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VOLK: TOMATO LEAF ROLL It is evident that in the last twenty years we have doubled our yields in these crops. Seed has played its part in this condition as much as has any of the other contributing factors. Now let us see what has happened in the last ten years as far as some of our vegetable crops are concerned: (2) Total Acreage Crop Year 1948 Snap Beans (Winter) 1948 1957 Celery (Winter) Celery(Winter) 6,300 6.3CO 1948 Celery 5,300 4,000 1957 1957 (Spring) Yield per A. 87 Bu. 19,000 16,900 123 Bu. 540 Crates 653 CrateB 430 Crai 600 Cr< 9,600 26,300 1948 1957 Tomatoes (Spring) 1948 1957 15,900 18,800 We can see from the above figures that we have made good gains in production in the past decade. By using all our know-how and obtaining better seeds for our crops, we should be able to make continued progress and im prove the quality of our crops. A study of the Annual Reports from our Florida Experiment Station shows that con siderable work and effort is being made to ward improving seed quality. This is as it should be, for improving the seed we use is 69 quite as important as any other project the Experiment Station could undertake. One final word on this subject of adaptabil ity for our farming conditions. We all know of crops which will grow well and produce good quality yields in some areas, but which, for some unknown reason, will not do well at all under our crop conditions. With this thought in mind, our company is experimenting this year with two types of celery. The first is a variety grown from Florida-produced seed and selected for its growth habits. The second is the original parentage, and has not been crossed to get hybrid vigor: It is this second type of celery which is the best we have in our fields. Both types were planted the same day, transplanted into the field the same day, and all other contributing factors were as equal as we were able to make them. This problem of seed adaptability is a big one, and to solve it satisfactorily, all of us in the industry must work together. A practica\ solution to the seed question is our only means of staying in the business. LITERATURE CITED 1. Information supplied by Dr. H. G. Hamilton of the Agricultural Economics Department, University of Florida. 2. From the Florida Vegetable Crops Statistical Summary of 1957. EFFECT OF UREA NITROGEN ON NUTRITIONAL LEAF ROLL OF TOMATOES Gaylord M. Volk1 Florida Agricultural Experiment Station Gainesville The correlation between nutritional leaf roll of solanaceous plants and low supply of ni trate nitrogen in the soil was first brought to attention by Volk and Gammon (2) as a re sult of work on Irish potatoes, and by observa tions on tobacco, tomatoes and certain other solanaceous crops (3). It appeared that the roll developed when nitrate nitrogen and am monia nitrogen were out of balance, and the plant was using nitrogen primarily in the am monia form. Urea nitrogen is a widely used form of fer tilizer nitrogen, both for direct application to 'Soils Chemist. Florida No. 829. Agricultural Experiment Station Journal Series. the soil and as an addition to spray materials for application to aerial portions-of the plant. It is important that the effect of urea as com pared to the effect of ammonia and nitrate be determined with respect to effect on both, nutritional leaf roll and the uptake of other ions, particularly calcium and potassium. Such information would help to determine whether the high concentration of the ammonia ion or the low concentration of the nitrate ion in the plant is primarily responsible for the leaf roll, and to what extent the nitrate ion may be in directly influencing the relative uptake of various bases such as calcium and potassium. Typical nutritional leaf roll on potatoes was shown in a previous publication (2). The de velopment of leaf roll of tomatoes is typified by Figure 1. This condition resulted from planting tomatoes on land that had been in grass sod for the eleven years previous to turn- 70 FLORIDA STATE HORTICULTURAL SOCIETY, 1958 carboys of fresh solution prepared daily. The plants were grouped according to size for each replicate so that results within a replicate would be comparable. The solutions used in the study were similar except for the source of nitrogen used. Each five gallons of solution contained the follow ing: 2.8 grams Nitrogen (variable sources de pending on treatment) 7.0 grams CaSO, • 2H2O 6.0 " KHJPO 8.0 " MgSO, • 7H,,O 51 mgm H3BO3 33 " MnCL • 4H,,O 4 " ZnSO4 • 7HaO 1.4 " CuSO4 • 5H.O 0.4 " KLMoO4 • 4H2O 90 " Iron tartrate Nitrogen sources for the four different solu tions were as follows: I Calcium nitrate Fig. 1. Typical nutritional leaf roll on tomatoes. These tomatoes were planted on turned eleven year old sod, and fertilized at planting with a mixture low in nitrate nitrogen. . grew New leaves are developing free of leaf roll. They recfollowing application of 70 pounds of nitrate of soda soc ommended to correct the condition. ing for tomatoes. The drill application of fer tilizer was 1800 pounds per acre of 5-7-5 con taining 0.75 percent nitrate nitrogen, followed by a side dressing of 5-0-10 containing only 1.5 percent nitrate nitrogen. The new leaf development at the top of the plant was