Non-Peer ReviewedA field experiment with barley monoculture (1983-1996), and wheat/barley-canola-triticale-pea
rotation (1997-2009) was conducted on a Gray Luvisol [Typic Haplocryalf] loam soil at Breton,
Alberta, to assess the influence of straw management (straw removed [SRem] and straw retained
[SRet]), N fertilizer rate (0, 25, 50 and 75 kg N ha-1) and N source (urea and polymer-coated urea
[called ESN]) under conventional tillage on seed yield, straw yield, total N uptake in seed +
straw and N balance sheet. On the average, SRet produced greater seed yield (by 102 kg ha-1),
straw yield (by 196 kg ha-1) and total N uptake (by 3.7 kg N ha-1) in the 1997-2009 period for
both N sources. There was a considerable increase in yield and total N uptake up to 75 kg N ha-1
rate. The ESN was superior to urea in increasing seed yield (by 109 kg ha-1), straw yield (by 80
kg ha-1) and total N uptake (by 2.4 kg N ha-1) in the 1983-1996 period (mainly at the 25 and 50
kg N ha-1 rates). The N balance sheets over the 1983-2009 study duration indicated large
amounts of applied N unaccounted for, ranging from 740 to 1518 kg N ha-1, suggesting a great
potential for N loss from the soil-plant system through denitrification and/or nitrate leaching, and
from the soil mineral N pool by N immobilization. In conclusion, the findings suggest that longterm
retention of crop residue may gradually improve soil productivity

Dyck, M.

Leach, D.

Malhi, S.S.

Nyborg, M.

Puurveen, D.

Solberg, E.D.

