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Which efficiency term int he yield potential equation is almost 1 for full/unstressed crop canopies? -
interception efficiency
Based on the information shown in class, which efficiency term In the Monteith equation is smallest
relative to its theoretical maximum for most crops? - Conversion efficiency
Based on the information shown in class, which efficiency term in the Monteith equation would give the
biggest increase to yield potential if it were increase by 0.01? - conversion efficiency
The link below contains a spread sheet with data on wheat yields in the Netherlands downloaded from
the FAO website. I have applied linear regressions (fits) to the data and split the data into three different
time ranges: 1961-1990, 1990-2013 and 1961-2013 and fit a linear regression for each time range. How
do the slopes for these three linear regressions compare?
The spreadsheet I showed in class is available at the link below.
(https://docs.google.com/spreadsheets/d/1lBySKjsjuHMJxVwEj7C0M5nnup2EfUcRNySJ
dF07efI/edit#gid=1428153391) - The slopes were different, 1960-1991 is the steepest meaning fast rate
of yield increase, and 1990-2013 is flattest, meaning slowest rate of yield increase
Think about the question described above. Can splitting the yield data into different time ranges
influence the conclusion you make about how wheat yield in the Netherlands are changing with time? -
Yes, the range of Tims examined can influence the conclusion drawn. Assuming the 1960-2013 slope
would over estimate yield estimates for 2030.
How much water (mm) would be required for a crop with a water use efficiency of 1x10^-3kg m^-2
mm^-1 to achieve a yield of 1 kg m^-2?(Hint: solve the water limited yield potential equation for the
water available term) - 1000 mm
How would the water requirement compare to if we doubled the water use efficiency? - 1/2 the original
What global average crop yield (kg m^-2) is needed to achieve 8.2 x 10^9 MT of total crop production on
the 15x10^6km^2 of land currently under crop production. To calculate your answer first convert the
crop production target in (kg) (Hint: 1 MT = 1000 kg) - 8.2 x 10^12 kg, 1.5 x 10^13 m^2