free of the symptoms at the time the pictures were taken. These leaves developed subsequent to two side dressings of nitrate of soda totalling 70 pounds per acre. The important factor in this instance may be that old pasture land was involved. Previous work has shown that some soils left in grass sod for several years have very limited ability to nitrify ammoniacal nitro gen to nitrate. The same is true of most virgin and strongly acid soils. (1) Experimental Procedure Tomato plants approximately four inches tall were placed in straight wall funnels, 3.5 inches high and 1.75 inches in diameter, as shown in Figure 2. Tests were run simultane ously in triplicate. Each funnel was fitted with an automatic syphon arrangement that re moved the liquid from the roots of the plant at approximately 10 minute intervals and al lowed the funnel to refill by a slow drip from II Ammonium nitrate III Ammonium sulfate IV Urea All solutions were approximately pH 5.0. Results and Conclusions Relative size of plants after 18 days growth are shown in Figure 2. Dry weights of plants and the chemical analyses of the tops are given in Tables 1 and 2. With the exception of one plant which made relatively poor growth in the third replicate of ammonium nitrate the data for a given treatment are reasonably consistent considering the fact that they are single plant tests. Typical nutritional leaf roll was evident on plants receiving ammonium sulfate or urea, but the leaves of plants receiving ammonium nitrate or calcium nitrate were normal. Figure 3 is a closeup of a plant from the urea treat ment and shows the leaf roll developing on the largest leaves. It is interesting to note that despite the greater plant dry weight and ob served size of the urea treated plants as com pared to the ammonium sulfate treated plants, the total nitrogen uptake from the two ma terials is relatively constant at .041 grams and .049 grams, respectively. These are one-half or less of the quantity found where nitrate nitrogen was present in the solution. Plants from the calcium nitrate and ammonium ni trate treatments were about equal in dry I III Fig. 2. Calcium nitrate im&nLwk sarolfate ! / Tomato plants growing in rapid flow nutrient solutions. FLORIDA STATE HORTICULTURAL SOCIETY, 1958 72 weights. Percentage nitrogen was lowest with urea and highest with ammonium nitrate. Percentage calcium was consistently low with the ammonium sulfate and urea treatments where leaf roll occurred, but total calcium uptake was considerably higher for urea than for ammonium sulfate. The effect of the nitrate ion in mobilizing calcium into the plant may be the actual reason for the effectiveness of nitrate nitrogen in preventing leaf roll in the field. Uptake of phosphorus was lowest per centage-wise with calcium nitrate and uptake of potassium was lowest with ammonium ni trate and ammonium sulfate. Fig. 3. Effect of urea nitrogen on the development of nutritional leaf roll. Note the trough-shaped older leaves typical of the first stages of development of nutritional leaf roll. It was anticipated that limited root develop ment might be observed where leaf roll oc curred, but this was not the case except for the ammonium sulfate treatment, where gen erally limited growth occurred. A comparison of ammonium nitrate and urea treatments is particularly interesting because all ions ex cept those of nitrogen were exactly the same. Table 1 Effect of Nitrogen Source in Rapid-Flow SolutL on Cultures on Percentage Composition and Nutritional Leaf Roll of Tomatoes. Nitrogen Replication Source Calcium 1 2 Nitrate 3 I Plant Tops % Ca Dry Wt. Qrams % N 3.29 3.05 3.7U 2.87 3.88 Ave. 1 3.30 2 2.83 3 1.33 Ammonium* 1 2 1.12 1.60 Sulfate 3 II Ammonium Nitrate 2TIT9 Ave. III IV Urea* U.95 iu89 U.UU HTFo" 3.92 3.22 3^2 % P % K 3.53 1.12 2.9U Iu03 T733 3.30 2.15 2.00 U.10 U.U6 2.18 2.5U 1.69 1.58 T7IF 1 2.76 1.81 2.02 2.21 1.86 Aveo 233 2.52 T35 2.05 1755" L.S.D. .91 o78 •52 1.81 3 3.60 3.36 2.U0 2.U2 2.30 2.00 1.30 Ave. 2 l.Ul 1.U6 Statistical value for least significant difference .91 .95 .82 7m 2.69 1.98 2.08 1.30 1.28 .59 .57 1.50 1735 $ 2oll 2.82 1.10 2.58 3.00 3.10 2.75 2.97 .6U at .91 27S7 .30 * Nutritional leaf roll was evident where nitrate nitrogen was lacking. L.S.D. .36 OF 2725 1.72 Plant Roots Wt. Grams the 5% point. .70 .8U 75F .23 73 VOLK: TOMATO LEAF ROLL Table 2 Effect of Nitrogen Source on Total Uptake of Nitrogen, Calcium, Phosphorus and Potassium by Tomatoes Total Grams in Plant Tops Dry Nitrogen Source I Calcium Nitrate Replication Weight N 1 2 3.29 .100 Nitrate ITI IV Urea .037 .OUO K .097 .103 .080 .107 .100 TiiU 3.30 .151 .138 .072 .072 2iU9 TuZ 7b59 vO5U 705? 1 2 1.12 .oUU •021 .019 .030 .032 .015 3 .013 .017 3 1 2 3 Av. Ammonium Sulfate .116 .118 P 2.87 2.39 Av. II Ammonium Ca 2T% 2.83 Ia32 1.60 .093 .059 Av. .