FERTILIZERS FOR THE GARDEN. 



288 



dener. The plots were only part of an acre 

 each. One good feature, however, was that four 

 plots were left without manure. These plots pro- 

 duced at the rate of 88, 97, 68 and 59 bushels per 

 acre each. The variation in the land, therefore, 

 was 38 bushels per acre. Bearing this fact in mind, 

 let us liiok at some of the more important results 

 bearing ^n the subject we are discussing. 



RESULTS OF EXPERIMENTS ON POTATOES, BY E. S. CARMAN, 

 EDITOR RURAL NEW-YORKER. Bushels 



per acre. 



1 — No manure (avei age 4 plots) 74 



2 — 300 pounds sulphate of potash 95 



3 — 400 pounds superphosphate 103 



4 — 200 pounds nitrate of soda 141 



5 — 1 100 pounds blood, nitrate of soda and sulphate of 



ammonia 1S3 



6 — 10 tons two year-old farm manure 139 



7 — 200 pounds nitrate of soda | 

 120 pounds muriate of potash f 



8 — 200 pounds nitrate of soda | 



120 pounds muriate of potash r 156 



700 pounds superphosphate j 



There is certainly nothing in these results contra- 

 dictory to the principles we have advocated in The 

 American Garden. Mr. Carman states that the soil 

 had been cropped for many years without manure 

 of any kind, and that it " would not grow beans, or 

 even a good crop of weeds without manure." And 

 yet it will be seen that nitrogen alone, on plot 5, pro- 

 duced 183 bushels of potatoes per acre, while on 

 plot 8, 1,020 pounds of a "complete manure" pro- 

 duced only 156 bushels, or 27 bushels less than ni- 

 trogen alone. Why is this ? Did the phosphoric 

 acid and potash do harm ? No ; there was not ni- 

 trogen enough. The phosphoric acid and potash 

 could not increase the crop for lack of nitrogen. 



Mr. Carman tells us that he used from 1200 to 

 2,000 pounds of a complete fertilizer, guaranteed 

 to contain 3 per cent, of nitrogen, 12 per cent, 

 phosphoric acid and 6 per cent of potash, and that 

 when he added more ?iitrogen, it did no good. Why 

 should it ? Oats are good for horses, but when a 

 horse has all the oats he will eat, throwing more 

 oats into the manger will not increase his strength 

 or improve his appearance. If the ton of complete 

 fertilizer furnished all the nitrogen the plants want- 

 ed, more could do no good. But for the sake of 

 getting 70 pounds of nitrogen, what folly it is to 

 use a ton of fertilizer that contains a great deal 



more phosphoric acid, costing 8 cents per lb., than 

 the crop can possibly want ? This is the point we 

 wish to impress on our readers. And it is a mat- 

 ter of surprise that so clear-headed and able a man 

 as Mr. Carman does not see that his own experi- 

 ments demonstrate, if they demonstrate anything, 

 that, so far as the production of potatoes is con- 

 cerned, this worn out soil, that was so poor that it 

 would not grow a good crop of weeds, was more de- 

 ficient in available nitrogen than in any other 

 constituent of plant-food. Superphosphate and 

 potash, without nitrogen, did no good. They could 

 produce no effect from lack of nitrogen. Thirty- 

 two pounds of nitrogen per acre, in the form of 

 nitrate of soda, raised the crop from 74 bushels per 

 acre (or possibly 59 bushels) to 141 bushels per 

 acre. The same amount of nitrogen on plot 8, in 

 1,020 lbs of "complete manure" produced 156 

 bushels, the 820 lbs. of superphosphate and pot- 

 ash only increasing the yield 15 bushels per acre, 

 — not as much as the difference in yield of the un- 

 manured plots. Nitrogen alone, on plot 5, produc- 

 ed 183 bushels per acre. It is clear, therefore, 

 that a complete manure, like that used on plot 8, 

 containing about 3^- per cent, of nitrogen is a very 

 costly and "badly balanced ration" for potatoes. 

 It does not, for Mr. Carman's poor, worn out 

 soil, contain half nitrogen enough. It is true 

 that by using enough of it you could grow a large 

 crop, but it would be done at a fearful and unneces- 

 sary expense. We feel perfectly safe in saying that 

 a ton of it per acre would produce no larger a crop 

 than half a ton that contained double the amount 

 of nitrogen. 



A complete manure, such as that used on plot 8, 

 would probably cost %\o per ton. The 200 lbs. of 

 nitrate of soda in the mixture can be bought for ^5. 

 In other words, the phosphoric acid and potash in 

 the ton of this complete manure cost ^35. Leave 

 half of it out and double the nitrate and you will, in 

 our judgement, get quite as large a crop at far less 

 cost. There is nothing in Mr. Carman's experi- 

 ments, or any other, to lead us to suppose otherwise. 



Morcton Farm. Joseph Harris. 



