xii. CEOPS 251 



CLASS 3. FODDER CROPS. 



In these the seeds are of little importance, the foliage and stems 

 being the main parts. They include gramineous (grasses), legumin- 

 ous and other plants. 



Meadow and Pasture Crops. These consist of very variable 

 mixtures of different plants. The grasses are usually predominant in 

 quantity, and they, in general chemical properties, resemble the 

 cereals. Their ash is rich in silica and potash, but poor in lime ; 

 while in the organic portion they contain comparatively little 

 nitrogen, but are rich in carbohydrates. The roots of grasses are 

 mainly confined to the surface soil, so that application of manure 

 must be made if grass land is not to diminish in fertility. Moreover, 

 the root debris of grass land by its accumulation gradually produces a 

 peaty or humic character in the upper portion of the soil, with conse- 

 quent nitrification and loss of calcium. Hence manuring with bones, 

 lime, or basic slag, or other calcareous substances is generally advan- 

 tageous. 



Liberal additions of nitrate of soda, potash salts and phosphates 

 produce very heavy crops of hay by encouraging the growth of coarse 

 grasses ; but clover and some of the finer grasses are thereby dimin- 

 ished and the quality of the hay deteriorates. 



Leguminous Crops, e.g., clovers, trefoil and lucerne, are also pre- 

 sent in orlinary grass land, but in varying amount. These fodder legu- 

 minous crops have the same general characteristics as the leguminous 

 grain crops. Their growth is greatly favoured by additions of potash 

 and lime compounds and by stinting the nitrogenous manuring ; the 

 clovers, etc., having an independent supply of nitrogen, are thus able 

 to outgrow their competitors, the grasses. As already stated, legumin- 

 ous plants are remarkable for the large amounts of nitrogenous matter, 

 lime and potash which they contain. The lime is mainly contained 

 in the leaves. Silica is almost absent. Clover, lucerne, etc., are also 

 grown as crops upon arable land with valuable after-effects. The land 

 is thereby actually enriched in nitrogen, notwithstanding the fact that 

 a very large amount of nitrogen is removed in the crop. The nitrogen 

 is obtained from the air in the manner already described. The bene- 

 ficial effect of the growth of clover upon the soil has long been known 

 and utilised in agriculture ; but it was not until after many laborious 

 researches had been made, that the explanation of the fact was discovered 

 by Hellriegel and Wilfarth about 1888. 1 



By repeated cropping of land with clover a condition known as 

 " clover sickness " is often set up. The seed in the summer germinates 

 and grows well until the autumn or winter, when the plants die off 

 rapidly, and, in many cases, a minute eel-worm attacks the root and 

 stem. Whether these nematoids (Tylenchus) are the cause or a con- 

 sequence of the disease appears to be uncertain. Clover sickness has 

 also been ascribed to certain fungi. It is said that deficiency of the 

 soil in potash and lime is a predisposing cause .of this disease. 



1 Vide p. 67. 



