32 EXPERIMENTS UPON WHEAT 



straw crops were taken immediately prior to the first experi- 

 mental crop of wheat sown in the autumn of 1843, so that the 

 land was in low condition from an agricultural point of view at 

 the beginning of the trials. This is also shown by the fact that 

 the first experimental crop in 1844 amounted to only 15 bushels 

 per acre on the unmanured plot, although the wheat crop was 

 generally much above the average in that year. 



The soil of the Broadbalk field consists of a stiff greyish 

 loam containing an abundance of flints ; the subsoil is of a 

 similar character, rather stifi'er and redder in colour — "the clay- 

 with-flints " of the geologist. The chalk lies below at a variable 

 depth, rarely less than 8 or 10 feet, thus providing good 

 natural drainage. In addition, each plot has a tile drain 

 running down the centre of the plot at a depth of 2 to 2h feet, 

 the mouths of all the drains being led into a brick trench, where 

 the water draining from each plot can be separately collected 

 for analysis. 



The field cannot be described as more than fair average 

 wheat land, nor do the analyses show any special reserve of 

 fertility beyond that natural to moderately strong land which 

 has been under arable cultivation for a very long time. 



The usual practice is to scuffle the land immediately after 

 harvest and remove the weeds ; the land is then ploughed 5 or 

 6 inches deep ; the mineral and other autumn -sown manures 

 are sown and harrowed in, after which the seed is drilled. The 

 following varieties of seed have been used : Old Red Lammas, 

 five years, 1843-4 to 1847-8; Red Cluster, four years, 1848-9 to 

 1851-2; Red Rostock, twenty-nine years, 1852-3 to 1880-1; 

 Club or Square Head (Red), eighteen years, 1881-2 to 1898-9 ; 

 and Square Head's Master (Red), in 1899-1900 and since. 



The chief difficulty experienced in growing wheat con- 

 tinuously is that of keeping the land clean ; not only does the 

 crop occupy the ground for the greater part of the year, and so 

 leave little opportunity for cleaning operations, but the weeds 

 whose habit of growth is favoured by the crop tend to 

 accumulate from year to year. Thus in spite of repeated hand- 



