272 VEGETABLE GROWING PROJECTS 



markable asparagus fields of France. In the United States many 

 growers plow down heavy clover sods in the fall of the year before 

 the asparagus is planted. Others make large applications of stable 

 manure. There is no question about the desirability of a liberal 

 supply of humus. Commercial fertilizers are also employed in 

 large amounts for this crop. Some is used before the roots are 

 planted and later applications are made along the rows. A high- 

 grade mixture is preferred. Nitrogen is highly essential, and phos- 

 phorus may be the limiting factor in some soils. Before the great 

 World War potash was used in large amounts for this crop. A mix- 

 ture of 200 pounds of nitrate of soda and 500 pounds of acid phos- 

 phate, scattered along the rows after the plants are up, should be 

 highly beneficial. 



1. What crops might be selected to precede asparagus? Give 



reasons for suggesting them. 



2. What preliminary tillage operations are necessary? 



3. What kind of fertilizer treatment do you recommend ? 



W-VG : 213. 



4. Why is a liberal supply of organic matter recommended for this 



crop? 



5. How do nitrogen, phosphorus, and potassium function in the 



growing of asparagus? 



6. What do you know about the fertilizer treatments for this crop in 



California and elsewhere f H : 72-82. 



6. Planting. — Asparagus should be planted very early in the 

 spring. For green shoots the rows need not be more than 4 feet 

 apart, though many growers allow more space. The plants are 

 generally spaced 18 to 24 inches apart in the row. The usual 



