Miscellaneous. 



[July, 1012. 



animal life in the soil. Chemistry also 

 plays its part in controlling and regul- 

 ating the chemical reaction, and hence 

 the dominance or decadence of various 

 types or even of individual representa- 

 tives of the soil flora. 



There is reason to believe that we 

 are to-day but entering upon the study 

 of the organisms and of the condition 

 best suited to ensure the assimilation of 

 atmospheric nitrogen by non-symbiotic 

 means. 



The whole question of use of fertilizers 

 and of their action is daily becoming 

 more complex, It was a simple proposi- 

 tion when one supposed that it was 

 merely essential to learn what elements 

 crops removed from the soil and then to 

 supply a proper part thereof, without 

 special reference to the particular com- 

 pounds used to supply them. To-day, 

 cognizance must be taken of the effect 

 of the associated compounds. The sul- 

 furic acid and chlorin combined with 

 ammonia in ammonium sulphate and 

 ammonium chlorid may have a highly 

 toxic effect from the outset, or such 

 effects may soon develop in certain soils 

 if care is not taken to maintain a proper 

 basic condition. The subsequent effect 

 of organic nitrogenous manures is quite 

 different on some soils from that of 

 nitrate of soda: Even though the avoid- 

 ance of chlorin and sulphuric acid, when 

 combined with ammonia, is of vital im- 

 portance under certain circumstances, it 

 is often less necessary under the same 

 condition if they are in combination 

 with potassium, calcium and magnesium. 

 For still other crops, or on another soil, 

 they may nevertheless be used with 

 good effect. 



Another illustration is afforded by 

 nitrate of soda. The residual effect of 

 repeated annual applications may result 

 in the most marked soil improvement, 

 rendering successful the cultivation of 

 a whole series of crops where they could 

 not be grown successively before, The 

 same statement, even for a long series of 

 years, may still fail to correct the exist- 

 ing soil conditions enough for other 

 groups of plants, The continued use of 



nitrate of soda on another soil may 

 cause it to become puddled until it is 

 rendered practically unfit to be a habitat 

 for most agricultural plants. For cer- 

 tain plants, such as the radish and beet 

 the residual sodium from nitrate of soda 

 may perform valuable physiological 

 functions which would be lacking, or of 

 slight importance, in connection with 

 certain other plants. Raw rock phos- 

 phate may be valuable as a fertilizer on 

 the black soils of the Illinois corn-belt 

 and for crops usually grown there, but 

 for the light sandy soils of the Atlantic 

 coast and for certain trucking crops, its 

 use at prevailing prices could perhaps 

 not be recommended. To add to this 

 complexity certain text-books proscribe 

 the use of lime with superphosphates, or 

 on soils where undissolved phosphates 

 are to be used and yet there may be soils 

 on which liming is essential to the most 

 economical use of each. It is, in fact, 

 not enough that the agronomist should 

 bear in mind and master all of these 

 details, but now he is called upon to 

 consider the specific requirements for 

 lime and other substances, of hundreds 

 of varieties of plants. He must also 

 consider the alleged toxic root excreta 

 and methods for rendering them innocu- 

 ous, and he must take cognizance of 

 the catalytic action of manganese and 

 other elements not heretofore grouped 

 in the galaxy of fertilizers and soil 

 amendments. He must now consider 

 the effect of legumes and other plants 

 upon those growing in association with 

 them and the effect of given crops upon 

 those which follow. The whole question 

 of maintaining conditions favourable to 

 nitrification is of prime importance in 

 certain sections of the United States, 

 and in this connection chemistry is 

 again the handmaid of agronomy ; yet 

 in certain of the semi-arid regions of the 

 middle west excessive nitrification is 

 said to have become a scourge which is 

 wiping out many of the most promising 

 orchard industries. It must be evident 

 that the agronomist must therefore be 

 something of a climatologist, for in 

 certain of these features the weather 



