On-Farm Evaluation of Twin-Row Corn in Southern Minnesota (2010 to 2012) Stahl, Lizabeth A.B. and Jeffrey A. Coulter

Transcription

1 On-Farm Evaluation of Twin-Row Corn in Southern Minnesota (2010 to 2012) Stahl, Lizabeth A.B. and Jeffrey A. Coulter INTRODUCTION AND OBJECTIVES Growers are continually striving to increase corn yield and profits. Planting corn in narrow rows is one potential way to do this. University of Minnesota research in southern and central Minnesota has shown that corn yields can be increased 7 to 9% by planting in 20-inch rows compared to 30 inch rows, but increases have not been consistently observed (1). It is also hypothesized that populations that optimize yields are greater in narrow rows than in 30-inch rows. Results from University of Minnesota trials conducted in northwestern MN from indicated that yields were optimized at higher populations in narrow rows than in 30-inch rows (2). In a twin-row corn system, which is a variation of narrow-row corn, corn is planted in row pairs six to eight inches apart with 30 inches separating the center of the row pairs. Plant arrangement is more spread out in twin rows compared to 30-inch rows at the same planting population, because the same number of seeds would be planted in two adjacent rows in a twin-row system versus in one row in a 30-inch system. A major advantage of planting corn in twin row rows compared to 15- or 22- inch rows is that beyond modifications to the planter, no additional major equipment modifications are needed. For example, a standard combine head can be used to harvest the crop, and narrow row tires, which can be very costly compared to standard tires, are not essential. Trials conducted in more southern states indicate that yields may be increased by planting corn in twin rows compared to 30-inch rows, although results have been inconsistent (3). Anecdotal reports from growers in planting corn in twin rows in southern Minnesota indicate there is potential to increase yields by planting corn in twin rows compared to 30-inch rows. Little research information exists in Minnesota, however, regarding the effects of planting corn in twin-rows. This study was initiated in 2010 at two on-farm locations in southern Minnesota to determine 1) If row width (30-inch vs. 22-/8-inch twin rows) influences corn grain yield, harvest moisture, stalk lodging, and economic return and 2) If corn planted in twin-rows has a greater response to an increased seeding rate than corn planted in 30-inch rows. MATERIALS AND METHODS On-farm trials were initiated the spring of 2010 in southern Minnesota with two farmer cooperators by Welcome and Wilmont who have been planting corn in twin rows for a number of years. Trials were conducted at both locations in 2010 and 2011, and only at the Welcome site in Fertilizer was applied according to soil test recommendations and herbicides were applied to control weeds at each site. Both sites had a long-term history of manure use. Further details regarding field histories for each site are listed in Table 1. The planter used at Wilmont was designed by a manufacturer for twin-row corn production, while the planter used at the Welcome location was modified by the farmer to plant twin rows. Treatments were arranged in a 2 x 3 factorial experiment in a randomized complete block design with four replications. Two row widths (30-inch vs. 22-/8-inch twin rows) at three target plant populations (33,000, 38,000, and 43,000 plants per acre (ppa)) were evaluated, for a total of six treatments. The lowest population represented what is considered a typical optimal planting population for 30-inch rows. The other two populations were higher than what would be considered an optimal planting population in 30-inch rows to test the hypothesis that optimal populations may be higher for corn planted in twin rows. Plot length was 400 feet and individual plot width was 30 feet (Welcome) or 40 feet (Wilmont). The same planter was used for all treatments within a site. Each planter had dual toolbars and planting units were turned off on one tool bar for the 30-inch rows. Due to the size of the plots and area to be harvested, hand thinning to desired populations was not feasible, so instead the seeding rate was adjusted for the different target populations by changing settings on the planter. Planter seeding rates were adjusted according to planter manual guidelines for each population by row spacing combination. At the Welcome site, the seeding rate was slightly higher for planter units on one tool bar than the other to help prevent seeds from being planted next to each other in the twin-rows. At the Wilmont site, planting rates were first tested in the field using planter monitor readings in order to try and match target populations as closely as possible. The goal was to have seeding rates between row spacing within a target population differ by no more than 1,000 plants per acre, as yield would likely not be influenced by populations this similar to each other.

