Comparison of transgressive overyielding effect and plant diversity effects of annual and perennial legume-grass mixtures

doi:10.17521/cjpe.2020.0048

Abstract

Abstract:

Aims Our objective was to explore mechanisms underlying the effects of transgressive overyielding and plant diversity effects associated with legume-grass mixtures in Zhaosu Basin, Yili Prefecture, Xinjiang Uygur Autonomous Region, China.
Methods Replicate plots (n = 3) were sown in 2013 as legume and grass monocultures (8 in total, including Vicia sativa, Avena sativa, Onobrychis viciaefolia, Bromus inermis, Trifolium pratense, Phleum pratense, Medicage sativa, Dactylis glomerata), a two-species mixture (AM2, annual legume and grass; PM2, perennial legume and grass), a four-species mixture (PM4, 2 perennial legumes and 2 grasses), a six-species mixture (PM6, 3 perennial legumes and 3 grasses), and three mixed-ratio combinations (legume : grass = 6:4, 5:5 and 4:6). Total plot productivity was measured as forage yield (dry matter) each summer between 2013 to 2015, which were used to calculate transgressive overyielding effect (OV), transgressive overyielding effect 1 (OV₁), and transgressive overyielding effect 2 (OV₂). Plant diversity effects were determined by calculating the complementary effect (CE), selection effect (SEF), and net biodiversity effects (∆Y).
Important findings The OV amplitudes of AM2 in 2013, 2014 and 3 years average were less than those of PM2 and PM6. The OV amplitude of AM2 in 2015 was greater than those of PM2, PM4 and PM6. The difference between the productivity of the mixed community and the yield of the most productive product species in the community components and the average yield of each species showed similar laws. CE of AM2 in 2013, 2014, and 3 years average was greater than PM2, PM4 and PM6 in the respective years. While SEF were much smaller than CE in AM2, changes in CE were relatively stable in PM2, PM4 and PM6. Fitted curves of species richness, species evenness, and forage yield (community productivity) predominantly showed a single maximum in PM4, yet productivity was highest in the 5:5 ratio plot. CE, SEF,and ∆ Y in perennial legume-grass mixtures decreased over time, which also led to declines in OV amplitude, OV₁ and OV₂, and their stability. Thus, in the initial study year, CE and SEF jointly dominated OV, OV₁ and OV₂ in perennial legume-grass mixtures. Over the next two growing years, SEF became the main factor that influenced OV, OV₁ and OV₂ in perennial legume-grass mixtures. OV, OV₁ and OV₂ of annual legume-grass mixtures were all influenced by CE from 2013 to 2015.

Key words: species richness, species evenness, transgressive overyielding effect, complementarity effect, selection effect, net effect of biodiversity, growth years

LI Song-Song, WANG Ning-Xin, ZHENG Wei, ZHU Ya-Qiong, WANG Xiang, MA Jun, ZHU Jin-Zhong. Comparison of transgressive overyielding effect and plant diversity effects of annual and perennial legume-grass mixtures[J]. Chin J Plant Ecol, 2021, 45(1): 23-37.

