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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
Forage mass and chemical composition of signal grass under eucalyptus clones and sampling sites on
crop-livestock-forest
Cíntia Gonçalves Guimarães1, Karina Guimarães Ribeiro2, Maria Celuta Machado Viana3,
Rosana Cristina Pereira4, José Barbosa dos Santos5
Engenheira Agrônoma. Doutoranda do Programa de Pós-Graduação em Biocombustíveis – UFVJM, Diamantina-MG, Brasil, Bolsista
CAPES. e-mail: [email protected]
2
Zootecnista, Pós-Doutora. Profa. Departamento de Zootecnia – UFV, Viçosa-MG, Brasil
3
Engenheira Agrônoma, Doutora. EPAMIG, Prudente de Morais-MG, Brasil
4
Zootecnista, Pós-Doutora. Profa. Departamento de Zootecnia – IFF, Bom Jesus do Itabapoana-RJ, Brasil
5
Engenheiro Agrônomo, Pós-Doutor. Prof. Departamento de Agronomia – UFVJM, Diamantina-MG, Brasil
1
Abstract: The objective of this study was to evaluate the forage mass and chemical composition of signal
grass (Urochloa decumbens cv. Basilisk) after maize harvest on crop-livestock-forest. The experimental
design was a randomized complete block, in a split split plot, with three replications. In the plots were
distributed eucalyptus clones GG 100 and I 144 (Eucalyptus grandis x Eucalyptus urophylla) and VM 58
(Eucalyptus grandis x Eucalyptus camaldulensis), in the subplots were used growth ages of signal grass (10,
17, 24, 31, 38, 45 and 52 days after maize harvest for silage), and, in the subsub plots, the sampling sites,
were made in the center between rows and under the eucalyptus canopy. It was verified that there was not
effect of the triple interaction (clone x age x shading) in any of the variables studied. Regarding the double
interactions, it was observed effect of growth ages x sampling sites for forage mass, and clones x growth
ages to dry matter (DM) content, furthermore, it was observed effect of growth ages x sites sampling for the
neutral detergent fiber (NDF) content. Also, in this work was detected effect of clones for crude protein (CP)
and NDF, and age with CP. The signal grass has forage mass and height increasing with the growth ages and
it has a suitable chemical composition for grazing after maize harvest, especially the clone I 144.
Keywords: agrosilvopastoral system, crude protein, dry matter content, growth ages, neutral detergent fiber
Massa de forragem e composição química do capim-braquiária sob clones de eucalipto e locais de
amostragem na integração lavoura-pecuária-floresta
Resumo: Objetivou-se avaliar a massa de forragem e composição química do capim-braquiária (Urochloa
decumbens cv. Basilisk) após a colheita do milho na integração lavoura-pecuária-floresta. Utilizou-se o
esquema de parcelas subsubdivididas, no delineamento em blocos casualizados, com três repetições. Nas
parcelas distribuíram-se os clones de eucalipto GG 100 e I 144 (Eucalyptus grandis x Eucalyptus urophylla)
e VM 58 (Eucalyptus grandis x Eucalyptus camaldulensis), nas subparcelas as idades de crescimento do
capim-braquiária (10, 17, 24, 31, 38, 45 e 52 dias após a colheita do milho para silagem), e, nas
subsubparcelas, os locais de amostragem, no centro da entrelinha e sob a copa de eucalipto. Verificou-se que
não houve influência da interação tripla (clone x idade x sombreamento) em nenhuma das variáveis
estudadas. Em relação às interações duplas, encontrou-se efeito de idades de crescimento x locais de
amostragem para a massa de forragem, de clones x idades de crescimento para o teor de matéria seca (MS) e
efeito de idades de crescimento x locais de amostragem para o teor de fibra em detergente neutro (FDN).
Observou-se efeito dos clones para os teores de proteína bruta (PB) e de FDN e da idade sobre a PB. O
capim-braquiária apresenta massa de forragem e altura crescente com as idades de crescimento e adequada
composição química para pastejo após a colheita do milho, com destaque para o clone I 144.
