Oakes Irrigation Research
Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Voice: (701) 742-2189, FAX: (701)
742-2700, email: rgreenla@ndsuext.nodak.edu
PUMPKIN COVER CROP AND LIVING MULCH STUDY
Richard Greenland
Table 52. Pumpkin number of fruits and yield responses to a barley cover crop and living mulches
Pumpkins are planted in wide rows, leaving large areas of bare ground. In current pumpkin production, the between-row area is usually cultivated early in the season, before the pumpkin plants begin to run, to control weeds. This exposes the soil to erosion and also reduces soil organic matter. Later in the season hand weeding is used to control weeds. After harvest of pumpkins, little residue is left to protect the soil and it is usually too late in the season for cover crop establishment. Cover crops and living mulches planted between the pumpkin rows could prevent soil erosion and increase soil organic matter, but if they compete too much with the pumpkins then pumpkin yield could be reduced. In this study a barley cover crop was planted in early spring, leaving unplanted strips, 3 ft wide, for planting pumpkins in mid- to late-May. When the barley headed, it was flailed and a living mulch (hairy vetch, rye, soybean, and/or corn) was planted between the pumpkin rows. Data on height, stand, and vigor of pumpkin, living mulches, and weeds were collected to determine competitiveness of the living mulches. Total dry matter was measured at the end of the season. Our objective was to find a cover crop/living mulch combination that protects the soil, helps control weeds, but doesn’t compete with the pumpkins enough to reduce pumpkin yield.
MATERIALS AND METHODS
Soil: |
Embden loam and Gardena loam; pH=7.3; 2.2% organic matter; soil-P and soil-K were very high; soil-S was medium. |
Previous crops: |
2001 - potato; 2000 - sweetcorn, cabbage, onion, sugarbeet, field corn, pepper, soybean, carrot, wheat, and edible bean; 1999 - field corn. |
Seedbed preparation: |
Coulter chiseled 15 inches deep on April 18. Multiweeded (field cultivated) once on April 22. |
Planting: |
‘Rockstar’ pumpkin seeds were planted 1 ft apart in rows 8 ft apart on May 17. On June 12 thinned to an in-row spacing of one plant every 3 ft. |
Plots: |
Plots were 20 ft long by 16 ft (two rows) wide. |
Fertilizer: |
On April 18, broadcast 18 lbs N/acre and 20 lbs S/acre as 21-0-0-24. On April 22 sprayed 50 lbs N/acre as 28-0-0. Side dressed 50 lbs N/acre as urea on June 12. |
Irrigation: |
Overhead sprinkler irrigation as needed. |
Pest control: |
Weeds were controlled by hand weeding the three foot strip (where the pumpkins were planted) on all plots and by weed control treatments given in Table 51. Sprayed Asana (8 oz/acre on June 10, 18, & 25, and July 2 & 30) and Ambush (8 oz/acre on July 11) to control cucumber beetles. |
Harvest: |
Hand harvested September 26 to October 2. |
The pumpkin variety we used this year, Rockstar, was a very vigorous, vining type pumpkin. Pumpkins grew faster and were too big when we flailed the barley, so they were injured a little by the tractor, flail, and planter (when planting the living mulch). Just before flailing the barley, pumpkin plants were shorter in the check treatment than in treatments with a barley cover crop. Despite the injury, the pumpkins quickly covered the ground and drastically reduced living mulch growth, especially rye. Living mulch growth and end of season dry matter were much lower than last year. Neither the barley cover crop planted between pumpkin rows nor the living mulches affected pumpkin yield. The barley cover crop increased end of season dry matter and helped protect the soil.
Sweetcorn was planted in 2002 on the 2001 pumpkin cover crop study area. Lambsquarters and hairy nightshade growth was slightly greater on plots that had previously been planted to cover crops and living mulches, but sweetcorn yields were not affected.
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Table 51. Treatments applied to the Oakes Irrigation Research Site 2002 pumpkin cover crop/living mulch study.
Cover crop/living mulch treatments1
No barley cover crop nor living mulch (check)
Barley cover crop; no living mulch
Barley cover crop; hairy vetch
Barley cover crop; rye
Barley cover crop; hairy vetch + rye
Barley cover crop; soybean
Barley cover crop; soybean + corn
Barley cover crop; corn
Weed control treatments
Herbicide - Buctril (1 pt/acre on May 17 before planting pumpkin) and Poast + Dash (1.5 + 1 pt/acre on June 20 just before flailing barley)
No herbicide - The 3 ft strips were cultivated just before planting pumpkins.
Note: The 3-ft wide strip the pumpkins were planted in was hand weeded in all plots. The area between the pumpkin rows was not weeded except for the check (no barley, no living mulch) plots.
