361 



A glance at the analyses in Table 1 will show that although most of 

 the soil ingredients have not changed enough to make any great difference 

 in the chemical composition of the virgin and cropped soils, there are some 

 notable exceptions. 



The most serious losses from the standpoint of soil fertility are those 

 of nitrogen, which shows a loss of 28%, and the organic matter, which 

 shows a loss in tbe volatile matter of 26%, and in the humus of 47%. 

 These losses are without doubt the main reason why our cropped soils are 

 no longer as fertile as they formerly were. Fortunately the remedy for 

 replacing nitrogen and organic matter is not beyond the means of the 

 average farmer. Greater care in utilizing crop residues and barnyard 

 manure, also the growing of legumes in a good crop rotation are necessary 

 steps in replacing these vital losses. The purchase of organic matter, 

 other than farmyard manure, is out of the question, while the use of nitro- 

 genous fertilizers which often give profitable returns, can only be recom- 

 mended as a temporary resort. 



While the phosphoric acid and potash show only about 10% loss, it 

 should be remembered that this 10% was the most available portion of 

 these important elements. Fertilizer practice in the older and more worn 

 lands of Indiana shows that there has been a loss in these elements and 

 that in a great many cases their use as fertilizers is very profitable. Due 

 to the fact already mentioned that the soil through natural agencies is 

 constantly in motion, it should be pointed out that the addition of one or 

 two tons of rock phosphate per acre to the land for the purpose of increas- 

 ing the phosphorus content of it for a long time to come, is a practice of 

 doubtful efficiency. There is a strong probability of loss of such fertilizer, 

 due to removal by wind or water, or to being buried out of reach of the 

 plants by these or other natural agencies. Smaller amounts of more avail- 

 able phosphorus or potash fertilizers, on the other hand, will be quickly 

 utilized by the crops and hence not so liable to be lost. Experiments 

 which have been conducted by the Purdue Experiment Station show great- 

 er profit from the use of acid phosphate than from raw rock phosphate. 

 (Bui. 155, Purdue Experiment Station and the 27th Annual Report, Pur- 

 due Experiment Station, 1914.) 



The analyses of calcium and magnesium in the virgin and cropped 

 soils show no apparent change. This is rather surprising as we have been 

 led to think of these elements, especially calcium, as being very soluble. 

 Tbe loss of lime, as reported by the Rothamsted Station, has been shown 



