s 6 ROYAL SOCIETY OF CANADA 



culture. In such cases as we are considering, the interrogation of the 

 soil, so much favoured by a certain class of so-called practical farmers, 

 would be of little or no value. Chemistry, however, shows the true state 

 of affairs and points out before it is too late the losses of plant food 

 that are taking place. We shall, further, show that it is this same 

 science which teaches us how such soils may have their fertility econ- 

 omically maintained, and thus how to prevent the depreciating of this 

 principal asset of the farmer — a productive soil. 



Loss of Nitrogen due to Cultural Methods and Removal of 'Crops. 



It will now be of interest to note what proportion of this 

 considerable loss of 'plant food may be attributed to chemical changes, 

 and possibly in part to leaching, concomitant with cultural operations. 

 A calculation of the amount of nitrogen contained in the various 

 crops produced during the period of twenty-two years shows that the 

 soil's store of nitrogen has been reduced, from this cause, by 694 lbs. 

 (approximately) per acre. In this estimation the average composition 

 of the different cereals and the average yields of the same as recorded 

 at Indian Head, have been taken — the result (694 lbs.) may, therefore, 

 be regarded as approximately correct. "We are "consequently justified 

 in making the following statement: — 



Pounds per acre. 



Total depletion of nitrogen, to depth of 8 inches 2203 



Nitrogen removed in crops 694 



Loss of nitrogen due to cultural operations 1512 



These results are highly significant. They bring us face to face 

 with facts of the greatest importance to the future welfare of our great 

 North-west. More than twice as much nitrogen is lost by our methods 

 of cultivjj,tion than is removed in the crops. This is a very serious 

 matter and one which calls for immediate and earnest investigation. 



We are aware that all methods of cultivation Avhich open up the 

 land — ploughing, "harrowing, etc. — tend to the oxidation and nitrification 

 of the humus, resulting not only in the loss of organic matter but also 

 to some extent of nitrogen, especially when crops do not quickly follow 

 to utilize the nitrates so formed. To a certain extent and under cer- 

 tain circumstances this 'dissipation of nitrogen is unavoidable. The 

 land must by these cultural methods be brought into a suitable condition 

 for root extension and 'plant food prepared for the nourishment of the 

 crops. But this loss, we believe, is small compared with that attendant 

 on fallowing — an operation to which the soil under discussion had 

 been subjected to every other season for a period of seventeen yearcj. 

 Fallowing is most useful in keeping the land free from weeds, and as has 



