Características morfogênicas e estruturais do capim-xaraés submetido a intesidades de pastejo

Galzerano, Leandro; Malheiros, Euclides Braga; Raposo, Elisamara; Morgado, Eliane da Silva; Ruggieri, Ana Cláudia

doi:10.5433/1679-0359.2013v34n4p1879

Cited by 6 publications

(12 citation statements)

References 7 publications

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“…When the environment is modified and required growth conditions are affected, e.g., luminosity, plants activate mechanisms to reduce leaf appearance. This activation can directly affect phyllochron, and then plant metabolism starts to redirect photoassimilates for the preservation of living tissues (GALZERANO et al, 2013). SER increased with increasing pre-grazing heights due to high light competition.…”

Section: Factormentioning

confidence: 99%

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Short-term evaluation of Massai grass forage yield and agronomic characteristics and sheep performance under rotational grazing with different pre-grazing canopy heights

Cardoso

Sousa

Ferreira

et al. 2019

SCA

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This study aimed to evaluate the morphogenic, structural, chemical characteristics, and forage yield of Massai grass, as well as the performance of sheep under three pre-grazing canopy heights. Eighteen Dorper x crossbred sheep (12 males and 6 females) were subjected to three pre-grazing canopy heights of Massai grass (45, 35, and 25 cm). Rotational grazing was adopted, with a fixed rest period of 12 days and occupation of four days. Before placing animals in the paddock, stocking rate was estimated to ensure a reduction of about 50% in the initial height. Morphogenic and chemical characteristics of forage were evaluated, as well as animal intake and performance. Pasture managed at 25 cm height induced reductions in stem and sheath sizes, and phyllochron but an increased leaf: stem ratio. However, the pasture cut at 35 cm above ground promoted an increase in total dry mass and foliar leaf productions, in addition to greater forage availability and daily accumulation. Yet, pastures with a height of 45 cm had a higher percentage of stem and senescent material, decreasing leaf intake by animals. Among the studied heights, 35 cm is the most suitable for Massai grass, when used for rearing sheep for meat production under pasture conditions in the northern Tocantins. This is because this management provided a greater availability of good quality forage and thereby increasing weight gains per area in animals.

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Section: Factormentioning

confidence: 99%

“…The lower the LSR and the higher the NLL, the better the pasture nutritional quality will be. Forage mass must comprise living tissues capable of being converted into an animal product (GALZERANO et al, 2013).…”

Section: Factormentioning

confidence: 99%

Short-term evaluation of Massai grass forage yield and agronomic characteristics and sheep performance under rotational grazing with different pre-grazing canopy heights

Cardoso

Sousa

Ferreira

et al. 2019

SCA

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“…The best point to begin animal grazing is considered to be when the sward is achieving an average of 95% light interception. Regarding the interruption of animal grazing, the residual leaf area index (rLAI) technique was and is being used in research in different forages and conditions in Brazil (CUTRIM JÚNIOR, 2010SILVA et al, 2013;GALZERANO et al, 2013), though less commonly than other techniques such as measurement of postgrazing heights, herbage allowance, or fixed days.…”

Section: Introductionmentioning

confidence: 99%

“…Measurement of light interception (LI) by the sward in order to determine the best time to start grazing has been used in experimental conditions in tropical regions, mainly in Brazil, because several scientific results showed a correlation between LI with forage production and nutritive value (CUNHA et al, 2010;DIFANTE et al, 2010;GALZERANO et al, 2013;SOUSA et al, 2013;SILVA et al, 2013). The best point to begin animal grazing is considered to be when the sward is achieving an average of 95% light interception.…”

Section: Introductionmentioning

confidence: 99%

Effects of postgrazing residue on morphogenetic and structural characteristics of Tifton 85 pastures