Palavras–chave: fibra em detergente neutro, idades de crescimento, proteína bruta, sistema
agrossilvipastoril, teor de matéria seca
Introduction
The crop-livestock-forest system is characterized by the regular distribution of trees along the area,
and the spacing between the trees is larger than conventional, this way is allowed planting the lines of
species for agriculture and grazing of several species, consortium and/or rotation (Venturin et al., 2010). The
objective was to evaluate the forage mass and chemical composition of signal grass, that was under three
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
eucalyptus clones, and different growth ages after maize harvest, and the signal grass was sampled in the
center between rows and under the canopy of trees on crop-livestock-forest.
Material and methods
The experiment was conducted in the experimental area of EPAMIG in Prudente de Morais, MG. The
climate, according to Köppen, classification is Aw, and it has a dry season from May to October and wet
season from November to April. The soil is classified as red yellow latosol and this has a clay texture. The
experimental design was a randomized complete block, in a split split plot, with three replications. The plots
were distributed to the three eucalyptus clones: GG 100 and I 144 (Eucalyptus grandis x Eucalyptus
urophylla) and VM 58 (Eucalyptus grandis x Eucalyptus camaldulensis). The subplots corresponded to the
seven growth ages of signal grass (Urochloa decumbens cv. Basilisk) (10, 17, 24, 31, 38, 45 and 52 days
after maize harvest for silage, hybrid BRS 3060), and the subsub plots consisted of two sampling sites (in the
center between rows and under the eucalyptus canopy). Eucalyptus was planted in double rows, (3x2) + 20
m, the first number refers to the distance between the lines of trees, the second refers to distance between the
trees, and the third the distance between the tracks of trees, so it has 434 trees eucalyptus per hectare. The
forage mass, height and DM, CP and NDF were evaluated (Detmann et al. 2012). The data were subjected
to analysis of variance; for qualitative variables Tukey test was used at 1% probability and for quantitative
variables was applied regression analysis.
Results and discussion
The triple interaction was not significant for any of the variables studied. The forage mass ranged
from 0.7 to 2.7 t ha-1 in the center between rows and 0.4 to 1.8 t ha-1 under the eucalyptus canopy (Table 1).
The lowest forage mass production occurred under the eucalyptus canopy, and it shows a negative effect of
shading for this variable. However, the forage mass of signal grass was not affected by eucalyptus clones
and it yielded an average of 1.30 t ha-1. There was positive linear correlation of heights depending on the
growth age, from 28.3 to 85.3 cm in the center between rows, and from 28.0 to 77.2 cm under the eucalyptus
canopy. The lower heights were obtained under the eucalyptus canopy, where it was in the higher shading,
so it can be awarded the growth of these plants in this condition. There was no effect of clones to signal
grass height in this study, obtaining a mean of 54.7 cm.
Table 1. Forage mass (FM) (t ha-1) and height (cm) of signal grass in function of growth ages
(X) under sampling sites (average of eucalyptus clones).
