Leach, D.

Malhi, S.S.

Schoenau, J.J.

English

University of Saskatchewan Research Archive

 Maximizing N Fertilizer Use Efficiency and Minimizing the Potential for Nitrate-N Accumulation and Leaching in Soil by Balanced Fertilization   S. S. Malhi1, J. J. Schoenau2 and D. Leach1  1Agriculture and Agri-Food Canada, P.O. Box 1240, Melfort, Saskatchewan S0E 1A0 (Telephone: 306 752 2776 Ext.230; Fax: 306 752 4911; E-mail: malhis@agr.gc.ca);  2Department of Soil Science, University of Saskatchewan, Saskatoon, Saskatchewan  Rationale and Objective • In the Parkland region and other areas of the Prairie Provinces, most soils are deficient in plant available N, many soils are low in available P, and soils in certain areas contain insufficient amounts of available S or K for optimum crop growth. So, fertilizers are normally applied for high crop yields. • When a nutrient is lacking in soil, it can reduce utilization of other nutrients, resulting in poor crop yield, and nutrient and water use efficiency. • This imbalance of nutrients can result in large amounts of residual nitrate-N in soil after harvest, and increase the potential for N loss through denitrification and leaching. • This poster summarizes the results obtained in field experiments conducted mostly in northeastern Saskatchewan to compare unbalanced versus balanced fertilization for their effects on crop yield, N fertilizer use efficiency (NFUE - kg seed/straw/forage DMY ha-1 kg-1 of applied N ), water use efficiency (WUE), and residual nitrate-N in the soil profile.   Material and Methods Study 1. N and S Fertilization of Canola (Brassica napus L.)  Site 1: Porcupine plain   Fertilizer Treatments: 120 kg N ha-1; 120 kg N ha-1 + 15 kg S ha-1  Site 2: Tisdale    Fertilizer Treatments: 120 kg N ha-1; 120 kg N ha-1 + 20 kg S ha-1  Site 3: Star City    Fertilizer Treatments: 120 kg N ha-1; 120 kg N ha-1 + 30 kg S ha-1 Study 2. N and S Fertilization of Wheat (Triticum aestivum L.)  Site 1: Porcupine Plain   Fertilizer Treatments: 120 kg N ha-1; 120 kg N ha-1 + 15 kg S ha-1  Site 2: Tisdale   Fertilizer Treatments: 120 kg N ha-1; 120 kg N ha-1 + 20 kg S ha-1 Study 3. N and Cu Fertilization of Wheat (Tritium aestivum L.)  Site: Porcupine Plain   Fertilizer Treatments: 105 kg N ha-1; 105 kg N ha-1 + Variable rates of Cu in    3 experiments  Study 4. N, S and P Fertilization of Timothy (Phleum  partense L.)  Site: Star City   Fertilizers Treatments: Two Rates of N (0 and 120 kg N ha-1) x Two Rates of S (0  and 15 kg S ha-1) x Two Rates of P (0 and 22 kg P ha-1) Study 5. N, S and K Fertilization of Grass  Site: Canwood   Fertilizer Treatments: 112 kg N ha-1; 112 kg N + 11 kg S ha-1;  112 kg N + 11 kg S +  40 kg K ha-1 Study 6. Organic versus Conventional N and P Fertilization   Site: Scott   Fertilizer Treatments: Organic – No fertilizer input; Conventional – Recommended rates of N and P  Summary of Results Study 1. N and S Fertilization of Canola (Brassica napus L.) • The N and S imbalance with too much N and too little S in the zero-S treatment on the S-deficient soil produced very low seed yield and NFUE (kg seed ha-1 kg-1 of applied N) and relatively low oil content of canola seed. • Compared to N alone, balanced application of N and S resulted in substantial increase in seed yield from 17 to 1378 kg ha-1 and NFUE from 0.1 to 7.1 kg seed ha-1 kg-1 of applied N and oil content from 30.9 to 40.5%. • At Site 2, the corresponding values were 134 and 765 kg ha-1 for seed yield, 1.1 to 