Results of the mixed-effects model analysis of the effect of the water table depth on total aboveground biomass production on sand and loam soils in 1952 and 1953.

<p>Note that there is little evidence for limitation of production by water: no drought was imposed. On the contrary, in 1953 there may have been some water logging on the loam since conditions were more productive as depth to the water table increased. The lines are slopes from the mixed-effects model with their 95% confidence intervals (shaded).