120 MASSACHUSETTS HORTICULTURAL SOCIETY. 



phosphoric acid, will produce good crops. This result is due to 

 the fact that soils vary in their natural supply of plant food, and 

 one may be well stocked with potash, but lacking in phosphoric 

 acid. On such, dissolved bone alone will enable the plant to 

 make a full growth. Another soil may be abundantly supplied 

 with phosphoric acid but deficient in potash ; under these condi- 

 tions the use of bone would be wasteful, but potash fertilizers 

 would work great benefit. Thus it happens that we must consult 

 the soil before we can decide upon the kind of fertilizer needed. 



To test the soil is not a difficult task. A few rows fertilized 

 with ashes, will often tell us whether potash is the principal thing 

 needed. A few other rows, on which dissolved bone-black alone 

 is used, may give valuable indications. But the most valuable 

 method of testing is, to select some three of the crude materials 

 above tabulated, — say sulphate of ammonia, muriate of potash 

 and dissolved bone-black in various proportions, thus giving mixed 

 fertilizers which shall contain varying percentages of nitrogen, 

 phosphoric acid, and potash, and by using equal values per acre, 

 and leaving certain parts with no fertilizer, we ma}' form very 

 accurate estimates of the relative value of each combination. This, 

 it seems to me, is the true test. The following table shows the 

 combinations which were used in the cooperative experiments in 

 New Hampshire in 1889. The top row of figures gives the num- 

 bers of the plots ; the amounts under these, in the vertical columns 

 represent the amount of each chemical (the name of which is 

 given in the left hand column) used per ^ of an acre. The cost 

 is fifty cents per plot, or $10 per acre, except one, the manured 

 plot, where $20 per acre was invested. The lower part of the 

 table shows what the chemical composition of the mixture was, 

 e. g., plot 1 had a mixture of 18J lbs. of dissolved bone-black, 

 3f lbs. of muriate of potash, 3f lbs. of sulphate of ammonia ; 

 the analysis of this was, phosphoric acid 11.4%, potash 7%, 

 nitrogen 2.8%. To any who might like to test this method, but 

 do not care to undertake so large an experiment, plots 1, 3, 5, 9, 

 13, and 16 might be selected and enough rows taken to give 200 

 hills of corn for each mixture, the fertilizer to be sown broadcast 

 on the rows after planting. 



