The effect of cultivation technique on root and shoot biomass production by young Sitka spruce (Picea sitchensis (Bong.) Carr.) trees on surface water gley soils

In Ireland much of the land available for plantation establishment requires some degree of soil cultivation and drainage to improve its suitability fo r tree growth. The method of cultivation and drainage normally varies depen ding upon the soil type and its drainage characteristics. Little research h as been carried out on the impact of practices such as mounding and mole dr ainage upon rooting and biomass production in young crops. The research rep orted in this paper was carried out on four sites where the general soil ty pe was surface water gley. Three of the sites studied were afforestations o n old farmland, while the fourth site was a reforestation of a windblown st and. The cultivation methods investigated included mounding, mole drainage with mounds, mole drainage only and ripping. Sitka spruce trees ranging in age from five to thirty years were excavated from these experimental sites to describe the impact of different soil cultivation techniques upon root a rchitecture and above and below ground biomass production. The results show ed that while the effect of mound drainage upon water table level varied fr om site to site, the establishment of trees on mounds led to an increase in above and below ground biomass production. Mole drainage of these sites wi thout mounds, did not lead to any increase in root or shoot development whe n compared with trees growing on uncultivated/undrained ground.