271 
table, there results an apparent confirmation of our view that the 
radiation during the flowering and ripening phases has an important, 
direct influence; in fact, the diminution of the average sunshine from 
4,284 to 3,827 actinometric degrees has been accompanied by a 
diminution of the crop from 25.9 to 20.4 hectoliters per hectare. 
This diminution of 25 per cent of the crop corresponds to a loss of 
about 1.2 hectoliters per hectare, or 4 per cent of the normal crop, 
for every 100 actinometric degrees. 
We have already seen that if we suppose the same number of stalks 
to the hectare and the same relative total sum of solid nutriment 
taken from the soil by each stalk, then, according to theory, the radia- 
tion can serve as a measure of the possible work of assimilation by the 
plant, and consequently of the actual sum total of the assimilated 
material. These conditions are never completely realized for many 
reasons, and one can not hope for an exact relation between the crop 
and the radiation, but it is interesting to see that the above-reported 
crops, both in detail and general averages, confirm the theory. 
Some of the minor departures from perfect agreement are ex- 
plained by a detailed examination of the conditions during the suc- 
cessive phases of germination, heading, flowering, and ripening 
during the good years and the poor years. The following table gives 
the average climatic conditions during the first three phases and 
shows that as between the good and bad years there can have been 
but shght average differences in the condition of the stalks and the 
embryo seeds up to the beginning of the ripening stage, as far as it 
depends on climatic conditions. 
Comparison of climates during five good and four poor years. 
Stage. yoate. youre 
Germinating period: 
UTR blO Mesa ae ae ee te oe ee ee er WR Rs SUS ek Ce days._| 28 23 
IPO OZATI SE WEB UNG Dp x sac note ae Naas eee ee ES a ee Sons ee days_-_| 11.6 9.0 
AVOLAZS MINIMUM beMperatures.=-2-. 2s. 220252222 =. fae te °C__|— 4.66 |— 3.7 
Raintalldurineithe:period |) 2-82 S20 2 se 22 cee edn =k millimeters__| 9.4 11.6 
Heading period: 
[DEERE UTR ca gc ae days__| 114 113 
IReDZIN Wea therwen aa nent Seek a le SO ASE RSS ANN EGER TEE LE days..| 5.7 6.1 
Average of the minimum temperatures _______- See Se eee Sw °C__|— 1.7 |= 21 
' Averczge temperature at the epoch of heading. ______- See ee See eee Oa aKa 9.7 
" Average rainfall at the epoch of heading __-_.________________.. millimeters__| 14.8 22.1 
Flowering period: 
DYES OI cases SSeS ne ee pee eRe days..| 75 80 
Mean daily temperature at the epoch of flowering _______-_______-________- Case 16:3 16.3 
Average rainfall at the epoch of flowering_______....____....-..-millimeters__| 26.3 31.6 
Average radiation during this period___._-_-_________. Actinometric degrees__| 2,826 2,525 
Ripening period: | 
Average radiation during this period__..._____________ Actinometric degrees._| 1,458 1,302 
