Características agronômicas, bromatológicas e econômicas de alturas de corte para ensilagem da cultura do milho

Abstract

ResumoObjetivou-se avaliar as características agronômicas, bromatológicas e econômicas de alturas de corte para ensilagem da cultura do milho. O experimento foi conduzido em delineamento de blocos ao acaso, avaliando-se quatro alturas de colheita: 20; 50; 80 e 110 cm em relação à superfície do solo. Após 114 dias, o milho foi avaliado, constatando-se acréscimo na concentração de matéria seca (MS) do colmo, quantidade de colmo remanescente na área colhida, participação de grãos na massa ensilada e quantidade de K remanescente no colmo devido à elevação na altura de corte (p<0,05). Em resposta a esse resultado, a quantidade de massa ensilada diminuiu proporcionalmente quando o corte das plantas foi realizado em alturas mais elevadas (p<0,05). Na medida em que aumentou a altura de corte da planta a ser ensilada, verificou-se melhora na qualidade das silagens produzidas, com acréscimo na concentração de proteína bruta (PB) e aporte energético, ao passo que houve redução na concentração de fibra nessas silagens (p<0,05). Entretanto, o custo de produção das silagens aumentou sobremaneira pela utilização de alturas de corte mais elevadas, verificando um custo 4,47 vezes maior do que a ciclagem de K na área por meio do colmo remanescente. As características agronômicas e bromatológicas da silagem de milho melhoram com a elevação da altura de corte, mas a elevação da altura de corte inviabiliza economicamente a prática da ensilagem quando a geração de produtos finais não é computada. Desta maneira, recomenda-se que a altura de corte da planta de milho seja de no máximo 50 cm. Palavras-chave: Conservação de forragem, custo de produção, energia, fibra, valor nutritivo AbstractThe aim was to evaluate agronomic, bromatologic and economical characteristics harvest heights for ensiling of corn. The trial was conducted in randomized block design and treatments corresponded to harvest heights of 20; 50; 80 and 110 cm from the soil surface. The agronomic evaluations were conducted 114 days after planting. The percentage of dry matter (DM) and productivity of stem, grain and participation of potassium remaining in the stem increased linearly with increasing cutting height 1 Prof., Instituto de Ciências Agrárias, Universidade José do Rosário Vellano, UNIFENAS, Alfenas, MG.

Silage production of corn intercropped with tropical forages in an integrated crop-livestock system with lambs

“…Increasing cutting heights improves the agronomic and chemical characteristics of corn silage; however, this practice may be economically unfeasible when the quality of the final product is not computed. For this reason, Rezende et al (2015) recommended that the maximum cutting height for corn should be at 0.50 m. In intercropping systems with tropical perennial grasses, low cutting heights can result in an increased removal of tillers, compromising pasture formation for the winter/spring period (Portes et al, 2000). However, the operational constraints of forage harvesters that are either coupled to tractors or self-propelled hamper cutting heights above 0.40-0.50 m.…”

Yield and nutritive value of mechanically processed corn silage from an integrated crop-livestock system

“…A significant difference (P <0.05) in the grain percentage was found only in relation to the cutting heights, with an increase in this parameter in silage harvested at the higher cutting height (45 cm above the soil surface). This increase occurred because the higher cutting height that eliminated the dilution effect from the proportion of stalks and leaves that occurs when the plant is cut at lower cutting heights (Caetano et al, 2011;Rezende et al, 2015).…”

“…Corn is one of the most commonly used forages for silage production since it provides high yields per area, high dry matter (DM) content, chemical and nutritional quality, low buffering capacity, high nutritional value from its kernels, easy mechanical harvesting and flexibility of use (Ferraretto, Shaver, & Luck, 2018). Furthermore, some strategies can be adopted to enhance the energy quality of corn silage, such as harvesting late-maturity corn plants, which have more starch in their grain; increasing cutting heights, which increases the proportion of grain in the forage mass (Caetano et al, 2011;Rezende, Watanabe, Silveira Rabelo, Silveira Rabelo, & Nogueira, 2015) and preserves the development of the intercropped grass after harvesting the corn for silage (Pariz et al, 2017).…”

“…Corn plants harvested at physiological maturity have more starch in their grain than plants harvested at earlier stages; consequently, they show greater lignification in their vegetative fraction due to crop senescence. For this reason, increasing the cutting height of corn plants to exclude the lower vegetative fractions decreases the proportion of fibrous components in silage (Caetano et al, 2011;Rezende et al, 2015), thereby increasing the energy concentration of the silage. On the other hand, the delay in harvesting leads to an increase in the vitreousness of the kernel (Ferraretto et al, 2018), decreasing its digestibility.…”

Effects of cutting height and bacterial inoculant on corn silage aerobic stability and nutrient digestibility by sheep

“…Treating silage with bacterial inoculants was found to result in low NDF contents due to the tendency to reduce the concentrations of hemicellulose (P>0.05), which are generally hydrolyzed in an acidic environment during efficient fermentation (Kamarloiy and Yansari, 2008). Increasing the height at which the corn is cut contributes to increasing the DM concentration of forage, owing to the higher proportion of ears and corn kernels in the ensiled mass, which are generally dryer than the vegetative proportion of forage (Neylon Kung Jr., 2003;Kung Jr. et al, 2008;Rezende et al, 2015).…”