I /6 Harshba per. — Maize 



S' 



The question is how best to conserve the nitrogen, the 

 supply of which in sufficient quantity is so invaluable. The 

 nitrogen is lost to the soil in three principal ways : (1) By 

 drainage ; (2) by removal of crops ; (3) through the air. This 

 waste goes on in all soils, in some more than in others. Sir 

 John Lawes, in a paper on fertility, concludes that 3000 

 pounds of nitrogen have been lost in the Broadbalk wheat 

 field at Rothamsted in the last 250 years. It is generally 

 conceded that this waste can be prevented directly, to some 

 degree, by growing crops through the season of the greatest 

 production of the nitrates. Rotations properly arranged 

 conserve the soil nitrogen. Thus, if red clover is sown in a 

 growing crop of barley the land is covered immediately after 

 the barley is cut, and the effect is as nearly perfect as pos- 

 sible, the growth of the second crop following the first without 

 a break in the continuity. At Rothamsted it was found that 

 on sampling the drainage waters and calculating the amount 

 of nitrogen as nitrates contained therein, that the maximum 

 discharge takes place from October to February, and the maxi- 

 mum nitrification takes place during the autumnal months. 



The cereals, after a wet winter, begin to grow in the spring 

 in a soil drained of nitrates, and the growth is over before 

 the greatest production of nitrates takes place. These crops 

 are, therefore, greatly benefited by nitrogenous manures. As 

 the growth of maize takes place in the late summer months, 

 it is-more independent of nitrogenous fertilizers 1 than wheat, 

 barley, etc. 



The nitrogen, therefore, is best conserved with a crop 

 whose period of growth extends into the period of maximum 

 nitrification and maximum drainage of nitrates from the soil. 

 Maize is just such a crop. Cereal crops whose growing- 

 periods are confined to the spring and early summer are very 

 poor conservers of nitrogen. This accounts for the fact that 

 maize does not exhaust the soil nearly so rapidly as wheat, 

 which has its period of growth much earlier in the year. 



1 See Page 174. 



