FROST PROTECTION IN LEMON ORCHARDS, 



17 



^eqooo — 



the freeze. In some of the nonheated plats, very few merchanta})lo 

 fruits were taken from the trees during the same period. On the 

 other hand, in the heated pLats the greater proportion of the fruit, 

 even during the period immediately following the freeze, was mer- 

 chantable, with a relatively small number of frozen lemons. 



In order to illustrate these comparisons graphically, 

 some diagrams are presented. Figure 6 gives the pro- 

 portion of frozen and merchantable fruits produced on 

 plat 1, an acre of nonheated Lisbon lemon trees, and 

 plat 4, an acre of heated Lisbon lemon trees, for each 

 picking during the calendar year 1913. This diagram 

 is based upon the data presented for these plats in 

 Tables V and VIII. 



As pointed out in a previous discussion of the data 

 presented in this bulletin, the only accurate way to 

 compare the behavior of the fruits in the heated and 

 nonheated plats is in terms of numbers of fruits rather 

 than weights. The frozen lemons dried out so rapidly 

 that no safe comparison could be made by using the 

 number of pounds or even the number of boxes of fruits 

 produced on an acre. For this reason, in this and all 

 succeeding diagrams, the differences are shown graphi- 

 cally in numbers of fruits. 



In the February picking in nonheated plat 1, the 

 estimated number of frozen fruits taken from the trees 

 was 183,410, as compared with 28,960 frozen fruits in 

 heated plat 4. No merchantable fruits were taken from 



the nonheated or- 

 chard at that pick- 

 ing, while 92,460 

 merchantable lem- 

 ons were picked in 

 the heated orchard 

 during the same pe- 

 riod. While many 

 of the frozen fruits 

 which were taken 

 from the trees at that time normally would not have been picked until 

 much later in the season, in order to obtain any records of these fruits 

 it was necessary to pick all which showed signs of having been frozen. 

 All fruits about which there was any question were left until later 

 pickings. This condition applied to all the plats. 



In the April picking the estimated number of frozen lemons removed 

 from the nonheated plat was 83,360, as compared with 1,980 from 



^-'-^£»77£0 



X 



JU 



nil - nn 



II 



Fig. 6.— Diagram sho\ving the number of frozen and merchantable fruits 

 produced on plat 1, a nonheated acre of Lisbon lemon trees, and plat 

 4, an acre of heated Lisbon lemon trees. The figures here sho\sTi are 

 taken from Tables V and VIII, respectively, which give the esti- 

 mated production by grades for each month's picking for these 

 plats during the calendar year 1913. 