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Figures/Tables 9

References 61

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处理编号 Treatment number	混播比例 Mixed ratio	豆科牧草 Legume		禾本科牧草 Grass
处理编号 Treatment number	混播比例 Mixed ratio	物种 Species	分播量 Sowing quantity (kg·hm^-2)	物种 Species	分播量 Sowing quantity (kg·hm^-2)
AM2-1	6:4	救荒野豌豆 Vicia sativa	72.00	燕麦 Avena sativa	60.00
AM2-2	5:5	救荒野豌豆 V. sativa	60.00	燕麦 A. sativa	75.00
AM2-3	4:6	救荒野豌豆 V. sativa	48.00	燕麦 A. sativa	90.00
PM2-A1	6:4	驴食草 Onobrychis viciaefolia	36.00	无芒雀麦 Bromus inermis	12.00
PM2-A2	5:5	驴食草 O. viciifolia	30.00	无芒雀麦 B. inermis	15.00
PM2-A3	4:6	驴食草 O. viciifolia	24.00	无芒雀麦 B. inermis	18.00
PM2-B1	6:4	驴食草 O. viciifolia	36.00	猫尾草 Phleum pratense	6.00
PM2-B2	5:5	驴食草 O. viciifolia	30.00	猫尾草P. pratense	7.50
PM2-B3	4:6	驴食草 O. viciifolia	24.00	猫尾草P. pratense	9.00
PM2-C1	6:4	红车轴草 Trifolium pratense	9.00	无芒雀麦 B. inermis	12.00
PM2-C2	5:5	红车轴草 T. pratense	7.50	无芒雀麦 B. inermis	15.00
PM2-C3	4:6	红车轴草 T. pratense	6.00	无芒雀麦 B. inermis	18.00
PM2-D1	6:4	红车轴草 T. pratense	9.00	猫尾草 P. pratense	6.00
PM2-D2	5:5	红车轴草 T. pratense	7.50	猫尾草P. pratense	7.50
PM2-D3	4:6	红车轴草 T. pratense	6.00	猫尾草P. pratense	9.00
PM4-1	6:4	驴食草 O. viciifolia	18.00	无芒雀麦B. inermis	6.00
PM4-1	6:4	红车轴草 T. pratense	4.50	猫尾草P. pratense	3.00
PM4-2	5:5	驴食草O. viciifolia	4.50	无芒雀麦B. inermis	7.50
PM4-2	5:5	红车轴草T. pratense	3.75	猫尾草P. pratense	3.75
PM4-3	4:6	驴食草O. viciifolia	12.00	无芒雀麦B. inermis	9.00
PM4-3	4:6	红车轴草T. pratense	3.00	猫尾草P. pratense	4.50
PM6-1	6:4	驴食草O. viciifolia	12.00	无芒雀麦B. inermis	4.00
		红车轴草 T. pratense	3.00	猫尾草P. pretense	2.00
		紫花苜蓿 Medicage sativa	3.00	鸭茅 Dactylis glomerata	2.00
PM6-2	5:5	驴食草O. viciifolia	10.00	无芒雀麦B. inermis	5.00
		红车轴草 T. pratense	2.00	猫尾草P. pretense	2.50
		紫花苜蓿M. sativa	2.00	鸭茅D. glomerata	2.50
PM6-3	4:6	驴食草O. viciifolia	8.00	无芒雀麦B. inermis	6.00
