Progress 02/01/04 to 01/31/10
Outputs
OUTPUTS: In 2004, progress was made in all four objectives. Field experiment on hay yield and quality responded to rate of N and cutting frequency was conducted in the Fairbanks area. Three N rates: 0, 50 and 150 kg N/ha; two cutting regimes: one or two cuttings per year were set up in a 182 m x 9 m plot. Randomized hay and soil samples were taken in five replicates within each N rate in June and August of 2004. Air-dried soil samples were aerobically incubated for 2 weeks and then extracted by chemical solutions of 2 M hot KCl, 1 M HCl, 1 M NaOH, and deionized water to determine mineralizable N. Total N, and total P, neutral detergent fiber (NDF) and acid detergent fiber (ADF) in plant samples were determined. Soil samples were taken in fall 2003 from a long-term tillage study. Soil samples were air-dried, and sieved (2-mm). Soil chemical and physical properties were determined. In 2005, field bromegrass experiment with 0, 50, and 150 kg N/ha has been conducted. Five randomized hay and soil samples were taken at each sampling time (June 13, July 11, and August 9). Plant samples were analyzed for N, P K and S concentration, and NDF and ADF. Mineral N, and potential mineralizable N in soil samples were analyzed. In 2006, field experiment of bromegrass with 0, 50, and 150 kg N/ha has been conducted. The experiment was started in 2004, and continued in 2005. To determine N use efficiency, N-15 enriched urea (10%) was applied in a 1 m x 1 m plot in each fertilizer rate. Plant samples were taken in June, July and August from N-15 plots, and N-15 content in the samples were analyzed. There was very little precipitation during the growing season of 2006, and that adversely impacted bromegrass yield. The biomass from the non-fertilizer treatment was only 20% of that in 2005. Soil samples from N-15 plots were taken and were analyzed. In the tillage research, results from 2003 soil samples were summarized and written for publications. In 2007, Soil samples of 0-5, 5-10, 10-15 and 15-20 cm depth were taken from the different tillage treatment plots, and were analyzed for total and extractable phosphorus using Bray, Olsen and Mehlich-3 methods. A phosphorus adsorption isotherm was also determined for the soil samples. Soil samples were also taken from CRP, forest, and agriculture land. In 2008, Soil samples from the tillage plots were analyzed using a modified Headley procedure. Soil samples from different land uses were analyzed for carbon, nutrient content, and biological properties. In 2009, data from different land uses, and Headley phosphorus fractionation were statistically analyzed. Two manuscripts were written and they are being reviewed and reedited prior to submission. The two manuscripts are "Soil Quality under Different Land Uses in a Subarctic Environment in Alaska"; "Soil Phosphorus Status under 23-year No-Tillage in a Subarctic Environment of Alaska". PARTICIPANTS: Mingchu Zhang is principal investigator. Stephen Sparrow, Professor of Agronomy, School of Natural Resources and Agricultural Sciences, University of Alaska Fairbanks, cooperated with some parts of the research. Robert Van Veldhuizen, research technician, School of Natural Resources and Agricultural Sciences,provided invaluable assitant for completing this research project. Research scientist Steven Seefeldt of USDA ARS cooperated with land use research. TARGET AUDIENCES: Agriculture producers, and researchers in Alaska and in circumpolar northern, extension personnel, state and federal agencies. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The project showed that 1) no tillage can increase soil organic matter and improve soil quality; 2) straw retention didn't affect soil properties, however, no tillage decreased soil bulk density, 3) nitrogen fertilizer application beyond 91 kg N/ha did not benefit barley grain yield. The results provided guidelines for producers to practice no tillage in Alaska. This is particularly important in the area that is sensitive to climate change and vulnerable to wind erosion. The results show practical ways in high latitude areas to mitigate climate impact and minimize soil erosion. Phosphorus analysis from a long-term tillage study showed phosphorus accumulation and stratification in soils with P fertilizer applications. In the no tillage treatment, most P was stratified in soils at 0-5 cm depth, in contrast, in conventional tillage, phosphorus accumulation occurred in all depths. Phosphorus used by barley grain is less than 11% on a seven-year average. The research provides crucial information on status of P in conventional and no till soils, and paves the way for future research on P soil test and fertilizer recommendations. Proper use of P fertilizers is important not only in crop