CLOVER AS A PREPARATORY CROP FOR WHEAT. ^fjQ 



phoric acid, and may be presumed to be well suited to the growth 



of clover. It contains more carbonate of lime, and is somewhat 



lighter than the sample from the part of the field twice mown for 



hay, and may be termed heavy calcareous clay. 



An acre of this land, 18 inches deep, weighed when very nearly 



dry : 



lbs. 



Surface, 6 inches 2,407,900 



Next " 2,444,200 



3d " 2,480,500 



Or in round numbers, every six inches of soil weighed per acre 

 2| millions of pounds, which agrees tolerably well with the actual 

 weight per acre of the preceding soil. 



The amount of phosphoric acid and nitrogen in each six-inch 

 layer was determined separately as before, when the following 

 results were obtained : 



In Dried Soil. • 



1st, 6 inches 2d, 6 inches. 3d, 6 inches. 



Percentage of phosphoric acid 159 16G 140 



Nitrogen..,. 189 134 089 



Equal to ammonia .229 162 108 



An acre, according to these determinations, contains in the three 

 separate sections : 



1st, 6 inches. 2d, 6 inches. • 3d, 6 inches, 

 lbs. 



Phosphoric acid 3975 



Nitrogen 4725 



Equal to ammonia 5725 



Here again, as might naturally be expected, the proportion of 

 nitrogen is largest in the surface where all the decaying leaves 

 dropped during the growth of the clover for seed are found, and 

 wherein root-fibres are more abundant than in the lower strata. 

 The first six inches of soil, it will be seen, contained in round 

 numbers 2| tons of nitrogen per acre, that is, considerably more 

 than was found in the same section of the soil where the clover 

 was mown twice for hay ; showing plainly that during the ripen- 

 ing of the clover seed the surface is much enriched by the nitro- 

 genous matter in the dropping leaves of the clover plant. 



Glover Boots. The roots from one square foot of this soil, freed 

 as much as possible from adhering soil, were dried at 212°, and 

 when weighed and reduced to a fine powder, gave on analysis the 

 following results : 



