Northern Great Plains Region
Dr. Adrian Johnston
Alberta
Stratification of pH and Nutrients in Two Surface Layers of the Three Hills Long-Term Cropping System Plots
Project Leader: Mr. Tom Goddard, Alberta Agriculture and Food, 7000 - 113 St., Edmonton, AB T6H 5T6 Canada.
Telephone: 780-427-3720.
A tillage by rotation study at Three Hills, Alberta, was evaluated after 11 years to determine if the use of no-till had led to nutrient stratification in the plots. The original study involved tilled versus no-till comparisons, and a number of crop rotations. The soil is a Solonetzic Black Chernozem, with a clay-loam texture. The study only evaluated nutrient stratification within the barley/canola/pea/wheat rotation. Soil samples were collected from the 0 to 3 in. and 3 to 6 in. soil depths and analysed for N, P, K, and S.
Soil pH levels trended slightly lower in the no-till plots (0.11 to 0.27 units), but never significantly lower. In the surface 3 in. of soil, no-till tended to increase soil test N, P, K, and S, but never to a significant degree. The largest difference in all nutrients considered occurred for wheat grown on pea stubble. The period of 10 years is considered a time when most of the changes in soils will have occurred in the conversion from conventional tillage to no-till. The results of this study indicate that nutrients did become stratified, but the effect was minor and of no significance to crop production to date.
Manitoba
Improving Phosphorus Management in Irrigated Potato Production Systems
Project Leader: Dr. Ramona Mohr, Agriculture and Agri-Food Canada, Brandon Research Centre, Box 1000A, RR 3, Brandon, MB R7A 5Y3 Canada.
Telephone: 204-726-7650.
Project Cooperator: Dale Tomasiewicz
Rapid expansion of the processing potato industry in Manitoba has generated a need for information regarding fertilizer management strategies for irrigated potato. The final year of a 4-year study was conducted in 2006 to determine the impact of P fertilizer rate on potato tuber yield and quality, and the effectiveness of petiole P concentration in assessing P status of potato (cv. Russet Burbank).
A field experiment was conducted at one location near Douglas, MB, in 2006 to assess the effect of four P rates (0, 30, 60, and 90 lb P
2O
5/A as broadcast/incorporated monoammonium phosphate) on tuber yield and quality, petiole P status, and post-harvest soil P status. The experimental site selected had a spring soil test P level of 9.7 ppm Olsen-extractable P in the top 6 in., which would have resulted in a recommendation for P fertilizer. In 2006, total tuber yield averaged 422 cwt/A. Preliminary analysis indicated that increasing P fertilizer rate resulted in a quadratic increase in marketable tuber yield and a similar trend (p=0.11) in total yield. In both cases, yield increased with moderate rates of P then declined. In 2006, the application of P appeared to contribute to a comparatively higher yield of larger tubers, although the number of tubers produced per acre was not significantly affected by P application. Neither specific gravity nor defects were affected by P rate. However, a trend toward a quadratic relationship between P fertilizer rate and both sugar ends (p=0.08) and dark ends (p=0.11) was evident. In both cases, the occurrence of sugar/dark ends tended to increase with moderate rates of P, then declined as P rate was further increased.
Impact of Cropping Sequence and Phosphorus Fertilization on Cadmium and Zinc Accumulation in Soybean and Durum Wheat
Project Leader: Dr. Cynthia Grant, Agriculture & Agri-Food Canada, Brandon Research Center, Box 1000A, RR 3, Brandon, MB R7A 5Y3 Canada.
Telephone: 204-726-7650.
Project Cooperators: Mario Tenuta, Don Flaten, and Eugene Gowalko
Crop sequence and tillage system can influence nutrient availability and response of crops to fertilizer applications, through effects on nutrient cycling, microbial population, soil temperature, and root growth. Therefore, optimum P fertilizer management may change with management practices as well as with crop type. The study evaluates the effects of cropping sequence and tillage practices on yield and quality response of durum wheat and soybean to different forms and placements of P fertilizer.
