THE CANADIAN H0BTICULTURI8T. 



135 



should therefore be renewed as soon 

 after a heavy shower as the tree has 

 become dry or nearly so, if the highest 

 efficiency is to be secured. 



It is also a very good plan to spray 

 but half of the tree, in order to have 

 the other half to compare with. If a 

 sufficient number of trees are used, 

 some of them might be totally sprayed, 

 however. It does not seem to me that 

 the results so far obtained are suffi- 

 ciently positive to warrant one in spray- 

 ing more of the orchai'd than is neces- 

 sary for an ample experiment. 



Yours truly, 



J. C. Arthur. 

 N. Y. Experiment Station, Geneva, N. Y. 



DRAINAGE WATER. 



BY C. C. JAMES, M.A., PROFESSOR OF CHEMISTRY. 



In estimating the worth of a fertili- 

 zer, commercial values are set only upon 

 the nitrogen, phosphoric acid and pot- 

 ash ; sometimes the lime is considered. 

 The three first mentioned are of most 

 importance, since nearly all soils con- 

 tain sufficient of the other plant foods 

 to sustain ordinary crops. To grow 

 crops it is necessaiy, therefore, to sup- 

 ply nitrogen, otherwise the land will 

 become exhausted. The ordinary crops 

 annually remove from the soil the fol- 

 lowing quantities of nitrogen per acre : 



Lbs. 



Wheat (30 bush.) Grain 33 



Barley (40 " jGrain 35 



oats (45 " Grain 38 



Hay (li tons.) 



Red Clover (2 " 



Turnips (17 " Roots 63 



Mangels.... (22 " I Roots 85 



Potatoes... (6 " I Roots 42 



Lbs. 



Straw , 

 Straw- 

 Straw , 



12 

 12 

 14 

 45 

 70 

 Tops .... 45 

 Tops 46.5 



45 



47 



52 



45 



70 



108 



131.5 



Tops, etc. IS I 60 



Total 

 Lbs. 



The rain carries into the soil from 

 the atmosphere every year from five to 

 ten pounds ; other sources of supply 

 besides that of direct applications of a 

 nitrogenous fertilizer are, as yet, some- 

 what uncertain. 



The nitrogen, however, before it is 

 in form available for the plant must be 



converted into a nitrate, a compound 

 resulting from the union of nitric acid 

 with some such substance as lime. This 

 formation of nitrates in the soil is called 

 nitrijication, and producing the various 

 fermentations. It is found in all fer- 

 tile soils, and for its development and 

 work demands a supply of air and 

 water. Tillage therefore assists in the 

 process. The presence of too much 

 water excludes the air and hinders the 

 work, even undoing it. Drainage 

 therefoi-e increases the range of nitrifi- 

 cation and deepens the fertility. A 

 proper degree of heat is also most im- 

 poi'tant. Nitrification ceases below 

 and near the freezing point. As the 

 temperature rises to 98° Fahrenheit 

 activity increases. From that point it 

 again diminishes to about 131° when 

 it ceases. Under these conditions ni- 

 trification proceeds most actively dur- 

 ing the summer, and continues even 

 into the autumn. The nitric acid thus 

 formed unites with lime principally, 

 forming nitrate of lime, or calciym 

 nitrate. 



In the spring there ai'e few, if any, 

 nitrates to be washed out of the soil ; 

 in the summer there is but little, if any, 

 drainage to wash out the nitrates ; in 

 the autumn, therefore, when nitrates 

 have accumulated and drainage is also 

 abundant, we may expect the greatest 

 loss. 



The following may be practised either 

 to clean dirty land or to rest exhausted 

 land : In the former case, to avoid 

 excessive loss by drainage, recourse may 

 be had to roots thoroughUj cultivated. 

 To improve an exhausted land, instead 

 of allowing the land to lie fallow a 

 whole year, a gi'een crop might be 

 plowed under, thus keeping all the 

 nourishment in the soil, increasing it by 

 drawing on the air and subsoil, and by 

 decreasing the drainage. For green 

 manuring, red clover, rye and buck- 

 wheat arespeciall}' recommended ; other 