2 When corn was V4 to V8 in 2010, V3 in 2011, and V4 in 2012 stand counts were taken by counting the number of plants in 100 feet of each harvest row. Stalk lodging was determined prior to harvest by counting the number of stalk-lodged plants (plants broken below the ear) in 100 foot of row at two locations within each plot. Grain yield, moisture, and test weight was determined by harvesting the center 6 (Welcome) or 8 rows (Wilmont) of each plot. A weigh wagon was used at each site to determine plot weight. Grain moisture was adjusted to 15% moisture in yield calculations. ANOVA was used for statistical analysis and means compared using Fisher s Protected LSD at the 0.05 significance level. Data are presented across site years as well as by individual site year. RESULTS AND DISCUSSION Plots were planted in a timely manner each year of the trial, although planting was delayed in 2012 until May 15 due to wet conditions (Table 1). The hybrid DKC 48-37, which has resistance to European corn borer, corn rootworm and glyphosate, was planted each year. Figures 1 & 2 show the planters used at each site. When setting planting populations, care was taken to reach target populations as closely as possible but settings were also selected so that populations could be matched as closely as possible between row spacings. The growing season in 2010 started out warm but a hard freeze was experienced May 9 th. By August, temperatures were warmer than average, and overall moisture was adequate throughout the growing season. In 2011, the season started slightly cooler than average, but extreme heat was experienced in early June, and July was hot and humid. Both sites also experienced hail in 2011 (Welcome on 7/5/11 and Wilmont on 7/10/11). Damage appeared uniform across the plot at Wilmont, and likely had minimal impact on yield at either site. Little precipitation was received in the fall from August on in In 2012, precipitation was above average in May, but drought conditions followed for the rest of the growing season, with the Welcome site being under an Extreme Drought by the latter part of the season. Population: Averaged across row spacing and site years, populations achieved in the field were 99 to 100% of the target populations, although when averaged across target populations and site years, populations achieved in the field were slightly less in twin rows than in 30 rows (Table 2). At the Welcome site, field populations averaged across target populations were consistently lower in twin rows than in 30-inch rows, although differences were significant only in 2010 and 2012 (Table 4). Field populations at Welcome were lowest in 2010 (Table 6). Adjustments were made in planter settings in 2011, and resulting field populations were very close to target populations in Although the sprocket settings on the planter for each row spacing at the lowest target population did not change between 2011 and 2012 at Welcome, there was a greater difference between field populations across row spacings in 2012 (1,040 plants per acre) than 2011 (350 plants per acre), indicating seed drop was higher in 30-inch rows compared to twin rows in Sprocket settings on the planter for each row spacing did not differ between years at the highest population as well, but in this case, differences in field populations between row spacings were only 470 and 630 plants per acre, respectively. Overall, differences in field populations between row spacings within a target population ranged from 330 to 1,180 plants per acre, with differences being the smallest overall in Overall, populations in the field at Wilmont were consistently lower than target populations in 2010 (Table 6). Adjustments made in 2011 resulted in populations that were within 60 to 1,800 plants per acre of target populations in When comparing field populations between row spacings with a target population at Wilmont, differences ranged from 490 to 1580 plants per acre (Table 6). The biggest difference in field populations between row spacings within a target population was at the 38,000 target population. At this target population, final populations were greater in the 30-inch rows than in twin rows both years. Equipment limitations influenced how closely target populations could be reached, and the highest setting possible for 30-inch rows was used for the highest population at Wilmont both years. Figures 3 through 8 show the three target populations at each row spacing early in the season at Wilmont in Figures 9 through 14 illustrate plant configuration at the three target populations in each row spacing at Welcome in 2011.