English

University of Saskatchewan Research Archive

 1 LONG-TERM STRAW MANAGEMENT AND N FERTILIZER RATE EFFECTS ON CROP YIELD, N UPTAKE AND N BALANCE SHEET IN A GRAY LUVISOL  S.S. Malhi1, M. Nyborg2, E.D. Solberg3, M. Dyck2, D. Puurveen2 and D. Leach1  1Agriculture and Agri-Food Canada, P.O. Box 1240, Melfort, Saskatchewan, Canada S0E 1A0 (E-mail: sukhdev.malhi@agr.gc.ca); 2Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada; and 3Alberta Agriculture, Food and Rural Development, Edmonton, Alberta, Canada  Abstract A field experiment with barley monoculture (1983-1996), and wheat/barley-canola-triticale-pea rotation (1997-2009) was conducted on a Gray Luvisol [Typic Haplocryalf] loam soil at Breton, Alberta, to assess the influence of straw management (straw removed [SRem] and straw retained [SRet]), N fertilizer rate (0, 25, 50 and 75 kg N ha-1) and N source (urea and polymer-coated urea [called ESN]) under conventional tillage on seed yield, straw yield, total N uptake in seed + straw and N balance sheet. On the average, SRet produced greater seed yield (by 102 kg ha-1), straw yield (by 196 kg ha-1) and total N uptake (by 3.7 kg N ha-1) in the 1997-2009 period for both N sources. There was a considerable increase in yield and total N uptake up to 75 kg N ha-1 rate. The ESN was superior to urea in increasing seed yield (by 109 kg ha-1), straw yield (by 80 kg ha-1) and total N uptake (by 2.4 kg N ha-1) in the 1983-1996 period (mainly at the 25 and 50 kg N ha-1 rates). The N balance sheets over the 1983-2009 study duration indicated large amounts of applied N unaccounted for, ranging from 740 to 1518 kg N ha-1, suggesting a great potential for N loss from the soil-plant system through denitrification and/or nitrate leaching, and from the soil mineral N pool by N immobilization. In conclusion, the findings suggest that long-term retention of crop residue may gradually improve soil productivity.  Rationale and Objective Crop residues are a source of soil organic matter, which is the primary source of plant nutrients and an energy source for soil micro-organisms. Long-term use of continuous cropping, retaining crop residues and improved fertilization can improve soil quality/fertility and sustain productivity. There is limited information on the long-term effects of crop residue management and N fertilizer rate on crop production and nutrient uptake. The objective of this study was to determine the long-term influence of straw management, N fertilizer rate and N source on seed yield, straw yield, total N uptake in seed + straw and N balance sheet over 27 years (from 1983 to 2009) on a Gray Luvisol soil under conventional tillage.  Materials and Methods Field experiment was conducted from 1983 to 2009 at Breton, Alberta, Canada, on an Orthic Gray Luvisol (Typic Haplocryalf), with loam texture, pH of 6.6 and initial total C concentration of 13.75 g C kg-1. This area has 2356 growing degree days (GDD) at >0°C and 1335 GDD at >5°C, 118 days frost free period, mean growing season precipitation 335 mm (range of 182 to 514 mm) and a growing season mean temperature of 14°C (7°C to 20°C). The growing season is from May to August, and approximately 60% of the total precipitation occurs in the growing season. The mean annual precipitation is 475 mm. The experiment was initiated in the autumn of 1982.   2 The treatments included: two straw managements (straw removed [SRem] and straw retained [SRet]), four N rates (0, 25, 50 and 75 kg N ha-1) and two N sources (urea and polymer-coated urea [called ESN]) under conventional tillage in a randomized complete block design in four replications. All plots were tilled twice, once  in autumn and once in spring, with a chisel cultivator followed by a  coil packer. The plots were planted to barley (Hordeum vulgare L.) monoculture from 1983 to 1996 (Solberg et al. 1997). However, after 1996, barley (2002, 2009) was rotated with other crops to include spring wheat (Triticum aestivum L.; 1997, 1998, 2006), canola (Brassica napus L.; 1999, 2003, 2007), triticale (X Triticosecale, Wittmack; 2000, 2004, 2008), or pea (Pisum sativum L.; 2001, 2005). Data were collected on seed and straw yield, and total N uptake. For N balance sheet, N fixed by pea was estimated based on the published information in the region (Annonymous 2005), with slight modifications after taking into account for variations in crop yield.   Summary of Results Growing conditions Precipitation during the growing season (May, June, July and August) was substantially below the long-term average in 8 years (1984, 1985, 1992, 2002, 2003, 2005, 2006 and 2009) and above average in 4 years (1986, 1988, 1989 and 2007). In other years, the GSP was either slightly below average or slightly above average. Seed and straw yield, and total N uptake (Figures 1 to 6) On the average of 1983 to 1996, seed and straw yield increased up to 75 kg N-1 rate. Seed and straw yields and their responses to applied N were essentially similar for SRet and SRem. Seed and straw yields were greater with ESN than urea, under both SRet and SRem treatments, mainly at 25 and 50 kg N ha-1 rates. Response trends of N uptake in seed + straw to treatments were usually similar to seed and straw yield. Responses of yield and total N uptake to straw management, N rate and N source during the period from 1997 to 2009, were generally similar to that during 1983 to 1996, with only few exceptions. For example, seed and straw yield and total N uptake tended to be greater with SRet than SRem during the 1997 to 2009 period.  