		红车轴草 T. pratense	2.50	猫尾草P. pretense	3.00
		紫花苜蓿 M. sativa	2.50	鸭茅D. glomerata	3.00

处理编号 Treatment number	混播比例 Mixed ratio	豆科牧草 Legume		禾本科牧草 Grass
处理编号 Treatment number	混播比例 Mixed ratio	物种 Species	分播量 Sowing quantity (kg·hm^-2)	物种 Species	分播量 Sowing quantity (kg·hm^-2)
AM2-1	6:4	救荒野豌豆 Vicia sativa	72.00	燕麦 Avena sativa	60.00
AM2-2	5:5	救荒野豌豆 V. sativa	60.00	燕麦 A. sativa	75.00
AM2-3	4:6	救荒野豌豆 V. sativa	48.00	燕麦 A. sativa	90.00
PM2-A1	6:4	驴食草 Onobrychis viciaefolia	36.00	无芒雀麦 Bromus inermis	12.00
PM2-A2	5:5	驴食草 O. viciifolia	30.00	无芒雀麦 B. inermis	15.00
PM2-A3	4:6	驴食草 O. viciifolia	24.00	无芒雀麦 B. inermis	18.00
PM2-B1	6:4	驴食草 O. viciifolia	36.00	猫尾草 Phleum pratense	6.00
PM2-B2	5:5	驴食草 O. viciifolia	30.00	猫尾草P. pratense	7.50
PM2-B3	4:6	驴食草 O. viciifolia	24.00	猫尾草P. pratense	9.00
PM2-C1	6:4	红车轴草 Trifolium pratense	9.00	无芒雀麦 B. inermis	12.00
PM2-C2	5:5	红车轴草 T. pratense	7.50	无芒雀麦 B. inermis	15.00
PM2-C3	4:6	红车轴草 T. pratense	6.00	无芒雀麦 B. inermis	18.00
PM2-D1	6:4	红车轴草 T. pratense	9.00	猫尾草 P. pratense	6.00
PM2-D2	5:5	红车轴草 T. pratense	7.50	猫尾草P. pratense	7.50
PM2-D3	4:6	红车轴草 T. pratense	6.00	猫尾草P. pratense	9.00
PM4-1	6:4	驴食草 O. viciifolia	18.00	无芒雀麦B. inermis	6.00
PM4-1	6:4	红车轴草 T. pratense	4.50	猫尾草P. pratense	3.00
PM4-2	5:5	驴食草O. viciifolia	4.50	无芒雀麦B. inermis	7.50
PM4-2	5:5	红车轴草T. pratense	3.75	猫尾草P. pratense	3.75
PM4-3	4:6	驴食草O. viciifolia	12.00	无芒雀麦B. inermis	9.00
PM4-3	4:6	红车轴草T. pratense	3.00	猫尾草P. pratense	4.50
PM6-1	6:4	驴食草O. viciifolia	12.00	无芒雀麦B. inermis	4.00
		红车轴草 T. pratense	3.00	猫尾草P. pretense	2.00
		紫花苜蓿 Medicage sativa	3.00	鸭茅 Dactylis glomerata	2.00
PM6-2	5:5	驴食草O. viciifolia	10.00	无芒雀麦B. inermis	5.00
		红车轴草 T. pratense	2.00	猫尾草P. pretense	2.50
		紫花苜蓿M. sativa	2.00	鸭茅D. glomerata	2.50
PM6-3	4:6	驴食草O. viciifolia	8.00	无芒雀麦B. inermis	6.00
		红车轴草 T. pratense	2.50	猫尾草P. pretense	3.00
		紫花苜蓿 M. sativa	2.50	鸭茅D. glomerata	3.00

