantas são incrementadas comparando-se com a ausência de algum sistema.
The downforce system is a system mounted to individual row-units in order to keep the gauge-wheels at the right seeding depth, ensuring constant contact with the soil. Currently, there are three main downforce systems on market: hydraulic, mechanical and pneumatic. The hydraulic system can be set in two operational modes: active (automatic) or fixed (manual). The pre-set down force is automatically adjusted according to terrain variability in automatic mode. In contrast, the manual mode maintains the previously defined target force, not considering ground variability, which can cause changes in the applied forces. The same applies to the mechanical system (springs). The objective was to verify if the operational quality of the vertical forces distribution in two operational modes has influence on soil characteristics, sowing depth, emergence and plant growth in cotton, corn and soybeans. Studies with cotton and corn crops were conducted in 2019 and 2020 at the E.V. Smith Research Center in Shorter, AL, USA in areas with sandy loam, clay loam and sandy clay loam predominance. For soybean crop, studies were carried out in commercial areas near Itapeva, SP, Brazil and Rondonópolis, MT, Brazil in 2020 in soils predominantly clay. A John Deere Max Emerge Plus planter with six row units was equipped with a commercial hydraulic down force system for experiments with cotton and corn, and for soybeans, a MF 73 HF planter was used with 12 row units , equipped on the six rows on the left side of the machine with a mechanical down force system (springs), as well as on the right side with a commercial hydraulic system. The analyzed variables were level of vertical force, soil mechanical resistance to penetration (RMSP), soil density, sowing depth, emergence velocity index and plant height. The experimental design was a randomized blocks with four replications for the experiments with cotton and corn, however, for the soybean crop the design followed a 5x3 factorial scheme (5 vertical forces and three tilling tools) in three replications. Data was collected through the time, according to the specifications of Statistical Process Control (SPC). The treatments for cotton and corn crops for each operational mode (Manual and Automatic), were levels of vertical forces: No down force; Very low; Low; Average; High and Very High for both manual and automatic operation modes, totaling eleven treatments. For soybean crop, two levels of vertical forces: Very Low and Low in automatic and manual mode, using two different systems (mechanical and hydraulic), as well as two types of tilling tools (rod and double disc). Sowing process variability was evaluated by I-MR and Xbar-S control charts. Analysis of variance was performed and, when significant, means were compared by Tukey's test at 5% probability. The variability of vertical forces distribution was greater without application of load (0 N). There was no difference between operational quality when comparing manual or automatic modes. The depth-related seeding process was considered uniform with high or very high vertical loads. RMSP and soil density were not influenced by the applied downforces. Sowing depth was increased with the increase of applied loads regardless of the soil type. Corn emergence was increased in clay loam soil with increasing vertical loads. For soybean crop, there was an increase in seedling emergence using a hydraulic system together with tilling tools. In general, the use of a hydraulic downforce system in the row-units provides better seed distribution. When using the correct load, the emergence of seedlings and plant height are increased compared to the absence of any system
The downforce system is a system mounted to individual row-units in order to keep the gauge-wheels at the right seeding depth, ensuring constant contact with the soil. Currently, there are three main downforce systems on market: hydraulic, mechanical and pneumatic. The hydraulic system can be set in two operational modes: active (automatic) or fixed (manual). The pre-set down force is automatically adjusted according to terrain variability in automatic mode. In contrast, the manual mode maintains the previously defined target force, not considering ground variability, which can cause changes in the applied forces. The same applies to the mechanical system (springs). The objective was to verify if the operational quality of the vertical forces distribution in two operational modes has influence on soil characteristics, sowing depth, emergence and plant growth in cotton, corn and soybeans. Studies with cotton and corn crops were conducted in 2019 and 2020 at the E.V. Smith Research Center in Shorter, AL, USA in areas with sandy loam, clay loam and sandy clay loam predominance. For soybean crop, studies were carried out in commercial areas near Itapeva, SP, Brazil and Rondonópolis, MT, Brazil in 2020 in soils predominantly clay. A John Deere Max Emerge Plus planter with six row units was equipped with a commercial hydraulic down force system for experiments with cotton and corn, and for soybeans, a MF 73 HF planter was used with 12 row units , equipped on the six rows on the left side of the machine with a mechanical down force system (springs), as well as on the right side with a commercial hydraulic system. The analyzed variables were level of vertical force, soil mechanical resistance to penetration (RMSP), soil density, sowing depth, emergence velocity index and plant height. The experimental design was a randomized blocks with four replications for the experiments with cotton and corn, however, for the soybean crop the design followed a 5x3 factorial scheme (5 vertical forces and three tilling tools) in three replications. Data was collected through the time, according to the specifications of Statistical Process Control (SPC). The treatments for cotton and corn crops for each operational mode (Manual and Automatic), were levels of vertical forces: No down force; Very low; Low; Average; High and Very High for both manual and automatic operation modes, totaling eleven treatments. For soybean crop, two levels of vertical forces: Very Low and Low in automatic and manual mode, using two different systems (mechanical and hydraulic), as well as two types of tilling tools (rod and double disc). Sowing process variability was evaluated by I-MR and Xbar-S control charts. Analysis of variance was performed and, when significant, means were compared by Tukey's test at 5% probability. The variability of vertical forces distribution was greater without application of load (0 N). There was no difference between operational quality when comparing manual or automatic modes. The depth-related seeding process was considered uniform with high or very high vertical loads. RMSP and soil density were not influenced by the applied downforces. Sowing depth was increased with the increase of applied loads regardless of the soil type. Corn emergence was increased in clay loam soil with increasing vertical loads. For soybean crop, there was an increase in seedling emergence using a hydraulic system together with tilling tools. In general, the use of a hydraulic downforce system in the row-units provides better seed distribution. When using the correct load, the emergence of seedlings and plant height are increased compared to the absence of any system
Descrição
Palavras-chave
Agricultura de precisão, Semeadura, Milho, Soja, Algodoeiro