|
|
|
|
|
|
|
||
|
|
||
|
|||
2003
Table of Contents |
BACKGROUND
In the agricultural regions of the Pacific Northwest (PNW), adoption of reduced tillage systems lags that of the United States as a whole. The limited adoption of this practice in the PNW is due not only to economic and agronomic concerns, but also to the lack of trouble free, reliable seeding equipment for planting into the heavy residue encountered in this region. Commercial shank and disc type no-till drills were developed primarily for low crop residue conditions for crops planted in wide rows. In heavy crop residue or when row spacing is narrow, shank type drills are prone to plugging, causing operator frustration and reducing field capacity. They also tend to cause large piles of residue to form which cover the crop row and choke out young seedlings. Another problem with shank type drills is that the furrow opening shank disturbs the soil with sufficient force that the uncontrolled soil is thrown out of the seed furrow and occasionally onto the adjacent seed row. This adversely affects seeding depth and seedling emergence. Disc type drills are prone to “hair-pinning” straw into the seed furrow rather than placing seed into moist soil with good seed to soil contact. In an effort to overcome this problem, a project was initiated to develop residue management strategies and equipment to improve no-till drill performance.
OBJECTIVES
The objectives of these projects were to:
1. Develop a seeder attachment that would allow a hoe-type no-till drill to handle large amounts of residue and improve drill performance.
2. Evaluate the performance of the seeder attachment in terms of stand establishment and grain yield.
3. Develop a strategy for managing heavy wheat (Triticum aestivum L) residue that would provide adequate drill performance.
4. Evaluate commercial no-till drill performance in various wheat residue conditions and with different seeder attachments.5. Characterize the amount and condition of post harvest wheat residue and record the associated no-till drill performance.
RESIDUE MANAGEMENT WHEEL DESCRIPTION
The seeder attachment developed is a patented prototype device (Siemens et al., 2002) which consists of a fingered rubber wheel, a rubber inner ring, and a spring loaded arm which pivots about vertical and horizontal axis (Fig. 1). The unit is designed to attach to the tool bar of hoe-type no-till drills and positioned so that the inner ring is approximately one half inch away from the furrow opening shank. When seeding, the ground driven rubber fingered wheel and inner ring hold down and “walk” through crop residue, preventing it from building up on the shank and seed tube. They also help control soil disturbed by the furrow opener so that it stays within the seed row. When clumps of crop residue build up between the wheel and the shank, the arm holding the wheel is able to rotate away from the shank, causing the pile of crop residue to dislodge. After swinging out, the wheel will naturally track back into its operating position, close to the shank. Other features of the design are that the wheel has adjustable, spring loaded down pressure and vertical height adjustment.
METHODS
The present invention was evaluated in crop years (CY’s) 2000 and 2001 at various locations in northeastern Oregon and southeastern Washington. Test site locations varied significantly in the amount and condition of crop residue and were planted to a variety of different crops including yellow mustard, winter Canola, winter wheat, spring wheat, spring barley, and lupin (Table 1 and Table 2). Three types of combines/header arrangements were used to harvest the plots prior to sowing: a cylinder type combine equipped with a stripper header, a rotary combine equipped with a conventional pick-up reel, and a cylinder-type combine equipped with a conventional pick-up reel. Some of the combines were equipped with chaff spreaders, some with chaff spreaders and straw choppers, and some with neither (Table 1 and Table 2). In some experiments the residue was left standing, while in other experiments the residue was flailed, rotary mowed, harrowed or forage chopped (Table 1 and Table 2). Amounts of residue present at the time of seeding ranged from a low of approximately 1,600 lb/acre to a high of almost 9,400 lb/acre, while stubble height ranged from less than 2 in. to slightly greater than 24 in. In CY 2000, all plots were seeded with a 12-ft-wide, 12-in-row spacing, hoe-type no-till plot drill manufactured by Conserva-Pak™ Seeding Systems of Indian Head, Saskatchewan, Canada. The performance of the residue wheel was evaluated by equipping one side of the drill (six openers) with the residue management wheel, the opposite side (six openers) without. This procedure was also used to evaluate the residue wheels at the Adams and Helix sites in CY 2001. Slightly different procedures were used at other locations in CY 2001. At the Pendleton and Moro sites, an additional six residue wheels were manufactured and mounted on the drill so that all twelve drill openers were either equipped or not equipped with the residue wheels during seeding. At the Prescott location, the device was tested by mounting 4 wheels on a 36 opener, 36 foot wide, 12 in. row spacing commercial scale Conserva-Pak drill and comparing those rows with the rows made by openers without the wheels.