3 Stalk Lodging: Averaged across site years and row spacing, stalk lodging was greater at the highest population compared to the lower populations (Table 2). Overall, row spacing did not have a significant effect on stalk lodging. Stalk lodging was greatest in 2011, particularly at the Wilmont site, but minimal in 2010 and 2012 (Table 5). Grain Moisture, Test Weight, and Yield: Averaged across site years, grain moisture was not affected by the target population when averaged across row spacing, or by row spacing averaged across populations (Table 2). Grain moisture, however, was slightly higher in the 30-inch rows at the highest population and the middle population in the twin rows (Table 3). Since grain moisture at harvest was very low at each site year (less than 15%), any differences detected were of little practical significance. Averaged across site years, grain test weight was not affected by row spacing, population or the interaction between these two factors (Tables 2 and 3). Averaged across site years, row spacing averaged across target populations, and population averaged across row spacing had no effect on yield (Table 2), but there was a significant interaction between population and row spacing. Yields were optimized in twin rows at the highest planting population (Table 3). Although this trend was not observed each individual site year, these results indicate that planting corn in twin rows at a higher population than what would be normally considered optimal has the potential to increase yield. CONCLUSIONS: Overall, populations achieved in the field were similar to target populations, and were similar between row spacings within a target population. Stalk lodging was greatest at the highest population but was not significantly affected by row spacing. Grain moisture was not affected by row spacing averaged across populations, or population averaged across row spacing. Slight differences were found among row spacing x target population combinations, but differences detected were of little practical significance. Test weight was not affected by population, row spacing, and there was no significant interaction between these factors for test weight Averaged across site years yields were greater in twin rows at the highest population compared to the lower populations. This indicates that corn was able to take advantage of a higher planting population better in twin rows than in 30-inch rows. The likelihood of a yield response, however, would need to be considered against the increased cost involved with planting at such a high population. ACKNOWLEDGEMENTS This project was made possible by funding from the Minnesota Corn Growers Association/Minnesota Corn Research and Promotion Council, and the significant efforts of our farmer cooperators: Bryon Kittleson and Brian, John and Richard Penning. Also a special thanks to NuWay Coop of Trimont and the Agronomy Center LLC of Wilmont Adrian for their assistance with the plots and in collecting the harvest data. REFERENCES 1) Stahl, L., J.A. Coulter, and D. Bau Narrow-row corn production in Minnesota. Online. Univ., of MN, M M1266.html (posted 15 Jun. 2009). University of Minnesota, St. Paul. 2) Coulter, J.A., and R. Severson Corn Response to Plant Population in Northwestern Minnesota. Online. 3) Nelson, K.A., and R.L. Smoot Twin- and single-row corn production in northeast Missouri. Online. Crop Management doi: /cm RS.

4 Figure 1: Twin-row planter used at the Wilmont, MN site. Figure 3: Twin-row corn at 33,000 ppa. Figure 2: Twin-row planter used at the Welcome, MN site. Figure 4: 30-inch corn at 33,000 ppa.

5 Figure 5: Twin-row corn at 38,000 ppa. Figure 7: Twin-row corn at 43,000 ppa. Figure 6: 30-inch row corn at 38,000 ppa. Figure 8: 30-inch row corn at 43,000 ppa.

6 Figure 9: 33,000 ppa in 30-inch rows. Figure 11: 38,000 ppa in 30-inch rows. Figure 10: 33,000 ppa in twin rows. Figure 12: 38,000 ppa in twin rows.

7 Figure 13: 43,000 ppa in 30-inch rows. Figure 14: 43,000 ppa in twin rows.

8 Table 1. Background information for twin-row corn sites (2010 to 2012) Welcome Wilmont Previous Crop Soybean Soybean Tillage Conventional Conventional Planter White planter with dual toolbars Kinzie Twin Row Planter, with auto guidance Hybrid DKC DKC Planting Date 4/29/10 4/28/10 Stand Counts 6/17 & V8 corn V4 corn Lodging Ratings 10/12/10 10/14/10 Harvest Date 10/12/10 10/20/ Welcome Wilmont Previous Crop Soybean Soybean Tillage Conventional Conventional Planter White planter with dual toolbars Kinzie Twin Row Planter, with auto guidance Hybrid DKC DKC Planting Date 5/6/11 5/6/11 Stand Counts V3 corn V3 corn Lodging Ratings 10/6/11 10/12/11 Harvest Date 10/7/11 10/12/ Welcome Previous Crop Soybean Tillage Conventional Planter White planter with dual toolbars Hybrid DKC Planting Date 5/15/12 Stand Counts V4 corn Lodging Ratings 9/17/12 Harvest Date 10/2/12

