370 EXPERIMENTS WITH FERTILISERS [chap. 



of the manures upon the constitution of the plant. At 

 harvest-time cereal plots can either be cut by scythe or 

 a small reaping-machine ; if the plots are large and the 

 paths wide, an ordinary binder can be employed, as is 

 done on the Broadbalk vvheatfield at Rothamsted. As 

 the sheaves are tied they must all be gathered on to 

 the plot from which they were cut, and a distinguishing 

 label may also be tied to each, especially if the plots are 

 small. In some cases threshing is done in the field, but 

 generally in the United Kingdom it will be necessary 

 to carry the unthreshed sheaves to a rick or preferably 

 a barn. To keep the produce of each plot separate 

 until threshing time, a number of squares of thin 

 canvas should be prepared, of a fabric sufficiently open 

 to allow of the freest ventilation but not the passage of 

 any shed corn. The bottom of the stack should begin 

 with some non-experimental corn over which one of the 

 canvas squares is thrown, followed by the produce of one 

 plot together with two wooden tallies by which it can 

 be identified. Another cloth is then spread before the 

 produce of the next plot is stacked, and so on with the 

 other plots. Threshing may be done with a special 

 machine, but the ordinary travelling steam-thresher, if 

 of modern construction, will do all that is required ; at 

 the end of each run the screens must be removed and 

 a little of the straw again put through the machine, 

 so as to work out all the grain, the last pint or so of 

 which must be extracted by hand from the hopper. 

 The grain should be measured out bushel by bushel, and 

 every bushel weighed and recorded ; the tail corn should 

 be weighed as a whole ; the straw and cavings should 

 also be weighed. Hay is best weighed ar» it leaves 

 the field on the way to the stack, and a^ different 

 manures are liable to lead to different rates of drying, 

 it is well to take a weighed sample from each plot of 



