THE PRODUCTIVE TOWER OF LAXD VARIES. 193 



Continiioiis drought, before or during sprouting time, 

 produces the opposite effect ; the store of formative mat- 

 ter accumuhxted in the roots is used in ftir greater propor- 

 tion for tlie production of seed, and the relation of straw 

 to corn is smaller than it would be in ordinary weather. 



When all these circumstances are taken into account, 

 the consideration of the produce obtained from unmanured 

 fields in the Saxon experiments will leave only a few 

 general points for further investigation. 



The tabular statement of the result shows that each 

 field has a power of production peculiar to itself, and 

 that no two of them have produced the same amount of 

 rye corn and straw, or potatoes, or oats and straw, or 

 clover. 



If we compare the numberless manuring experiments 

 of the last few years, in which the crops obtained from 

 unmanured plots were Hkewise taken into account, we 

 see that this is a general rule admitting of no exception : 

 no two fields have exactly the same productive power ; 

 nay, there are not even two plots in the same field which 

 are identical in this respect. We need only look at a 

 turnip field to see at once that every turnip differs in 

 size and weight from the one growing next to it. This 

 fact is so universally known and admitted, that in all 

 countries where the land is taxed, the amount of the 

 impost is assessed according to the quality of the soil, in 

 some countries in eight classes, in others in twelve or 

 sixteen. 



Since, then, no two fields are alike in productive power, 

 and every field must necessarily contam the conditions 

 required for the production of the crops which it yields, 

 it is clear that the conditions for the production of corn 

 and straw, or of turnips and potatoes, or of clover or any 

 other plant, are in no two fields alike : in one field the 

 