production but also in preventing P loss to surface fresh water systems causing eutrophication. This is especially important in subarctic Alaska due to high cost of P fertilizers for crop production, and nutrient sensitive fresh water systems. As increase demand in food and biofuel increases, more land will be converted for agricultural uses. Soil samples taken for different land uses in the Delta Junction area of Alaska is the first step to characterize soil property changes under different land uses in high latitude area. Organic matter in native land is stratified at high latitudes due to lack of macro fauna activities (i.e. organic matter is not mixed with mineral soils below). Because of this, results indicated that agricultural soil has better soil quality than forest soils reflected in soil properties such as soil organic matter content, wet aggregate stability and microbial population. This is quite different than similar studies reported elsewhere. Therefore, to better understand soil quality change under different land uses in high latitude areas, new methods need to be developed. The results from N-15 plant and soil samples indicated the cumulative N use efficiency for bromegrass in three years was high in 150 kg N/ha in one cut, and 50 kg N/ha in two cuts per year. The results of the bromegrass experiment provide information for producers to manage N and hay quality under different cutting regimes. Hay is one of the major crops in Alaska. This information is relevant given the fact that fertilizer prices increase rapidly in recent years. Soil incubation showed that among different chemical extractions, water extracted total N is highly correlated with mineral N released over time. Water extraction can be a tool to estimate potential mineralizable N in soil in high latitude areas. Since this test was only in one soil type, further verification is still needed for soils of different types and land uses.
Publications
- Sharratt, B., M. Zhang, and S. Sparrow. 2006. Twenty years of tillage research in subarctic Alaska: I. Impact on soil strength, aggregation, roughness and residue cover. Soil & Tillage Research, 91:75-81.
- Sharratt, B., M. Zhang, and S. Sparrow. 2006. Twenty years of tillage research in subarctic Alaska: II. Impact on soil hydraulic properties. Soil & Tillage Research,91:82-88.
- Seefeldt, S.S., J.S. Conn, M. Zhang, and P.N. Kaspari. 2009. Vegetation changes in Conservation Reserve Program lands in interior Alaska. Agriculture, Ecosystems and Environment, 135:119-126.
- Zhang, M., S. Sparrow, C. Lewis, and C. Knight. 2007. Soil Properties and barley yield under 20-year experiment of tillage, straw management, and nitrogen application rate in the subarctic area of Alaska. Agricuturae Scadinavica- Section B Soil & Plant Science, 57:375-383.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Soil samples of 0-5, and 5-10 cm soil depth from the tillage plots were analyzed using a modified Headley P fractionation procedure. The results showed that labile P concentration both in resin and bicarbonate P was higher at the surface layers of 0-5 and 5-10 cm soil depth for No tillage treatment in comparison with Disk Once and Conventional Tillage treatments. The least labile P concentration was with the Conventional Tillage treatment. However, there was little difference in Fe-, and Al-bound P (NaOH-P) and Ca-bound P (HCl-P) among the tillage treatments. This was consistent with our previous results that no difference in P adsorption capacity was found among the three tillage treatments. Phosphorus accumulation occurred only in the labile P pools of No till treatment. There is little information on no tillage impact on soil properties in high latitude soils. For the sensitivity of the area to climate change, the information from this project will be useful for producers, agencies and researchers to develop strategies to mitigate climate change impact on agriculture. Part of the information from this research project is disseminated in scientific journals of high latitude countries, in presentations of national conferences, and local producers meetings. PARTICIPANTS: Dr. Mingchu Zhang is principal investigator. Robert Van Veldhuizen, research technician. TARGET AUDIENCES: Alaskan agronomic producers and agronomic producers in circumpolar northern environments. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Proper use of P fertilizers is important not only in crop production but also in preventing P loss to surface fresh water systems that can cause eutrophication. This is especially important in subarctic Alaska due to high cost of P fertilizers for crop production, and nutrient poor fresh water systems. This study will provide fundamental information for P management in arable land in interior Alaska.
