Asparagus investigations in south Louisiana

Transcription

1 Louisiana State University LSU Digital Commons LSU Agricultural Experiment Station Reports LSU AgCenter 1936 Asparagus investigations in south Louisiana William Duke Kimbrough Follow this and additional works at: Recommended Citation Kimbrough, William Duke, "Asparagus investigations in south Louisiana" (1936). LSU Agricultural Experiment Station Reports This Article is brought to you for free and open access by the LSU AgCenter at LSU Digital Commons. It has been accepted for inclusion in LSU Agricultural Experiment Station Reports by an authorized administrator of LSU Digital Commons. For more information, please contact

2 LIBRARY ^7 JANUARY, 1936 LOUISIANA BULLETIN No. 270 Asparagus Investigations In South Louisiana By W. D. KIMBROUGH LOUISIANA STATE UNIVERSITY AND AGRICULTURAL AND MECHANICAL COLLEGE AGRICULTURAL EXPERIMENT STATIONS C. T. DOWELL Director

3

4 3 Introduction Occasionally a venture in commerical asparagus production is tried in the far South. A fewi of these trials have been made in Louisiana. Judging by the growth made by the plants the first year after the crowns are set out, the projects seem very encouraging, but none has proved successful. The usual explanation for the failure of asparagus in this section is that the winters are not cold enough to insure a sufficient dormant period. The size of spears produced has been in general relatively small. Review of Literature Asparagus has received considerable attention from investigators in some sections of the United States, but very little emphasis has been placed on it in the South and practically none in the far South. Jones and Robbins (3) state that in the Imperial Valley a few growers cut asparagus in the fall. It was thought possible to cut part of the crop in the spring and part in the fall, but indications were that spring cuttings were delayed on beds that had been cut in the fall. They say that the age to begin cutting asparagus beds is from two to three years, varying with the growth of the plants and the section of the country. Starting to harvest the crop the second year is practiced rather generally in the South. Jones (2) found at Davis, California, that 18-inch spacing of crowns was best on 71/2-^ ^ rows for asparagus which was cut green. Greene (1) reported that staminate plants were more productive than pistillate plants. This was later found to be true in California by Jones and Robbins (3) and in Massachusetts by Tiedjens (6). These investigators found that a higher percentage of large sprouts was produced by pistillate plants. On this account, Tiedjens did not believe selections of staminate plants for planting to be of practical value. Results in California indicate that staminate plants yield more profitably than pistillate plants. Working (7) found that the branching of asparagus shoots is governed chiefly by temperature, being more rapid at higher temperatures.

5 4 Lewis (4) presents data which show that severe cutting of asparagus injured both the yield and grade of spears. The more severe the cutting, especially in the early years of the plantation, the greater the permanent injury. Morse (5) conducted extensive studies concerning the chemical composition of the asparagus plant. He found that the reserve material stored in the asparagus roots in the autumn was principally sugars. The spring cutting of an asparagus crop considerably reduced the sugars in the storage roots. The Problem The work here reported was undertaken to answer the question of whether or not commercial asparagus production can be successful in the far South and, if not, to determine the reasons why. The cutting of asparagus in the fall is practiced to some extent, and it was thought desirable to get information concerning the possibilities of fall production here. It was believed that the fall crop might prove worthwhile, even if the spring crop was not a success. As pistillate plants have been found to produce larger shoots than staminate ones, it was thought that the use of pistillate crowns might help overcome the handicap of the production of small spears. The Mary Washington variety, which produces large spears, was used to help overcome this problem. The age to begin cutting and the fertilizer requirements were studied. Procedure and Methods Seed of the Mary Washington variety was planted in the spring of 1930, and the crowns used in this experiment were grown from them during the growing season that year. In the fall many seedling plants were blooming and it was possible to select the pistillate and staminate plants needed for that phase of the work. The crowns were set in the field in December of The soil on which they were planted was a rich Lintonia silt loam at the Louisiana Agricultural Experiment Station. The crowns were set 18 inches apart on rows 5 feet wide and 150 feet long. Ridged rows were used because they are necessary for drainage in this section of the country. The size of plots on which records were kept was 5 by 100 feet for all treatments except the ferti-

6 lizer test, the other, 50 feet of row being used to obtain crowns 0 for sampling purposes. The size of plots in the fertilizer test was 5 by 50 feet. All treatments were run in triplicate except the "sex of plant" tests, which were run in duplicate. All plots except those in the fertilizer test received an application of 800 pounds of per acre, which was applied in early spring, and a top-dressing of 200 pounds of nitrate of soda, applied after the cutting season was over. The treatments given were: 1. Time of cutting test. Cut in the fall. Cut in the spring. Cut l/ 2 in fall and l/ 2 in spring. The first fall cutting was made after two growing seasons, and the first spring cutting was made the following year. The full fall cutting season was six weeks. 2. Effect of sex of plant. Staminate plants. Pistillate plants. Alternate staminate and pistillate plants. The first the crowns were set out. cutting was made in the spring two years after 3. Age to begin cutting. Cutting started in the spring one year after the plants were set out. Cutting started in the spring two years after the plants were set out. Cutting started in the spring three years after the plants were set out. The cutting season for plots cut one year after setting out was about four weeks. After the second year, the cutting season in the spring was about two months. 4. The various fertilizer applications used in the fertilizer test are given in table 5. The crop was harvested as green cut asparagus. Spears were trimmed to a length of 8% inches. Arbitrary grades were used as follows: Spears weighing 15 grams or over were called No. l's; those weighing from 10 to 15 grams, No. 2's; and those

