90 Pecan-Growing 



duces a dark green color in the foliage. Nitrogen is assisted 

 in its circulation from the leaves to the fruit by phosphorus. 

 It is a valuable element of plant-food when it is desired to 

 rush the growth of young plants. 



The chief function of potassium is the formation of starch 

 and cellulose. It thickens the cell-walls and makes the plant 

 more rigid. It goes into the plant in solution as do other 

 foods and assists in the assimilation or utilization of phos- 

 phorus and nitrogen. It increases root development and in 

 some instances enables plants to resist disease. Like nitrogen, 

 it delays maturity. 



The source of the various elements of plant-food that make 

 up a fertilizer is important in order to get the slowly available 

 and quickly available elements in the correct proportion. 

 There is frequently a great discrepancy between the costs of 

 plant-food from different sources, and it behooves the grower 

 to select such materials as will give him the desired fertilizer 

 mixture at the least cost. 



Fertilizer experiments. 



Various fertilizer mixtures have been proposed for both 

 young and bearing pecan trees by practical growers and 

 investigators. While there is a wide range in the mix- 

 tures recommended, enough experimental data have been 

 accumulated under actual orchard conditions to be indi- 

 cative of the plant-food requirements of the pecan on 

 a number of soil types used for commercial plantings. 

 Even though the pecan-grower has the results of carefully 

 conducted fertilizer experiments on the same soil type as his 

 own, he should give serious thought to fertilizing his trees. 

 Especially should he observe the effect of each fertilizer ma- 