Publications
- Zhang, M., S. Sparrow, C. Lewis, and C. Knight. 2007. Soil Properties and Barley Yield Under 20-years Experiment of Tillage, Straw Management and Nitrogen Application Rate in the Subarctic Area of Alaska. Actao Agri. Scan. Section B, Soil and Plant Sci. 57:374-382.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: In 2007, major progress was made in assessing soil phosphorus status in the 23-year long term tillage plots. Soil samples of 0-5, 5-10, 10-15 and 15-20 cm depth from the different tillage treatment plots were analyzed for total and extractable phosphorus using Bray P, Olsen P and Mehlich-3 methods. A phosphorus adsorption isotherm was also determined on the soil samples. The results showed that high phosphorus concentrations both in total phosphorus and three forms of extractable phosphorus was high at the surface layers of 0-5 and 5-10 cm soil depth, especially with the No tillage (NT) and Disk Once( DO) treatment. Comparing among tillage treatments, phosphorus concentration was lower with conventional tillage in all sampling depths than NT and DO treatments. However, there was little difference in phosphorus adsorption capacity among three tillage treatments in soil samples of all depths. This is opposite to our hypothesis, "high phosphorus concentration should be found in
surface soil of NT treatment corresponding with the low P adsorption capacity". Our next step is to determine soil phosphorus forms using Headley sequential phosphorus fraction methods.
PARTICIPANTS: Dr. Mingchu Zhang, Assistant Professor of Agronomy is the Principal Investigator. Dr. Stephen Sparrow, Professor, Department of Plant, Animal and Soil Science, School of Natural Resources and Agriculture Sciences is a research partner for this project, and we have published several papers together. Research technicians are Bob Van Veldhuizen and darleen masiak. Partners and collaborators: State of Alaska Division of Agriculture (DNR), Federal USDA ARS & NCRS; Carol E. Lewis, Professor, Dean and Director, School of Natural Resources and Agriculture Sciences and Alaska Agricultural and Forestry Station; Charles Knight, Alaska Department of Natural Resources, Division of Agriculture.
TARGET AUDIENCES: Extension personnel, producers, researchers in high latitude countries. State of Alaska Division of Agriculture (DNR), Federal USDA ARS & NRCS
Impacts
There is little information on no-tillage impact on soil properties in high latitude soils. For the sensitivity of the area to climate change, the information from this project will be useful for producers, agencies and researchers to develop strategies to mitigate climate change impact on agriculture. Part of the information from this research project is disseminated in scientific journals of high latitude countries, in presentations of national conferences, and local producers meetings. Proper use of phosphorus fertilizer is important not only in crop production but also in preventing phosphorus loss to surface fresh water system that can cause neutrification. This is especially important in subarctic Alaska due to high cost of phosphorus fertilizers for crop production, and nutrient poor fresh water system. This study will provide fundamental information for phosphorus management in arable land in interior Alaska.
Publications
- Zhang, M., S. Sparrow, C. Lewis, and C. Knight. 2007. Soil Properties and Barley Yield Under 20-years Experiment of Tillage, Straw Management and Nitrogen Application Rate in the Subarctic Area of Alaska. Actao Agri. Scan. Section B, Soil and Plant Sci. 57:374-382.
