Response of pea to rate and placement of triple superphosphate fertilizer in Alberta

Transcription

1 Response of pea to rate and placement of triple superphosphate fertilizer in Alberta R. H. McKenzie 1, A. B. Middleton 1, E. D. Solberg 2, J. DeMulder 2, N. Flore 3, G. W. Clayton 4, and E. Bremer 5 1 Agronomy Unit, Alberta Agriculture, Food and Rural Development, Lethbridge, Alberta, Canada T1J 4V6; 2 Agronomy Unit, Alberta Agriculture, Food and Rural Development, Edmonton, Alberta, Canada T6H 4P2; 3 Westco, Calgary, Alberta, Canada T2C 4M5; 4 Agriculture and Agri-Food Canada, Lacombe, Alberta, Canada, T4L 1W1; and 5 Symbio Ag Consulting, Lethbridge, Alberta, Canada T1K 2B5. ( ross.mckenzie@gov.ab.ca). Received 9 January 2001, accepted 24 May McKenzie, R. H., Middleton, A. B., Solberg, E. D., DeMulder, J., Flore, N., Clayton, G. W. and Bremer, E Response of pea to rate and placement of triple superphosphate fertilizer in Alberta. Can. J. Plant Sci. 81: The expansion of the pea acreage on the Canadian prairies has increased the need for more information on P fertilizer response by pea to both rate and method of placement. To determine responsiveness, 52 field trials using triple superphosphate (TSP) were conducted from 1995 to 1998 over a wide range of soil types across Alberta. Five rates of 0, 6.5, 13.1, 19.6 and 26.2 kg P ha 1 were placed with the seed or in bands applied prior to seeding. The application of TSP significantly (P < 0.1) increased pea seed yield at 19 of 52 sites. The average increase in seed yield due to TSP application was 7%, with values ranging from 12 to +33% across all trials. The average yield benefit was similar in the Thin Black, Black and Gray soil zones, but was negligible in the Dark Brown soil zone and in irrigated trials. Of the 31 trials with soil test P (modified Kelowna method) levels of less than 30 kg P ha 1 to 15 cm, 52% had a significant yield increase due to application of TSP, while only one of 17 trials with soil test P levels of more than 30 kg P ha 1 had a significant yield increase. Application of 13.1 kg P ha 1 was sufficient to attain close to maximum yields in trials with soil test P levels of less than 30 kg P ha 1. The yield response of pea was insensitive to TSP placement. The mineral impact of seed placement on yield in this study was likely due to the less damaging effects of seedling growth of TSP than of the more commonly used source of P, monoammonium phosphate (MAP). Seed protein and P concentrations were not strongly affected by TSP application. Key words: Pisum sativum, phosphorus fertilizer, fertilizer placement McKenzie, R. H., Middleton, A. B., Solberg, E. D., DeMulder, J., Flore, N., Clayton, G. W. et Bremer, E Réaction du pois au taux d application et à l emplacement du triple superphosphate en Alberta. Can. J. Plant Sci. 81: L expansion de la culture du pois dans les Prairies canadiennes a accru la demande de données sur la manière dont cette espèce réagit au taux d application des engrais phosphatés et à l endroit où ceux-ci sont appliqués. Pour remédier à cette lacune, entre 1995 et 1998, les auteurs ont effectué 52 essais avec du triple superphosphate, sur des sols très variés, en Alberta. On a placé 0, 6,5, 13,1 ou 26,2 kg de P par hectare avec la graine ou en bandes avant l ensemencement. L application de TSP a augmenté significativement (P < 0,1) le rendement grainier du pois à 19 endroits sur 52. La hausse de rendement moyenne résultant de l application de TSP s élevait à 7 %, avec une variation de 12 à 33 % pour l ensemble des essais. L accroissement du rendement est similaire dans les zones de minces sols noirs, de sols noirs et de sols gris, mais il est négligeable dans celle des sols brun foncé et dans les parcelles irriguées. Dans 52 % des 31 endroits où la concentration de phosphore dans le sol (méthode d analyse Kelowna modifiée) était inférieure à 30 kg par hectare, à 15 cm de profondeur, l application de TSP entraîne une hausse sensible du rendement, mais on n a relevé de hausse de rendement significative qu à un des 17 endroits où il y avait plus de 30 kg de P par hectare. L application de 13,1 kg de P par hectare suffit pour atteindre le rendement presque maximal sur les terrains où la concentration de P dans le sol est inférieure à 30 kg par hectare. Le rendement du pois ne varie pas avec l endroit où l engrais est placé. Dans le cadre de cette étude, l incidence minime de la fertilisation au niveau de la semence est sans doute attribuable au fait que le TSP cause moins de dommages à la plantule que le monophosphate d ammonium, plus couramment utilisé comme engrais phosphaté. L application de TSP n a pas beaucoup d effets sur la concentration de protéines et de P dans la graine. Mots clés: Pisum sativum, phosphore, engrais phosphaté, placement de l engrais Phosphorus is the major fertilizer nutrient required for dry pea (Pisum sativum) production on the Canadian prairies, but few studies exist on the P response of pea. Sosulski et al. (1974) reported on trial with Century pea that showed no benefit of P fertilization on seed yield, but a slight benefit in protein concentration. Henry et al. (1995) conducted experiments on seed placement and side banding of P fertilizer for Trapper pea at three Saskatchewan locations during a 3-yr period. They found quadratic responses of pea yield to six 645 rates (0 to 44 kg P ha 1 ) of MAP, but also noted that pea emergence was highly sensitive to seed placement: plant counts were inversely proportional to rate of seed-placed P and seed yield was reduced by seed placement of P at all locations. Seed protein concentration was not affected by rate P application (Henry et al. 1995). In related studies con- Abbreviations: MAP, monoammonium phosphate; TSP, triple superphosphate

