Defoliation height and potassium fertilization of Mulato II grass

Abstract

A pot trial in greenhouse conditions was carried out to identify at which defoliation height Mulato II grass (Urochloa hibrida cv. Mulato II) should be managed and to determine whether potassium fertilization is necessary in soil with high potassium content. The experiment was carried out in a greenhouse in a randomized block design with six treatments and five replications. Treatments consisted of a 3 × 2 factorial arrangement, with three defoliation heights (50, 65, and 80 cm) and with or without potassium maintenance fertilization. The production characteristics and chemical composition of the forage plant were evaluated. There was no interaction effect between defoliation height and fertilization with or without potassium on any of the analyzed variables, except for mineral content in Mulato II grass. The tillers and leaves number, shoot dry matter, leaf+sheath, root system, and residue were influenced by defoliation heights and potassium fertilization, except for the leaf blades and root dry matter, leaf blade/ stem+sheath ratio, and leaves number, which were not influenced by potassium fertilization. Higher shoot dry matter was observed at the heights of 65 and 80 cm; however, comparing these two heights, leaf + sheath dry matter was lower at 65 cm. Regarding the grass's chemical composition, there was an increase in neutral and acid detergent fiber and indigestible neutral detergent fiber contents as the defoliation height increased, which resulted in lower production of potentially digestible dry matter, which can compromise the potential use of the forage by animals. Among evaluated treatments, Mulato II grass defoliation is recommended for a maximum height of 65 cm. Potassium fertilization increases the yield and the potentially digestible dry matter content of Mulato II grass, even when cultivated in soil with high potassium content. teor de potássio. O experimento foi realizado em casa de vegetação, em delineamento experimental em blocos casualizados, com seis tratamentos e cinco repetições, em esquema fatorial 3x2. Os tratamentos consistiram em três alturas de desfolha (50, 65 e 80 cm), sendo cada altura de desfolha avaliada com ou sem adubação de manutenção com potássio. Foram avaliadas as características produtivas e a composição bromatológica da forrageira. As alturas de corte e adubação ou não com potássio não apresentaram efeito de interação para nenhuma das variáveis analisadas, exceto para teor de minerais no capim Mulato II. O perfilhamento, massa seca da parte aérea, colmo + bainha, número de folhas e massa seca de raiz e resíduos foram influenciadas pelas alturas de corte e adubação com potássio, com exceção a massa de lâminas foliares, raiz, relação lâmina foliar/colmo+bainha e número de folhas, que não foram influenciadas pela adubação potássica. Observou-se maior massa seca de parte aérea nas alturas de 65 e 80 cm, contudo, comparando estas duas alturas, houve menor massa seca de colmo+bainha na altura de 65 cm. Em relação à composição bromatológica do capim Mulato II, houve inc...

The amazonian capim-açú is less nitrogen dependente than antelope grass to produce leaf dry matter

“…In addition, other researchers determined that capim-açú retains high rates of leaf elongation as well as high values of leaf area for actively growing tillers when fertilized with N (Machado et al, 2013). Also, in the present study living tillers of capim-açú responded to N and K similar to mulato grass (Cabral et al, 2017), and better than palisade grass which is extensively used by farmers due to its high productivity (Sanchês et al, 2013). This supports that capim-açú could be considered as a potential alternative as forage plant to be used in the floodplain Maranhão region, Brazil, Therefore, its replacement by exotic and potentially invasive species like antelope grass (López Rosas et al, 2015) would not seem to be a good alternative.…”

“…The N dose induced a quadratic effect, increasing the number of dead tillers until the dose of 78 mg dm -3 N, but values slightly decreased upon further N doses ( Figure 4C). Also, 30 mg dm -3 K 2 O caused pot -Plastic pots with 6 dm 3 and soil surface area of 0,032 m 2 ; *, ** -Significant by F test at p ≤ 0,05 and p ≤ 0,01, respectively; Means (bars) followed by distinct letter differ at p ≤ 0.05 by the Tuckey test a smaller number of dead tillers compared to the dose of 10 mg dm -3 K 2 O ( Figure 4D), probably because K stimulated the maintenance of living tillers as reported by Cabral et al (2017). Another interesting characteristic of capim-açú is the ability to maintain more living tillers than antelope grass ( Figure 4A).…”

“…These results also indicated that increasing K dose leaded to smaller proportion of leaves dry matter, independently of species ( Figure 3B). However, this K effect was not observed for mulato grass (Cabral et al, 2017). The Maranhão floodplain area has periods of flooding and intense dry seasons.…”

Investigating the Optimal Day for Nitrogen Fertilization on Piatã palisadegrass and Quênia guineagrass after Defoliation

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Morphological characteristics and production of Xaraes and Zuri grass fertilized with combinations of sulfur and potassium

“…Because of this, in the Urochloa hybrid cv. Mulate II grass, potassium promotes more tillers and leaves production by the plant, which causes the occurance of forage accumulation (CABRAL et al, 2017). Bonfim-Silva et al (2018) observed an increase in leaves number and mass produced by Urochloa brizantha cv.…”