Depending on location, plot length varied from a minimum of 40 ft to a maximum of 300 ft. All experiments were a randomized complete block design with four replications except for the winter wheat experiment at Pendleton, Oregon in CY 2000. In this experiment, the plot was laid out as a split-plot design with two replications. After the seedlings had emerged and the date of the last killing frost had past, stand counts in each plot were taken using the following procedure. First, a random sampling location, at least 15 ft from either end of the plot, was selected for each replication. The number of plants within 1.64 ft of either side of the sampling location were then counted and recorded for the inner 4 rows of each 6-row plot. The outer rows of the plots were not counted to avoid edge effects. For the 12-row plots, the inner 9 rows were counted and recorded. For the 36' wide plots at the Prescott site, the four rows that were seeded using the wheels were counted at two locations and compared with stand counts taken from 8 rows seeded with the standard opener. Yield was determined by harvesting 5 rows from each 6-row plot and 9 rows from each 12-row plot with a plot combine. Yield data were not collected from the 36' wide plots.
Experiments were also conducted in CY’s 2000 and 2001 to determine the effect of various residue management techniques on direct-seed stand establishment, plant vigor and crop yield. In CY 2000, the experiment was conducted on a farm located near Helix, Oregon where the average annual precipitation is 15 in. and the soil is a Walla Walla silt loam (Typic Haploxerall, coarse mixed mesic). The experimental site area yielded 85 bu/ac of winter wheat and approximately 9,000 lbs/ac of straw and chaff residue in CY 1999. The plot area was divided into two sub plots - one for seeding winter wheat, the other for spring wheat. Sampling unit size was 12 ft by 200 ft and the experimental design was a randomized complete block with four replications and 11 treatments in each block.
Fall plots were seeded with 50:50 blend of Stephens and Madsen soft white winter wheat with a 12 foot wide, hoe-type no-till plot drill manufactured by Conserva-Pak™ Seeding Systems of Indian Head, Saskatchewan, Canada. Row spacing was 12 in. and seeding rate was 105 lb/ac. Starter fertilizer (16-20-0) was placed with the seed and applied at a rate of 105 lb/ac at a depth of approximately 1.25 in. Main fertilizer Urea (46-0-0) was applied at a rate of 221 lb/ac and placed approximately 2.75 in. below and 1 in. to the side of the seed. Planting dates were 11/02/99 and 11/03/99. Spring plots were also seeded with the Conserva-Pak™ plot drill and planted to 108 lb/ac of Alpowa spring wheat. Starter fertilizer (16-20-0) was placed with the seed at a rate of 101 lb/ac and at a depth of approximately 1.25 in., while the main fertilizer Urea (46-0-0) was applied at a rate of 211 lb/ac and placed approximately 2.75 in. below and 1 in. to the side of the seed. Planting date was 3/30/00.
To characterize the condition and amount of residue present after harvesting, stubble height was measured and residue exiting the combines was collected and analyzed. The method used was patterned after the one developed by Allmaras et al. (1985). The procedure involved mowing a strip of unharvested wheat approximately 3.5 ft wide at ground level perpendicular to the direction of combine travel and removing all plant material. A 3 ft wide canvas apron was then laid in this strip and aligned with the edge of uncut wheat. When the combine passed over the area, all material exiting the combine was deposited on the apron. The apron was partitioned into at least six equal length sections of approximately 2 feet, and the residue from each section was collected, screened and weighed. Lengths of straw greater than 7 in. in length were separated by hand, while straw lengths less than 7 in. in length were separated from chaff by running the sample over a Clipper Cleaner outfitted with a 3/4 in. x 3/16 in. screen.
In this study, eight different residue management strategies resulting from different combinations of two types of combines, two types of headers and various seed bed preparation methods and two different seeder attachments were investigated (Table 3). Combine types included a rotary combine equipped with a flail type straw spreader and pick-up reel, a cylinder type combine outfitted with a straw chopper, an after market chaff spreader and a pick-up reel, and a cylinder type combine equipped with a stripper header and an after market chaff spreader. The rotary combine without a chaff spreader left a heavy chaff and straw row to one side of the 24' wide harvested strip (Fig. 2). Consequently, this area was divided into two 12' wide plots designated “in the chaff row” and “outside the chaff row”. One pair of these plots was disked prior to seeding to incorporate some of the residue, while a second pair of these plots was seeded into non-tilled stubble. Residue from the plots harvested with the combine equipped with the stripper header were managed in three ways. The first was to leave the stubble standing to represent a tall standing stubble treatment (Fig. 3). The other two were to cut the residue at ground level with a forage chopper and either blow the residue back onto the plot area or remove the residue. These treatments were imposed to simulate a combine equipped with a super fine straw chopper to chop the residue into chaff sized pieces (Fig. 4) and a baling operation respectively. The final residue management strategy was to cut the residue at height of 8 in. and use the combine’s straw chopper and chaff spreader to chop up and distribute the residue (Fig. 5). Seeder attachments evaluated included a gang of twelve 16 in. diameter smooth coulters positioned in-line with and ahead of the furrow opening shanks and the residue management wheel.
