Progress 09/01/05 to 09/30/07
Outputs
OUTPUTS: Results of this research have been presented to farmers, crop consultants, regulatory personnel, and others during four Field Days over two years. Field Days were held at the Arlington and Marshfield Ag Research Stations where the research was conducted. The results were explained in the context of why the research needed to be conducted and what the results meant. Approximately 450 people total attended these field days. Results, both preliminary and final, were presented to crop consultants, regulatory personnel, and fertilizer dealers at the 2006 North Central Extension-Industry Soil Fertility Conference, the 2007 Wisconsin Fertilizer, Aglime, and Pest Management Conference, and the annual Soil, Water, and Nutrient Management meetings. These meetings reached approximately 1200 people and the presentations are documented in Proceedings of the Conferences. The scientific community was apprised of the project results during presentations at the 2006 and 2007 Soil Science
Society of America Annual Meetings. Two manuscripts are being prepared for publication in a peer reviewed journal.
PARTICIPANTS: PI(1) - Supervised research, assisted plot establishment and field sample collection, reported results, extended results to clientele; Graduate Research Assistant (1) - conducted the laboratory and field research, responsible for sample collection and analysis, and supervised undergraduate student hourly; Undergraduate Student hourly workers (3) - assisted graduate student with sampling and analysis; Technical staff (2) - assisted in plot maintenance; Volunteers (7) - assisted in plot establishment
TARGET AUDIENCES: Target audiences include: 1)regulatory personnel who will use information to make decisions on nutrient management regulation; 2)crop consultants and fertilizer dealers who write farm nutrient management plans; 3)farmers who are responsible for applying nutrients in a manner that complies with regulations; and 4)other researchers who may find this information useful.
Impacts
The results of this field research show that phosphorus (P) from manure can increase corn grain and silage yield similarly to inorganic fertilizer P in both the year of application and one year after application. These results suggest that current University of Wisconsin-Extension manure nutrient availability guidelines may need to be revised. In both laboratory incubations and field plots, it was found that the P buffer capacity (PBC, amount of phosphorus needed to increase soil test P by 1 ppm) varies both with soil type and P source (manure v. fertilizer) and can be both greater or less than the PBC values which are currently used in nutrient management planning. These results suggest that allowable manure application rates may need to be reduced on some soils and could be increased on other soils and still be protective of surface water quality. Soil test P (a routine test) is used to predict water extractable P (a non-routine test) and subsequent potential for P
loss to surface water. It was previously known that the relationship between soil test P and water extractable P was dependent on soil type (coarse- vs. medium- and fine-textured soils). However, until this study was completed, it was unknown that the source of P, which had been applied to the field, would impact that relationship. Fully understanding differences between soil types in their ability to release P is important to assessing a soils risk for P loss to surface water. A major outcome of this research is that we found much more variability in PBC and relationship between soil test P and water extractable P than what was expected. This is particularly important because it was previously thought that the two soils used in this study would behave more similarly. Thus, further exploration of the interactions between manure and soils, using many more soils and manure types, are needed before nutrient application guidelines and models predict P loss to surface water will be
changed. Project results were used to successfully obtain additional funding to continue this research.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
Work completed 2006 Field: The second field season of research was completed at Arlington and Marshfield Agricultural Research Stations. Data collected included soil samples taken prior to planting, four and ten weeks after planting, and post harvest. These samples are being analyzed for Bray P. Tissue samples were collected at V5, ear leaf at silking, at physiological maturity. Both silage and grain yield were collected. Lab: Laboratory analysis of soil and plant samples collected during the growing season is in progress. An incubation study was conducted by applying 3 rates of each manure type used in the field to soil collected from each field sites prior to treatment applications in 2005. Subsamples were collected during the incubation at 1, 2, 4, and 10 weeks after treatment application. The incubation was terminated at 15 weeks. All samples were analyzed for Bray P. Water extractable P will we analyzed on samples from at least one sampling date. Data analysis:
Data analysis of the 2005 data was nearly completed along some analysis of the 2006 data. Planned work in 2007 Laboratory: A second incubation study will be conducted to assess the effect of manure history on phosphorus buffer capacity. Soil was collected at the end of the 2006 growing season from the plots with the highest rate of P applied for each P source at both locations (9 total soils). One rate of each manure type and fertilizer (7 P sources) will be applied to each soil and incubated at 50 % moisture content for 10 weeks. All laboratory analysis of samples will be completed by May 2007. Data analysis: All data analysis from the 2005 and 2006 growing seasons along with all incubation experiments will be completed by June 2007. Final interpretation of the data will be completed in August at which time the graduate student working on this project will complete her M.S. thesis. Preliminary Results It has been found that P buffer capacity varies with the source of P (manure type
or fertilizer) and with soil type. This is very interesting and suggests that all manures should not be expected to have the same effect on changing soil test level for all soils as is currently recommended in University of Wisconsin-Extension (UWEX) publications. From the standpoint of a corn crop, as long as the total amount of P applied is adequate for crop production the source of P is in material. These results are also contradictory to UWEX recommendations that the total amount of manure P is only 60% available to a crop; our data suggests that it is 100% available. It is not surprising that these results do not confirm current practices, because the database for manure P availability prior to this experiment was very limited.