Silva

Ruggieri

Reis

et al. 2016

SCA

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The ideal time to start grazing is when pastures reach 95% light interception. The use of residual leaf area index (rLAI) to time the interruption of grazing under intermittent grazing has recently been studied in forage species in different climatic conditions in Brazil. However, studies evaluating the formation and development of leaves and tillers through morphogenetic and structural variables in functional rLAI are still lacking for Tifton 85 pastures. Therefore, the objective of this study was to evaluate the effects of varying rLAI in successive grazing cycles on morphogenetic and structural characteristics of Tifton 85 pasture grazed intermittently by sheep. Morphogenetic and structural characteristics were evaluated in three grazing cycles under three rLAI conditions (0.8, 1.6, and 2.4). The regrowth interval (time taken to return to 95% light interception) of pastures increased from 21.33 to 29.66 days with decreasing rLAI. The leaf appearance rate increased at a rate of 0.02 leaves tiller -1 day -1 and the number of live leaves per tiller increased by 0.41 with decreasing rLAI. Phyllochron, leaf elongation rate, final leaf length, leaf senescence rate, and stem elongation rate decreased linearly with decreasing rLAI. The number of live leaves per tiller was lower (7.97) in the third grazing cycle, probably owing to the higher senescence rate observed that same cycle, while the other variables had higher values. The 2.4 rLAI condition promotes excessive stem elongation, reduced leaf appearance, lower number of live leaves per tiller, and increased senescence of leaves, while the 0.8 and 1.6 rLAI conditions promote desirable morphogenetic and structural characteristics, which correlate directly with forage quality. In order to avoid excessive forage losses, grazing must occur preferentially by the end of March, when climatic conditions still support the appropriate development of the plants. Key words: Grazing cycles. Leaves appearance. Light interception. Residual leaf area index. Stem elongation. ResumoO momento de iniciar o pastejo quando os pastos atingem 95% de interceptação luminosa e de interrupção do pastejo por meio de índices de área foliar residual (IAFr), em situação de pastejo intermitente, recentemente vem sendo estudado em espécies forrageiras em distintas condições climáticas do Brasil, porém, pesquisas avaliando a formação e desenvolvimento de folhas e perfilhos por meio das variáveis morfogênicas e estruturais em função de IAFr são ainda inexistentes em pastos de Tifton 85. Por isso,

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“…Under intermittent grazing, the postgrazing residual leaf blade (RLB) length can be used as a guideline for grazing management because defoliation intensity can alter the morphophysiological and structural characteristics of the plant, directly affecting animal performance (CÂNDIDO et al, 2005b;GALZERANO et al, 2013;MARCELINO et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Effect of post-grazing residual leaf blade-length on the regrowth vigor of Piatã grass grazed under intermittent stocking

Costa

Alexandrino

Neto

et al. 2019

SCA

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The objective of this study was to evaluate the effect of post-grazing residual leaf blades (RLB) of different lengths on the morphogenic and structural characteristics of Urochloa brizantha ‘Piatã’ grazed upon by beef cattle. A completely randomized design was used, with three RLB lengths (2, 4, and 6 cm) and two paddocks as replicates over two grazing seasons (wet and wet-dry transition). To monitor the weekly forage growth, two representative clumps and 48 tillers per treatment were marked after grazing. The procedure continued until the plants reached the target pre-grazing height of 35–40 cm. Morphogenic characteristics were not affected by the treatments or seasons, with minor changes observed in mean sheath length (MSL) within season and tiller population density (TPD). The MSL reached its peak value of 210.37 mm during the wet season relative to 175.89 mm during the wet-dry transition. The TPD reached its lowest value (680 tillers m-2) at the highest defoliation intensity (2 cm) relative to that at the lowest defoliation intensity (720 tillers m-2). The different RLB lengths modified canopy height variably; canopy height was the highest with the 6 cm leaves (24.31 cm), but did not vary between the 2 cm and 4 cm leaves. The post-grazing leaf area index and interception of photosynthetically active radiation were modified by season. The highest defoliation intensity (2 cm) increased the rest period by seven days when compared with the lowest defoliation intensity (6 cm).

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Características morfogênicas e estruturais do capim-xaraés submetido a intesidades de pastejo

Cited by 6 publications

References 7 publications

Short-term evaluation of Massai grass forage yield and agronomic characteristics and sheep performance under rotational grazing with different pre-grazing canopy heights

Short-term evaluation of Massai grass forage yield and agronomic characteristics and sheep performance under rotational grazing with different pre-grazing canopy heights

Effects of postgrazing residue on morphogenetic and structural characteristics of Tifton 85 pastures

Effect of post-grazing residual leaf blade-length on the regrowth vigor of Piatã grass grazed under intermittent stocking

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