2 646 CANADIAN JOURNAL OF PLANT SCIENCE ducted in other parts of the world, pea was less responsive to P fertilizer than wheat or canola on neutral/alkaline, finetextured soils in western Australia (Bolland et al. 1999) and less responsive to P fertilizer than winter wheat in northern Idaho (Mahler and McDole 1985). The introduction of new pea types and the considerable expansion of pea on the Canadian prairies have increased the need for more information on the P fertilizer response of pea. Pea production on the Canadian prairies has expanded from less than ha yr 1 in the early 1990s to more than ha yr 1 since 1997 (Agriculture and Agri-Food Canada 2000), primarily due to the introduction of determinant, semi-leafless cultivars with improved harvestability, disease tolerance and yield potential. The objective of this study was to determine the responsiveness of pea yield, seed protein and seed P concentration to P fertilizer rate and placement for a broad geographic region of Alberta. MATERIALS AND METHODS Fifty-nine trials were conducted across Alberta from 1995 through 1998 at the same locations as those reported by McKenzie et al. (2001). Data from seven trials were excluded due to high variability (coefficients of variation > 25%). Trial locations ranged from Bow Island (49 52 N, W) in southeastern Alberta to Fairview (56 04 N, W) in northwestern Alberta. At least eight trials were conducted in each major soil zone except the Brown soil zone. All trials were established on land that had grown a cereal crop in the previous year. Minimum tillage practices were used in all trials except two that were direct seeded. Soil samples were obtained prior to fertilizer application in the spring for all trials except three from the Black soil zone. Extractable soil phosphate was measured using the modified Kelowna extract (0.015 M ammonium fluoride, 1.0 M ammonium acetate and 0.5 M acetic acid) (Ashworth and Mrazek 1995) except in nine trials in the Black and Gray wooded soil zones, where soil phosphate was measured using the Miller-Axley (0.03 M NH M H 2 SO 4 ) extract (Bray and Kurtz 1945). Soil test P levels determined using the Miller-Axley extraction were transformed into values based on the modified Kelowna extract using the following relationship obtained from other trials in this study that had soil test P levels determined by both methods and a soil ph less than 7.5: modified Kelowna P = Miller-Axley P 1.51 (R 2 = 0.84, n = 20). Each experiment was set up in a randomized complete block design with four to six replications. Treatments consisted of rate and placement of triple superphosphate (TSP) (0 45 0). The rates of application were 0, 6.5, 13.1, 19.6 or 26.2 kg P ha 1. Placement of TSP was either with the seed (seed-placed) or as soil-applied bands applied prior to seeding (banded). Banded fertilizer was applied at an 18-cm or 20-cm row spacing and a depth of 7 to 9 cm in all trials except the two direct-seeded trials, where fertilizers were side-banded. Urea was also banded at 40 kg N ha 1 in all treatments and KCl and K 2 SO 4 fertilizers were banded at rates of 50 kg K ha 1 and 20 kg S ha 1 in most of the trails conducted in the Black soil zone (17 out of 19) and about half of the trials conducted in the Thin Black and Gray soil zones (11 out of 24). Each plot consisted of eight rows of Carneval pea planted at an 18-cm or 20-cm spacing. All plots received 5 kg ha 1 of granular rhizobia inoculant (LiphaTech Inc., Madison, WI) in the seed row at the time of seeding. Weed control was achieved by application of recommended herbicides. At maturity, six or eight rows were harvested in each plot with a small plot combine. Total seed weight and moisture content was determined. Protein concentrations were determined using near infrared spectroscopy (Foss NIRSystem Model #6500, Silver Spring, MD). All seed weights and concentrations were adjusted to 16% moisture. Statistical significance of treatment effects in each trial was determined by analysis of variance (Cohort Software 1995). A combined analysis of variance for all 52 site-year combinations was conducted. RESULTS AND DISCUSSION Application of TSP significantly (P < 0.1) increased seed yield of pea in 19 of 52 trials and decreased seed yield in one trial (Table 1). The average increase in seed yield due to TSP application was 7%, with values ranging from 12 to +33% in individual trials. The average yield benefit was similar in the Thin Black, Black and Gray soil zones (8 to 10%), but was negligible in the Dark Brown soil zone (3%) and in irrigated trials (2%) (Table 1). The lack of response to TSP application in irrigated trials was attributable to high soil test P levels. No explanation was evident for the lack of a response in the Dark Brown soil zone. The response of pea yield to TSP application was correlated with soil test P levels (Fig. 1). Of the 31 trials with soil test P levels of less than 30 kg P ha 1 to a depth of 15 cm, 16 (52%) had a significant (P < 0.1) yield increase due to application of TSP, of which 10 (32%) trials had a yield increase in excess of 15% (Fig. 1; Table 1). Only one trial with soil test P levels of more than 30 kg P ha 1 (n = 17) had a yield increase that was significant or in excess of 15%. In comparison, yield increases of barely in excess of 15% occurred in 76% of trials conducted on soils with less than 15 mg P kg 1 (equivalent to 33 kg P ha 1 ) and 16% of trials conducted on soils with more than 15 mg P kg 1 (Ashworth and Mrazek 1995). In trials conducted on soils with less than 30 kg soil test P ha 1, seed yields were close to maximum at an application rate of 13.1 kg P ha 1 (Fig. 2). Seed-placement of TSP did not reduce seed yield, even at the two highest rates of application (Fig. 2.). On a site-bysite basis, seed-placement of TSP at the two highest rates of application only significantly reduced seed yield in 3 of the 52 trials (Table 1). In comparison, Henry et al. (1995) found that seed placement of MAP at rates of 7 to 44 kg P ha 1 reduced seed yield of pea at all locations tested. The smaller impact of seed placement in our study was likely due to the lower ammonium (0 vs. 11% N) and salt index (0.210 vs ) of TSP than MAP (Tisdale et al. 1985). The similar yield response for seed-placed and banded placements of TSP indicates that pea is likely insensitive to placement of TSP, but this conclusion is confounded by the possible effects of co-application of urea and other fertilizers in the banded treatment and not the seed-placed treatment.

