Effects of Different Fertilizers and Continuous No-Till Production on Diseases, Growth, and Yield of Staked Tomato

Craig H. Canaday, Jim E. Wyatt, and Don D. Tyler

Interpretative Summary

The effects of plant growth-promoting rhizobacteria (PGPR) and different potash fertilizers on diseases, growth, and yield of no-till and conventional tillage staked tomatoes were evaluated in a factorial experiment. Eight different tillage-PGPR-potash combinations were included in the study. In this fifth year of the continuous no-till system, no-till tomato production led to slower plant growth and lower yields than the conventional tillage system. Use of sulfate of potash instead of muriate of potash increased plant growth early in the season, but led to an increase in the incidence of Sclerotinia stem rot. Yields of extra-large tomatoes were increased with sulfate of potash while yields of medium and large tomatoes were decreased. Use of PGPR increased the growth of transplanted tomatoes. Early yields were also increased with PGPR without affecting total yields.

Introduction

West Tennessee silt loam soils are some of the most highly erosive soils in the United States. No-till production of West Tennessee row crops has increased significantly in recent years as growers have learned the advantages of this production system and as UT researchers have developed the management techniques needed for successful no-till production of cotton, corn, and soybeans. Advantages include decreased soil erosion, improved soil structure, increased water infiltration, and more timely access to fields for applying pest management sprays or for conducting planting and harvesting operations. Some of these advantages, e.g. improved soil structure and water infiltration, are not fully realized until no-till production systems have been continuously used for several years.

Most research on no-till production of vegetable crops has not been of a continuous nature. Fields are tilled in the fall to plant a winter cover crop, such as wheat or hairy vetch. The cover crop is killed the following spring with herbicides, then vegetable crops are planted using no-till production techniques. At the end of the growing season, however, the field is again tilled and seeded with another winter cover crop. The research reported here seeks to evaluate the effects of a continuous no-till production system on diseases, growth, and yield of staked tomato. Effects of other management decisions, such as fertilizer choice, are incorporated into the study. Their specific location within the test changes each year.

Materials and Methods

Site description. The soil in the test field was a Calloway-Henry silt loam complex, 0-2% slope with 1% O.M., high soil test levels of available P, and moderate to high soil test levels of available K. The soil contained over 1280 lb Ca/acre, over 64 lb Mg/acre, and approximately 5 lb Zn/acre. Soil pH in plots ranged from 6.0 to 7.0 with a mean pH of 6.6 (fall 2000 soil tests). Pelletized Dolomitic Limestone with a Tennessee Relative Neutralizing Value (RNV) of 98.2 was hand-broadcast Feb 4, 2001, as needed over each 5 x 50 ft. plot at rates recommended by the fall 2000 soil tests.

Experimental design. The 2001 test was a factorial experiment with three factors: (1) tillage (i.e., no-till vs conventional tillage), (2) use of Plant Growth-Promoting Rhizobacteria (hereafter referred to as PGPR) (i.e., use of BioYield vs none), and (3) potash source (i.e., muriate vs sulfate). Each of the eight possible combinations of these factors was replicated four times in a randomized complete block design.

Tillage. The no-till plots had not been tilled since the fall of 1996 when they were seeded with Kentucky 31 tall fescue, while conventional tillage plots were tilled annually. In the 2001 test, a 'middle-buster' was used to simulate the use of a chisel plow in the latter plots. On April 9, the middle-buster with a single center shank was pulled down the middle of each conventional tillage plot, cutting a furrow 7 in. deep and 45 ft. long. The center shank was then removed and the remaining two shanks mounted on the toolbar 32 in. apart (16 in. on either side of the former center shank). The middle-buster was then pulled through the plots a second time with this new configuration, creating a ridge down the center of the plot and cutting two new furrows 5-6 inches deep on either side of the ridge. Hand rakes were used to pull soil tossed outside the conventional tillage plots by the second pass with the ‘middle-buster’ back into the plots (i.e., off the undisturbed grass beside the plots). A small disk was run over the plots (twice) on April 10 to cut-up large soil clods and to reduce the height of the ridge. After all operations were complete, the plots appeared as a tilled strip, 6 ˝ ft. wide, with a low ridge, 2 - 3 in. high, down the center of the each plot.

Fertilizers. The first application of nitrogen to both no-till and conventional tillage plots was on Apr 11, 3 ˝ weeks before setting transplants, at 15 lb N/4356 row-ft as a broadcast strip down the center of each plot. Nitrogen was applied after setting transplants six additional times (May 8 and 18; June 5, 13, 21, and 27) to all plots as sidedressings at 15 lb N/4356 row-ft per application. All plots were fertilized twice with potash at 30 lb K2O/4356 row-ft per application, once 3 ˝ weeks before setting transplants and again as a sidedressing one month after transplanting.