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Progress 01/01/06 to 12/31/06
Outputs
The objectives of the project are: 1) to determine optimal N fertilizer application rate and cutting frequency on yield and quality of bromegrass hay; 2) to analyze barley yield from different tillage, straw management; and N fertilizer application rate since 1983; 3) to determine soil carbon quantity and quality affected by different land management and tillage; and 4) to quantify the potential mineralizable N in agricultural land under different management practices. In 2006, several major progresses have been made. In 2006, field experiment of bromegrass with 0, 50, and 150 kg N/ha has been conducted. The experiment was started in 2004, and continued in 2005. To determine N use efficiency, N-15 enriched urea (10%) was applied in a 1 m x 1 m plot in each rate of fertilizer treatment. Plant samples were taken on June, July and August from N-15 treated plots, and N-15 concentration in plant samples will be determined. There was very little precipitation during the
growing season of 2006, and that adversely impacted bromegrass yield. For example, the biomass from the non-fertilizer treatment was only 20% of that in 2005. Soil samples from N-15 plots were also taken and will be analyzed for their N-15 concentration. In the long-term tillage research, results from 2003 soil samples were summarized and published in peer reviewed journal (Acta Agriculture Scandinavica, Section B, Soil and Plant Science). The research results from the long-term tillage study had shown that no tillage can improve soil quality and reduce erosion in the subarctic environment. But one of the major problems for producers to practice no tillage is the weeds control, especially for the fox tail barley (Hordeum jubatum L), due to a short growing season and lack of rotational crops. For the 21-year long term experiment, chemical fellow was used four times. To find a weeds controlling method in no tillage system, a new tillage study using different frequency of tillage was
implemented in the spring of 2006. There were six treatments: 1) Disk once every year; 2) Disk once each 3rd year; 3) Disk once each 6th year; 4) Disk once each 9th year; 5) Disk once each 15th year; and 6) No tillage. Each treatment will be split into two, and straw-on and straw-off treatments will be added. All tillage will be carried out in spring, and each treatment was replicated four times in a randomized complete block design. Benchmark soil samples were taken in the spring 2006, and will be analyzed for chemical and physical properties.
Impacts
The results from N-15 plant and soil samples will indicate the N use efficiency for bromegrass in subarctic environment. Even though the weather condition was less than idea in 2005, the results will provide some guidance for N management on bromegrass in interior Alaska. This is especially important under high energy and global warming perspectives. The results in tillage research showed that no tillage benefits soil conservation and barley yield. From the past tillage research results, a new tillage experiment was conducted in 2006, and this new tillage experiment will provide much needed information on weeds management for no tillage systems in the subarctic environment when there is no rotational crops.
Publications
- Sharratt, B., M. Zhang, and S. Sparrow. 2006. Twenty years of tillage research in subarctic Alaska: I. Impact on soil strength, aggregation, roughness and residue cover. Soil and Tillage Research. Soil & Tillage Research 91:75-81.
- Sharratt, B., M. Zhang, and S. Sparrow. 2006. Twenty years of tillage research in subarctic Alaska: II. Impact on soil hydraulic properties. Soil and Tillage Research. Soil & Tillage Research 91:82-88.
- Zhang, M., S. Sparrow, C. Lewis, and C. Knight. 2007. Soil Properties and Barley Yield Under 20-years Experiment of Tillage, Straw Management and Nitrogen Application Rate in the Subarctic Area of Alaska. Actao Agri. Scan. Section B, Soil and Plant Sci. (in press).
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Progress 01/01/05 to 12/31/05
Outputs
The objectives of the project are: 1) to determine optimal N fertilizer application rate and cutting frequency on yield and quality of bromegrass hay; 2) to analyze barley yield from different tillage, straw management; and N fertilizer application rate since 1983; 3) to determine soil carbon quantity and quality affected by different land management and tillage; and 4) to quantify the potential mineralizable N in agricultural land under different management practices. In 2005, several major progresses have been made. In 2005, field experiment of bromegrass with 0, 50, and 150 kg N/ha has been conducted. This is the continuation of the experiment in 2004. Five randomized hay and soil samples were taken at each sampling time (June 13, July 11, and August 9). Plant samples were analyzed for N, P K and S concentration, and neutral detergent fiber (NDF) and acid detergent fiber (ADF). Available nitrogen (NH4-N + NO3-N), and potential mineralizable N (soluble organic N,
hot KCl N) in soil samples will be analyzed. The results showed that nitrogen concentration in plant samples increased as the rate of N application increased from 0 to 150 kg N/ha. However, there are little changes in ADF and NDF concentrations among N application rates for plant samples taken both in 2004 and 2005. The growth stage for the first cutting in 2005 was in boosting stage and the second cutting was in heading stage (> 50% heading). Apparently, there was little difference in ADF and NDF concentrations between early and late cuttings in all three N application rates. In the long-term tillage research, results from 2003 soil samples showed that tillage has a tendency to impact soil bulk density at 0-5 cm depth, but not at the depth below that. Soil organic matter from 5 to 10 cm was increased (p < 0.06) with the straw retention, but not with the no-tillage treatment. No tillage treatment benefits barley yield, however, weed control is a constant problem in last 21 years in no
tillage practice in sub-arctic area due to short in growing season and lack of options in rotational crops. In addition, soil physical properties have been studied (infiltration, penetration resistance, aggregate size distribution et al.) in the tillage research plots. The results were published in Soil and Tillage Research in 2005.