After the seedlings had emerged and the date of the last killing frost had past, stand counts were taken and recorded for 3.1 ft length of row for the inner 10 rows of each 12 row plot. The outer two rows of each plot were not counted to avoid end effects. Sampling location was randomly selected using the method described for the residue management wheel experiments. At the 5 leaf stage of growth, approximately 100 plants were collected from the innermost four rows of each plot at the designated sampling location. These young plant samples were analyzed for yield potential parameters including plant height, plant weight, plant growth stage and presence of tillers. Grain yield was determined by harvesting 5 rows from each 12-row plot with a plot combine. An ANOVA was performed using SAS (SAS Institute Inc., 1996) to determine if there were statistical differences between the treatment means.
In CY 2001, a similar type of experiment was conducted on a farm adjacent to the Columbia Plateau Conservation Research Center in Pendleton, Oregon. In this experiment, three of the most promising residue management methods from the previous year’s experiment were investigated. These included the baling off the residue, harvesting the residue with a combine equipped with a stripper header and then chopping the residue into fine pieces (~ 1 in. in length) using a forage chopper, and cutting the crop at a height of 8 in.-12 in. and using the combines straw chopper and chaff spreader to evenly distribute the residue. In addition to these techniques, three other residue management methods that were also thought to hold promise were investigated. One of these techniques was a slight modification of harvesting the crop with a stripper header equipped combine and then chopping the residue into small pieces using a forage chopper. The previous year’s good results were obtained with the forage chopper having the maximum 8 blades installed to chop the residue into as small of pieces as possible (~ 1 in. in length). It was thought that a longer length of cut may work equally as well and have lower power requirements. This hypothesis was tested by having a treatment where the stripper header residue was chopped using the forage chopper with only 2 blades installed. Unfortunately, the length of cut was only increased about ½ in. from 1 in. to 1.5 in. and the differences between these methods was considered negligible. The other methods involved harvesting the crop at a cutting height of 16 in. and then flailing the residue or harvesting the crop at a height of 16 in. and then cutting the standing stubble with a sickle bar mower to a height of 8 in. The residue management wheel was also evaluated in all but the baled and forage chopped with 8 blades installed treatments.
The site selected to conduct the study yielded 105 bu/ac of winter wheat in CY 2000 and had approximately 9,400 lbs/ac of residue. Spring and winter plots were laid out in a randomized complete block design with four replications and ten treatments in each block. Fall plots were seeded to Stephens winter wheat with a 12' wide, 12" row spacing Conserva-Pak™ hoe-type drill. Application rates were 100 lb/ac of seed, and 154 lb/ac of N in a combination of 100 lb/ac of 16-20-0 placed with the seed and 300 lb/ac of 46-0-0 placed 2 in. below and 1 in. to the side of the seed. Planting date was 10/30/00. Alpowa spring wheat was planted with the 12' wide hoe-type plot drill on 3/15/01. Applications rates were 100 lb/ac of seed and 117 lb/ac on N applied in the form of 100 lb/ac of 16-20-0 with the seed and 218 lb/ac of 46-0-0 below and to the side of the seed. Stand establishment and yield potential parameters were recorded using the methods previously described for the CY 2000 study. Plot yield was obtained by harvesting the inner 9 rows of each 12 row plot with a plot combine.
RESULTS
Results from the CY 2000 residue wheel experiment are shown in Table 1. Depending on residue treatment, the residue management wheel was found to increase seedling stand count of winter Canola by 44-53 percent, spring barley by 24 percent, mustard by 41 percent, lupin by 9 percent, spring wheat by 15-16 percent, and winter wheat by 17-20 percent as compared to the standard drill (Table 1). These differences were statistically significant at the levels indicated in Table 1. Use of the residue management wheel also increased the yield of winter Canola by 8-11 percent, spring barley by 3 percent, mustard by 5 percent, lupin by 8 percent, spring wheat by 1-6 percent, and winter wheat by up to 8 percent (Table 1). Although increased yields ranging from 1 to 11 percent were observed in all but one trial, these differences were not always statistically significant (Table1).