7 6 weighing less than 10 grams, No. 3's. Yield records were obtained in grams from the weight of the spears. Storage roots were analyzed for moisture content, reducing sugars, total sugars as invert, acid hydrolyzable material, and soluble and insoluble nitrogen. Approved methods were used. Plants for sampling were selected for uniformity of top growth. Crowns to be dug when there was no top grown were staked while top growth was present, and samples for analysis were taken by selecting representative storage roots from three carefully dug crowns. The roots were thoroughly washed and the excess moisture allowed to dry off. They were then ground in a food chopper and samples preserved in alcohol until analyses could be made. Moisture content was determined by drying about 10 grams of ground material to constant weight at 90 C. To harvest a fall crop of asparagus the tops were cut at the surface of the ground and removed. The new shoots that were put out were harvested. Experimental Results The plants came up and grew splendidly the first year, attaining a height of about five feet. It was noticed, however, that a new set of shoots came up approximately every month and thus there was a continual production of shoots and new top growth during the growing season. This continual production of shoots and tops occurred every growing season and is believed to be an important factor concerning the culture of asparagus here. Results obtained with the time of cutting test Yields obtained from this test are shown in table 1. The harvest seasons are divided into periods, so that yields for the plots cut half in the fall and half in the spring may be compared with cutting periods of the same lengths of time for plots cut in the fall or spring only. The data show that after three weeks practically no yield was obtained in the fall, except for No. 3 spears. After the first year's results were obtained, it was thought that possibly the harvest season was started too late; so the next year the harvest was begun three weeks earlier but with similar results. Yields in the fall were very low, being almost nothing the third year harvests were made. Cutting in the fall materially reduced the yield produced by those plants in the spring.

8 7 TABLE 1. YIELDS OF ASPARAGUS IN POUNDS PER ACRE IN TIME OF CUTTING TEST No. l's No. 2's No. 3's Treatment 1932* Cut in Fall (6 weeks) 1st 3 weeks nd 3 weeks Total Cut V2 Fall % Spring 3 weeks in Fall % Spring season Total Cut in Spring 1st half of season nd half of season Total Spring harvest is following year in each case. TABLE 2. ANALYSIS OF CROWNS IN THE TIME OF CUTTING TEST* Non- Acid Reduc- reduc- hydroing ing lyzable Insolu- N % Date of Mois- sugar sugars mater- ble Soluble Treatment sampling ture % % % ial % N % Cut in Spring Aug. 31, None Cut in Fall Aug. 31, Cut in Spring... Oct. 6, Cut % Fall % Spring.Oct. 6, Cut in Spring Oct. 27, Trace Cut in Fall Oct. 27, Cut in Spring. Jan. 19, Trace Cut in Fall Jan. 19, Results given are for Quite similar results were obtained in 1932 and In table 2 are shown analyses of crowns made in connection with the fall cutting test. The important food reserves in the crowns are non-reducing sugars. The data show that with the cutting of spears the reserve sugars are rapidly depleted. When these are reduced to between 4 and 5 per cent on a fresh weight basis, only very small spears are produced. From the time cutting was stopped in the fall until the newly put out tops were killed by cold, the plants did not build up as much reserves as did uncut plants. Effect of sex of plant on yield obtained Yields from this test are given in table 3. The data show

9 8 that the staminate plants consistently outyielded the pistillate ones. This was true even for the larger sized shoots. The low yields in either case show that pistillate plants cannot be expected to produce good yields of large spears in the far South. "Age to begin cutting" results The yields obtained in this test are given in table 4. Spears were cut for a period of only four weeks on the plots that were cut the first year. Cool weather prevailed during this period and very small yields were obtained. A hard freeze killed the shoots of all plots to the ground during this period. The small cutting made the first year did not affect subsequent yields. Plots that were not cut until the third year gave slightly higher yields that year than those that had been cut previously, but all yields were very low. From 1933 to 1935 yields decreased rapidly, showing that under the conditions of the experiment there was no need to continue it. TABLE 3. EFFECT OF SEX OF PLANT ON YIELD YIELD IN POUNDS PER ACRE No. l's No. 2's No. 3's Type of plant Staminate Pistillate Alternate Staminate and Pistillate TABLE 4. EFFECT OF AGE WHEN CUTTING WAS STARTED ON YIELDS OF ASPARAGUS IN POUNDS PER ACRE Age cutting No. 1 No. 2 No. 3 was begun First year after setting crowns Second year after setting crowns Third year after setting crowns