Transplants. Greenhouse-grown ‘Mountain Fresh F1' tomato transplants were used for all treatments in 2001. Tomatoes not receiving PGPR were seeded in 72-cell Speedling trays filled with Pro-Mix BX on March 14. Tomatoes that received treatment with PGPR were seeded in 72-cell Speedling trays on March 26. The latter trays were filled with Pro-Mix BX to which PGPR had been added. PGPR were incorporated into the potting mix by mixing one liter of BioYield with 39 liters of dry Pro-Mix BX to achieve a ratio of 1 part BioYield to 40 parts treated mix. [BioYield contains two difference species of bacteria that are purported to promote plant growth and yield.]

Other Cultural practices. Herbicides, supplemented with occasional mowing or hand-hoeing, were used for weed control. Roundup-Ultra at 1.5 quart/acre (2.0% solution) was applied down the center of no-till plots on March 15 in a 30-inch-wide band. Roundup-Ultra (2.0% solution) was applied to both no-till plots (30-inch-wide band) and conventional tillage plots (84-inch-wide) on April 5. A final application of Roundup-Ultra (2.0% solution) on May 3 was applied to both conventional and no-till plots one day before setting transplants to kill emerging yellow nutsedge.

The test was planted on the morning of May 4 using a modified mechanical transplanter (18 transplants/row). Plants were suckered once. Plots were irrigated as needed to avoid moisture stress and to help dissolve sidedressed fertilizers using a drip irrigation system consisting of 0.5 gallon/hr emitters spaced every two feet along side tomato rows. Plants were tied to stakes using a modified ‘Florida weave’.

Poast at 1.5 pint/acre was applied as a directed spray on each side of rows on June 8 to both no-till plots (18-inch-wide bands) and conventional tillage plots (18-inch-wide bands). Sencor 75 DF at 1.25 lb/acre was applied as a directed spray on each side of the rows on June 12 (15-inch-wide bands, no-till rows; 42-inch-wide bands, conventional tillage rows).

Fungicides were applied four times using a hydraulic sprayer: three applications of Quadris 2.08 SC at 5.8 - 6.2 fl oz/acre/application (on May 25, June 18, and July 24) plus one application of Bravo WeatherStik at 1.3 quart/acre (on June 29). Insecticides were applied five times: SpinTor 2SC at 5.8 fl oz/A on May 25 and Asana XL at 7.0 - 9.6 fl oz/acre on June 18, June 29, July 24, and July 30. All fungicide and insecticide sprays were applied at 300 psi using a hydraulic sprayer equipped with one to four (depending on plant height) ceramic, hollow-cone drop nozzles on each side of rows.

Data collection. The heights of all plants were recorded May 19 and June 22. Plots were checked every 1-2 weeks for the presence of any diseases, and disease incidence or severity ratings were collected as appropriate. Tomatoes were picked 2-3 times/week from July 6 through August 7 at the 'breaker-stage' of maturity (10 harvests). A final (11th) harvest of all green tomatoes of marketable size remaining on plants was made on August 7-8. Harvested tomatoes of marketable quality were graded by size into four categories: small (7 x 7 boxes), medium (6 x 7 boxes), large (5 x 6 boxes), and extra-large (4 x 5 boxes). Yields (boxes/acre) in the following tables are based on 3600 plants/acre. Small tomatoes were considered unmarketable and are not included in yield tables. All disease, growth, and yield data were subjected to analysis of variance (ANOVA) for a factorial experiment with a randomized complete block (RCB) design.

Results and Discussion

There was no difference in the mean heights of tomato transplants grown with or without BioYield; transplants with either treatment averaged 5.3 in. tall when set. Mean plant height by June 6 was significantly greater with use of BioYield than without BioYield (Table 1). Use of sulfate of potash instead of muriate of potash also increased mean plant height (Table 1). In contrast, mean plant height was significantly decreased with no-till compared to conventional tillage (Table 1). The growth advantage with BioYield was still apparent two weeks later but not the benefits with sulfate of potash.

The 2001 test was the second time in the five-year study in which significant disease losses were noted early in the growing season. Three tomato diseases were observed on the West Tennessee Experiment Station during the spring and early summer. An outbreak of Sclerotinia stem rot (white mold) appeared in early May and eventually killed many plants. Disease losses were significantly greater in plots receiving sulfate of potash than with muriate of potash (Table 2). Southern blight and tomato spotted wilt virus appeared in late May and killed or stunted an occasional plant throughout the remainder of the season. No treatment factors significantly affected the incidence of the latter two diseases (Table 2).

