Richard K. Sutton
Date of this Version
Zhuqing Xu. (2017). Patch seeding on an extensive green roof: Initial experiment on microclimate impacts. Master’s Thesis, UN-Lincoln.
The green roof provides not only aesthetic values but also many ecological benefits. In North America, seeding or reseeding with native species becomes increasingly popular as a result of its high efficacy and low cost. The extreme temperature and a lack of water on the green roof impose restrictions on seeds germination that determines the success of a seeding program.
The study started on June 1 and was completed by July 15. Five Great Plains native species were hand-seeded in two blocks on Larson Building green roof, along with two blocks set up in the greenhouse at University of Nebraska-Lincoln East Campus for comparison. A 5 x 5 Latin Square was randomized in each block and the germination percentage for every three seeds was the experimental unit. Daily, mid-day values of a suite of microclimate variables were measured and recorded in the greenhouse and on the green roof.
Germination results were better overall in the greenhouse than those on the green roof, except two warm-season species, Liatris squarrosa and Eragrostis spectablis. The two blocks on the green roof differed with little germination in the near building plot and the significant difference for environmental variables suggested a heterogeneous environment on this green roof. Germination difference was attributed to solar radiation energy driving extreme temperature along with large quantity of water loss which inhibited the seeds’ germination or even killed the seeds. The extra energy was largely caused by light reflection and thermal transmission from the adjacent buildings.
Advisor: Richard Sutton