6.4 kg seed ha-1 kg-1 of applied N and 31.0 to 38.2% for oil content. • The corresponding improvements at Site 3 were 635 to 2422 kg ha-1 for seed yield, 5.3 to 20.2 kg seed ha-1 kg-1 of applied N for NFUE and 33.3 to 37.4% for oil content. • It should be remembered that protein content generally decreased, because of dilution effect from the substantial increase in seed yield. • Soil nitrate-N increased from 19 kg N ha-1 in NS treatment to 194 kg ha-1 in N alone (zero-S) treatment at Site 1 (a substantial increase in soil nitrate-N). • Corresponding values of nitrate-N in soil for NS versus N alone treatment were 108 and 179 kg N ha-1 at Site 2, and 106 and 149 kg N ha-1 at Site 3. Study 2. N and S Fertilization of Wheat (Triticum aestivum L.) • At site 1, compared to N alone, combined application of N and S increased seed yield form 2351 to 2701 kg-1, NFUE for seed from 19.6 to 22,5 kg seed ha-1 kg-1 of applied N, straw yield from 3810 to 4962 kg ha-1, and NFUE for straw from 31.7 to 41.3 kg straw ha-1 kg-1 of applied N. • At Site 2, the corresponding values for N alone versus NS treatment were 1763 and 2061 kg ha-1 for seed yield, 14.7 and 17.2 kg seed ha-1 kg-1 of applied N NFUE for seed, 2475 and 3695 kg ha-1 straw and 20.6 and 30.5 kg straw ha-1 kg-1 of applied N for NFUE for straw. • Residual soil nitrate-N in soil for NS versus N alone treatments was 78 and 159 kg N ha-1 at Site 1, and 112 and 178 kg N ha-1 at Site 2. Study 3. N and Cu Fertilization of Wheat (Tritium aestivum L.) - 3 Tests • Compared to N alone treatments, application of N in combination with Cu increased seed yield from 607 to 2680 or 2850 kg ha-1, NFUE from 5.8 to 25.5 or 27.1 kg seed ha-1 kg-1 of applied N and Cu uptake 0.9 to 10.7 or 6.4 g Cu ha-1 in Experiment 1. • Corresponding values were 1121 and 1908 kg ha-1 for seed yield, 10.7 and 18.2 kg seed ha-1 kg-1 of applied N for NFUE, and 2.6 and 5.6 g Cu ha-1 for Cu uptake in Experiment 2, and 1367 and 2388 kg ha-1 for seed yield, 13.0 and 22.7 kg seed kg-1 of applied N for NFUE, and 2.8 and 6.2 g Cu ha-1 for Cu uptake in Experiment 3. • Soil nitrate-N in Experiment 1 decreased substantially with application of N and Cu together in all soil layers compared to N alone. This suggests that nitrate-N accumulation and leaching can be reduced considerably with balanced fertilization. • Soil nitrate-N in Experiments 2 and 3 also tended to decrease when N and Cu were applied together. Study 4. N, S and P Fertilization of Timothy (Phleum  partense L.) • Combined application of N, S and P together gave the highest forage DMY and NFUE. For example, for N, NP, NS and NPS, respectively, DMYs were 4412, 5524, 7302 and 7998 kg ha-1, and NFUE were 36.8, 46.0, 60.9 and 66.7 kg DMY ha-1 kg-1 of applied N. • The corresponding values for soil nitrate-N in the 0-60 cm depth were 16.3, 17.3, 3.2 and 2.6 kg N ha-1. Study 5. N, S and K Fertilization of Grass  • The DMYs were considerably higher when N and S or N, S and K were applied  together compared to N alone (4944 kg ha-1 for NS and 5448 kg ha-1 for NSK vs  1285 kg ha-1 for N). • NFUE was 11.5 kg DMY ha-1 kg-1 of applied N with N alone, 44.1 kg DMY ha-1  kg-1 of applied N with NS, and 48.6 kg DMY ha-1 kg-1 of applied N with NSK  treatment. • Soil nitrate-N in the 0-60 cm depth decreased from 21.0 kg N ha-1 with N alone to  11.3 kg N ha-1 with NS, and to 6.9 kg N ha-1 with NSK treatment. Study 6. ORGANIC Input versus HIGH Input N and P Fertilizers • For 6-year Rotation Cycle 1, WUE increased from 5.5 kg yield mm-1 in ORGANIC input (no fertilizer input to a soil low in available P) to 8.5 kg yield mm-1 in HIGH input treatment. The WUE values for the 6-year Rotation Cycle 2 were 3.1 and 4.9 kg yield mm-1. • Crop yields were 1115 kg ha-1 for ORGANIC input and 1849 kg ha-1 for HIGH  input in Rotation Cycle 1, and 673 kg ha-1 for ORGANIC input and 976 kg ha-1  for HIGH input in Rotation Cycle 2.  