Blog entry 1:
What is the impact of a higher interception on evapotranspiration and
the final water use? Is interception diminishable?
Due to
climate change and therefore rising temperature, water is going to be more and
more the limited factor for plant growth. This urges people to be more
sensitive at dealing with water. By minimising transpiration and evaporation water loss is getting
reduced a lot. Another way to deal with that problem is to decrease the runoff (Prosdocimi
et al., 2016). However, up to half of the water
loss is on the account of the evaporation from water of wet canopy (van
Dijk et al., 2015). To reduce this interception loss, plantations
in Japan get thinned because, according to Tsukamoto, 1998 and Kuraji, 2003, found
in Shinohara
et al. 2015, the repellency of precipitation
and therefore the interception of unthinned plantations is higher. This causes
reduced runoff on a short-term and water loss. Furthermore, drops falling from
canopy cause often more soil erosion than open rainfall as a result of their
higher kinetic energy (Zhou et al., 2002 and Nanko et al., 2004
found in Shinohara et al., 2015). These drops disaggregate the soil
structure which leads to a lower infiltration rate and therefore to more runoff
on a long-term and a higher evaporation rate.
The tree
nursery Zulauf Ag irrigates its plants with water from a pont. This water flues
back into the pont again. Despite of this sophisticated circulation, the tree
nursery needs to buy a lot of additional water. An option to decrease the amount
of bought water could be to diminish the amount of evaporation of Intercepted
water. This leads to the following questions:
Is
interception at the tree nursery Zulauf Ag measureable? Does a higher
interception loss make a big difference to water? Is there an opportunity to
reduce interception at Zulauf Ag?
Prosdocimi,
M., Jordán, A., Tarolli, P., Keesstra, S., Novara, A., & Cerdà, A. (2016).
The immediate effectiveness of barley straw mulch in reducing soil erodibility
and surface runoff generation in Mediterranean vineyards. The Science of the
Total Environment, 547, 323–30.
http://doi.org/10.1016/j.scitotenv.2015.12.076
Shinohara, Y.,
Levia, D. F., Komatsu, H., Nogata, M., & Otsuki, K. (2015). Comparative
modeling of the effects of intensive thinning on canopy interception loss in a
Japanese cedar (Cryptomeria japonica D. Don) forest of western Japan. Agricultural
and Forest Meteorology, 214-215, 148–156.
http://doi.org/10.1016/j.agrformet.2015.08.257
van Dijk, A.
I. J. M., Gash, J. H., van Gorsel, E., Blanken, P. D., Cescatti, A., Emmel, C.,
… Wohlfahrt, G. (2015). Rainfall interception and the coupled surface water and
energy balance. Agricultural and Forest Meteorology, 214-215, 402–415.
http://doi.org/10.1016/j.agrformet.2015.09.006
Dieser Kommentar wurde vom Autor entfernt.
AntwortenLöschenThe idea of reducing interception is quite innovative and problem focused. Stewart (1977) documented after a measurement in Pine forests: “The average rate of evaporation of intercepted precipitation has been found to be three times the average rate of transpiration.”
AntwortenLöschenSo one of your questions can already be answered: A higher interception loss certainly makes a big difference to the water cycle. A response to your third question could be as follows: Yes, if you replace the overhead sprinkler irrigation with other methods, or at least minimize the use of these overhead sprinklers.
Still remains the big question remains, how can we measure the interception at the tree nursery Zulauf AG? It might be an idea to compare the amount of used water by irrigation during a period with the amount of throughfall or stemflow on the floor (Helvey & Patric, 1965). In the extrapolation, we should take into account that the interception is plant specific.
The impact of the interception is an important factor, if we want to describe the whole water balance of the tree nursery Zulauf AG.
Helvey, J. D., Patric, J. H., (1965). Canopy and litter interception of rainfall by hardwoods of Eastern United States. Water Resources Research 1 (2), 193–206.
Stewart, J. B. (1977). Evaporation from the wet canopy of a pine forest, Water Resources Research, 13(6), 915–921.
Dear Christoph,
AntwortenLöschenyou found an interesting topic by dealing with interception. Especially your research question if interception is measurable in the tree nursery fascinates me.
It is clear that less plants (therefor surface) per ground area leads to less interception and maybe erosion but think about the limit of this issue: Down from a certain number of plants surface runoff and soil erosion would increase dramatically. Furthermore from the view of a plant, the amount of intercepted water makes hardly any difference because that water is not available for the roots anyway. As you know it is all about the water in the soil.
You wrote about „an option to decrease the amount of bought water could be to diminish the amount of evaporation of intercepted water” - but how could that work in a tree nursery? In my opinion only climatic factors such as radiation, heat, humidity and wind determine the evaporation so there is only one way to decrease the water loss by interception: You have to reduce the number of plants and plant cover. Therefore the tree nursery had to offer less plants in order to get a fewer interception amount. That is slightly unworkable for the company. Additionally the entire ground of the Zulauf AG is sealed and less interception primarily leads to more surface runoff instead of soil infiltration.
Unfortunately, you do not write about possible methods to measure interception. It would have been interesting to read about your considerations.
In view of the formal requirements you worked quite well. By the way, be aware of spelling mistakes like “pont” or the use of capital or small letters like “Intercepted water” or “Zulauf Ag”. What I am missing is the reference of your statement about climate change and the full reference of “van Dijk et. al”. Furthermore from a scientific view it is usual to refer to the original articles (Tsukamoto, 1998 and Kuraji, 2003) not the article you read about that referred articles.
I am looking forward to reading more from your research project!
Björn Fuhrer (2-RW-fuhrebjo)
You looking at interception in a very general way, what is good as a starting point. Consequently your research questions are quite ambitious. For the problem of the water balance in the tree nursery the interception of different groups of plant species are of mayor importance. To have good strategies to measure it will be a challenge; your next posts. It is nice, if you additionally have ideas how to diminish interception, but I think there will not be enough time to test them in the project week.
AntwortenLöschenDon’t give up your research questions even if Luzi is a bit suspicious. Your questions are quite interesting especially the third. I can imagine that there are some ways to reduce interception. Maybe the style a plant is cut could make different. Or some species should be grown under a roof because they have a bigger amount of interception than others. Or the Zulauf AG looking forward to selling smaller plants to have less water losses through interception. I’m sure you will have some ideas.
AntwortenLöschenSommesa and 2-RW-fuhrebjo about sum up what I would have to write about this article.
AntwortenLöschenWhat interessts me most is the way to measure interception in the comentar by somesa. to compare such to irregation systems, whole sections would be needed with the same plants but with different irregaton system to be able to compare all needed parameter, especially out-flow, as we can only measure it in the gutter at the bottom of a field
@panellusstypticus
AntwortenLöschenWe might have to estimate, when we extrapolate, with all the different plant species. But we could get an idea about the quantity of interception with the help of a plastic sheet, which we could lay out on the ground, where the throughfall or stemflow will be collected and then compared with the used water for irrigation. I am aware that the result won't be more than an estimate.