GRASS AND THE NATIONAL FOOD SUPPLY 



461 



Since the war we have learned a good deal about the management of 

 grassland, and, as I hope to show you, we can now get very much more 

 food for our cattle from an acre of land than was previously possible. 



Grass grows mostly during the summer, but the rate of growth is not at 

 all even during the warmer part of the year. If left to itself, grass grows 

 during the spring and then ripens. Most grasses flower during June and 

 July, and the seed falls during July and August. If the grass is cut or 

 grazed before it ripens or flowers, it will grow again in an endeavour to 

 flower. Even if it is left uncut, some grasses will start growing again in 



THE FOOD or A COW 



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Hay. Root5. 



Cake & Cereals 



Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec 



Month 



Fig. 2. 



the autumn if light can get through the matt of dead grass to the young 

 shoots. But these conditions do not apply to a well-managed pasture 

 which is kept grazed and prevented from flowering, though they do apply 

 to the overgrown grass found on rough grazings. 



In discussing the yield of food given by crops I shall not consider the 

 total weight of the crop but the crude protein content. This is the weight 

 of nitrogen in the crop (found by analysis) multiplied by a factor (6-25), 

 since this is the ratio of nitrogen to total weight in a protein. In grass the 

 crude protein content is usually about 50 per cent, higher than the protein 

 equivalent. In some foods the difference is less. 



