Influence of soil water on plant growth under controlled conditions
2 North Wyke Research, Okehampton, UK
P 1.4 in Ecosystem Function
The amount of soil water has an influence on several soil properties like pH, oxygen availability. Within a long term field experiment on drained vs. undrained plots from the Rowden experiment (North Wyke, Okehampton, UK) the soil profile reveals significant influences of the different water levels in the soil. Additionally, the plant community changed in the undrained plots towards less water-adopted plants like Juncus effusus towards grasses adopted to various conditions like Lolium perenne. Within a laboratory experiment we want to obtain information on the influence of different water levels (differing by 20-30% of WHC) on the quality of the plant biomass (C-, N-, and lipid contents) as well as carbon and lipid incorporation and stabilization in soils. Therefore, Lolium perenne was grown on loess under controlled conditions for two months. Nutrition was performed by adding identical amounts of a modified Hoagland nutrition solution daily, added by de-ionized water to adjust the different water levels. First results indicate an improved quality of the biomass kept at high water level as determined by chlorophyll measurements especially for young plants, whereas the difference is absent for mature plants. A higher water demand of the high water table plants is not related to the high soil water content, but to an improved plant growth.