年份 Year	处理编号 Treatment number	产量 Yield (kg·m^-2)		超产 Overyielding (kg·m^-2)			超产效应1 Transgressive overyielding effect 1 (OV₁)	超产效应2 Transgressive overyielding effect 2 (OV₂)	豆科产量比 Legume proportion (%)
年份 Year	处理编号 Treatment number	混播处理 Mixed treatment	单播对照 Monoculture control	与单播相比 Difference by monoculture control	与PM2相比 Difference by PM2	与PM4相比 Difference by PM4	超产效应1 Transgressive overyielding effect 1 (OV₁)	超产效应2 Transgressive overyielding effect 2 (OV₂)	豆科产量比 Legume proportion (%)
2013	AM2	1.26 ± 0.11 ^a	1.22 ± 0.37	0.04			0.07 ± 0.14 ^b	0.08 ± 0.05 ^b	12.33 ± 1.52 ^c
	PM2-A	0.70 ± 0.06 ^b	0.39 ± 0.12	0.28			0.77 ± 0.13 ^a	0.92 ± 0.24 ^a	21.67 ± 5.40 ^b
	PM2-B	0.68 ± 0.12 ^b	0.40 ± 0.15	0.28			0.15 ± 0.09 ^b	0.62 ± 0.21 ^ab	27.03 ± 17.02 ^b
	PM2-C	0.28 ± 0.07 ^c	0.22 ± 0.06	0.06			-0.09 ± 0.04 ^c	-0.31 ± 0.17 ^c	34.00 ± 5.53 ^b
	PM2-D	0.28 ± 0.05 ^c	0.24 ± 0.13	0.04			-0.13 ± 0.11 ^c	0.08 ± 0.03 ^b	81.67 ± 3.47 ^a
	PM4	0.73 ± 0.07 ^b	0.31 ± 0.06	0.42	0.42		0.86 ± 0.15 ^a	1.54 ± 0.35 ^a	29.33 ± 3.79 ^b
	PM6	0.63 ± 0.10 ^b	0.28 ± 0.10	0.35	0.32	0.32	0.62 ± 0.15 ^a	1.30 ± 0.24 ^a	32.33 ± 18.13 ^b
2014	AM2	0.75 ± 0.05 ^a	0.79 ± 0.33	-0.04			-0.15 ± 0.06 ^c	-0.06 ± 0.06 ^cd	32.33 ± 1.53 ^b
	PM2-A	0.33 ± 0.01 ^bc	0.14 ± 0.02	0.19			0.55 ± 0.17 ^b	0.19 ± 0.06 ^b	10.00 ± 9.64 ^d
	PM2-B	0.26 ± 0.04 ^cd	0.09 ± 0.03	0.17			0.23 ± 0.13 ^b	0.07 ± 0.03 ^cd	21.33 ± 11.59 ^c
	PM2-C	0.19 ± 0.01 ^d	0.16 ± 0.11	0.03			-0.02 ± 0.01 ^c	-0.15 ± 0.10 ^d	15.67 ± 5.13 ^cd
	PM2-D	0.15 ± 0.03 ^d	0.10 ± 0.07	0.05			0.30 ± 0.12 ^b	0.10 ± 0.02 ^b	52.33 ± 15.57 ^a
	PM4	0.41 ± 0.03 ^b	0.13 ± 0.06	0.28	0.18		1.01 ± 0.17 ^a	0.36 ± 0.03 ^a	13.67 ± 6.43 ^cd
	PM6	0.35 ± 0.04 ^bc	0.32 ± 0.21	0.03	0.12	0.22	-0.76 ± 0.02 ^d	-0.07 ± 0.04 ^cd	12.00 ± 6.56 ^cd
2015	AM2	0.36 ± 0.03 ^a	0.21 ± 0.10	0.16			0.17 ± 0.14 ^a	0.80 ± 0.17 ^a	29.33 ± 8.33 ^c
	PM2-A	0.25 ± 0.04 ^c	0.27 ± 0.07	-0.02			0.01 ± 0.09 ^ab	0.64 ± 0.18 ^ab	4.33 ± 1.15 ^d
	PM2-B	0.29 ± 0.02 ^b	0.39 ± 0.16	-0.10			-0.04 ± 0.06 ^b	0.25 ± 0.11 ^b	10.67 ± 0.58 ^d
	PM2-C	0.33 ± 0.03 ^ab	0.37 ± 0.15	-0.04			-0.30 ± 0.12 ^d	-0.08 ± 0.04 ^c	8.33 ± 2.31 ^d
	PM2-D	0.36 ± 0.01 ^a	0.31 ± 0.13	0.05			-0.06 ± 0.13 ^b	-0.18 ± 0.11 ^c	80.67 ± 4.04 ^a
	PM4	0.25 ± 0.03 ^b	0.87 ± 0.29	-0.62	-0.08		-0.31 ± 0.06 ^d	-0.07 ± 0.06 ^c	42.26 ± 4.62 ^b
	PM6	0.31 ± 0.01 ^b	0.27 ± 0.14	0.04	-0.02	-0.56	-0.21 ± 0.06 ^bc	0.29 ± 0.06 ^bc	21.67 ± 2.31 ^c
3年平均值 Three years average	AM2	0.80 ± 0.25 ^a	0.74 ± 0.34	0.06			0.03 ± 0.07 ^b	0.27 ± 0.10 ^a	21.33 ± 2.08 ^b
	PM2-A	0.46 ± 0.10 ^b	0.27 ± 0.08	0.19			0.44 ± 0.10 ^a	0.58 ± 0.12 ^a	21.00 ± 10.44 ^b
	PM2-B	0.43 ± 0.07 ^b	0.29 ± 0.17	0.14			0.10 ± 0.23 ^ab	0.15 ± 0.20 ^ab	23.33 ± 10.41 ^b
	PM2-C	0.26 ± 0.03 ^c	0.25 ± 0.12	0.01			0.04 ± 0.10 ^b	-0.20 ± 0.10 ^b	19.33 ± 1.53 ^b
	PM2-D	0.23 ± 0.05 ^c	0.22 ± 0.09	0.01			-0.01 ± 0.08 ^b	-0.21 ± 0.24 ^b	74.67 ± 4.04 ^a
	PM4	0.48 ± 0.01 ^b	0.44 ± 0.12	0.04	0.22		0.52 ± 0.14 ^a	0.61 ± 0.18 ^a	29.67 ± 2.89 ^b
	PM6	0.46 ± 0.04 ^b	0.29 ± 0.13	0.17	0.12	0.02	-0.09 ± 0.12 ^b	0.51 ± 0.14 ^a	28.00 ± 11.53 ^b

