PLANT NUTRITION. 47 



which they require so closely that they will finally destroy them, 

 and leave the plants that the cattle want, to grow, so that the 

 pasture is improved for cattle. The question was asked why the 

 manure of sheep is better than that of cattle? The diflerence is 

 in its physical condition. The manure of cattle and sheep fed 

 on the same substance is about the same. 



Plaster is used everywhere and for all crops, and you will hear 

 wonderful stories of its effects. Should there be a very great 

 want of sulphur in the land, or a great amount of decomposition 

 going on, the application of plaster would produce chemical 

 changes, and very marked results would follow. If there is nitro- 

 gen or ammonia being formed it would convert the volatile gases 

 into soluble salts. Again, if there is organic matter to be decom- 

 posed decomposition in that soil would set the lime free and a 

 round of changes would go on that would develop plant food. On 

 a light soil where no decomposition is going on you would not 

 get that result. 



Secretary Boardman. Will you give us the proportion for the 

 compost of porgy scrap with ashes and lime for a top-dressing for 

 pasture or mowing lands ? 



Prof. Stockbridge. I should use them on pasture lands of the 

 second class, for on the steep side hills they are not easily drawn. 

 Take two hundred pounds of porgy pomace, containing about 

 seven per cent, nitrogen as I remember, and mix it with twenty 

 bushels of wood ashes and three casks of lime. I would rather, 

 myself, have the porgy pomace made fine and sow it on, and then 

 sow on my ashes, and not take the trouble to cast on the lime. I 

 should get twenty pounds of potash for the mineral element, and 

 that would make a good top-dressing. 