3 MCKENZIE ET AL. PHOSPHORUS RESPONSES OF PEA IN ALBERTA 647 Table 1. Effect of TSP application on seed yield, protein and P concentration of pea in 52 trials conducted across a wide geographic area of Alberta, Canada Yield Protein concentration P concentration Soil TSP Placement TSP TSP test P z Mean benefit x effect v Mean benefit x Mean benefit x Trial code (kg P ha 1 ) (kg ha 1 ) (%) (g kg 1 ) (%) (g kg 1 ) (%) Dark Brown Soil Zone BA * 11* SM CH CL * SM * CL *** WL * ** Ave Thin Black Soil Zone BK *** * IR ** BK ND ND ND ND HR IR *** 5* ND ND ND ND PC ** BK ** HR IR *** BK IR *** 6** ** Ave Black Soil Zone EL * OL RD *** VG VK95 ND y *** EL *** OL *** 2 ND ND ND ND PK96 ND * RD ** 4 ND ND ND ND RY96 ND * EL * OL ** RD *** *** VG DV EL RD *** 6** VG98 ND * Ave Gray Soil Zone BH BV BH BV ** * RC FV * WB ** FV Ave Irrigated trials, Brown and Dark Brown Soil Zones BI LB * BI

4 648 CANADIAN JOURNAL OF PLANT SCIENCE Table 1. Continued. LB BI LB BI LB *** Ave All z Modified Kelowna method (Ashworth and Mrazek 1995). y Not determined. x TSP benefit = average increase of all TSP-amended treatments relative to non-p-fertilized control, statistical significance (*P < 0.1, **P < 0.05, ***P < 0.01) based on contrasts. v Placement effect = average yield reduction due to seed-placement of TSP at the two highest rates of application (19.2 and 26.2 kg P ha 1 rates only); statistical significance (*P < 0.1, **P < ***P < 0.01) based on contrasts. The modest overall response of pea to application of TSP is consistent with studies that have shown that pea is less responsive than cereal crops to P application (Mahler and McDole 1985; Bolland et al. 1999) and that increases in pea yield due to P application were infrequent despite low soil test P levels (Henry et al. 1995). Another possible contributing factor to the modest response in this study was the use of TSP rather than MAP. Previous studies with Alkaline soils have noted a pronounced increase in early uptake of fertilizer P and growth when ammonium is blended or combined with a P source (Rennie and Mitchell 1954; Rennie and Soper 1958). It is possible that yield benefits due to P application may have been more frequent if MAP had been used. Seed protein and P concentrations were not strongly affected by TSP application. The maximum increase in protein concentration due to TSP application was only 3.4% or 7 g kg 1, with an average increase of only 0.2% (Table 1). Fig. 1. Effect of soil test P (modified Kelowna method) on the response of Carneval pea to TSP application. Each value is the mean yield of the non-p-fertilized check from one trial expressed as a percentage of the maximum yield achieved by application of TSP. Henry et al. (1995) also reported that protein concentration of pea was not responsive to application of MAP. Seed P concentration was only significantly (P < 0.1) increased in 4 of the 52 trials, with an average increase of 1.3% or 0.04 g P kg 1 (Table 1). In