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A comparison of evapotranspiration and energy balance closure between perennial Kernza and annual rapeseed in southern Sweden

Purnomo, Joakim Samuel LU (2025) In Student thesis series INES NGEK01 20251
Dept of Physical Geography and Ecosystem Science
Abstract
Approximately 80% of agricultural land in the world is comprised of annual crops which have a life span of only one year. Research has shown that these crops are unsustainable because of these short life spans. Soil erosion, nutrient leaching, and losses of soil carbon are just a few problems caused by annual monocultures. Additionally, with the changing climate, these cropping methods are both vulnerable and contributing to the problem. Perennial agriculture is a proposed mean of mitigating these negative effects. Kernza is a novel perennial wheatgrass (Thinopyrum intermedium) being developed in the USA, a major difference from annual counterparts being a much more extensive underground structure.
This thesis aimed to compare the... (More)
Approximately 80% of agricultural land in the world is comprised of annual crops which have a life span of only one year. Research has shown that these crops are unsustainable because of these short life spans. Soil erosion, nutrient leaching, and losses of soil carbon are just a few problems caused by annual monocultures. Additionally, with the changing climate, these cropping methods are both vulnerable and contributing to the problem. Perennial agriculture is a proposed mean of mitigating these negative effects. Kernza is a novel perennial wheatgrass (Thinopyrum intermedium) being developed in the USA, a major difference from annual counterparts being a much more extensive underground structure.
This thesis aimed to compare the evapotranspiration (ET) and energy balance closure, two major indicators of the characteristics of a crop, of Kernza with annual rapeseed (Brassica napus) as the control crop. The measurements of this study were of a Kernza field and control field over a period of 13 months, from seeding to post-harvest and the reseeding of the control field. The results showed that Kernza had a lower ET than the control but was able to maintain its high ET for longer, especially after harvest where the ET of the control field sharply fell, indicating that Kernza was still transpiring after harvest. Additionally, Kernza was found to have a lower energy balance closure until harvest. Implying that Kernza had a greater ability to absorb energy than the control.
The year-round cover provided by Kernza would provide more stable and consistent surface-to-atmosphere exchanges, and possibly, if widespread adoption of perennial crops occurs, contribute to the mitigation of climate extremes. This was shown by the Kernza field maintaining its ET and surface energy storage more effectively than the rapeseed field post-harvest. (Less)
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author
Purnomo, Joakim Samuel LU
supervisor
organization
course
NGEK01 20251
year
type
M2 - Bachelor Degree
subject
keywords
Energy Balance, Perennial, Agriculture, Kernza, Intermediate Wheatgrass, Evapotranspiration
publication/series
Student thesis series INES
report number
705
language
English
id
9201462
date added to LUP
2025-06-17 15:48:52
date last changed
2025-06-17 15:48:52
@misc{9201462,
  abstract     = {{Approximately 80% of agricultural land in the world is comprised of annual crops which have a life span of only one year. Research has shown that these crops are unsustainable because of these short life spans. Soil erosion, nutrient leaching, and losses of soil carbon are just a few problems caused by annual monocultures. Additionally, with the changing climate, these cropping methods are both vulnerable and contributing to the problem. Perennial agriculture is a proposed mean of mitigating these negative effects. Kernza is a novel perennial wheatgrass (Thinopyrum intermedium) being developed in the USA, a major difference from annual counterparts being a much more extensive underground structure. 
This thesis aimed to compare the evapotranspiration (ET) and energy balance closure, two major indicators of the characteristics of a crop, of Kernza with annual rapeseed (Brassica napus) as the control crop. The measurements of this study were of a Kernza field and control field over a period of 13 months, from seeding to post-harvest and the reseeding of the control field. The results showed that Kernza had a lower ET than the control but was able to maintain its high ET for longer, especially after harvest where the ET of the control field sharply fell, indicating that Kernza was still transpiring after harvest. Additionally, Kernza was found to have a lower energy balance closure until harvest. Implying that Kernza had a greater ability to absorb energy than the control. 
The year-round cover provided by Kernza would provide more stable and consistent surface-to-atmosphere exchanges, and possibly, if widespread adoption of perennial crops occurs, contribute to the mitigation of climate extremes. This was shown by the Kernza field maintaining its ET and surface energy storage more effectively than the rapeseed field post-harvest.}},
  author       = {{Purnomo, Joakim Samuel}},
  language     = {{eng}},
  note         = {{Student Paper}},
  series       = {{Student thesis series INES}},
  title        = {{A comparison of evapotranspiration and energy balance closure between perennial Kernza and annual rapeseed in southern Sweden}},
  year         = {{2025}},
}