9 Table 2. Effect of row spacing (averaged across populations) and population (averaged across row spacings) on plant stand, stalk lodging, grain moisture, test weight, and yield averaged across 5 sites years (2010 to 2012). Averaged Across 5 sites years ( ) Row Spacing Plant Stand Stalk Lodging Grain Moisture Test Weight Yield (plants/ac) (plants/ac) (%) (%) (lb/bu) (bu/ac) 30" Rows 38, Twin Rows 37, LSD (.05) 250 NS NS NS NS Averaged Across 5 sites years ( ) Target Population Plant Stand Stalk Lodging Grain Moisture Test Weight Yield (plants/ac) (plants/ac) (%) (%) (lb/bu) (bu/ac) 33,000 33, ,000 37, ,000 42, LSD (.05) NS NS NS Table 3. Evaluation of interaction between row spacing and target population on stand, stalk lodging, grain moisture, test weight, and yield averaged across 5 site years (2010 to 2012). Averaged Across 5 sites years ( ) Target Plant Stand Stalk Lodging Grain Moisture Test Weight Yield Population 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows (plants per acre) (plants/ac) (%) (%) (lb/bu) (bu/ac) 33,000 33,310 32, ,000 38,380 37, ,000 42,580 42, LSD (.05) 440 NS 0.3 NS 4.9

10 Table 4. Effect of row spacing averaged across target populations on plant stand, stalk lodging, grain moisture, test weight, and yield by individual site year (2010 to 2012). Row Spacing 2010 Plant Stand Stalk Lodging Grain Moisture Test Weight Yield Welcome Wilmont Welcome Wilmont Welcome Wilmont Welcome Wilmont Welcome Wilmont (plants/ac) (%) (%) (lb/bu) (bu/ac) 30" Rows Twin Rows LSD (.05) 440 NS 0.2 NS NS NS NS NS NS 2.5 Row Spacing 2011 Plant Stand Stalk Lodging Grain Moisture Test Weight Yield Welcome Wilmont Welcome Wilmont Welcome Wilmont Welcome Wilmont Welcome Wilmont (plants/ac) (%) (%) (lb/bu) (bu/ac) 30" Rows Twin Rows LSD (.05) NS 320 NS NS NS NS NS NS NS NS Row Spacing 2012 (Welcome only) Plant Stand Stalk Lodging Grain Moisture Test Weight Yield (plants/ac) (%) (%) (lb/bu) (bu/ac) 30" Rows Twin Rows LSD (.05) 460 NS NS 0.4 NS

11 Table 5. Effect of target population averaged across row spacing on plant stand, stalk lodging, grain moisture, test weight, and yield by individual site year (2010 to 2012). Plant Stand Stalk Lodging Grain Moisture Test Weight Yield Target Population Welcome Wilmont Welcome Wilmont Welcome Wilmont Welcome Wilmont Welcome Wilmont (plants per acre) (plants/ac) (%) (%) (lb/bu) (bu/ac) 33, , , LSD (.05) NS NS NS NS 2.9 NS Plant Stand Stalk Lodging Grain Moisture Test Weight Yield Target Population Welcome Wilmont Welcome Wilmont Welcome Wilmont Welcome Wilmont Welcome Wilmont (plants per acre) (plants/ac) (%) (%) (lb/bu) (bu/ac) 33, , , , , LSD (.05) NS NS NS NS NS NS (Welcome only) Plant Stalk Grain Target Population Stand Lodging Moisture Test Weight Yield (plants per acre) (plants/ac) (%) (%) (lb/bu) (bu/ac) 33, , , LSD (.05) 580 NS 0.4 NS NS

12 Table 6. Evaluation of interaction between row spacing and target population on stand and yield by individual site year (2010 to 2012). Target Population Welcome Wilmont Welcome Wilmont Welcome 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows (plants per acre) population (plants per acre) , , , LSD (.05) NS 850 NS 580 NS Welcome Wilmont Welcome Wilmont Welcome Target Population 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows 30" Rows Twin Rows (plants per acre) Yield (bu/ac) , , , LSD (.05) NS 4.3 NS NS NS