Sustainable Agriculture Literature Review - Boulder County

! ! !!
"#$%&!'())! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! )=!>1.;#-2!
Summary
!
1. Climate
The climate in Boulder County determines to a great extent which crops can grow
efficiently in the local agricultural ecosystem due to precipitation, temperature, and wind
constraints. Overall, the climate in Boulder County is characterized by low annual
precipitation, strong temperature variations, and periods of drought. Temperatures range
from an average daily maximum of 64.3° F and average daily minimum of 38.2° F with
extremes reaching -15° F to 115° F. The growing season averages about 140 days
annually for Northeastern Colorado, with the average period of frost-free days occurring
between May 3 rd to October 2 nd (Boulder) and May 8 th to October 2 nd (Longmont).
Without the presence of a large body of water nearby, precipitation is generally light with
about 15-18 inches of rainfall annually. Of this precipitation, about seventy to eighty
percent falls between the months of April and September. During lower precipitation
years Boulder County is heavily dependent upon snowmelt from the Rocky Mountains to
feed the local network of ditches, rivers, lakes, and reservoirs for both irrigation and
power. The area has experienced eight periods of drought since 1930, with an average
of one significant drought every 9.34 years.
!
Colorado is expected to see the affects of human induced climate change in the coming
decades. In this report, the implications of climate change for agriculture are focused on
two main areas; (1) the potential impacts to the local climate and weather patterns and
the associated impacts to agriculture in the area and (2) the role of land use in mitigation
efforts to reduce greenhouse gas (GHG) emissions and atmospheric concentrations of
carbon.
Climate change has already begun to affect agricultural ecosystems across the Western
U.S., directly impacting the types of crops that can be grown and indirectly impacting
biodiversity and the prevalence of invasive species. The main impacts expected are an
increase in both the average temperature and occurrence of extreme weather events
(heat waves, intense hail, strong thunderstorms, etc.). Periods with decreased
precipitation are also expected, which will likely increase competition with other sectors
for water resources as well as reliance on the storage capacity of lakes and reservoirs.
As the climate continues to change, agriculture in Boulder County will experience both
positive and negative impacts. For example, a low or gradual increase in the level of
carbon dioxide (CO2) and average temperature may bring a positive response in overall
growth of crops, but will likely negatively impact the yields of crops such as corn, wheat,
sorghum, and beans due to a shorter grain filling time. The challenge for agriculture will
be to adapt to these changes fast enough to protect productivity, while working to shift
production practices to reduce agricultural greenhouse gas emissions.
"*"
!*+,-#./#012!34$.%+1-+$2!
5.-2$#-+$2!627.28!