Composição química do capim-tanganica submetido a níveis de sombreamento arbóreo em sistema silvipastoril

CARVALHO, Carlos Augusto Brandão de; SILVA, Pedro Henrique Ferreira da; ZANELLA, Pablo Giliard

RESUMO

O objetivo deste trabalho foi avaliar o efeito de diferentes níveis de sombreamento arbóreo da espécie Clitoria fairchildiana sobre a composição bromatológica do capim-tanganica (Megatyrsus maximus Jacq. cv. Tanganica), nas estações do verão I (2011/2012), primavera (2012) e verão II (2012/2013). Para tanto, foi instalado um experimento sob delineamento inteiramente casualizado, com quatro tratamentos (níveis de sombreamento) e cinco repetições em Seropédica, Rio de Janeiro, Brasil. Foram avaliados os teores de: matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN) e em detergente ácido (FDA), proteína insolúvel em detergente neutro (PIDN) e em detergente ácido (PIDA), lignina (LIG) e matéria mineral (MM). Os dados foram analisados pelo PROC MIXED do SAS^®, com medidas repetidas no tempo, e as médias dos tratamentos comparadas pelo teste de Tukey (P<0,05); ou pelo PROC REG do SAS^® para as análises de regressão (P<0,05). Houve efeito de interação entre nível de sombreamento e estação do ano para teores de MS, PB, FDN, FDA, PIDN, PIDA e MM. Os teores de lignina foram influenciados apenas pelo nível de sombreamento. Os teores de MS, FDN, FDA e lignina foram reduzidos, enquanto aqueles de PB, PIDN e MM aumentaram linearmente em função dos níveis de sombreamento. Maiores teores de PIDA foram verificados somente na primavera. O aumento do sombreamento arbóreo de Clitoria fairchildiana melhora a composição bromatológica da forragem do capim-tanganica, durante o verão.

Palavras-chave:
fibra insolúvel em detergente neutro; Megatyrsus maximus; proteína bruta; proteína insolúvel; sombra

[1] *Mail for correspondence: pehenrique1709@gmail.com

Season	Shading level
Season	FS (%)	SS (%)	MS (%)	HS (%)
Summer I	0	26	46	54
Spring	0	27	54	59
Summer II	0	31	47	56

Season	Shading level¹ 1 Values respectively described in Table 1 for each season of year. FS: full sun; SS: slight shading; MS: mild shading; HS: heavy shading. The seasons of year occurred between the following dates: summer I from 12/27/2010 to 03/20/2011; spring occurred from 09/02/2011 to 12/20/2011 and summer II from 12/21/2011 to 03/01/2012. X: percentage of shade. Means followed by different letters in the same column are significantly different by Tukey's test (p<0.05). SEM: standard error of the mean. (%)				SEM	Regression equation	R²
Season	FS	SS	MS	HS	SEM	Regression equation	R²
		DM (g kg^-1)
Summer I	258.0b	214.0ab	207.0a	226.0a	17.3	$\hat{Y} = 226.0$ ^ns	-
Spring	249.0b	247.0a	194.0a	181.0b	3.3	$\hat{Y} = 259.6 - 1.195 X$ ^ (p<0.01) and ns: non-significant.	0.80
Summer II	313.0a	210.0b	188.0a	172.0b	12.9	$\hat{Y} = 298.8 - 2.433 X$ ^ (p<0.01) and ns: non-significant.	0.86
		MM (g kg^-1)
Summer I	91.0a	106.0a	123.0a	122.0a	2.6	$\hat{Y} = 90.69 + 0.449 X$ ^* * (p<0.05),	0.84
Spring	78.0b	72.0b	100.0b	103.0b	2.5	$\hat{Y} = 71.57 + 0.477 X$ ^* * (p<0.05),	0.62
Summer II	68.0c	70.0b	95.0b	103.0b	2.4	$\hat{Y} = 64.51 - 0.697 X$ ^* * (p<0.05),	0.78

