This paper reports the impacts of 5 years of factorial experimental manipulations of soil nutrients, water availability, and deer exclusion on plant community production, species richness and composition of an old field meadow ecosystem in Eastern Ontario, Canada. We recently discovered a fundamental error in our calculation of the soil texture data that does not affect the overall broad conclusions of the paper, but does influence our interpretation of the results from one of the watering treatments. In essence, the description of the overall soil texture at the site in the Discussion Section 4.1 is incorrect. The soil is in fact a ‘sandy-loam’ (based on USDA texture categorisation) with 57% sand and 8% clay (− not 45% sand and 15% clay as originally indicated in the paper), and there is considerable heterogeneity across the experimental field with some of the 240 experimental plots now characterised as ‘loamy-sand’ and others as ‘clay-loam’ (USDA). The correct texture data for our site is available as Appendix S1.
We reanalysed all the statistical models that included plot soil texture as a covariate and found no substantial changes in the conclusions. For example, soil texture is still a critical determinant of soil moisture through the growing season (Appendix S6), but not a statistically significant covariate explaining aboveground biomass (Appendix S7). However, the texture correction is important because the Warm Summer Continental Climate’ (Koppen classification Dfb) of this region results in very dry soils from early to mid-summer that we predicted would cause plant growth to be limited by soil water availability. Hence, we had hypothesized that our weekly water additions through the summer would substantially enhance plant biomass. The revelation that the soil is particularly sandy – and therefore has an innately low capacity to hold and supply water to plants – means that the causal interpretation we offered in the Discussion to explain the absence of a water addition treatment effect on plant biomass is now even better supported.