FOOD FOR PLANTS 125 



Grain cover crops are not desirable as they directly 

 compete with the trees. Wild oats do harm. 



Irrigation furrows should be constructed so they 

 are not as deep as the plowed under cover crop. 

 This allows the water to carry the food to the roots. 



Functions of Nitrogen. 



1. Develops wood growth, insuring healthy, 

 strong trees. 



2. Develops leaf growth, making healthy leaves 

 of a dark green color, which enables the plant to take 

 in the necessary supply of carbon dioxide. 



3. Promotes quantity, quality and good-sized 

 vegetables. 



4. Makes up the tissues of the fruit, thus insuring 

 a good size. 



5. Most of the essential Nitrogen is taken up by 

 the plant at an early period in the growth, hence 

 early applications of Nitrogen hasten maturity, and 

 late and too great applications tend to retard ma- 

 turity by forcing leaf and wood growth at a time 

 when the plant should be concentrating on develop- 

 ing and sweetening its fruit. 



Analysis of Various Nitrogenous Fertilizers. 



Nitrate of Soda IS^/^Or Nitrogen, 25''^ Sodium. Recovery of Nitrogen 

 by crop, dZyz'/c 



Nitrate of Lime 12' r Nitrogen, 26^'r Calcium. Recovery of Nitrogen 

 by crop, 62i/^9'f. 



Sulphate of Ammonia ZOYi'/c Nitrogen, 22'7f Sulphur. Recovery of 

 Nitrogen by crop, 47^/^%. 



Dried Blood l3%Vc Nitrogen. Recovery of Nitrogen by crop, 38^%. 



