Final Report for SW97-012
The effectiveness of no-till forage establishment was assessed at six locations in Alaska. Direct seeding of grass into established grass stands usually did not improve forage yields or quality. Seeding rate and N rate had little effect on establishment of newly seeded forages, especially in no-till. Grass yields were depressed when companion crop yields were high and sometimes did not recover in subsequent years. Red clover established well, producing high yields of good quality forage under no-till at one site, but established poorly at two other sites.
The objectives of this project were to:
1. Evaluate the efficacy of no-till planting as compared to planting into tilled soil under various N fertilizer rates for establishment of timothy (Phleum pratense L.) and smooth bromegrass (Bromus inermis Leyss.) in Alaska.
2. Evaluate promising annual companion crops for forage production during perennial grass establishment in no-till and conventional tilled planting systems.
3. Determine the effectiveness of no-till establishment of perennial grasses and red clover (Trifolium pratense L.) at various seeding rates.
Approximately 68% of the agricultural land in Alaska is in perennial grasses. These grass stands periodically need to be renovated due to occasional winterkill or stand depletion over time. Current recommendations for reestablishing forage grasses in Alaska call for reseeding into well tilled seedbeds. However, dry and often windy spring conditions prevail in much of Alaska, making establishment of small seeded crops difficult. Loss of soil moisture and wind erosion are major problems following spring seeding of crops into tilled soil. Thus, better methods for restoring degraded pastures, haylands, and grass seed fields are needed for Alaska.
Experiments were established on farmers' fields at two locations in interior Alaska and four locations in southcentral Alaska. The interior Alaska sites were at Fairbanks (64o55'N, 147o43'W) on Columbia Creek Farm and at Delta Junction (63o55'N, 145o44'W) on Shultz Farms. The southcentral Alaska sites were at Palmer (61o39'N, 149o07'W) on Peter Scorup's farm, at Point Mackenzie (61o24'N, 149o54'W) on the Trytten Farm, at Sterling (60o32'N, 150o39'W) on Paul Rumley's farm, and near Anchor Point (59o45'N, 151o39'W) on Edna Anderson's farm. The interior Alaska sites experience strongly continental climates, the Palmer, Point MacKenzie, and Sterling sites are moderately continental, and Anchor Point experiences a moderately maritime climate. All of the soils were moderately to strongly acidic silt loams.
Field composition and stand in farmers' fields varied considerably:
Fairbanks: smooth bromegrass hayfield, fair stand.
Delta Junction: abandoned Kentucky bluegrass seed field, very poor stand.
Palmer: smooth bromegrass hayfield, good stand.
Point MacKenzie: timothy hayfield, fair stand.
Sterling: mixture of Kentucky bluegrass and red fescue, fair stand.
Anchor Point: mixture of timothy, native grasses, and native forbs, fair stand.
Objective 1 (nitrogen rate study under till and no-till).
This experiment was established at all six sites. Manchar smooth bromegrass was planted at Delta Junction, Fairbanks, and Palmer at a rate of 20 kg viable seeds per ha. Engmo timothy was planted at a seeding rate of 9 kg/ha at the other three locations. Seeds were planted into both tilled and untilled soil at all locations except Anchor Point and Sterling where only no-till was used. Also, only no-till treatments were planted at Fairbanks in 2000 due to lack of plot space. For tilled plots, soils were planted within one day of tilling. All plots were seeded with a plot drill designed to seed into untilled sod. Each site received P and K fertilizer based on soil tests from that site. Nitrogen was applied as ammonium nitrate with the seed at 0, 20, 40, and 60 kg N/ha. An unseeded control treatment was included at two N fertilizer rates (0 and 40 kg N/ha).
Objective 2 (companion crop study).
Toral oats (Avena sativa L.), Gulf Westerwold ryegrass (Lolium multiflorum Lam.), and Dwarf Essex fodder rape (Brassica napus L.) were planted as companion crops with Manchar smooth bromegrass at Delta Junction and with Engmo timothy at Anchor Point and Point MacKenzie. At Anchor Point, only no-till seeded was done; at the other two sites, seed was drilled into tilled and untilled soil. Fertilizer rates were the same as for objective 1 for P and K; N fertilizer was applied with the seed as ammonium nitrate at 40 kg N/ha.
Objective 3 (seeding rate study).
