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On the Influence of Soil Temperature on the Germination Interval of Crops

Published online by Cambridge University Press:  27 March 2009

J. O. Irwin
J. O. Irwin
Affiliation:
Statistical Dept., Rothamsted Experimental Station, Harpenden, Herts
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Extract

The data collected under the Agricultural Meteorological Scheme of the Ministry of Agriculture have provided information for a number of years in a number of places on the dates of sowing and appearance above ground of wheat, winter oats, spring oats, spring barley, turnips and swedes.

Type
Research Article
Information
The Journal of Agricultural Science , Volume 21 , Issue 2 , April 1931 , pp. 241 - 250
Copyright
Copyright © Cambridge University Press 1931

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References

1 For each crop in each year, the variance in interval between sowing and appearance above ground was analysed into portions due to differences between varieties and differences within varieties. Of twenty-three cases so examined there were fifteen in which there was no significant difference between the variances within and between varieties, four cases in which the variance between varieties was significantly lower than that within, and four in which it was significantly higher. The four cases in which the variance between varieties was significantly higher were

(1) Winter oats, 1924–5. Here an examination showed that the higher variance between varieties was due to one variety, Potato—Victory grown at Craibstone only.

This variety gave an interval of 15 days between sowing and appearance above ground, the mean value for all the other varieties being between 20 and 24 days.

(2) Turnips, 1924–5. Here two varieties, Aberdeen Green Top and Aberdeen Bullock Yellow, gave a mean interval of 6 or 7 days and the other two, Favourite Purple and Top Aberdeen, grown at Cockle Park only, gave an interval of 24 days, an undoubtedly significant difference.

(3) Spring oats, 1927. Here an examination showed that the higher variance between varieties was due to two varieties, Svälof Victory and Swedish King, grown at Rothamsted only. For these two the intervals were respectively 35 and 38 days, all the others being between 14 and 26 days.

(4) Swedes, 1928. Here out of ten varietal means all were between 10 and 14 days, except Lord Derby grown only at Aber, Model grown only at Wye and Caledonian grown only at Cockle Park. These gave intervals of 6, 7 and 17 days respectively.

Of these Model and Caledonian were grown in 1927 and 1926 when the interval was not outstandingly different from the average.

There was almost certainly a tendency for reporters to report different varieties sown in the same place on the same day as appearing above ground on the same day, whether this was strictly true or not, and this is very probably the explanation of the four cases in which the variance between varieties was significantly lower than that within; it is probable also that for this reason the variance between varieties is too low in other cases. But, although the variance is too low, there is no reason to suppose that the mean values are biased and this is the justification of the use of the data for the present purpose.

So as to maintain the apparent homogeneity of the material, the varieties which caused the varietal differences in cases (1), (2), (3) and (4) just mentioned have been omitted from the investigation.

This would in any case have been necessary in cases (1) and (2) because the corresponding soil temperature data were not available. For turnips there are in any case insufficient data for working out correlations.