[SHUTT & charron] NITROGEN-ENRICHMENT OF SOILS B^ 



The clovers and alfalfa are pre-eminently the legumes most 

 serviceable as soil enrichers. If sown with the grain crop in the spring- 

 their growth is so rapid 'after the harvesting of the grain that before- 

 the close of the season, from 100 to 150 lbs. of nitrogen are stored in 

 their tissues. If this is then ploughed under, nitrification of the organie 

 matter follows and there is rendered available for the succeeding crop 

 as much nitrogen as would be furnished by an application of, say, 10' 

 tons of ordinary barnyard manure. 



An important feature, however, in connection with 'the clover and 

 alfalfa is their large root system. Eeference to the figures shows that 

 somewhat 'more than one-third, of the total nitrogen in the case of the- 

 clovers, and nearly one-half in the case of alfalfa, is in the roots. The- 

 crop may, therefore, be used 'for " soiling " purposes or otherwise har- 

 vested and yet a very considerable manurial efi'ect obtained, simply by 

 the decay of "the roots. Apart, therefore, from other and. important 

 considerations, such as the low price of seed and the case w4th which 

 good seed can be procured, 'it is evident that there is distinct advantage- 

 in employing one or other of these crops when there is stock that 'cart 

 profitably consume their growth.^ 



The Hairy A^etch, in spite of its large nitrogen content, is not so- 

 generally useful as the aforementioned legumes. Its root ' system is 

 quite meagTQ compared with theirs, and would in itself be of little- 

 manurial value. It is, however, a valuable crop for sowing in orchards,, 

 where it may serve the purpose of a catch crop, a winter protection 

 and a soil enricher. 



Horse Beans and Soja Beans, though not equal to the foregoing- 

 in the amount of nitrogen they can furnish, have been used in the 

 orchard with good effect, for they can he grown in drills and thus 

 permit cultivation until the summer is well advanced. Since cultiva- 

 tion means conservation of soil moisture for the tree's growth, the 

 adoption of a soil-enriching crop permitting of this operation is a 

 matter of considerable importance in parts of the country in which the 

 rainfall may be sparse in the spring and early summer months. 



Evidence from the Analysis of the Soil. 



The experiments now to be described were undertaken with the 

 view of ascertaining by anal.ysis of the soil the amount of nitrogen 



^ In this connection, it may be remarked that for many years it has been the 

 practice on the Experimental Farm to sow clover, usually at the rate of 8 to 10 

 lbs. per acre, with all classes of grain crops. The clover after the harvestin.sj of 

 the grain crop, is ploughed under at the close of the season. If, however, corn or 

 potatoes are to follow, the clover is allowed to remain and ploughing under post- 

 poned till the early weeks of the following May, when, as a rule, there will be a 

 good mat of growth. 