Phosphorus fertilization increased the biomass yield in durum wheat, but not in soybean. The source of P used did not affect the biomass response. Final grain yield was not affected by P application or P source in either durum wheat or soybean, indicating that grain yield was limited by factors other than P supply. Mycorrhizal colonization in durum wheat was not affected by P fertilization, but was highest when durum wheat was grown under reduced tillage following flax, and lowest when grown under conventional tillage following canola. There was also an interaction between tillage system and preceding crop on biomass and grain yield, with both soybean and durum wheat generally producing higher yields after flax than after canola under reduced tillage, but lower yields after flax than canola or barley under conventional tillage. The effect of preceding crop and tillage was greatest on the silty clay soil. The reasons for the tillage by preceding crop interaction are not apparent, but nutrient analysis of the crops may help to clarify some of the factors causing the yield response. It is possible that the increased mycorrhizal colonization due to the combination of reduced tillage after flax may encourage nutrient uptake and improve crop performance on the silty clay soil.
Saskatchewan
Strategies for Improving the Crop Safety and Efficiency of Starter Fertilizer for Saskatchewan Crops
Project Leader: Dr. Jeff Schoenau, University of Saskatchewan, Department of Soil Science, 51 Campus Drive, Saskatoon, SK S7N 5A8 Canada.
Telephone: 306-966-6844.
Questions on safe rates of seed-placed P and K fertilizer are commonly asked by crop advisers each year on the Northern Great Plains. A series of experiments on the effects of form and rate of seed-row placed P and K fertilizer were carried out under controlled environment conditions on a P-deficient soil. The experiments were conducted in the laboratory and growth chamber using seed-placed P fertilizer at rates up to 89 lb P
2O
5/A with and without K fertilizer added at 18 lb K2O/A. Two forms of monoammonium phosphate (MAP) fertilizer compared: 1) conventional MAP and 2) controlled release P (CRP) fertilizer from Agrium Inc. made with a polymer coating to slow the release of P into the soil solution. Eleven crops were considered, including: spring wheat, canola, pea, flax, oat, mustard, canary seed, chickpea, pinto bean, alfalfa, and bromegrass. Parameters measured were percentage of planted seeds that had emerged after 2 weeks, plant biomass yield, and P uptake after 4 weeks.
Most of the crops tested showed no negative impact on emergence with seed-placed conventional P fertilizer, with or without 18 lb K2O/A, at rates up to 18 to 27 lb P
2O
5/A. Pea, flax, and mustard tended to be most sensitive to high rates of seed-placed MAP, while wheat and oat were least sensitive. The CRP product greatly increased the tolerance of crops to high rates of seed placed P, with rates of 71 lb P
2O
5/A placed in the seedrow producing no significant injury for most crops. This effect is attributed to the coating reducing the harmful salt injury that occurs when high rates of fertilizer are placed in the seedrow in close proximity to the seed. Generally, a rate of 27 lb P
2O
5/A was sufficient to produce maximum early season biomass yield and P uptake for both conventional MAP and CRP fertilizers. Large differences in early P availability were not evident between the conventional P and CRP fertilizer products. For most crops, the addition of 18 lb K2O/A as a starter along with the P fertilizer in the seedrow did not have detrimental effects on germination and emergence, but some additional injury potential was evident with crops that appeared more sensitive to seed-placed K, such as canary seed and yellow pea.
Yield, Nitrogen, and Phosphorus Responses of Wheat to Long- and Short-Term Phosphorus Fertilization in a Brown Chernozem
Project Leader: Dr. Con Campbell, Agriculture and Agri-Food Canada, SPARC, Box 1030, Airport Road, Swift Current, SK S9H 3X2 Canada.
Telephone: 306-778-7200.
Project Cooperators: F. Selles and R.P. Zentner
A long-term field research experiment was designed to evaluate the impact of removing P fertilization from a fallow-wheat-wheat and a continuous wheat crop rotation after having applied P fertilizer for nearly three decades. The two cropping sequences were managed for 27 years, at which time the plots were split and fertilizer P was withheld from one half. Yields and soil P was then monitored for the next 12 years to assess the impact of fertilizer management. Over the first 27 years, soil analysis showed that soil P increased when fertilizer P was applied. This increase was attributed to lower yields than expected from the P rates being applied, due mainly to dry conditions.
