Table 2: Summary of repeated measurements analysis of variance of cumulative yield using restricted maximum likelihood with autoregressive correlations.

Number of years (d.f.) -value years -value subsystems -value interaction

2 5.22*†3.92**0.23 n.s.
3 9.10**17.44***0.64 n.s.
4 7.25***42.18***0.58 n.s.
5 50.05***71.05***1.83**
6 62.08***79.62***2.25**
7 66.12***80.84***3.56**
8 77.96***79.55***3.87**

Values followed by *, **, *** are significantly different at the 5, 1, and 0.1% level of probability, respectively; n.s., not significant.