conclusion, application of TSP at 13.1 kg P ha 1 was sufficient to ensure optimal seed yields of pea when soil test P levels were less than 30 kg P ha 1. Seed-placed and banded applications of TSP were equally effective in increasing seed yield. Although seed-placement of TSP did not reduce pea yields in this study, it should be noted that commercially available sources of P (MAP) have a much greater potential to damage seedlings than TSP. ACKNOWLEDGEMENTS The authors gratefully acknowledge the field staff of Alberta Agriculture, Food and Rural Development,

5 MCKENZIE ET AL. PHOSPHORUS RESPONSES OF PEA IN ALBERTA 649 Agriculture and Agri-Food Canada and Westco for assistance in conducting the field trials. We would also like to thank the Agri-Food Laboratory Branch, Alberta Agriculture, Food and Rural Development for soil and seed analysis and Alberta Agricultural Research Institute, Alberta Pulse Growers Association, Westco and Agrium for funding support. Agriculture and Agri-Food Canada Special crop statistics. [Online] Available [10 November 2000]. Ashworth, J. and Mrazek, K Modified Kelowna test for available phosphorus and potassium in soil. Commun. Soil Sci. Plant Anal. 26: Bolland, M. D. A., Siddique, K. H. M., Loss, S. P. and Baker, M. J Comparing responses of grain legumes, wheat and canola to applications of superphosphate. Nutr. Cycle. Agroecosyst. 53: Bray, R. H. and Kurtz, L. T Determination of total, organic and available forms of phosphorus in soils. Soil Sci. 59: Cohort Software CoStat. Minneapolis, MN. 371 pp. Henry, J. L., Slinkard, A. E. and Hogg, T. J The effect of phosphorus fertilizer on establishment, yield and quality of pea, lentil and faba bean. Can. J. Plant Sci. 75: Fig. 2. Effect of placement and rate of TSP application on seed yield of pea in 31 trials with soil test P (modified Kelowna method) levels of less than 30 kg P ha 1 or in 17 trials with soil test P levels of more than 30 kg P ha 1. Values are the mean of all trials expressed as a percentage of the maximum yield achieved by application of TSP. Mahler, R. L. and McDole, R. E The influence of lime and phosphorus on crop production in northern Idaho. Commun. Soil. Sci. Plant Anal. 16: McKenzie, R. H., Middleton, A. B., Solberg, E. D., DeMulder, J., Flore, N., Clayton, G. W. and Bremer, E Response of pea to rhizobia inoculation and starter nitrogen in Alberta. Can. J. Plant Sci. 81: Rennie, D. A. and Mitchell, J The effect of nitrogen additions on fertilizer phosphorus availability. Can. J. Agric. Sci. 34: Rennie, D. A. and Soper, R. J The effect of nitrogen additions on fertilizer phosphorus availability. II. J. Soil Sci. 9: Sosulski, F. W., McLean, L. A. and Austenson, H. M Management for yield and protein of field peas in Saskatchewan. Can. J. Plant Sci. 54: Tisdale, S. L., Nelson, W. L. and Beaton, J. D Soil fertility and fertilizers. Macmillan Publishing Co., Inc., New York, NY. 754 pp.

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