However, the following 12 years were wetter than normal, and in the absence of P additions the soil test P leveled off at 7 to 10 ppm Olsen P. Even after the build-up of soil P with fertilizer additions, 75% of the time there was a response to starter P for wheat grown on stubble rated as having high soil P (>12 ppm). There was no response to starter P for wheat seeded on fallow, attributed to the mineralization of P during the fallow period. As expected, grain yields were directly related to soil-available P, with the yield response being much greater during the wetter years. These results clearly indicate that accumulated soil P is drawn-down by cropping in the absence of fertilizer P additions.
Montana
Effect of No-Till and Sweep-Till on Vertical Phosphorus Stratification and Phosphorus Uptake in Dryland Cropping
Systems
Project Leader: Dr. Clain Jones, Montana State University, Central Agricultural Research Center, Rm 334 Leon
Johnson, Bozeman, MT 59717-3120.
Telephone: 406-994-6076.
Project Cooperator: Chengci Chen
A 10-year no-till study was used to evaluate the stratification of soil P and uptake of P by crops in the rotation. Comparisons were made between conventional till (CT) and no-till (NT). Soil samples to a depth of 12 in., in 1.1 in. increments, were collected from the fallow phase of a winter wheat/fallow rotation. Tillage treatments included 10-yr NT, 10-yr CT, CT converted to NT in 2005 (1-yr CT), and NT converted to CT in 2005 (1-yr NT).
Stratification of Olsen P was relatively similar among 1-yr NT, 10-yr NT, 1-yr CT, and long-term CT, except that 10-yr NT had significantly less Olsen P in the 1.1 to 2.4 in. layer than long-term CT. This difference appeared to be partially related to higher pH in the 10-yr NT system, considered responsible for fixation of the soil P. The highest concentrations of Olsen P in all four systems was in the top 1.1 in.. Above-ground P uptake was not significantly different among tillage treatments, and was most highly correlated with Olsen P concentrations in the 2.4 to 3.5 in. layer. The results of this study suggest that in long-term reduced tillage systems where P has only been placed with the seed, deeper placement (1.4 to 2.6 in. below the seed) should be considered a more efficient use of P fertilizer, at least in winter wheat systems. The combined results suggest that P fertilizer rates should continue to be based on Olsen P concentrations in the upper 6 in. in Montana soils and do not need to consider the type of tillage system.
Effect of Phosphorus Fertilization on Field Pea Nitrogen Production
Project Leader: Dr. Jed Waddell, USDA-ARS, 1500 N Central Ave., Sidney, MT 59270.
Telephone: 406-433-9402.
Project Cooperator: Andy Lenssen
Field pea fixes its own N, but is very dependent on using soil or fertilizer P, K, and S to both fix N and increase grain yields. A study was conducted at Culbertson, Montana, to evaluate the effect of fertilizer P use on field pea yields and P uptake in the grain. While the site had been cropped to fallow-wheat with no fertilizer addition, initial soil P levels in plots was greater than expected at 19 parts per million (ppm). State of Montana recommendations suggest limited P application is required to grow field peas at this level of P fertility. However, a significant yield response was still observed to increased application of P fertilizer. This suggests that fertilizer P application may be advantageous to increase field pea yields even if soil test P levels are adequate. Increasing fertilizer P rate up to 35 lb P
2O
5/A had no effect on seed P concentration, which was maintained at 0.364 to 0.373% over the 3 years of study. Only when 70 lb P
2O
5/A was applied did seed P concentration increase to a significantly higher level of 0.394%. Results suggest a grain P removal of 0.5 lb P
2O
5/bu for field pea and further indicate that the current estimate of 0.6 lb P
2O
5/bu may be high.
North Dakota
Agronomic Evaluation of New Sulfur Sources for Canola
Project Leader: Mr. John Lukach, North Dakota State University, Langdon Research Extension Center, 9280 107th Ave NE, Langdon, ND 58249.
Telephone: 701-256-2582.
Fertilizer sulfur (S) plays a major role in the production of canola. The balance between N and S is also critical to flowering and seed formation in this crop. Research trials were carried out to evaluate a number of S sources on canola production at a S deficient location at Langdon, North Dakota. Two fertilizer S products, which incorporate N, P, and S into a common granule, were evaluated in comparison with monoammonium phosphate and ammonium sulfate alone. Unfortunately, the two research trial sites were damaged by hail late in the growing season and yields were lost. This research will continue in 2007.
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