8 



for the three crops of 46 per cent. Lime always gives an increase in 

 growth on Leonardtown loam, poor, no matter whether used alone or 

 in combination with barnyard manure, chemical fertilizers, or green 

 manure. Its most pronounced effect, however, was where it has been 

 used in connection with barnyard manure. In this instance manure 

 was used with' and without lime, the former at the rate of 10 tons 

 per acre and the latter at the rate of 2,000 pounds per acre. Foul- 

 successive crops of seedling wheat were grown without re-treatment 

 of the soil. In the first crop manure gave an increase of 14 per cent, 

 and manure and lime together gave an increase of 93 per cent, or an 

 increase attributed to the lime of 79 per cent. The succeeding crops 

 showed a marked diminution in growth for both the treated and un- 

 treated soil, the diminution being equally as great in the manure- 

 treated soil as in that which was untreated, but much less marked in 

 the case where lime was applied with the manure. The results of the 

 four crops showed an aggregate increase attributable to the lime equiv- 

 alent to 26^ bushels of wheat. If results approximating these can 

 be obtained in field practice, it is plain that the application of lime 

 at the rate of a ton per acre as above used would be an exceedingly 

 profitable treatment, especially in view of the fact that where lime 

 is obtainable near by its cost should not exceed $3 per ton. It is 

 not at all improbable, however, in this case that the application of the 

 lime in conjunction with the manure has rendered the manure more 

 effective. This seems most likely because the lime in this instance 

 has been about twice as effective as when used alone, and, further- 

 more, the manure used without lime has had very little permanent 

 effect, the application of 10 tons producing an aggregate increase in 

 yield for the four crops equivalent to a little less than 5 bushels of 

 wheat, the main effect showing in the first crop. 



EFFECT OF CHEMICAL FERTILIZERS. 



Nitrate of soda', sulphate of potash, and tricalcium phosphate have 

 been used in numerous instances alone, in combination with each 

 other, and in various combinations with manure, lime, and both 

 manure and lime. Nitrate of soda and sulphate of potash have been 

 used in amounts approximately 250 and 500 pounds per acre each, 

 while tricalcium phosphate has been used at the rate of 150 and 300 

 pounds per acre. Nitrate of soda, whether used alone or in combina- 

 tion with other constituents, has usually given an increase in growth 

 except where lime enters into the combination. In the presence of 

 lime, nitrate of soda invariably either gives no increase or produces 

 a slight decrease in the effect of the lime alone. Its beneficial effects 

 are most pronounced where used in combination with barnyard ma- 

 nure. In the experiment above referred to under the heading of lime. 

 where four successive crops were grown without re-treating the soil. 



