CONCLrsiONS -ji:. 



crops foil off more slowly, and tin* cereals. csiiccialK I In- wheal, 

 maintain a fair production for a lon^ period. 



*2. The unmanurtMl wlu\ii and harlrv ^rown in i-otaiion 

 continue to .uive nuich .ureater produee than thev do on land 

 similarly unmanured but urowini: the same ci'ops vcar after 

 year. This is, however, chiefly in virlue of the two tallow in^^s 

 the laud receives duriuo- the four-years' couise. the umnannrcd 

 land losing about the same amount of plant food in the om- 

 case as in the other. 



3. On the manured plots the yield of Swedes is determined 

 by ])oth phosphatic and nitrogenous mainuv, chiefly by the 

 former: the yield of cereals is determined by the available 

 nitrogen in the soil. 



Leguminous crops like clover and beans are dependent on 

 the supply of minerals, particularly of potash, and are even 

 somewdiat decreased by the presence of nuich nitrogen in the 

 soil. 



4. The inclusion of a clover crop in the rotation, besides 

 providing a crop of hay, leaves the land so nuich richer in 

 nitrogen that the succeeding wheat crop is greatly increased. 

 The good effect of the clover persists and may be traced through 

 all the crops of the rotation. With beans in place of the 

 clover, no beneficial effect is produced on the succeeding 

 crops. 



o. The effect of such residues as are left by an organic 

 manure like rape cake applied to the Swedes, or those left on 

 restoring the Swedes to tlie land, or the residues left by a 

 clover crop, is to be traced in the three following crops at 

 least. In the third crop they are, however, becoming small, 

 and even in the second year after the apj)lieation of the 

 manure the effect of the residues becomes masked by any 

 new^ addition of nitrogenous manure, although they may still 

 remain and go to build up the "condition of the soil. 



6. The losses of nitrogen to strong land farmed on the four 

 com-se system are almost made up by the growth of a crop of 

 clover, and w^ill be more than repaired by a dressing of 1.') tons 



