202 



It was clear that there was some substance in the nitrated plots 

 which had brought the soil into a deflocculated condition and this 

 substance could not well be anything else than an alkali. On 

 testing, in fact, the soils from the nitrated plots were found to be 

 slightly alkaline. 



TABLE IV. SHOWS THE QUANTITIES OF CARBONATE OF SODA 



IN POUNDS PER ACRE (KGS. 1. 1 2 PER HECTARE) IN SOIL OF PLOT 14. 



SUMMARY. 



1) The long continued use of sulphate of ammonia on soils poor 

 in lime results in the soils becoming acid. 



2) The acidity is caused by certain micro-fungi in the soil which 

 seize upon the ammonia, setting free sulphuric acid. 



3) The infertility of such soils is due to the way all the re- 

 gular bacterial changes in the soil are suspended by the acidity. 



4) The remedy, as may be seen at Woburn, is the use of suf- 

 ficient lime to keep the soil neutral. 



5) From the Rothamsted soils the carbonate of lime is being 

 washed out at the rate of 800 to 1000 Ibs per acre (896 to 1120 kgs. 

 per hectare) per annum. The losses increase with the use of sul- 

 phate of ammonia and diminish by dung or nitrate of soda. 



6) Nitrate of soda, in large quantities, destroys the texture of 

 heavy soils. 



7) Some of the nitrate of soda gets converted into carbonate 

 of soda by the action of plants and bacteria ; and carbonate of 

 soda, deflocculating the clay particles, destroys the tilth. 



8) The best remedies are the use of soot or superphosphates; 

 the best preventive is the use of a mixture of nitrate of soda and 

 sulphate of ammonia instead of either separately. 



9) Soluble potash manures and common salt may also injure 

 the tilth of heavy soils through the production of a Jittle soluble 