Total marketable yields were significantly higher with conventional tillage than with no-till (Table 3). This was largely due to a significant increase in the number of extra-large tomatoes. Sulfate of potash also significantly increased the number of extra-large tomatoes, with concomitant decreases in the number of medium and large tomatoes (Table 3). Total marketable yields were not significantly affected by potash treatment despite the significant differences in plant loss to Sclerotinia stem rot with sulfate of potash.

Use of PGPR (BioYield) significantly increased early yields (first six harvests) of marketable tomatoes (Table 4). The highest yield during this period was with conventional tillage combined with use of muriate of potash and BioYield (Table 5). Highest marketable yield for all 11 harvests was with this same combination, though it did not differ significantly from other seven combination treatments (Table 5). Severe yield losses due to insect damage were incurred during the middle of July as corn ear worms moved from a nearby sweet corn test to the tomatoes. When the total weight of fruit produced per plot (including culls and small tomatoes) was examined, yields with use of BioYield were consistently higher than those without BioYield for the first ten harvests, although not always at the 0.05 probability level (Table 6). The potential for BioYield to increase yields of marketable tomatoes, particularly early yields, needs to be verified with additional tests. The trends in the 2001 test at Jackson appear promising.

Table 1. Effects and interactions of tillage method, PGPR use, and potash source on plant height and flowering of staked tomato, Jackson, TN, 2001.

 

 

Factors

Mean plant height (in.)

Mean plant growth

June 6 and June 20-21

(in.)

June 6

June 20-21

Tillage method*

conventional

17.3 a

26.8 a

9.5

no-till

16.4 b

25.4 b

9.0

PGPR use*

none

16.3 b

25.4 b

9.1

BioYield

17.4 a

26.9 a

9.5

Potash source*

muriate (KCl)

16.5 b

26.1

9.6

sulfate (K2SO4)

17.2 a

26.2

9.0

Results of ANOVA (Probability > F)

tillage

0.003

0.02

0.28

PGPR

0.0003

0.01

0.40

tillage X PGPR

0.06

0.84

0.16

potash (K2O)

0.009

0.90

0.14

tillage X potash

0.003

0.93

0.04

PGPR X potash

0.04

0.05

0.22

tillage X N X K2O

0.73

0.17

0.06

replication

0.003

0.02

0.12

*Values are the means of 16 different plots. Significant differences within a factor are indicated by the use of different letters following the means (P = 0.05).

Table 2. Effects and interactions of tillage method, PGPR use, and potash source on plant losses to diseases of staked tomato, Jackson, TN, 2001.

 

 

Factors

Total plant losses by Aug 9

(%)

Sources of disease losses (% plants)

Sclerotinia stem rot

tomato spotted wilt virus

southern

blight

Tillage method*

conventional

13

9

2.4

1.4

no-till

17

14

1.4

0.7

PGPR use

none

14

10

1.4

1.7

BioYield

15

12

2.4

0.3

Potash source

muriate (KCl)

9 b

7 b

2.1

0.0

sulfate (K2SO4)

20 a

15 a

1.7

2.1

Results of ANOVA (Probability > F)

tillage

0.33

0.13

0.41

0.61

PGPR

0.79

0.50

0.41

0.31

tillage X PGPR

0.79

1.0

0.78

1.0

potash (K2O)

0.01

0.01

0.78

0.14

tillage X potash

0.26

0.50

0.18

0.61

PGPR X potash

0.54

0.82

0.78

0.31

tillage X N X K2O

0.79

0.65

0.02

1.0

replication

0.39

0.04

0.56

0.72

*Values are the means of 16 different plots. Significant differences within a factor are indicated by the use of different letters following the means (P = 0.05).

Table 3. Effects and interactions of tillage method, PGPR use, and potash source on marketable yields of staked tomato, July 6 - August 8 (11 harvests), Jackson, TN, 2001.

 

 

Factors

Number 20 lb boxes per acre

6 X 7

5 X 6

4 X 5

Total

Tillage method*

conventional

169

448

831 a

1449 a

no-till

188

445

622 b

1254 b

PGPR use*

none

176

435

697

1308

BioYield

181

458

756

1396

Potash source*

muriate (KCl)

206 a

483 a

651 b

1339

sulfate (K2SO4)

151 b

411 b

802 a

1364

Results of ANOVA (Probability > F)

tillage

0.20

0.91

0.001

0.03

PGPR

0.70

0.43

0.30

0.31

tillage X PGPR

0.10

0.44

0.15

0.34

potash (K2O)

0.0007

0.02

0.01

0.77

tillage X potash

0.32

0.85

0.28

0.62

PGPR X potash

0.93

0.54

0.43

0.45

tillage X N X K2O

0.63

0.38

0.80

0.83

replication

0.89

0.77

0.19

0.38

*Values are the means of 16 different plots. Significant differences within a factor are indicated by the use of different letters following the means (P = 0.05).

