Comparative response of tall fescue and perennial ryegrass swards to variation in defoliation interval and height

Figures & data

Table 1. Defoliation events of tall fescue (TF) and perennial ryegrass (PR) plots subjected to different defoliation intervals (one-leaf stage, -1; two-leaf stage, -2; three-leaf stage, -3; four-leaf stage, -4) during the experimental period.

	Defoliation events
Growing years	TF-1	TF-2	TF-4	PR-1	PR-2	PR-3
Year 1 (2013)
Flowering period^1	6 Oct			4 Oct
	^a	^a		22 Oct	22 Oct
	8 Nov			5 Nov		5 Nov
	15 Nov	13 Nov	13 Nov	21 Nov	21 Nov
	3 Dec			11 Dec	11 Dec
	28 Dec	28 Dec		28 Dec		28 Dec
	^a			^a
Year 2 (2014)
Summer/autumn	25 Jan	25 Jan	25 Jan	25 Jan	25 Jan
	13 Feb			10 Feb	10 Feb	12 Feb
	25 Mar	25 Mar		25 Mar
Winter/spring	2 May			2 May
	27 May	27 May	27 May	27 May	27 May	27 May
	17 Jul	17 Jul		17 Jul	17 Jul
	15 Aug	15 Aug		15 Aug	15 Aug
	28 Aug			28 Aug		28 Aug
	2 Sept	2 Sept	26 Sept	26 Sept
Flowering Period^2	15 Oct	15 Oct		15 Oct	15 Oct
	23 Oct 7 Nov	7 Nov	7 Nov	23 Oct	23 Oct	23 Oct

Note: Flowering period¹ (4 October–31 December 2013); summer/autumn (1 January–30 April 2013); winter/spring (1 May–30 September 2013) and flowering period² (1 October–7 November 2014).

^aTreatments missed defoliation.

Table 2. Available dry matter (DM) yield and cumulative DM yield (kg DM/ha) of tall fescue (TF) and perennial ryegrass (PR).

	Flowering period^1	Summer/autumn	Winter/spring	Flowering period^2	Cumulative DM yield
	kg DM/ha
Species
TF	5197 ± 293	2699 ± 356	2855 ± 175	2927 ± 226	13,678 ± 587
PR	3334 ± 233	1437 ± 94.9	2519 ± 98.1	1451 ± 151	8740 ± 379
P-value	P < 0.001	P < 0.01	NS	P < 0.001	P < 0.001

Notes: Flowering period¹ (4th October–31st December); summer/autumn (1st January–30th April); winter/spring (1st May–30th September); flowering period² (1st October–7th November). Means ± standard error are different at the significance levels shown. Not significant = NS.

Table 3. Available dry matter (DM) yield and cumulative DM yield (kg DM/ha) of tall fescue (TF) and perennial ryegrass (PR) subjected to defoliation at different defoliation intervals (one-leaf stage, -1; two-leaf stage, -2; three-leaf stage, -3; four-leaf stage, -4) during the experimental period.

	TF-1	TF-2	TF-4	PR-1	PR-2	PR-3	Species (S)	Interval (I)	S × I
Period	kg DM/ha						P-value
Flowering period^1	4853^b	6751^a	3987^c	2820^d	2625^d	4558^b	<0.001	<0.001	<0.001
Summer/autumn	1654^c	1734^c	4711^d	1385^b	1842^c	1083^a	NS	<0.001	NS
Winter/spring	2367^bc	2450^bc	3749^a	2580^bc	2186^c	2790^b	NS	<0.001	NS
Flowering period^2	2130^c	2619^b	4032^a	603^d	1735^c	2015^c	<0.001	<0.001	<0.05
Cumulative yield	11,003^c	13,553^b	16,479^a	7388^d	8387^d	10,446^c	<0.001	<0.001	NS

Notes: Flowering period¹ (4 October–31 December 2013); summer/autumn (1 January–30 April 2014); winter/spring (1 May–30 September 2014); flowering period² (1 October–7 November 2014). Means within rows having different superscripts are different at the significance levels P < 0.05. Not significant = NS.

Figure 1. Effect of defoliation interval (one-leaf stage, -1; two-leaf stage, -2; three-leaf stage, -3; four-leaf stage, -4) and sown grass species (TF, tall fescue; PR, perennial ryegrass) on the botanical composition (%DM, dry matter) of the sward during year 2 (27 May 2014). The standard error bars are 8.3% for sown grass species, 1.2% for white clover and 7.5% for other species.

Figure 2. Effect of leaf stage (one-leaf stage, -1; two-leaf stage, -2; three-leaf stage, -3; four-leaf stage, -4), defoliation height; low (L, 5 cm) and high (H, 8 cm) and sown grass species (TF, tall fescue; PR, perennial ryegrass) on the botanical composition (%DM, dry matter) of the sward at the end of the experimental period (October/November 2014; year 2). The standard error bars are 5.8% for sown grass species, 0.7% for white clover and 5.7% for other species.

Table 4. Herbage quality values (metabolisable energy, ME; crude protein, CP%) of tall fescue (TF) and perennial ryegrass (PR) subjected to different defoliation intervals (one-leaf stage, -1; two-leaf stage, -2; three-leaf stage, -3; four-leaf stage, -4.

Nutritive values	TF-1	TF-2	TF-4	PR-1	PR-2	PR-3	P-value
Flowering period^1 4 October–31 December 2013
ME (MJ/kg DM)	10.7^ab	9.7^bc	9.6^c	11.2^a	11.2^a	9.3^c	P < 0.001
CP%	20.7^a	12.9^b	13.3^b	19.7^a	19.3^a	11.5^b	P < 0.001
Winter/spring 1 May–30 September 2014
ME (MJ/kg DM)	11.1^b	10.4^c	9.5^d	11.4^a	10.3^c	10.3^c	P < 0.001
CP (%)	32.2^a	28.8^b	24.5^c	27.6^b	23.6^c	22.9^c	P < 0.001
Flowering period^2 1 October–7 November 2014
ME (MJ/kg DM)	11.7^a	11.5^b	9.6^d	11.7^a	11.3^c	11.7^a	P < 0.001
CP (%)	26.2^a	23.8^b	14.6^d	23.3^b	21.2^c	14.1^d	P < 0.001

Note: Means within columns/seasons having different superscripts are significantly different at P < 0.05.

Figure 3. Tiller density (tillers/m²) of tall fescue (TF) and perennial ryegrass (PR) plots under two defoliation heights (low, 5 cm, L; high, 8 cm, H) and subjected to defoliation at different defoliation intervals (one-leaf stage, -1; two-leaf stage, -2; three-leaf stage, -3; four-leaf stage, -4) at the end of the experiment (vertical columns) (October/November 2014). Horizontal dotted lines represent the tiller densities at the commencement of the experiment (January 2013). The standard error bars represent standard errors at P < 0.05.