Impacts
The results with bromegrass experiment showed that ADF and NDF concentrations after boosting stage can not be changed even with high N application rate. Long day length in high latitude might hasten the conversion of nonstructural fiber in plant. The results in tillage research showed that no tillage benefits soil conservation and barley yield, but new strategies should be developed in order to manage weeds in no tillage practice.
Publications
- Sharratt, B., M. Zhang, and S. Sparrow. 2005. Twenty years of tillage research in subarctic Alaska: I. Impact on soil strength, aggregation, roughness and residue cover. Soil and Tillage Research. (in press)
- Sharratt, B., M. Zhang, and S. Sparrow. 2005. Twenty years of tillage research in subarctic Alaska: II. Impact on soil hydraulic properties. Soil and Tillage Research. (in press)
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Progress 01/01/04 to 12/31/04
Outputs
In 2004, progress was made in all four objectives. Field experiment on hay yield and quality responsive to rate of N application and cutting frequency was carried out in the University Research Farm in Fairbanks. There were three N application rates: 0, 50 and 150 kg N/ha; two cutting regimes: one cutting and two cuttings per year. Each treatment was set up in a 182 m x 9 m plot. Randomized hay samples as well as soil samples were taken in five replicates within each treatment in June and August of 2004. Soil samples were air-dried, passing through a 2-mm sieve. A portion of soil samples were incubated for 2 weeks under aerobic and anaerobic conditions and then respectively extracted by different chemical solutions to determine the amount of mineralizable N. The chemical solutions were 2 M hot KCl, 1 M HCl, 1 M NaOH, and deionized water. The broomgrass samples were dried, ground, and total N, and total P, neutral detergent fiber (NDF) and acid detergent fiber (ADF)
are to be determined. Currently soil and plant samples are being analyzed in the laboratories. The long-term tillage research has been conducted for 21 years. Soil samples were taken in fall 2003 from three tillage treatments: no-tillage, minimum tillage and conventional tillage; two straw amount treatments: straw retention and straw removal; and two N rate treatments: 11 and 131 kg N/ha. The sampling depths were 0-5 cm, 5-10 cm, 10-25 cm, 25-45 cm. Soil samples were air-dried and passed through a 2-mm sieve. The soil total organic C, total N, available N, extractable P (Melhich 3, Bray-2 and Olsen), and exchangeable K, CEC, Eh, pH from these samples were determined. The results showed that no-tillage did increase soil organic matter content, but only on the 0-5 cm soil depth. This is quite different from what has been reported in the literature in which soil organic carbon increases at a depth below the surface layer of 0-5 cm, and in a much shorter period of time (1.5 - 13 years).
In comparison, straw retention did not affect soil organic C or total N content. This is probably associated with short growing season and cold and dry climatic conditions in the Delta Junction area, that reduced the decomposition rate of residue on soil surface. In addition to determining soil chemical changes from different treatments, yield results of barley from 1983 to 2003 were summarized, and statistically analyzed. Nitrogen fertilizer application together with no tillage increased barley grain yield. But the increase was yearly dependent. This might be related to the weather in the Delta Junction area (such as time of rain fall, early spring temperature et al.). Further analysis is required to ascertain the impact of tillage on barley grain yield.
Impacts
The project impact are, 1) the result of 21-year long term tillage experiment provided guideline for producer to practice no tillage in Alaska; 2) quantitatively demonstrated the amount of carbon can be sequestrated by no-tillage practice; 3) estimation of potential mineralizable N will help producers to improve N fertilizer use efficiency; and 4) bromegrass yield and quality in response to N fertilizer application and cutting regime will result in good management practice for quality hay production.
Publications
- M. Zhang, and S. Sparrow. 2004. Impact of tillage, straw management and nitrogen fertilizer rate on barley yield and soil properties in a 21-year tillage study in subarctic Alaska. Soil Science of American annual meeting abstracts, 31 October - 4 November 2004. Seattle WA. (available on CD-ROM).
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