年份 Year	处理编号 Treatment number	产量 Yield (kg·m^-2)		超产 Overyielding (kg·m^-2)			超产效应1 Transgressive overyielding effect 1 (OV₁)	超产效应2 Transgressive overyielding effect 2 (OV₂)	豆科产量比 Legume proportion (%)
年份 Year	处理编号 Treatment number	混播处理 Mixed treatment	单播对照 Monoculture control	与单播相比 Difference by monoculture control	与PM2相比 Difference by PM2	与PM4相比 Difference by PM4	超产效应1 Transgressive overyielding effect 1 (OV₁)	超产效应2 Transgressive overyielding effect 2 (OV₂)	豆科产量比 Legume proportion (%)
2013	AM2	1.26 ± 0.11 ^a	1.22 ± 0.37	0.04			0.07 ± 0.14 ^b	0.08 ± 0.05 ^b	12.33 ± 1.52 ^c
	PM2-A	0.70 ± 0.06 ^b	0.39 ± 0.12	0.28			0.77 ± 0.13 ^a	0.92 ± 0.24 ^a	21.67 ± 5.40 ^b
	PM2-B	0.68 ± 0.12 ^b	0.40 ± 0.15	0.28			0.15 ± 0.09 ^b	0.62 ± 0.21 ^ab	27.03 ± 17.02 ^b
	PM2-C	0.28 ± 0.07 ^c	0.22 ± 0.06	0.06			-0.09 ± 0.04 ^c	-0.31 ± 0.17 ^c	34.00 ± 5.53 ^b
	PM2-D	0.28 ± 0.05 ^c	0.24 ± 0.13	0.04			-0.13 ± 0.11 ^c	0.08 ± 0.03 ^b	81.67 ± 3.47 ^a
	PM4	0.73 ± 0.07 ^b	0.31 ± 0.06	0.42	0.42		0.86 ± 0.15 ^a	1.54 ± 0.35 ^a	29.33 ± 3.79 ^b
	PM6	0.63 ± 0.10 ^b	0.28 ± 0.10	0.35	0.32	0.32	0.62 ± 0.15 ^a	1.30 ± 0.24 ^a	32.33 ± 18.13 ^b
2014	AM2	0.75 ± 0.05 ^a	0.79 ± 0.33	-0.04			-0.15 ± 0.06 ^c	-0.06 ± 0.06 ^cd	32.33 ± 1.53 ^b
	PM2-A	0.33 ± 0.01 ^bc	0.14 ± 0.02	0.19			0.55 ± 0.17 ^b	0.19 ± 0.06 ^b	10.00 ± 9.64 ^d
	PM2-B	0.26 ± 0.04 ^cd	0.09 ± 0.03	0.17			0.23 ± 0.13 ^b	0.07 ± 0.03 ^cd	21.33 ± 11.59 ^c
	PM2-C	0.19 ± 0.01 ^d	0.16 ± 0.11	0.03			-0.02 ± 0.01 ^c	-0.15 ± 0.10 ^d	15.67 ± 5.13 ^cd
	PM2-D	0.15 ± 0.03 ^d	0.10 ± 0.07	0.05			0.30 ± 0.12 ^b	0.10 ± 0.02 ^b	52.33 ± 15.57 ^a
	PM4	0.41 ± 0.03 ^b	0.13 ± 0.06	0.28	0.18		1.01 ± 0.17 ^a	0.36 ± 0.03 ^a	13.67 ± 6.43 ^cd
	PM6	0.35 ± 0.04 ^bc	0.32 ± 0.21	0.03	0.12	0.22	-0.76 ± 0.02 ^d	-0.07 ± 0.04 ^cd	12.00 ± 6.56 ^cd
2015	AM2	0.36 ± 0.03 ^a	0.21 ± 0.10	0.16			0.17 ± 0.14 ^a	0.80 ± 0.17 ^a	29.33 ± 8.33 ^c
	PM2-A	0.25 ± 0.04 ^c	0.27 ± 0.07	-0.02			0.01 ± 0.09 ^ab	0.64 ± 0.18 ^ab	4.33 ± 1.15 ^d
	PM2-B	0.29 ± 0.02 ^b	0.39 ± 0.16	-0.10			-0.04 ± 0.06 ^b	0.25 ± 0.11 ^b	10.67 ± 0.58 ^d
	PM2-C	0.33 ± 0.03 ^ab	0.37 ± 0.15	-0.04			-0.30 ± 0.12 ^d	-0.08 ± 0.04 ^c	8.33 ± 2.31 ^d
	PM2-D	0.36 ± 0.01 ^a	0.31 ± 0.13	0.05			-0.06 ± 0.13 ^b	-0.18 ± 0.11 ^c	80.67 ± 4.04 ^a
	PM4	0.25 ± 0.03 ^b	0.87 ± 0.29	-0.62	-0.08		-0.31 ± 0.06 ^d	-0.07 ± 0.06 ^c	42.26 ± 4.62 ^b
	PM6	0.31 ± 0.01 ^b	0.27 ± 0.14	0.04	-0.02	-0.56	-0.21 ± 0.06 ^bc	0.29 ± 0.06 ^bc	21.67 ± 2.31 ^c
3年平均值 Three years average	AM2	0.80 ± 0.25 ^a	0.74 ± 0.34	0.06			0.03 ± 0.07 ^b	0.27 ± 0.10 ^a	21.33 ± 2.08 ^b
	PM2-A	0.46 ± 0.10 ^b	0.27 ± 0.08	0.19			0.44 ± 0.10 ^a	0.58 ± 0.12 ^a	21.00 ± 10.44 ^b
	PM2-B	0.43 ± 0.07 ^b	0.29 ± 0.17	0.14			0.10 ± 0.23 ^ab	0.15 ± 0.20 ^ab	23.33 ± 10.41 ^b
	PM2-C	0.26 ± 0.03 ^c	0.25 ± 0.12	0.01			0.04 ± 0.10 ^b	-0.20 ± 0.10 ^b	19.33 ± 1.53 ^b
	PM2-D	0.23 ± 0.05 ^c	0.22 ± 0.09	0.01			-0.01 ± 0.08 ^b	-0.21 ± 0.24 ^b	74.67 ± 4.04 ^a
	PM4	0.48 ± 0.01 ^b	0.44 ± 0.12	0.04	0.22		0.52 ± 0.14 ^a	0.61 ± 0.18 ^a	29.67 ± 2.89 ^b
	PM6	0.46 ± 0.04 ^b	0.29 ± 0.13	0.17	0.12	0.02	-0.09 ± 0.12 ^b	0.51 ± 0.14 ^a	28.00 ± 11.53 ^b