Table 4. Effects and interactions of tillage method, PGPR use, and potash source on marketable yields of staked tomato, first six harvest in July, Jackson, TN, 2001.

 

 

Factors

Number 20 lb boxes per acre

6 X 7

5 X 6

4 X 5

Total

Tillage method*

conventional

32

135 a

335 a

502 a

no-till

37

111 b

193 b

342 b

PGPR use*

none

28 b

116

245

388 b

BioYield

42 a

130

284

456 a

Potash source*

muriate (KCl)

36

135 a

261

431

sulfate (K2SO4)

34

111 b

268

413

Results of ANOVA (Probability > F)

tillage

0.43

0.05

0.0001

0.0001

PGPR

0.03

0.22

0.13

0.05

tillage X PGPR

0.59

0.15

0.04

0.27

potash (K2O)

0.73

0.05

0.80

0.56

tillage X potash

0.44

0.46

0.01

0.02

PGPR X potash

0.73

0.54

0.15

0.16

tillage X N X K2O

0.75

0.15

0.44

0.24

replication

0.13

0.001

0.18

0.02

*Values are the means of 16 different plots. Significant differences within a factor are indicated by the use of different letters following the means (P = 0.05).

Table 5. Effects of different tillage method, PGPR use, and potash source treatment combinations on marketable yields of staked tomato, first six harvests in July, Jackson, TN, 2001.

 

Factor combinations

Number 20 lb boxes per acre*

First 6 harvests

All 11 harvests

Tillage

PGPR use

Potash

4 X 5

Total

4 X 5

Total

conventional

none

muriate

309 b

496 ab

685 ab

1349

conventional

none

sulfate

266 bc

405 bc

834 a

1378

conventional

BioYield

muriate

422 a

607 a

888 a

1566

conventional

BioYield

sulfate

344 ab

501 ab

917 a

1502

no-till

none

muriate

137 d

253 d

511 b

1176

no-till

none

sulfate

266 bc

398 bc

757 a

1327

no-till

BioYield

muriate

177 cd

369 bcd

518 b

1265

no-till

BioYield

sulfate

194 cd

346 cd

701 ab

1250

Results of ANOVA (Probability >F)

0.0002

0.0007

0.008

0.37

*Values are the means of four plots. Means in the same column followed by the same letter are not significantly different by Fisher’s (protected) LSD (P = 0.05).

Table 6. Effects of BioYield on tomato yields, Jackson, TN, summer 2001- by harvest date.

Harvest

date

(mo/day)

Marketable 20 lb boxes/acre 1

Total weight/plot 2

(lb)

Mean weight per healthy plant 3 (lb)

no PGPR 4

BioYield

no PGPR

BioYield

no PGPR

BioYield

7/06

2

2

0.5

0.7

0.03

0.04

7/10

11

13

2.0

2.5

0.12

0.15

7/13

41

65*

5.5

8.4*

0.35

0.53*

7/16

53

79*

6.4

9.6*

0.40

0.62*

7/20

128

148

14.4

16.4

0.91

1.05

7/24

152

148

17.5

17.8

1.12

1.19

7/27

170

169

20.3

21.3

1.30

1.41

7/31

238

255

31.1

34.0

1.96

2.21

8/03

205

236

26.6

31.2

1.69

2.04

8/07

177

190

23.1

24.9

1.52

1.67

8/07-08 #

129*

89

18.1*

13.9

1.18

0.94

Totals

1339

1364

165.5

180.7

10.58

11.85

1 Yields of marketable medium, large, and extra-large tomatoes harvested at the "breaker-stage". Values are means of 16 one-row plots each planted with 18 ‘Mountain Fresh F1’ tomatoes transplants on May 5, 2001.

2 Includes marketable tomatoes plus small tomatoes and culls. Yields are NOT corrected for the number of plants lost in each plot due to disease, etc.

3 Includes marketable tomatoes plus small tomatoes and culls per healthy plant at each harvest.

These yields ARE CORRECTED for plant losses due to disease, etc.

4 no PGPR = no plant growth-promoting rhizobacteria used.

*Indicates a significant difference between tomatoes with and without BioYield for that harvest.

# Includes all medium-size or larger fruit remaining after the tenth harvest (on 8/07).

 

Email all comments and suggestions to ghonea@utk.edu
Copyright © 1999 by The University of Tennessee. All rights reserved.

This research represents one season's data and does not constitute recommendations.  After sufficient data is collected over the appropriate number of seasons, final recommendations will be made through research and extension publications.