160 Some Experiments on the Growth of Potatoes, 



the leaves occupy but an inconsiderable proportion of such a space ; 

 where the produce is greater, but still less than in closer cultivation, 

 it is connected with a more vigorous growth ; if the produce is in 

 both cases nearly equal, it takes place among kinds that, although 

 vigorous growers, are less so than many others, and appear to have 

 the power of adapting themselves to circumstances ; but that when 

 the produce is materially in favour of very wide, instead of closer 

 culture, the varieties are so rank and coarse in their growth as in 

 the latter case to choke each other up. 



Hence it is to be inferred that, in eighteen cases in twenty, in the 

 first experiment now detailed, the distance allowed by Mr. Knight 

 for cultivation was too great, and that, if in those cases a greater 

 number of plants had been put in four feet square (the number to 

 be determined by the habits of the variety) the produce per acre 

 would not only have been materially increased but that such a result 

 would have been obtained at a considerable saving of the number 

 and weight of tubers planted. This will appear clear from a little 

 calculation. 



No. 7, the early Kidney Potatoe, is so small, that its leaves do not 

 cover two feet square. In a four feet square it yielded at the rate of 

 3 tons, 19 cwt. per acre. In six inches square it produced 7 tons, 

 2 cwt. 911b. But if two plants had been allowed to grow in four feet 

 square instead of one, so as to occupy all the ground, 7 tons, 18 cwt. 

 would have been the produce; this would have been a gain of 

 15 cwt. 21 lb. upon the acre ; add to this the difference between 

 the number of tubers planted in the one case beyond those em- 

 ployed in the other, or 16,332 tubers, which may be estimated at a 

 further weight of 14 cwt. 95 lb., and the gain upon the acre would 

 be about a ton and a half. And if, as is most probable, three plants 

 of so small a topped variety as this would have had abundant room 

 to grow in four square feet, then the planting them at that distance, 

 instead of eight in the same compass, would have made a difference 



