Table 2.

Linear mixed effects model for annual yield, above ground biomass, below ground biomass, below ground allocation and leaf area for the four willow varieties over two rotations, testing for the effects of genotype, site, sampling date and any interactions therein. Significance levels were set at P < 0.05 and n.s is not-significant. Annual yield data is from a single time point so sampling date was not included in the analysis (n/a).

Rotation 1	Annual yield		Above ground biomass		Below ground biomass		Below ground allocation		Leaf area
	n	P	n	P	n	P	n	P	n	P
Genotype	4	n.s	4	<0.001	4	<0.001	4	<0.001	4	<0.001
Site	2	n.s	2	n.s	2	<0.05	2	<0.05	2	<0.01
Date	–	n/a	11	<0.001	11	<0.001	11	<0.001	8	<0.001
Genotype × site	8	n.s	8	<0.05	8	<0.05	8	n.s	8	<0.01
Genotype × date	–	n/a	44	n.s	44	n.s	44	n.s	32	n.s
Site × date	–	n/a	22	<0.001	22	<0.001	22	<0.001	16	<0.001
Genotype × site × date	–	n/a	88	n.s	88	n.s	88	n.s	64	n.s

Rotation 2	Annual yield		Above ground biomass		Below ground biomass		Below ground allocation		Leaf area
	n	P	n	P	n	P	n	P	n	P
Genotype	4	<0.001	4	<0.001	4	<0.001	4	<0.01	4	<0.001
Site	2	<0.001	2	<0.001	2	<0.01	2	<0.001	2	n.s
Date	–	n/a	4	<0.001	4	<0.001	4	<0.001	2	<0.001
Genotype × site	8	n.s	8	n.s	8	<0.01	8	n.s	8	n.s
Genotype × date	–	n/a	16	n.s	16	n.s	16	n.s	8	n.s
Site × date	–	n/a	8	<0.01	8	n.s	8	n.s	4	n.s
Genotype × site × date	–	n/a	32	n.s	32	n.s	32	n.s	16	n.s