Increases in stand establishment and yield were also found when the residue management wheel was used during CY 2001 (Table 2). Increases in seedling stand establishment of 0.4-6 percent were found in spring barley, 4-34 percent in spring wheat and 3-5 percent in winter wheat. These increases were statistically significant in the 4 trials where residue densities were high (> 9,000 lb/ac) and when the increases in stand establishment were large (>17 percent). In two of the trials, stand establishment decreased by 4.6 and 9 percent when the residue management wheel was used. These differences, however were not statistically significant. Increases in stand establishment also generally resulted in increased yields. Statistically significant increases in yield of over 9 percent were found in the two spring barley trials and an increase in yield of 7 percent was observed in one of the spring wheat trials. In the other trials, increased yields ranging from 0.1 to 14.6 percent were found in all but one experiment, however none of these differences were statistically significant (Table 2). It should be noted that during the CY 2001, it was observed that the residue wheel did not perform as well in the wet residue conditions as it did in the drier residue of CY 2000. This was due to the fact that the residue wheel holds down residue and effectively pulls it to the wheel side of the opener as the drill moves forward. In wet conditions, the residue is heavy and does not easily flow around the shank as compared to when the residue is dry. Thus in wet conditions, residue tended to hang up on the shank and get pinched between the residue wheel and opener rather than flowing smoothly around the shank.
The residue management study results for the CY 2000 winter wheat and spring wheat trials are presented in Table 3 and Table 4 respectively. The data from the winter wheat plots were affected by the amount of uncontrolled volunteer wheat and hence should be interpreted with some caution. The best stand establishments and early plant growth were in treatments that had little residue or in treatments where the residue had been cut into small pieces and evenly distributed (Table 3). There were no statistically significant differences in stand establishment, plant weight or presence of tillers amongst the residue management treatments evaluated. Although yield differences of up to 15 bu/ac were found, an explanation for this based on the early plant growth data could not be formulated. The worst residue management strategy was leaving tall standing stubble as was the case in the treatment where the crop was harvested with a combine equipped with a stripper header. This method was considered a failure because in all four replications, the drill plugged shortly after entering the plot. The plots seeded with the residue management wheel were found to have taller plants and more tillers as compared to plots where the wheel was not used or coulters were used. This did not translate into a significantly different yield increase, possibly due to the fact that adequate plant stands were obtained. Data from the spring wheat trial are shown in Table 4. Again, the best stands, early plant growth and yield were obtained when there was little residue or when the residue had been chopped and spread evenly. In treatments with heavy chaff or that had been disked, stands were up to 40% lower and yields suppressed by as much as 20%. The disked treatments did poorly because in loose soil, the furrow opening shanks threw soil onto the adjacent row which inhibited seedling emergence. The residue management wheel and coulter improved stand establishment by 15%, however this did not translate into increases in grain yield.
Results of the winter wheat and spring wheat trials for the CY 2001 experiment are presented in Table 5 and Table 6 respectively. Winter wheat stand establishment was poor and considered inadequate. The baled treatment had the highest stand establishment of 14.2 plants/ft2, but this represents only 53% of the seeds planted. Other residue management treatments had less than 36% percent of the seeds that were sowed become viable plants. Poor emergence was due to a combination of extremely wet seeding conditions, very heavy residue, a late planting date followed by prolonged periods of cold weather and problems with seed tube plugging. The baled treatment also showed superior plant growth and weight as compared to the other treatments, although these differences were not always statistically significant (Table 5). Differences in stand establishment or early plant vigor between the other residue management treatment methods were not found. The only treatment that caused unacceptable drill plugging was the treatment where the 16 in. standing stubble was cut with a sickle bar cutter to height of 8 in. Between residue management treatments, the maximum yield difference was only 4 bu/ac was not statistically significant. Seeding conditions in the spring were considered good and marginally adequate plant stands were achieved. As with the winter wheat plots, the baled treatment had significantly higher stand establishment and superior plant development, but did not improve yield as compared to the other treatments. No significant differences in stand establishment or plant growth were found between the other residue management treatments. Use of the residue management wheel did not positively or negatively affect stand establishment, plant growth or yield in the fall or spring seeded plots.
CONCLUSIONS
The residue management
wheel study showed that for small seeded crops, such as mustard and winter Canola,
use of the residue management wheel increased stand counts by more that 40 percent.
