Project: MLMMI 01-01-08
Objective
To quantify leaching losses of nitrate-N, phosphorous and dissolved organic carbon. To determine the effect of rates of manure and fertilizer on nutrient leaching losses. To use data generated to formulate and refine nitrate and phosphate leaching simulation models which can then be used to estimate leaching losses from agricultural fields.
Performer
O. Akinremi
University of Manitoba
Details
Status: Completed
Started: 2002-09-01
Completed: 2004-03-02
Funding Partners: who have contributed to MLMMI in support of this project:
Manitoba Pork Council and industry groups - $60,000
Amount Funded: $60,000.00
Performer Funded: $127,810.00
Total Cost: $187,810.00
Activity
First Progress Report received Feb. 28/02.
Second progress Report received Sept. 5/02.
Third Progress Report received March 7/03.
Final report due September 1, 2003.
Finish Date extended to Jan. 1, 2004.
Final Report received on March 2, 2004.
Summary
Objectives
The objectives of this field study were to compare organic (hog manure) and inorganic (commercial fertilizer) sources of nitrogen and phosphorus on crop yield and nutrient losses on a coarse textured soil. To determine the effect of rate of hog manure on nutrient movement in the soil and compare the lysimeter method of measuring nutrient movement to the traditional soil profile sampling technique of measuring nutrient movement.
Major Findings
We conducted this study on a coarse textured soil (Fairland soil series) located near Carberry, Manitoba. Each spring, we applied swine manure at rates of 2500, 5000 and 7500 gal acre-1 to a plot of land measuring 10 m by 10 m. Commercial fertilizer was added to two other plots to provide similar amount of nitrogen and phosphorus as did hog manure. These treatments, together with a control constituted 6 treatments which were replicated 4 times for a total of 24 plots. One of the fertilized plots was seeded while the other was left in fallow during the two growing seasons. A lysimeter was installed in each plot to collect leachate below the root zone and received treatment similar to that imposed on the surrounding plot. Grain yield was similar in both years and was about one-half of that expected for the area.
The growing season precipitation in both years was below normal for the area and may partly explain the low yield obtained in this study. In both years, the fertilized treatment produced grain yield that were greater than the manure treatments. The grain yield from the manure treatments were not significantly greater than the control plot. The dry growing season probably limited the availability of nutrient from manure treatments. Maximum uptake of nitrogen by wheat was from the fertilized treatment (63 kg ha-1 in 2002 and 48 kg ha-1 in 2003). In both year, however, fertilizer use efficiency was less than 20% when measured relative to the control plot. This was much below an average efficiency of 50% for cereal on the prairies. In comparison to commercial fertilizer, the nitrogen use efficiency in manure treatments was 10% or less. For phosphorus, there was no significant treatment effect in 2002 while commercial fertilizer produced higher uptake in 2003. Little or none of the manure phosphorus was available to wheat in both years from swine manure. This may be due to the low input of P caused by an unusually high N:P ratio of the manure used in this study.
The distribution of nitrate nitrogen followed the same pattern in both years, high close to the soil surface shortly after application, with levels declining at the surface while increasing at depth, as a result of nitrate movement with time. Nitrate movement was limited to a depth of 45 cm in the year of application, possibly due to the dry growing season in 2002. By fall of 2003 however, nitrate nitrogen has reached a depth of 80 cm at the 7500 gal rate. More nitrate nitrogen was measured in the soil that received commercial fertilizer compared to plots with manure. In the fallow plot that received commercial fertilizer, nitrate nitrogen was found at the 120 cm depth in 2002 and lower amount of nitrogen after spring snowmelt in 2003 signifying the loss of nitrogen by leaching in this treatment. This result was supported by data obtained from the lysimeters. No leachate was collected in 2002 and only from 7 of the 24 lysimeters in 2003 starting with the spring snow melt. Results showed that nitrate leaching occurred mainly in the spring and the fall with significant amount of nitrate loss from soil in fallow. At the end of the growing season in 2003 , the two most productive fallow lysimeters lost 12 and 7 cm of water containing 119 and 40 kg ha-1 of nitrate-nitrogen, respectively. The lysimeter on the control plot yielded 5 cm of water containing 18 kgha-1 of nitrate-nitrogen in 2003. While leachate containing nitrate was expected from the fallow lysimeters as a result of fertilizer addition and water accumulation in 2002, the amount of water and nitrate from the control lysimeter shows that soil organic matter breakdown can result in loss of nitrate from these sandy soils without the additions of fertilizer or manure. It is feasible to use swine manure on these sandy soils at rates below the 5000 gal acre, however, the limitation imposed by water may make manure nutrient unavailable to crop. Nitrate leaching can be minimized but it may be unavoidable on sandy soils as losses were measured where no fertilizer and manure was applied.