参数 Parameter	变异来源 Source of variation	自由度 df	均方根 Mean square	F	p
产量 Yield	混播物种 Mixed species	6	0.852	12.756	0.000^**
	混播比例 Mixed proportion	2	0.005	0.080	0.923
	年份 Year	2	18.983	96.640	0.000^**
	混播物种×混播比例 Mixed species × Mixed proportion	9	0.017	0.262	0.994
	混播物种×年份 Mixed species × Year	9	2.746	13.978	0.000^**
	混播比例×年份 Mixed proportion ×Year	4	0.013	0.068	0.991
	混播物种×混播比例×年份 Mixed species × Mixed proportion × Year	12	0.046	0.235	0.996
	误差 Error	171	0.067
	总计 Total	192
互补效应 Complementary effect	混播物种 Mixed species	3	0.665	10.564	0.000^**
	混播比例 Mixed proportion	2	0.030	0.473	0.625
	年份 Year	2	0.285	20.190	0.000^**
	混播物种×混播比例 Mixed species × Mixed proportion	6	0.070	1.106	0.365
	混播物种×年份 Mixed species × Year	6	0.130	9.221	0.000^**
	混播比例×年份 Mixed proportion × Year	4	0.018	1.258	0.295
	混播物种×混播比例×年份 Mixed species × Mixed proportion × Year	12	0.006	0.445	0.939
	误差 Error	96	0.063
	总计 Total	108
选择效应 Selection effect	混播物种 Mixed species	3	1.324	12.407	0.000^**
	混播比例 Mixed proportion	2	0.004	0.035	0.966
	年份 Year	2	0.337	1.148	0.323
	混播物种×混播比例 Mixed species × Mixed proportion	6	0.033	0.313	0.929
	混播物种×年份 Mixed species × Year	6	5.210	17.742	0.000^**
	混播比例×年份 Mixed proportion × Year	4	0.134	0.455	0.768
	混播物种×混播比例×年份 Mixed species × Mixed proportion × Year	12	0.137	0.468	0.927
	误差 Error	96	0.107
	总计 Total	108
多样性净效应 Net effect of biodiversity	混播物种 Mixed species	3	0.143	4.168	0.008^**
	混播比例 Mixed proportion	2	0.022	0.630	0.535
	年份 Year	2	1.405	15.086	0.000^**
	混播物种×混播比例 Mixed species × Mixed proportion	6	0.022	0.637	0.701
	混播物种×年份 Mixed species × Year	6	2.450	26.300	0.000^**
	混播比例×年份 Mixed proportion × Year	4	0.007	0.077	0.989
	混播物种×混播比例×年份 Mixed species × Mixed proportion × Year	12	0.058	0.625	0.815
	误差 Error	96	0.034
	总计 Total	108