Impacts
This study seeks to understand how manure applications to soil influence soil phosphorus levels in a field and lab setting. The information will be used to improve recommendations related to phosphorus crediting of manures in Wisconsin. Improved crediting will help balance agricultural production and environmental quality.
Publications
- Marshall, S.K. and C.A.M. Laboski. 2006. Sorption of inorganic and total prhosphorus from dairy and swine slurry. J. Environ. Qual. 35:1836-1843.
- Harrigan, T.M. B.B. Bailey, W.J. Northcott, A.N. Kravchenko, C.A.M. Laboski. 2006. Field performance of a low-disturbance, rolling time, dribble-bar manure applicator. Appl. Engr. Agric. 22(1):33-38.
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Progress 01/01/05 to 12/31/05
Outputs
Work completed 2005 Field: This project began in March 2005 when research sites were selected at Arlington and Marshfield Agricultural Research Stations. On average, soil test phosphorus (P) levels at both locations were in the 10 to 15 ppm range. These soil test levels are considered low or optimum for corn production and an increase in yield with additional P application would be expected to occur 30 to 60 % of the time. Three rates each of manure (dairy semi-solid, dairy slurry, swine slurry, and poultry pellets) and fertilizer applications, along with a zero P control, were made at both locations in April and corn was planted within two weeks of application. Note poultry pellets were only applied in Arlington. Soil samples (0-5, 0-15, and 15-30 cm) were taken in each plot prior to application, at two, four, and ten weeks after application, and after harvest. Plant samples were collected at the V6, silking, and physiological maturity. Plots were harvested for both
silage and grain. After harvest plots were chisel plowed. Laboratory: Approximately 80 % of the soil samples have been analyzed for Bray-P and water extractable-P. Total P in plant samples and grain will be analyzed. Procedures for total P determination are being worked on. Planned work in 2006 Field: In plots that were intentionally left untreated last year, three rates of P fertilizer will be applied. This is being done to assess the second year credits from manure P compared to both a fresh application of fertilizer and the 2005 fertilizer application. Plots will be planted to corn. Soil will be sampled prior to fertilizer application, four weeks after application, and after harvest and then analyzed for Bray-P and water extractable-P. Plant samples will be collected and analyzed in the same manner as 2005. Both silage and grain yield will be measured. Laboratory: An incubation study will be completed in 2006. Bulk samples of manure that was applied in the field were previously
collected and being stored in a freezer. Bulk samples of soil from each location prior to treatment were collected, sieved, and air dried. These soil and manure samples will be used for the incubation. Prior to initiating the incubation experiment, several steps in the methodology must be determined. Soil will be incubated with various rates of each manure for nine weeks with several subsampling times. Preliminary Results Data analysis has just begun and results provided should be considered preliminary. In general, as the amount of P applied increased, so did the change in soil test level. The increases, however, were not always linear. The various P sources changed soil test P levels differently at Arlington and Marshfield. This may be caused by different soil types and/or different sources of manure. The swine slurry was the only manure used at both locations (manure was applied in Arlington and then hauled to Marshfield). The other manures were local to the area. The effect of
manure sources and soil type will be assessed in the incubation study as all manures used will be applied to both soils (eg. Marshfield dairy slurry will be applied to Arlington soil).
Impacts
This study seeks to understand how manure applications to soil influence soil phosphorus levels in a field and lab setting. The information will be used to improve recommendations related to phosphorus crediting of manures in Wisconsin. Improved crediting will help balance agricultural production and environmental quality.
Publications
- No publications reported this period
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