V 

 HORTUS GRAMIXEUS WOBURNENSIS. 389 



Green Food. Nutritive 

 Matter. 



lbs. lbs. 



The Swedish turnip, or ruta baga (Brassica 



rapa, var.), produces on a favourable soil, orj 



a strong loam, on an average, 13 tons per^ 29120 - 1830 



acre, a pound weight of which affords of nu- 

 tritive matter 440 grains. 

 Cabbages (Brassica oleracea, var.), which de-'\ 



light in a rich strong loam, afford of green/ 



food, on an average per acre, 25 tons, every > 56000 - 3440 



pound of which contains 430 grains of nutri-V 



tive matter - - - - / 



Kohl rabi {Brassica oleracea, var.), the produce 



from a soil similar to that for cabbages ori 



Swedish turnips, is on an average 14 tons). 31360 - 1881 



per acre,* and affords of nutritive matter ( 



per pound 420 grains. 



If a plant, therefore, impoverishes the soil in proportion to the 

 weight of vegetable substance it produces on a given space of 

 ground, the following will be the order in which the plants just 

 mentioned exhaust the land. 



The proportions which they bear 

 to each other with respect to 

 weight of produce. 



Experience has long since proved, that carrots exhaust the soil 

 in a much greater degree than white turnips; though, by this mode 

 of judging, they impoverish land in a less degree than any of these 

 plants. But when we take the weight of nutritive matter which a 

 plant affords from a given space of ground, the results are very 



* The average of some of these crops may be thouglit too small perhaps ; but from 

 information with which I have been favoured from extensive cultivators, and care- 

 ful comparisons of the produce, as stated in the Agricultural Surveys, and in 

 Mr. Young's Annals, with the produce obtained in numerous experiments which I 

 have conducted on the subject, I believe the above will be found a correct view of 

 the average produce of these plants. 