Season	Shading level¹ 1 Values described in Table 1 for each season of the year. FS: full sun; SS: soft shading; MS: moderate shading; SS: strong shading. The seasons of year occurred between the following dates: summer I from 12/27/2010 to 03/20/2011; spring occurred from 09/02/2011 to 12/20/2011 and summer II from 12/21/2011 to 03/01/2012. X: percentage of shade. Means followed by equal letters in the same column do not differ each other by the Tukey test (p<0.05). SEM: standard error of mean. *(p<0.05), (%)				SEM	Regression equation	R²
Season	FS	SS	MS	SS	SEM	Regression equation	R²
		NDF (g kg^-1)
Summer I	649.0b	665.0a	645.0a	650.0a	8.4	$\hat{Y} = 653.0$ ^ns	-
Spring	668.0a	666.0a	588.0b	618.0b	4.0	$\hat{Y} = 675, 74 - 1, 238 X$ ^ (p<0.01) and ns: not significant.	0,80
Summer II	669.0a	636.0b	639.0a	662.0a	4.8	$Y = 651.0$ ^ns	-
		ADF (g kg^-1)
Summer I	350.0b	346.0a	334.0a	340.0ab	5.4	$\hat{Y} = 342.0$ ^ns	-
Spring	378.0a	346.0a	327.0b	348.0a	3.9	$\hat{Y} = 377, 78 - 01.132 X$ ^ (p<0.01) and ns: not significant.	0,86
Summer II	367.0a	344.0a	353.0a	348.0a	4.3	$Y = 353.0$ ^ns	-

Season	Shading level¹ 1 Values respectively described in Table 1 for each season of year. FS: full sun; SS: soft shading; MS: moderate shading; SS: strong shading. The seasons of year occurred between the following dates: summer I from 12/27/2010 to 03/20/2011; spring occurred from 09/02/2011 to 12/20/2011 and summer II from 12/21/2011 to 03/01/2012. X: percentage of shade. Means followed by different letters in the same column are significantly different by Tukey's test (p<0.05). SEM: standard error of the mean. (%)				SEM	Regression equation	R²
Season	FS	SS	MS	SS	SEM	Regression equation	R²
		CP (g kg^-1)
Summer I	60.0a	83.0b	108.0a	123.0a	3.7	$\hat{Y} = 56.92 + 0.822 X$ ^ (p<0.01) and ns: non-significant.	0.83
Spring	69.0a	72.0c	94.0b	104.0b	3.7	$\hat{Y} = 64.65 + 0.583 X$ ^ (p<0.01) and ns: non-significant.	0.67
Summer II	70.0a	99.0a	98.0ab	110.0b	3.7	$\hat{Y} = 77.84 + 0.573 X$ ^ (p<0.01) and ns: non-significant.	0.57
		NDIP (g kg^-1)
Summer I	34.0a	48.0a	64.0b	85.0a	2.1	$\hat{Y} = 30.67 + 0, 607 X$ ^ (p<0.01) and ns: non-significant.	0.80
Spring	31.0a	32.0b	62.0a	65.0b	3.9	$\hat{Y} = 50.13 + 0, 634 X$ ^ (p<0.01) and ns: non-significant.	0.65
Summer II	28.0a	51.0a	53.0b	56.0c	2.8	$\hat{Y} = 34.56 + 0.423 X$ ^ (p<0.01) and ns: non-significant.	0.54
		ADIP (g kg^-1)
Summer I	21.0a	22.0a	24.0a	24.0a	1.2	$\hat{Y} = 23, 0$ ^ns	-
Spring	12.0b	13.0b	21.0a	22.0a	1.2	$\hat{Y} = 11, 22 + 0, 156 X$ ^* * (p<0.05),	0.76
Summer II	13.0b	18.0ab	15.0b	20.0b	1.3	$\hat{Y} = 17, 0$ ^ns	-