Manchar smooth bromegrass (Delta Junction) or Engmo timothy (Anchor Point and Point MacKenzie) and Altaswede red clover (all three sites) was planted at three seeding rates (0.5x, 1x, and 2x the normal rates). All seeds were direct drilled into untilled sod. For red clover, the 1x seeding rate was 13 kg viable seeds/ha, for timothy it was 9 kg/ha, and for smooth bromegrass it was 20 kg/ha. Nitrogen was applied as ammonium nitrate with the seed to the timothy plots at 40 kg N/ha and to the smooth bromegrass plots at 30 kg N/ha. Nitrogen fertilizer was not applied to the red clover plots; powdered rhizobia inoculant was applied with the seed.
Each of the above experiments was established in adjacent locations in spring of 1998, 1999, and 2000.
All plots, except the red clover plots, received a uniform application of N as ammonium nitrate in the years subsequent to the seeding year. At Palmer and the interior Alaska sites, 60 kg N/ha was applied in spring and 40 kg N/ha was applied after the first harvest. At the other sites, 80 kg N/ha was applied in spring. Plots were harvested by clipping biomass from 1 square meter areas in each plot. Harvest was done when grass plants were in early heading stage. Two harvests were obtained in some years at Delta Junction, Palmer, and Fairbanks; other sites were harvested once each year. Weeds and crop (crop included all grasses at southcentral sites) biomass was separated at time of harvest. Samples were dried at 60oC and weighed to obtain dry matter yield. Selected samples of crop biomass were analyzed for forage quality (crude protein, neutral detergent fiber, and acid detergent fiber).
At Anchor Point, the entire plot area was harvested by the farmer prior to sample collection in 2000, thus no yield or forage quality data were available for that site in 2000. One replication of the first harvest was lost at Fairbanks in 2001 because the farmer mowed the plots prior to sampling.
Objective 1 (nitrogen rate study under till and no-till).
Seeding year results
Forage crop yields were very low in establishment year for no-till ( 2.0 Mg/ha at other locations. However, yields were similar in unseeded and seeded no-till plots at all locations, indicating poor germination success of seeds direct drilled into untilled sod. Thus, most of the biomass in no-till plots resulted from grass in the existing stands rather than from the seeded crop. Crop yields in tilled soil were usually highest with highest N rate, indicating no damage to emerging seedlings when N fertilizer was applied with the seeds.
Forage quality at Delta Junction was generally higher in no-till than in tilled soil. For example, crude protein averaged 17.4 % in no-till vs. 12.2% in tilled soil, neutral detergent fiber (NDF) averaged 50.0% in no-till and 52.6% in tilled soil, and acid detergent fiber (ADF) averaged 29.3% in no-till and 30.5% in tilled soil. These differences probably reflected slower germination, hence later maturity in the no-till at time of harvest. The opposite was true at Palmer, with crude protein averaging 7.9% in no-till vs. 14.6% in tilled soil; NDF averaging 49.3% in no-till vs. 47.2% in tilled soil, and ADF averaging 26.5% under both tillage treatments. This different effect at Palmer was probably because the no-till consisted mostly of grass from the existing stand which would have reached maturity faster than seedlings. Results at Fairbanks and Point MacKenzie were similar to those at Palmer, probably reflecting effects of seeding into existing stands for the no-till. Forage quality usually improved with increases in N fertilizer rates.
Subsequent year results
No-till yields remained low throughout the study at Delta Junction, with seeded no-till plots averaging only 0.5 Mg dry matter/ha in the 3rd year of establishment compared to 1.6 Mg/ha for tilled plots. No-till plots at other sites yielded considerably higher than at Delta Junction in subsequent years, averaging > 5.5 Mg/ha at Palmer with no differences between seeded and unseeded plots. This again indicates that the yields obtained were result of existing stands rather than from grass seeded into the stands. At Palmer, yields by the 3rd year were similar in no-till and tilled soil, but yields were much higher in tilled soil than in no-till at Fairbanks (3.2 Mg dry matter/ha in no-till vs. 4.7 Mg/ha in tilled soil) and Point MacKenzie (2.1 Mg/ha in no-till vs. 3.9 Mg/ha in tilled soil), indicating that seeding into no-till is not likely to be a successful method for renovating grass stands in Alaska. Seeding year fertilizer rates did not affect subsequent year yields except that those that received 0 N generally did not recover to equal yields of the other fertilizer treatments. Forage quality was not affected in subsequent years by establishment year tillage or fertilizer treatment.
Objective 2 (companion crop study).
Companion crops produced higher yields under tillage than under no-till at Delta Junction (1.64 Mg/ha under no-till vs. 2.91 Mg/ha under tillage). Oats were the only crop crop showing promise under no-till at Delta, with average yields of 3.5 Mg dry matter/ha. At Point MacKenzie, growth of all companion crops under no-till was so poor that we did not harvest the plots; under tillage, companion crops had an average yield of 2.17 Mg/ha. Companion crop yields never yielded more than 0.5 Mg/ha at Anchor Point. Grass yields were severely depressed by high yielding companion crops.
