^22 



GTPSUJI. 



These results show to what extent gypsum is favorable t<s tfcfi 

 production of sainfoin. The cro . from the unplastered breadth be- 

 ing taken as 100, that upon the plastered breadth is 231 ; it is more 

 than doubled. The influence of gypsum was also found by Smith 

 to extend to grain ; assuming the grain crops on the ungypsed land 

 at 100, those on the gypsed soil were 192 ; they were nearly doubled. 



On comparing the weight of the herbaceous portion of the sain- 

 foin to that of the seed produced, widely different relations are ap- 

 parent. These Mr. ^mith attributed to the different depths of the 

 vegetable soil in different parts of the field. In the first experiment, 

 where the relative proportion of seed is highest, the arable soil was 

 three feet in thickness ; the other crops were taken from parts where 

 the depth of vegetable mould was considerably less. Thus the 

 gypsed soil produced at the rate per acre : 



cwts. qrs. lbs. 



In the first experiment of 5 22 the depth of soil being 3 feet. 

 In the second experiment of 3 1 15 " " 18 inches. 



In the third experiment of 1 3 15 " " 3 inches. 



With this interesting fact before him, Mr. Smith imagined that 

 soils of little depth wanted some principle essential to fructification, 

 which gypsum, in spite of the unquestionable assistance it gives, is 

 yet incompetent to supply. This principle is in all probability or- 

 ganic matter, which is naturally more abundant in the layer of true 

 vegetable mould which is deepest. 



Mr. Smith's observations on white clover were quite as decisive 

 in favor of gypsum as those on sainfoin, and are confirmatory of the 

 conclusions of the generality of farmers on the subject. The gyp- 

 sum in connection with this crop was applied in the dose of 6 bush- 

 els per acre, on the 22d of May, a date at which the clover looked 

 pale, and seemed to want sap. A fortnight afterwards, the effects 

 of the gypsum were obvious; although no rain had fallen in the in 

 terval, the clover had become vigorous, and soon formed a covering 

 thick enough to protect the ground from the scorching rays of the 

 sun, which burned up all the parts which had not been gypsed. 



COMPARATIVE GROWTHS OF WHITE CLOVER, GYPSED AND UNGYPSED, 

 BY MR. SMITH. 