Conclusions • Proper balanced application of N, S, P, or K fertilizers is essential for best crop yields, and highest utilization of nutrients, water and energy, while also reducing accumulation and leaching of nitrate-N in the soil profile. Thus, minimizing the potential for contamination of soil and ground water with nitrate-N.  Acknowledgements • Authors thank Karen Strukoff for technical help, and Erin Cadieu for printing the poster.   Table 1. Seed yield, NFUE, oil content and amount of nitrate-N in the 0-60 cm soil after growing canola without and with applied sulphate-S fertilizers at three sites on S-deficient soils in northeastern Saskatchewan (Study 1 - adapted from Malhi et al. 2005)    Location Date of initiation & Site  Date of soil sampling   S fertilizer treatment Seed yield (kg ha-1) NFUE (kg seed  ha-1 applied N)  Oil content (%) Nitrate-N in soil (kg N ha-1) Porcupine Plain 1999 – Site 1 Spring 2002 Control 17 0.1 30.9 194**z    Ammonium sulphate 1378 11.5 40.5 19         Tisdale  1999 – Site 2 Autumn 2002 Control 134 1.1 31.0 179●    Ammonium sulphate 765 6.4 38.2 108         Star City 2004 – Site 3 Spring 2005 Control 635 5.3 33.3 149**    Ammonium sulphate 2422 20.2 37.4 106 z● and ** indicate to treatment effect being significant at P < 0.10 and P < 0.01, respectively.  Table 2. Seed yield, NFUE, straw yield and estimated amount of nitrate-N in the 0-60 cm soil after growing wheat without and with applied sulphate-S fertilizers at two sites on S-deficient soils in northeastern Saskatchewan (Study 2 - unpublished)    Location Date of initiation & Site  Date of soil sampling   S fertilizer treatment Seed yield (kg ha-1) NFUE (kg seed  ha-1 applied N) Straw yield (NFUE1) Nitrate-N in soil (kg N ha-1) Porcupine Plain 1999 – Site 1 Spring 2002 Control 2351 19.6 3810 (31.7) 159*    Ammonium sulphate 2701 22.5 4962 (41.3) 78         Tisdale  1999 – Site 2 Autumn 2002 Control 1763 14.7 2475 (20.6) 178**    Ammonium sulphate 2061 17.2 3649 (30.5) 112 z* and ** indicate to treatment effect being significant at P < 0.05 and P < 0.01, respectively.   Table 3. Amount of nitrate-N in soil, seed yield and NFUE of wheat without and with Cu application in selected treatments in three Cu experiments (Study 3 - unpublished)  Cu application treatment  Nitrate-N (kg N ha-1) in soil depths (cm)  Formulation Rate (kg Cu ha-1) Timing  0-15  15-30  30-60  60-90  0-90   Experiment 1                    Control 0 n/a  20.1*z 20.1* 18.7* 17.8** 76.6*            Solution (EDTA) 0.50 + 0.50 4-leaf + flag-leafy  6.5 3.2 4.4 5.1 19.2            Solution (EDTA) 4.0  Spring (pre-tillage)x  8.2 4.4 5.0 5.5 23.1                          Seed yield (kg ha-1) NFUE (kg seed  ha-1 applied N) Uptake of Cu (g Cu ha-1)              Control 0 n/a  607 5.8 0.9              Solution (EDTA) 0.50 + 0.50 4-leaf + flag-leafy  2680 25.5 10.7              Solution (EDTA) 4.0  Spring (pre-tillage)x  2850 27.1 6.4                            Nitrate-N (kg N ha-1) in soil depths (cm)  Experiment 2    0-15  15-30  30-60  60-90  0-90             