Sampling
Growth Ages
Regression
Sites
(days after maize harvest)
Equation
10
17
24
31
38
45
52
r2
-1
FM (t ha )
0.8
0.7
0.9
1.5
2.3
2.2
2.7
Ŷ = 0.0241NS + 0.0513X**
0.91
0.4
0.7
0.8
0.8
1.2
1.8
1.3
Ŷ = 0.1773 NS + 0.0261X**
0.79
Center
28.4 32.0 46.4 61.2 75.3 75.8 78.2
Under the
26.0 35.0 44.0 52.0 68.0 74.0 69.0
canopy
NS = not significant; **P(<0.01)
Ŷ = 14.6987** + 1.3568X**
0.93
Ŷ = 16.3352** + 1.1699X**
0.93
Center
Under the
canopy
Height (cm)
In this work was verified that the DM content presented quadratic response in function of the growth
ages for clone I 144 DM minimum content of 20.2% to 29.8 days, and, for clone VM 58 minimum content
of 21.4% to 27.1 days growth, while the mean for the GG 100 clone was 22% (Table 2).After maize harvest,
the forage increased the production of young tissues, and that ended up reflecting in lower DM that had later
increased with advancing maturity. The interaction between growth ages x sampling sites for NDF content,
was also observed, however, none of the equations provided good experimental precision and the average
content was 68.1%, in the range usually obtained for tropical grasses. The growth age influenced the average
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52a Reunião Anual da Sociedade Brasileira de
Zootecnia
Zootecnia: Otimizando Recursos e Potencialidades
Belo Horizonte – MG, 19 a 23 de Julho de 2015
CP content of signal grass grown under eucalyptus clones, with cubic response (Table 2). The maximum of
CP content (12.7%) was obtained at 26 days after maize harvest and the minimum (12.4%) after 37 days.
The CP content were 10.2; 11.4; 9.7% and NDF content were 68.5; 67.0; 68.9% for clones GG 100, I 144
and VM 58, respectively. The highest CP content and lower NDF were obtained under the clone I 144,
compared to VM 58 clone, it showed a better chemical composition. The signal grass under the GG 100
clone did not differ from the others as the NDF, but this was lower than the grass under the clone I 144 for
the CP content (Table 3). It is noteworthy that the average contents of CP were obtained in plants with 10-52
days of growth after maize harvest, in autumn seasons.
Table 2. Dry matter content (% DM) of signal grass under the GG 100 clones, I 144 and VM
58 (average sampling sites), and crude protein (% CP) (average of three clones and two
sampling sites) in function of the growth ages (X).
Growth Ages
(days after maize harvest)
Clones
and CP
10
Regression Equation
17
24
31
38
45
GG 100
21.6
20.3
19.3
24.9
19.8
23.9
I 144
24.5
20.8
18.3
20.8
21.3
21.6
VM 58
24.4
21.0
20.0
22.7
21.8
23.5
CP
9.28
11.91
12.59
10.64
9.69
10.09
r2
52
24.0 X = 68.1
Ŷ = 1.3923 NS + 1.1456**X –
22.8
0.0377**X2
Ŷ = 1.3923 NS + 1.1456**X –
24.4
0.0377**X2
0.65
Ŷ = 1.3923 NS + 1.1456**X –
0.0377**X2 + 0.0004**X3
0.83
8.99
0.64
NS = not significant; **P(<0.01)
Table 3. Crude protein content (% CP) and neutral detergent fiber (% NDF) of signal grass
grown under eucalyptus clones (average of seven growth ages and two sampling sites).
Eucalyptus Clones
GG 100
I 144
1
CP
NDF
10.2 b
68.5 ab
11.4 a
67.0 b
VM 58
9.7 b
68.9 a
1
averages followed by the same letter in the columns do not differ by Tukey test (P<0.05)
Conclusion
The signal grass has forage mass and height increasing with the growth ages and chemical
composition suitable for grazing after maize harvest, especially the clone I 144.
Acknowledgements
At EPAMIG Centro-Oeste and support FAPEMIG, CNPq, CAPES and PRPPG / UFVJM.
References
Detmann, E.; Souza, M. A.; Valadares filho, S. C.; Queiroz, A. C.; Berchielli, T. T.; Saliba, E. O. S.; Cabral,
L. S.; Pina, D. S.; Ladeira, M. M. e Azevedo, J. A. G. 2012. Métodos para análise de alimentos. INCT –
Ciência animal. 1. Ed. Visconde do Rio Branco: Suprema.
Venturin, R. P.; Guerra, A. R.; Macedo, R. L. G. e Mesquita, H. A. de. 2010. Sistemas Agrossilvipastoris:
origem, modalidades e modelos de implantação. Informe Agropecuário 31:16-24.
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