Crude protein concentrations in both companion crops and grasses were low (< 10%) at Delta Junction and Point MacKenzie, with forage rape usually having higher crude protein than other species. At Anchor Point, crude protein values were higher, with forage rape exceeding 20% in both years for which data were available. NDF and ADF values were comparable for the perennial grasses and all companion crops except forage rape. NDF values were near 50% - 55% and ADF near 30% for those species. Forage rape, however, had NDF values of <25% and ADF values of < 20%. Thus, forage rape has potential for producing high quality forage in Alaska. However, other problems, such as difficulty in establishment, low yields, and high tissue moisture contents make in an unlikely candidate as a forage crops for widespread use in Alaska; especially in no-till planting. Tillage regime had little effect on companion crop forage quality.
Subsequent year results
Perennial grass yields were generally low in the year following the establishment year if the previous companion crops had high yields. At Point MacKenzie, timothy had recovered by the 3rd year to the point that yield differences following different companion crops were undetectable, but at Delta Junction, yields remained low in the 3rd cropping year following oats. Grass dry matter yields remained lower in no-till than in tilled soil through the 3rd cropping year following all companion crops at both Delta Junction and Point MacKenzie. At Delta Junction, 3rd year yields in no-till averaged only 0.86 Mg dry matter/ha as compared to 2.19 Mg/ha in tilled soil. At Point Mackenzie, 3rd year dry matter yields for direct seeded timothy was 2.41 Mg/ha as compared to 3.30 Mg/ha following seeding into tilled soil. Forage quality was not affected by previous companion crop or tillage treatment.
Objective 3 (seeding rate study).
Yields for both smooth bromegrass and red clover were very low (usually < 0.5 Mg/ha) in the establishment year at Delta Junction. Increasing seeding rate increased bromegrass yields somewhat, with the 2x seeding rate producing average yields of 1.07 Mg/ha. Red clover yields were not affected by seeding rate. Smooth bromegrass yields did not improve over time and red clover had completely died out by the 2nd cropping year at Delta Junction. Red clover establishment was also very poor at Anchor Point, with yields never exceeding 0.6 Mg dry matter/ha. Grass yields at Anchor Point averaged 1.90 Mg/ha, with no effect of seeding rate (including the 0 rate). At Point MacKenzie, harvests were not done in any of the establishment years. Average grass yields for years subsequent to establishment year averaged 4.82 Mg/ha for grass alone and 0.86 Mg/ha when red clover was seeded in the plots, with no effect of seeding rate on grass yields. Red clover yields averaged 3.7 Mg/ha in the 2nd cropping year, 1.39 Mg/ha in the 3rd cropping year, and had decreased to <0.1 Mg/ha by the 4th cropping year. These results indicate that direct seeding of red clover into untilled sod can be successful in some situations in Alaska but not others. We do not yet fully understand why red clover was able to establish under no-till at Point MacKenzie but not at Anchor Point or Delta Junction. Red clover appears to act as a short-lived perennial in Alaska, much as it does in other regions.
No-till seeding of perennial grasses into declining grass stands is not likely to be successful in Alaska.
Direct seeding of red clover and oats into existing sod may be successful under some conditions in Alaska, but further research is needed to determine under which conditions they are likely to work.
Companion crops can increase total forage yields in the establishment year, but may depress perennial forage grass yields to the point that they may not recover in subsequent years. Most companion crops are not likely to be successful under no-till.
Since results of this project were mostly negative, the main impact for farmers in Alaska will be to discourage them from using no-till seeding of forage grasses or using companion crops with forage grasses in Alaska. While results are too new to have yet had much impact, there is likely to be an increase in red clover as a short-lived perennial forage legume in the Point MacKenzie area, where dairy farming is prevalent.
Education and Outreach
Results of this project were shared orally at the Autumn Harvest Day (a field day for farmers) at Point MacKenzie in August 2001 and at the Alaska Forage Conference in Wasilla in February 2002. A poster showing results of the project was displayed at the Delta Farm Forum in Delta Junction in February 2002. Results were presented to the scientific community through a poster displayed at the annual meeting of the American Society of Agronomy in Charlotte, NC in October 2001. We plan to publish results as an Alaska Agricultural and Forestry Experiment Station bulletin.
Education and Outreach Outcomes
Areas needing additional study
The main impact of this work was to show which practices will not work for establishing forage crops in depleting grass stands in Alaska. Future research should emphasize finding out why these practices do not work and in developing better techniques to make them work better.