292 



Journal of Agricultural Research 



Vol. XIX, No. 7 



These data are, furthermore, of particular interest since they consist 

 of the records of yields for three successive years of the same crop on a 

 series of unirrigated plots in a region where crop production is subject 

 to many uncertainties because of inadequate rainfall. 



Fortunately for our present purposes the meteorological conditions 

 during the three years covered by this experiment were very different 

 from year to year. The values of the most significant factor, the July 

 to October rainfall, are given in Table I. This shows that the rainfall in 

 1906 was practically twice as heavy as in either of the other two years.^ 



Table I. — Rainfall at Hehbel, near Bangalore, Mysore State, India 



July 



August 



September. 

 October. . . . 



Total 



Inches. 

 1.77 



6-75 

 1.47 



5-76 



15-75 



1906 



Inches. 

 7.09 

 9.98 

 5-50 

 8.51 



31.08 



Inches. 

 4.17 

 1.50 



5.66 



12. 14 



Average of 

 10 years. 



Inches. 

 3-04 

 4-32 

 8.14 



5-97 



21.47 



Maps of the fields are given in the sixth annual report for 1904- 1905. 

 Further descriptive detail is given in the seventh, eighth, and ninth 

 reports for 1905-1908. The yield of grain and straw in plots of i/io 

 acre grown in 1905 is given in the seventh report. The eighth report 

 gives detail of the crop of 1906 but does not contain the yields, which 

 are summarized for the years 1905, 1906, and 1907 in Tables I and II 

 of the ninth report. 



Unfortunately the yields of a considerable number of the plots have 

 had to be omitted from maps I and II of Lehmann's report. In com- 

 bining in a 2 by 2 fold manner it is necessary either to disregard all com- 

 bination plots in which there are not four ultimate plots or to weight 

 properly in using those containing 2 or 3 plots only. The course followed 

 has been to group the plots by fours and to determine the correlation by 

 the formulae for a variable number of plots when all of the ultimate 

 plots were not planted. 



The following table shows the correlation between the yield of grain, 

 of straw, and of grain and straw: 



1906 



Grain 



Straw 



Total yield . 



3- 735 ±o- 031 

 .424± .055 



•4i5± -055 



3. 138 ±0.065 



. i64± . 065 

 . 145 ± -065 



o. 7i6±o. 032 



.573± -045 

 .636± . 040 



1 A discussion of the grow'th of these crops in relation to the distribution of the rainfall appears in Leh- 

 mann's ninth report {i2, p. 2-7). 



