436 



Trials of New Varieties of Cereals. 



[Aug., 



shown how very rapidly the rate of growth of maize falls off 

 above a certain temperature. Until we have similar information 

 for such crops as the oat and the swede, which are often injured 

 by heat, we are not able to interpret the effects of Temperature 

 records. 



It is the same with rainfall. In certain parts of the country 

 the average weekly rainfall is believed to be near an optimum 

 for oats, but it is not known exactly how near in any particular 

 locality. In East Anglia, for instance, as Mr. Hooker has shown, 

 the spring rainfall is below the optimum, so that there is a 

 marked positive correlation between rainfall and yield from the 

 13th to the 28th week in each year. No similar correlation has 

 been found in Scotland, presumably because there the average 

 rainfall is near the optimum. 



There is need of a study of the requirements of 

 various crops as regards water, temperature and sunshine. 

 Such study must include comparative investigation of 

 soils. It is not enough to ascertain the quantity of water which 

 a plant will require in the normal temperature and sunshine of 

 a given district; we must also know what quantity of water 

 typical soils, differently cultivated, can provide. Such informa- 

 tion has hitherto only been available from the Rothamsted drain 

 gauges ; now that these have also been installed in Aberdeen data 

 from a new district will be available. 



The Committee is convinced that a scheme of observations and 

 records, such as is outlined above, would greatly increase the 

 general interest in the question. For practical farmers it would 

 have an effect comparable to that of a sound system of book- 

 keeping on the financial side of their calling — the effect of co- 

 ordinating and articulating the very considerable fund of 

 knowledge of weather and crops, which, though vaguely and 

 almost unconsciously, is already theirs. 



****** 



TRIALS OF NEW VARIETIES OF 

 CEREALS. 



PART II. 

 E. S. Beaven, 



Member of Council, National Institute of Agricultural Botany. 



Part I of this Paper dealt with the subject of variety testing 

 in general and the present part deals with a method designed 

 to reduce the probable error of the results of trials of new races. 



