148 ELEMENTARY AGRICULTURAL CHEMISTRY 



mixture of plants. The grasses;, which usually predominate, 

 resemble the cereals in general chemical composition, being 

 rich in silica and potash and com pari, tivelypocr in nitrogenous 

 organic matter. Grasses are usually surface feeders, and the 

 root debris gradually imparts a peaty character to the upper 

 portion of the soil, thus leading to nitrification and loss 

 of calcium compounds. Hence phosphatic and calcareous 

 manures — basic slag, bones, lime — are beneficial. Heavy 

 dressings of nitrogenous manures favour the growth of coarse 

 grasses at the expense of clovers and some of the finer grasses. 

 Grasses are used on the farm either as permanent pastures 

 and meadows, or in the rotation in the form of " small seeds" 

 • — rye-grass usually mixed with clover. There are numerous 

 species of grass, differing in chemical composition and 

 palatability. 



Average Composition of Various Green Fodders. 



2. LegfuminOUS Fodder Crops.— Some leguminous plants 

 are usually present in pastures and meadows. Their growth 

 is favoured by additions of potash, lime and phosphates, and 

 by stinting the nitrogenous manuring ; the clovers, &c., having 

 their own peculiar supply of nitrogen (see chap, vi.), are 

 thus able to hold their own in competition w^ith the grasses, 

 which in the presence of abundant supplies of nitrogen would 

 probably outgrow and smother the Leguminosse. 