Control 0 n/a  10.2* 5.2● 5.2* 6.3● 26.9*            Solution (EDTA) 4.0  Spring (pre-tillage)x  6.9 3.9 4.5 4.8 20.1                Seed yield (kg ha-1) NFUE (kg seed  ha-1 applied N) Uptake of Cu (g Cu ha-1)              Control 0 n/a  1121 10.7 2.6              Solution (EDTA) 4.0  Spring (pre-tillage)x  1908 18.2 5.6                            Nitrate-N (kg N ha-1) in soil depths (cm)  Experiment 3    0-15  15-30  30-60  60-90  0-90             Control 0 n/a  11.4ns 7.1ns 7.7 7.1● 33.3●            Solution (EDTA) 4.0  Spring (pre-tillage)x  10.1 5.1 5.7 6.0 26.9                Seed yield (kg ha-1) NFUE (kg seed  ha-1 applied N) Uptake of Cu (g Cu ha-1)              Control 0 n/a  1367 13.0 2.8              Solution (EDTA) 4.0  Spring (pre-tillage)  2388 22.7 6.2   a● , *, ** and ns refer to significant treatment effects in ANOVA at P ≤ 0.10, P ≤ 0.05 and P ≤ 0.01, and not significant, respectively. yTwo foliar applications, first at tillering and second at flag-leaf. xSolution Cu-chelate EDTA spray-broadcast on soil surface, followed by incorporation into soil.     Table 4. Forage dry matter yield (DMY), NFUE and residual nitrate-N in soil in autumn 2007 after 3 annual applications of N, P and S fertilizers to timothy in 2005, 2006 and 2007 at Star City in northeastern Saskatchewan (Study 4 - unpublished)  Nitrate-N in soil (kg N ha-1) in soil layers (cm)  Treatment (kg N, P or S ha-1) 0-15 cm 15-30 cm 30-60 cm 0-60 cm  DMY (kg ha-1)  NFUE (kg DMY  ha-1 applied N) 120N (N) 3.79*z 6.39* 6.3* 16.3* 4412 36.8        120N + 22P (NP) 3.9* 7.37* 616* 17.3* 5524 46.0        120N + 15S (NS) 1.34 0.6 1.3 3.23 7302 60.9        120N + 22P + 15S (NPS) 1.0 0.6 1.0 2.57 7998 66.7 z* refers to significant treatment effects in ANOVA at P ≤ 0.05.    Table 5. Forage dry matter yield (DMY), NFUE and residual nitrate-N in soil in autumn 2005 after 26 annual applications of N, S and K fertilizers to grass from 1980 to 2005 at Canwood in  northeastern Saskatchewan (Study 5 - unpublished)  Nitrate-N in soil (kg N ha-1) in soil layers (cm)  Treatment (kg N, S or K ha-1) 0-15 cm 15-30 cm 30-60 cm 0-60 cm  DMY (kg ha-1)  NFUE (kg DMY  ha-1 applied N) 120N (N) 10.3 4.3 4.4 21.0 1285 11.5        120N + 11S (NS) 5.1 2.5 3.7 11.3 4944 44.1        120N + 11S + 40K (NSK) 2.0 1.1 3.8 6.9 5448 48.6 z* refers to significant treatment effects in ANOVA at P ≤ 0.05.   Table 6. Crop yield, water use efficiency (WUE) and residual nitrate-N in 0-90 cm soil in autumn 2006 after 12 years under ORGANIC (no fertilizer input) and HIGH (recommended rates of N and P fertilizers) inputs in DAG crop diversity in two 6-year rotation cycles with various crops from 1995 to 2006 at Scott, Saskatchewan (Study 6 – Malhi et al. 2008 Organic Presentation at SSCA Meeting)   Rotation Cycle 1   Rotation Cycle 2     Input level Yield (kg ha-1) WUE (kg yield ha-1 mm-1) Yield (kg ha-1) WUE (kg yield ha-1 mm-1)   Nitrate-N in soil (kg N ha-1) in selected treatments ORGANIC 1115 5.5 673 3.1 123* 94*        HIGH – Conv. 1849 8.5 976 4.9 42 45 z* refers to significant treatment effects in ANOVA at P ≤ 0.05.    

Maximizing N fertilizer use efficiency and minimizing the potential for nitrate-N accumulation and leaching in soil by balanced fertilization

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Maximizing N fertilizer use efficiency and minimizing the potential for nitrate-N accumulation and leaching in soil by balanced fertilization

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