^ .052 •028 1.18 1 2 2.76 1.81 1.81 .056 .oUo .0U6 3 Av. L.S.D. .107 .03U .071 .066 .065 .027 .068 .032 •020 .012 IbiS .051 .058 .050 .05U .020 .021 .031 TiUo .91 •OU6 .021 Tomato plants four inches tall were placed in straight wall funnels fitted with automatic syphons to change nutrient solutions every ten 7o93 7526 IoU7 Summary .037 ToiF 2.13 Use of the other two nitrogen sources re sulted in variation of calcium and sulfate ions. Plant growth and the total uptake of nitrogen and calcium were greater with ammonium nitrate than with urea, but the total uptake of potassium was higher and that of phos phorus about equal for urea, despite the greater growth with ammonium nitrate. Indi cations are that the urea was taken into the plant in a form other than the ammonia ion. In the process it had a unique effect on the uptake of associated ions as compared to other forms of nitrogen. .035 .0U7 .078 minutes. A complete nutrient solution was used, but nitrogen was supplied from four different sources—calcium nitrate, ammonium nitrate, ammonium sulfate or urea. Nutritional leaf roll was not present where nitrate nitrogen was added, but did occur where urea or ammonium sulfate was used. Uptake of calcium also was least with these two treatments. Plant growth was greatest where nitrate was present and least with am monium sulfate. Despite the fact that growth with urea was much greater than with am monium sulfate, the total nitrogen uptake was similarly low. With the ammonium nitrate and urea treatments it was possible to balance exactly all ions except those of nitrogen. Data indicate that the urea was taken into the plant in a form other than ammonia, probably as 74 FLORIDA STATE HORTICULTURAL SOCIETY, 1958 urea itself, and in the process had a unique effect on the uptake of other ions as compared to the effect of ammonium nitrate. It appears that the effect of nitrate nitrogen in mobilizing calcium into the plant should be given further consideration in efforts to determine the causes of nutritional leaf roll of solanaceous plants, even though the previous work on potatoes (2) did not indicate that calcium was factor. LITERATURE the CITED 1. Shih, Shui-Ho. Factors affecting the nitrifying power of certain Florida soils. Unpublished thesis, University of Florida. Sept. 1949. 2. Volk, G. M. and N. Gammon, Jr. Effect of liming and fertilization on yield and the correction of nutritional leaf roll of Irish potatoes. Fla. Agric. Exp. Sta. Bui. 504. 1952. 3. Volk, G. M. Maintenance of available nitrogen in Florida soils. Fla. Agric. Exp. Sta. Ann. Rept. 1952. p. 128. FLORIDA VERSUS CALIFORNIA CELERY IN THE MIDWEST CONSUMER MARKET ine quantitatively the nature of the competi tive relationship between Florida and Cali fornia celery. Marshall R. Godwin Marketing Economist University of Florida Method of Procedure Gainesville Throughout the harvesting and marketing season, the Florida celery crop faces direct competition from California in the market cen ters of the Eastern United States. Moreover, from both the standpoint of price and of ap parent market preference, California celery has generally occupied the most advantageous position in the marketplace. The fundamental role of firms within the structure of the terminal market is the acquisi tion of fruit and vegetable supplies in a fash ion that reflects the desires of the ultimate consumer. Thus, the manifest preference of marketing firms for California celery suggests that the underlying problem confronting the Florida celery industry stems from the exist ence of a similar preference on the part of the consumer. In recent years, growers and marketing agencies in Florida have demonstrated an in creasing interest in the nature of the competi tive relationship between Florida and Cali fornia celery. This interest stems from an ap preciation of the fact that one of the first steps toward improving the economic position of the Florida celery industry should consist of an examination of the competitive condi tions under which the crop is marketed. To partially meet the informational needs of celery growers and shippers in connection with this problem, a study was conducted in the Chi cago metropolitan area during the spring of 1958. The purpose of this study was to exam Since primary interest lay in the determina tion of the degree to which consumers prefer celery from one producing area over that from the other, the research procedure employed in the study entailed the creation of retailing situations where the homemaker could readily compare Florida and California celery in the process of making a buying decision. Within the market area selected, a series of retail store tests were conducted in which customers were afforded an opportunity to choose from either of two displays containing celery representa tive of the types produced in Florida and California. The test displays of California celery con sisted of the Utah 52-70 variety, while the Florida displays were Summer Pascal. Only celery of the U. S. No. 1 grade was employed in the market tests. While considerable effort was devoted to the maintenance of displays typical of this quality level, equal care was exercised to assure that the test displays did not reflect a quality level higher than that customarily found in U. S. No. 1 celery. Throughout the study, size 2& celery from both producing areas was used in the market ing tests. This size was selected because it ap proximated the modal group in the total range of sizes shipped from the two areas during normal growing seasons. The fact that consumers may prefer celery from one producing area over that grown in another is relevant only when this preference is established within the price frame of refer-