Barley flail height treatments2
High - flailed at 1 ft high
Low - flailed at less than 1 inch high
1Barley was planted with a drill (6-inch row spacing) on April 22 in strips 5 ft wide, leaving 3-ft
wide bare strips for planting pumpkins. Living mulches were no-till planted on June 26
with a Monosem specialty planter in 18-inch rows into the barley cover crop that had been
flailed. A trash whipper was used ahead of the planter units to move the barley away from the
planted row. Where two living mulches were planted, they were planted in alternating rows.
2Barley was flailed on June 21. This was just after barley headed, when the pumpkins began
to run, and before planting the living mulches.
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Table 52. Pumpkin number of fruits and yield response to a barley cover crop and living mulches in the Oakes Irrigation Research Site 2002 pumpkin cover crop/living mulch study.
Treatment |
Number of pumpkins |
Pumpkin yield |
Fruit size |
||||||
marketable |
not marketable1 |
green |
total |
marketable |
not marketable1 |
green |
total |
||
|
--------------- number per acre -------------- |
------------------ tons per acre ---------------- |
lbs/fruit |
||||||
Cover crop, living mulch |
|||||||||
No barley, no mulch |
1972 |
220 |
1181 |
3503 |
25.2 |
1.9 |
7.8 |
34.9 |
25.5 |
Barley, no mulch |
1982 |
180 |
1061 |
3373 |
23.2 |
1.7 |
6.8 |
31.7 |
23.7 |
Barley, hairy vetch |
2162 |
260 |
1041 |
3623 |
24.5 |
2.3 |
7.0 |
33.7 |
22.9 |
Barley, rye |
1942 |
290 |
1091 |
3473 |
22.4 |
2.3 |
6.5 |
31.1 |
23.2 |
Barley, hairy vetch + rye |
2102 |
200 |
881 |
3283 |
25.4 |
1.6 |
5.9 |
33.0 |
24.4 |
Barley, soybean |
2072 |
120 |
831 |
3183 |
24.4 |
1.0 |
5.5 |
30.9 |
23.9 |
Barley, soybean + corn |
2112 |
180 |
821 |
3153 |
24.8 |
2.0 |
5.4 |
32.2 |
24.1 |
Barley, corn |
2082 |
190 |
801 |
3213 |
24.4 |
1.8 |
4.7 |
31.0 |
23.5 |
|
|||||||||
Probability |
0.90 |
0.70 |
0.33 |
0.09 |
0.87 |
0.71 |
0.33 |
0.28 |
0.40 |
Herbicide treated |
|||||||||
No |
2092 |
220 |
958 |
3411 |
24.5 |
1.8 |
6.3 |
32.5 |
23.6 |
Yes |
2014 |
190 |
968 |
3291 |
24.1 |
1.9 |
6.1 |
32.1 |
24.3 |
|
|||||||||
Probability |
0.67 |
0.28 |
0.95 |
0.65 |
0.84 |
0.82 |
0.84 |
0.77 |
0.40 |
C.V. (%) |
19 |
89 |
44 |
14 |
15 |
99 |
53 |
13 |
10 |
Barley flail height |
|||||||||
High |
2065 |
220 |
935 |
3349 |
24.3 |
1.9 |
5.8 |
32.0 |
23.7 |
Low |
2065 |
186 |
929 |
3309 |
24.0 |
1.8 |
6.1 |
31.9 |
23.7 |
|
|||||||||
Probability |
1.0 |
0.21 |
0.95 |
0.77 |
0.73 |
0.60 |
0.62 |
0.87 |
0.99 |
C.V. (%) |
16 |
90 |
42 |
13 |
15 |
100 |
57 |
13 |
8 |
1Not marketable were those pumpkins that had disease spots, small rotten spots, major blemishes, or very odd shapes.
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Table 53. Pumpkin stand, size, injury, ground cover, and end of season dry matter as affected by cover crop and living mulches in the Oakes Irrigation Research Site 2002 pumpkin cover crop/living mulch study.
Treatment |
Stand1 |
Height2 |
Width2 |
Crop injury3 |
Ground Cover4 |
Dry matter5 |
|
1 to 10 |
------ inches ------ |
-------- % ------- |
tons/acre |
||
Cover crop/living mulch |
||||||
No barley, no mulch |
9.6 |
11.0 b6 |
23.5 |
13 a |
87 |
1.7 d |
Barley, no mulch |
9.6 |
14.6 a |
22.3 |
22 bc |
80 |
2.7 bc |
Barley, hairy vetch |
9.7 |
14.8 a |
22.8 |
23 c |
78 |
2.7 bc |
Barley, rye |
9.6 |
13.8 a |
21.6 |
21 bc |
76 |
2.5 c |
Barley, hairy vetch + rye |
8.0 |
14.3 a |
22.1 |
19 b |
77 |
2.8 bc |
Barley, soybean |
9.0 |
14.8 a |
22.6 |
23 c |
76 |
2.5 c |
Barley, soybean + corn |
9.7 |
14.7 a |
22.8 |
21 bc |
78 |
3.3 ab |
Barley, corn |
8.5 |
14.9 a |
22.6 |
20 b |
78 |
3.9 a |
|
||||||
Probability |
0.53 |
<.0001 |
0.94 |
<.0001 |
0.053 |
<.0001 |
Herbicide treated |
||||||
No |
9.4 |
14.3 |
22.9 |
21 |
80 |
2.7 |
Yes |
9.1 |
13.9 |
22.2 |
19 |
77 |
2.8 |
|
||||||
Probability |
0.38 |
0.31 |
0.39 |
0.02 |
0.33 |
0.50 |
C.V. (%) |
17 |
9 |
10 |
28 |
10 |
29 |
Barley flail height |
||||||
High |
9.1 |
14.4 |
22.0 |
19 |
78 |
2.8 |
Low |
9.2 |
14.7 |
22.8 |
23 |
77 |
3.0 |
|
||||||
Probability |
0.81 |
0.54 |
0.30 |
0.08 |
0.75 |
0.07 |
C.V. (%) |
15 |
7 |
8 |
23 |
8 |
31 |
1Pumpkin plants/17 ft of row before thinning. Plants later thinned to 6 plants/17 ft of row.
