Field Truck Crops 251 



On soils which possess only good mechanical condition, 

 and are very poor in plant-food, a heavier application of 

 both nitrogen and the mineral elements will be required, 

 in which case the following fertilization is recommended : 



Previous to setting the plants, or at the time they are 

 set, apply 75 pounds to the acre of phosphoric acid, pref- 

 erably derived from superphosphate, and 100 pounds of 

 potash, derived from muriate, and thoroughly harrow or 

 cultivate into the soil ; and at the time of setting apply 

 around the hill 100 to 150 pounds to the acre of nitrate of 

 soda. Three to four weeks later, make another application 

 of from 100 to 150 pounds to the acre of nitrate of soda. 

 Owing to the small bulk of nitrate, it should be mixed with 

 dry soil or sawdust, in order to insure even distribution. 

 The only precaution to be observed is to prevent its im- 

 mediate contact with the plant roots. If these methods 

 are practiced, the plant secures its nitrogen in an im- 

 mediately available form at a time when it is needed, 

 when it is set in the field. There is thus no delay in growth, 

 and because of the presence of an abundance of the mineral 

 elements, no excessive growth of vine is encouraged by the 

 use of the nitrate, as would be the case were the mineral 

 elements absent. Inasmuch as the nitrogen is applied 

 close to the plant, it is within the immediate reach of its 

 roots; and because it is all in an immediately available 

 form, which is used up rapidly, the tendency to late plant 

 growth, which would be caused by a continuous supply 

 of nitrogen, is not encouraged, and a normal and rapid 

 growth and development of fruit results. 



It is not stated that by this method of fertilization 

 maturity is increased in the sense that the date of the first 

 picking is earlier, but that a larger number of fruits is 

 picked earlier. It was not shown in any of the experiments 



