LOSSES DURING ROTATION 101 



of nitrates during a wet autumn or winter. This loss 

 may be prevented by the judicious use of catch croups. 

 The wheat stubble may be sown with mustard, turnips, 

 rape, rye grass, crimson clover, vetches, peas, &c. 

 According to circumstances, the crop obtained may be 

 ploughed in in November, or in the following spring. 

 The plan may prove thoroughly effective even when 

 the catch crop appears small, as the younger the plant 

 the richer it is in nitrogen. The advantage is, of 

 course, greater when a leguminous plant serves as the 

 catch crop. Some German agriculturists have now 

 adopted rotations to which no nitrogenous manure is 

 applied. When the corn is hand-high a leguminous 

 crop is sown among it ; this remains after harvest, and 

 is ploughed in deeply in the autumn or spring. The 

 plants most recommended by these investigators are 

 white lupins ; a mixture of Bokhara and alsike clover ; 

 and a mixture of red clover, alsike, and hop clover. 

 The particular croppii^ig best suited for each variety of 

 soil and climate can only be ascertained by experi- 

 ments in the particular locality. 



When it is desired to make the utmost use of the 

 natural sources of fertility, the land may be allowed 

 to remain more than one year in grass and clover ; 

 or one green crop may be followed by another, as 

 trifolium incarnatum by turnips ; or a perennial legu- 

 minous crop may be grown for several years. The 

 losses by sale of corn are thus diminished, and the 

 land is kept for some time under conditions favourable 

 to an accumulation of nitrogen in the surface soil. 



We have supposed that only corn and meat are 

 sold off the land during the rotation ; it will often be 

 profitable to sell a larger part of the produce and to 