2Height and width measured on June 21.
3Injury to pumpkins measured on June 24 after flailing barley and planting cover crop. Injury was mostly mechanical injury from tractor and implements, and from wind.
4Percent of ground covered by pumpkin plants on July 18.
5End of season dry matter.
6Values in the same column followed by the same letter are not significantly different at the 0.05 level. If no letters in column, then there were no statistically significant differences between values in that column.
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Table 54. Effects of cover crops/living mulches used in pumpkins in 2001 on weed growth and sweetcorn planted in 2002.
Treatment |
Weed ratings |
Sweetcorn |
||||||
Rrpw1 |
Colq1 |
Hns1 |
FT1 |
stand |
vigor |
ears |
yield |
|
|
---------------------- 0 to 102 -------------------- |
----- 1 to 10 ---- |
1000s/A |
tons/A |
||||
Cover crop/living mulch |
||||||||
No barley, no mulch |
9.7 |
8.1 a3 |
8.1 a |
9.8 |
6.7 |
7.7 |
12.2 |
6.2 |
Barley, no mulch |
9.8 |
6.9 c |
6.8 c |
9.6 |
6.3 |
7.6 |
12.4 |
6.2 |
Barley, hairy vetch |
9.8 |
7.0 bc |
6.8 c |
9.2 |
6.3 |
7.5 |
13.2 |
6.7 |
Barley, rye |
9.7 |
7.1 bc |
6.9 c |
9.3 |
6.5 |
7.7 |
13.1 |
6.4 |
Barley, hairy vetch + rye |
9.5 |
7.0 bc |
6.8 c |
9.4 |
6.6 |
7.4 |
12.4 |
6.2 |
Barley, soybean |
9.6 |
7.4 b |
6.9 bc |
9.5 |
6.6 |
7.8 |
12.2 |
6.2 |
Barley, soybean + corn |
9.8 |
7.1 bc |
7.8 ab |
9.4 |
6.1 |
7.6 |
11.8 |
5.8 |
Barley, corn |
9.9 |
7.4 b |
7.9 a |
9.5 |
6.6 |
7.5 |
11.1 |
5.3 |
|
||||||||
Probability |
0.19 |
0.002 |
0.006 |
0.90 |
0.67 |
0.54 |
0.67 |
0.60 |
Herbicide treated |
||||||||
No |
9.8 |
7.2 |
7.1 |
9.0 |
6.5 |
7.6 |
12.6 |
6.3 |
Yes |
9.6 |
7.3 |
7.3 |
9.9 |
6.3 |
7.6 |
12.1 |
6.1 |
|
||||||||
Probability |
0.21 |
0.82 |
0.33 |
0.03 |
0.21 |
0.93 |
0.29 |
0.37 |
C.V. (%) |
5 |
10 |
9 |
7 |
14 |
6 |
22 |
23 |
Barley flail height |
||||||||
High |
9.8 |
7.1 |
7.0 |
8.9 |
6.5 |
7.6 |
12.1 |
6.0 |
Low |
9.6 |
7.2 |
7.3 |
9.9 |
6.3 |
7.6 |
12.6 |
6.3 |
|
||||||||
Probability |
0.18 |
0.09 |
0.40 |
0.14 |
46 |
0.26 |
0.50 |
0.53 |
C.V. (%) |
4 |
9 |
9 |
6 |
14 |
5 |
19 |
20 |
1Weed identification: Rrpw - redroot pigweed; Colq - common lambsquarters; Hns - hairy nightshade; FT - yellow and green foxtail.
2Ratings: 0 is no effect (no weed control or no crop injury); 10 is complete weed or crop kill.
3Values in the same column and section followed by the same letter are not significantly different at the 0.05 level. If no letters in column, then there were no statistically significant differences between values in that column.
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Go to Oakes Irrigation Research Site Cover Crop Study page
Go to Oakes Irrigation Research Site 2002 annual report