Approximately 15 percent of this increase was estimated to be due to the observed
fewer piles of residue and clods covering the seed row. The remaining 25 percent
could not be explained and further study is warranted. The study also showed
that for larger seeded crops, such as wheat and barley, use of the residue management
wheel significantly increased stand counts by approximately 17 percent in CY
2000 and by over 17 percent in certain heavy residue conditions in CY 2001.
In the majority of the other trials in CY 2001, stand establishment increases
ranging from 3-8 percent were found, however these differences were not statistically
significant. In trials where residue density was greater than 5,000 lb/acre,
increased stand counts were observed to be due to fewer piles of residue covering
the seed row. Similar increases in stand count were seen in trials where residue
densities were lower than 5,000 lb/acre; however since there were no dramatic
differences between treatments in seedbed condition, a logical reason for this
increase could not be formulated. Although large differences in stand counts
were seen in the mustard and winter Canola crops, adequate plant stands were
present due to high seeding rates. Consequently, yield differences were not
statistically significant, or they were less than 5 percent higher. For the
larger seeded crops, increases stand establishment also generally resulted in
increases in crop yield. Yield increases of up to 15 percent were seen with
the larger seeded crops, but these differences were not always statistically
significant.
These results indicate that use of the residue management wheel improves stand
establishment and yield for a variety of crops in a wide range of residue densities
and stubble conditions. Other drill attachments such as coulters improved stand
establishment by about 10% in one trial, however this did not translate into
a significant increase in yield. Further testing and analysis is needed to determine
if the device, which costs approximately $300 per unit to fabricate, is economically
justifiable. Further study is also warranted to determine the cause of the increased
stand and yield performance in low residue conditions. It should be noted that
the device was observed to perform better when the residue is dry as compared
to when it is wet and that the residue wheel may promote drill plugging in wet
conditions. The USDA-ARS owned patent (US 6,345,671) on the device is available
for licensing to a manufacturer.
These studies showed that residue management can also have a significant effect on direct seeded crop stand establishment, plant growth and yield. Concentrated chaff rows, long straw and disking can hinder stand establishment by as much as 40% and reduce yield by 20%. Long straw and heavy concentrations of loose straw can also result in an unacceptable levels of drill plugging. Improved stand establishment can be obtained when residue density is reduced through baling, however, in these studies, this did not translate into significant increases in crop yield as compared to treatments where the full load of crop residue remained. It should also be mentioned that long term continuous removal of crop residue through baling may also not be biologically sustainable. Direct seed, annual cropping into heavy residue is challenging, but with proper equipment selection and residue management, adequate stand establishment, plant growth and yield in direct seeded, annual crop winter and spring wheat can be obtained. Successful residue management techniques in this study included spreading straw and chaff uniformly and having the residue chopped into small (< 6 in.) pieces.
ACKNOWLEDGMENTS
The authors would like to express their gratitude and appreciation to Allen Ford, Jim Duff, Clint and Paul Reeder, Don, Robert and Russell Lieuallen and to Elise Aquino for allowing this research to be conducted on their farm and for their cooperation in conducting these experiments.
REFERENCES
Allmaras, R.R., C.L. Douglas, Jr., P.E. Rasmussen and L.L. Baarstad. 1985. Distribution of small grain residue produced by combines. Agron. J. 77:730-734.
SAS Institute Inc. 1998. Cary, N.C.
Siemens, M.C., R. F. Correa and D. E. Wilkins. 2002. Flexible ground-driven residue management wheel. United States Patent No. US 6,345,671 B1.
Table 1. Site description, seedling stand count and yield results of residue management wheel evaluation studies in Oregon for crop year 2000.
Table 2. Site description, seedling stand count and yield results of residue management wheel evaluation studies in Oregon and Washington for crop year 2001.
Table 3. Stand establishment, seedling vigor and grain yield for winter wheat near Helix, OR, crop year 2000, when planted with a hoe-type no-till drill into 9,000 lb/ac of residue that had been managed in different ways.
Table 4. Stand establishment, seedling vigor and grain yield for spring wheat
near Helix, OR, crop year 2000, when planted with a hoe-type no-till drill into
9,000 lb/ac of residue that had been managed in different ways.
Table 5. Stand establishment, seedling vigor and grain yield for winter wheat near Pendleton, OR, crop year 2001, when planted with a hoe-type no-till drill into 9,400 lb/ac of residue that had been managed in different ways.
Table 6. Stand establishment, seedling vigor and grain yield for spring wheat near Pendleton, OR, crop year 2001, when planted with a hoe-type no-till drill into 9,400 lb/ac of residue that had been managed in different ways.
 Contact
us: Hans Kok, (208)885-5971
|
Accessibility | Copyright
| Policies | WebStats | STEEP Acknowledgement |