FIELD EXPERIMENTS ON MANURE CONSTITUENTS. 159 



1st Part : Field Experiments. 



Before giving an account of recent experiments on turnips, wheat, and 

 barley, not incorporated in the Report for 1859, it may appear desirable 

 briefly to state the chief deductions that naturally flow from my previous 

 experiments, extending over five seasons. 



In these experiments I found that, amongst other particulars — 



1. Ammoniacal salts, such as sulphate of ammonia, used alone, had a 

 decidedly injurious effect upon the turnip crop, even when used in small 

 quantities. 



2. Purely ammoniacal manures applied to swedes at first checked the 

 growth of the plant, and had ultimately no beneficial effect on the crop, 

 either alone or in conjunction with phosphates. 



3. Phosphates used alone, but in a readily available condition, produced a 

 larger increase in the yield of turnips than mixtures of phosphates with 

 ammoniacal matters. 



4. Sulphates of potash and soda had no decided effect on turnips. 



5- Sulphate of lime likewise was ineffective as a manure for turnips on the 

 soil on which the experiments were tried. 



■ 6. On the other hand, ammoniacal manures, so inefficacious for root-crops, 

 produced a considerable increase in the yield of wheat, grown on a soil 

 similar to that of the experimental turnip-field. 



7. Nitrate of soda, applied by itself, and still more soWn conjunction with 

 common salt, gave a very large increase per acre, both in straw and corn. 



These are the principal results of previous field trials. Chemico-agri- 

 cuUural experiments, however, are of little or no practical utility, unless 

 they are continued I'rom year to year for a long period, and tried on a variety 

 of soils, in good and in bad seasons, in a manner which allows us, if not to 

 eliminate, yet clearly to recognize the disturbing influences of climate, sea- 

 son, condition of soils, and other circumstances which often affect the produce 

 in a higher degree than the manures on which we experiment. A single 

 field experiment is as likely to lead us in a wrong as in a right direction. 



I have therefore continued field experiments similar to those already re- 

 ported upon, and proceed with an account of field trials on turnips made in 

 1859. 



Field Experiments on Swedish Turnips made in 1 859. 



The field selected for experimental trials in 1859 was in tolerably good 

 condition. It bore clover in 1857, and wheat in 1858. The soil is mode- 

 rately deep and well drained. A portion of the soil, taken from a large 

 sample from different parts of the field, was submitted to analysis, and the 

 following results obtained : — 



Moisture (when analysed) 3-960 



Organic matter and water of combination 9*616 



Oxides of iron and alumina 19*660 



Carbonate of lime 3*805 



Sulphate of lime *345 



Phosphoric acid '075 



Magnesia '783 



Potash 1-239 



Soda -090 



Insoluble siliceous matter (chiefly clay) 60*525 



9 100-098 