10 9 TABLE 5. YIELD IN POUNDS PER ACRE OF ASPARAGUS FROM PLOTS RECEIVING DIFFERENT FERTILIZER TREATMENTS. No. 1 No. 2 No. 3 Fertilizer treatment NP ft K R i ft q a NK PK NPK Check - no fertilizer fiftft-h- A 19 A nlno 9 ft ft NaNOgT. D # plus 200 NaNOgT. D # plus 200 NaNOgT. D # plus 200 NaNOgT. D # No topdressing Fertilizer Test Table 5 shows the results obtained from plots receiving different fertilizer treatments. The results do not show anyconsistent increase from fertilizer, although in general the fertilized plots produced higher yields than the unfertilized. Yields were low in all cases and showed a steady decrease in marketable spears from 1933 to The main value of these results is to show that the application of fertilizer cannot be expected to give and maintain profitable yields under climatic conditions unsuited to asparagus production. Analyses of Crowns from Plants Cut in the Spring Storage roots of crowns from pistillate and staminate plants and those cut the first, second, and third years were analyzed. No consistent differences due to treatments were found, so the results, which are presented in table 6, are given as averages rather than individual treatments. These data also show that sugars are the important food reserves and are rapidly depleted by the production of spears for harvest. Apparently not enough food reserves are stored to produce a good crop of spears. During the summer season some analyses were made of storage roots from plants from which spears had been harvested in the spring. In the spring of 1935 an analysis was made from plants which were not cut at all during the harvest season. These results are given in table 7. They indicate that during the active growing season only small amounts of reserves were accumulated. The results from the' uncut sample indicate that

11 10 reserves are depleted in crowns whether shoots are cut or not. The growth of tops was apparently a heavy drain on the food reserves. If this is true, it explains why the continual production of shoots during the growing season is so detrimental to the storage of reserve food in the roots. TABLE 6. ANALYSES OF CROWNS OF SPRING CUT ASPARAGUS TAKEN DURING THE DORMANT SEASON AND AT THE END OF THE HARVEST PERIOD. FRESH WEIGHT BASIS Acid hydro- Non- Reducing reducing lyzable Date of sampling Moisture sugar sugars material Insoluble Soluble % % % % N % N % January 26, April 17, January 19, Trace May 11, January 28, Trace 8.63 April 22, TABLE 7. ANALYSES OF ASPARAGUS CROWNS DURING THE GROWING SEASON, AND ONE FROM UNCUT PLANTS Treatment Date of sampling Moisture Reducing sugar % Non-Reducing sugar % Cut in Spring July 9, Cut in Spring August 9, 1934 Uncut April 26, Trace Trace Discussion The yield data which have been presented show that in the far South spring yields of asparagus may be expected to be much higher than fall yields. The spring yields obtained were low, however. Cutting for a short time in the fall seriously reduced spring yields. The production of spears of asparagus for harvest is dependent on the reserve food, mostly non-reducing sugars, stored in the roots. Analytical data presented show that the small yields of asparagus produced greatly reduced these materials in the storage roots, indicating that insufficient reserve food was stored to produce a good crop. The plants produced continual crops of new shoots during the growing season and thus, instead of storing adequate reserves to produce a good crop, dissipated their energy. During the growing season the sugar content in the storage roots varied to some extent, probably changing with production of new shoots, but not much storage of reserves occurred until late fall. At the period for fall cutting, food reserves in storage roots were lower than at the time for spring harvest to start.

12 11 The appearance of the top growth of neglected or uncut plants may easily give the impression that if plants were cared for they would produce a profitable crop. Each year there was sufficient cold in the winter for a period of dormancy. The results obtained from this experiment lead to the conclusion that the reason asparagus is not adapted to the far South is not so much lack of a winter dormant period as a lack of sufficient storage of reserve food to produce a goo'd crop. A warm spell during winter or early spring may cause shoot growth to start, and a subsequent freeze may cause injury. This is another disadvantage in tire growing of asparagus in this section. Hot weather in the fall or late spring may cause the spears to bud out very early and so interfere with the market grade. The eating quality of the asparagus produced in both spring and fall is excellent. The low yields and small size of the spears are the limiting factors of commercial production. Conclusions The commercial planting of even the Mary Washington variety cannot be recommended for either spring or fall production in south Louisiana. Fall harvests cannot be recommended under any condition. As asparagus is ready for harvest at a time when other locally-grown vegetables are relatively scarce, it might be grown for home use or local market to some extent. Asparagus should be grown only where weeds and grass can be controlled easily and where garden space is plentiful, as it occupies considerable space. Literature Cited 1. Greene, W. J. Asparagus. Ohio Agr. Expt. Sta. Bui Jones, H. A. Spacing studies with asparagus. Cal. Agr. Expt. Sta. Bui Jones, H. A., and Robbins, W. W. The asparagus industry in California. Cal. Agr. Expt. Sta. Bui Lewis, E. P. Asparagus yields as affected by severity of cutting Agr. Expt. Sta. Bui Morse, F. W. A chemical study of the asparagus plant. Mass. Agr. Expt. Sta. Bui Tiedjens, V. A. Some physiological aspects of asparagus officinalis. Proc. Amer. Soc. Hort. Sci. No Working, Earl B. Physical and chemical factors in the growth of asparagus. Ariz. Agr. Expt. Sta. Tech. Bui

13