Nitrogen balance sheet (Table 1) The estimated amounts of nitrate-N recovered in soil + N removed in seed in all treatments and in straw in SRem treatments ranged from 666 to 1645 kg N ha-1 in various treatments (Table 1). The estimated amounts of N applied as inorganic fertilizer in 24 years, plus BFN (biologically fixed N) in 3 years when pea was grown + N added in seed in 27 years ranged from and 394 to 2305 kg N ha-1. The amounts of N that could not be accounted for ranged from -336 to 848 kg N ha-1. The amounts of unaccounted N from N applied/fixed/added ranged from 740-1518. It is unlikely that a portion of applied N was leached down below 90 cm soil depth, as evidenced by the little nitrate-N recovered in deeper layers in autumn 2009 when soil was sampled to a depth of 90 cm. Our results suggest no over-application of N compared to crop requirement for this region where soil moisture usually is not a limiting factor for normal crop growth. It is possible that a portion of the applied N in N treatments may have been immobilized in soil organic N, as evidenced by higher amount of soil N in LFON especially in SRet than SRem plots (Malhi et al. 2011). In addition, it is also possible that a small portion of the applied N may have been lost from the soil-plant system through denitrification (e.g., nitrous oxide and other N gases) due to  3 wet soil conditions which temporarily exist in the present study in some years in early spring after snow melt or after occasional heavy rainfall during summer and/or autumn.  Conclusions There was a considerable increase in yield and N uptake with N application up to  75 kg N ha-1 rate for both N sources in both periods. On average, SRet produced greater seed yield (by 102 kg ha-1), straw yield (by  196 kg ha-1) and total N uptake in seed + straw (by 3.7 kg N ha-1) than SRem for both N sources in the 1997 to 2009 period. ESN was superior to urea in increasing seed yield (by 109 kg ha-1), straw yield (by 80 kg ha-1) and total N uptake in seed + straw (by 2.4 kg N ha-1) in the 1983 to 1996 period, mainly at 25 and 50 kg N ha-1 rates. Acknowledgements The authors thank Z. Zhang , D. Leach and K. Strukoff for technical help                     Balance sheets of long-term straw management and N rate treatments from 1983-2009 in field experiments established in the autumn of 1982 at Breton (Gray Luvisol), Alberta, Canada.Site/parameter Gray Luvisol - BretonTreatmentszSRem25-U SRet25-U SRem50-U SRet50-U SRem75-U SRet75-U SRem0 SRet0Nitrate-N recovered in soil (0-90 cm) in autumn 2009 (kg N ha-1) 6 6 13 6 4 4 10 23N removed in seed in 27 years (kg N ha-1) 911 982 1134 1217 1414 1453 650 643N removed in straw in SRem treatments in 27 years (kg N ha-1) 126 0 168 0 227 0 92 0N removed in seed in all treatments and in straw in SRem treatments in 27 years (kg N ha-1) 1037 982 1302 1217 1641 1453 742 643N recovered in soil after 27 years + N removed in seed + in straw in 27 years (kg N ha-1) 1043 988 1315 1223 1645 1457 752 666Inorganic N applied in fertilizers in 24 years (kg N ha-1) 600 600 1200 1200 1800 1800 0 0Organic N fixed when pea was crop in 3 years in 2001, 2005 and 2009 (kg N ha-1) 371 441 365 393 428 445 356 334Organic N added in seed in 27 years (kg N ha-1) 60 60 60 60 60 60 60 60N applied in 24 years + N fixed in 3 years + N added in seed in 27 years (kg N ha-1) 1031 1101 1625 1653 2288 2305 416 394N balance (N applied/fixed/seed – N removed in seed/straw) (kg N ha-1) -6 119 323 436 647 852 -326 -249Unaccounted N (N applied/fixed/seed – N recovered in soil + seed/straw) (kg N ha-1) -12 113 310 430 643 848 -336 -2732N removed in seed/straw in 27 years from applied N (kg N ha-1) 295 339 560 574 899 810N recovered in soil after 27 years + seed/straw in 27 years from applied N (kg N ha-1) 291 322 563 557 893 787N balance (N applied/fixed/seed – N removed in seed/straw from applied N) (kg N ha-1) 736 762 1065 1079 1389 1495Unaccounted N (N applied/fixed/seed – N recovered in soil + seed/straw from applied N) (kg N ha-1) 740 779 1062 1096 1395 1518Recovery of applied N in seed over 27 years (%) 43.5 56.5 40.3 47.8 42.8 45.0zSRem = Straw removed; SRet = Straw retained; 0, 25, 50 and 75 kg N ha-1. U = urea. 4                 Figure 1. Effect of long-term straw management, N source and N rate on mean seed yield, from 1983 to 1996 and 1997 to 2009 at Breton, Alberta, Canada (Gray Luvisol soil, experiment established in autumn, 1982).                   Figure 2. Effect of long-term straw management, N source and N rate on mean straw yield from 1983 to 1996 and 1997 to 2009 at Breton, Alberta, Canada (Gray Luvisol soil, experiment established in autumn, 1982).  21942162914165422492630223221232228 23301270195522892593229722610500100015002000250030003500SRem SRet 0 25 50 75 ESN UreaStraw Management Rate of N Source of NSeed yield (kg ha-1)1983 to 1996 1997 to 2009250624311062184725253032250824283256 34521672272834073927336133470500100015002000250030003500400045005000SRem SRet 0 25 50 75 ESN UreaStraw Management Rate of N Source of NStraw yield (kg ha-1)1983 to 1996 1997 to 2009 5                 Figure 3. Effect of long-term straw management, N source and N rate on mean total N uptake in seed + straw from 1983 to 1996 and 1997 to 2009 at Breton, Alberta, Canada (Gray Luvisol soil, experiment established in autumn, 1982).                    Figure 4. Effect of long-term straw management, N source and N rate interactions on mean seed yield from 1983 to 1996 and 1997 to 2009 at Breton, Alberta, Canada (Gray Luvisol soil, experiment established in autumn, 1982). 51.651.222.437.152.26552.650.267.3 71.038.956.667.883.170.068.30102030405060708090100SRem SRet 0 25 50 75 ESN UreaStraw Management Rate of N Source of NUptake of N in [seed+ Straw] (kg N ha-1) 1983 to 1996 1997 to 200989216672280263493616412218262722482139221621081295192621912566124519332387 261922622194 2332232805001000150020002500300035000 25 50 75 0 25 50 75 ESN Urea ESN UreaSRem SRet SRem SRetStraw X Rate of N Straw X Source of NSeed yield (kg ha-1)1983 to 1996 1997 to 2009 6                   Figure 5. Effect of long-term straw management, N source and N rate interactions on mean straw yield from 1983 to 1996 and 1997 to 2009 at Breton, Alberta, Canada (Gray Luvisol soil, experiment established in autumn, 1982).                  Figure 6. Effect of long-term straw management, N source and N rate interactions on mean total N uptake in seed + straw from 1983 to 1996 and 1997 to 2009 at Breton, Alberta, Canada (Gray Luvisol soil, experiment established in autumn, 1982). 1048186025773082107618352474298325572456246024011709268731953885163627703619396932813230 3440346405001000150020002500300035004000450050000 25 50 75 0 25 50 75 ESN Urea ESN UreaSRem SRet SRem SRetStraw X Rate of N Straw X Source of NStraw yield (kg ha-1)1983 to 1996 1997 to 200921.536.652.665.623.237.551.764.553.150.1 52.250.340.455.7 64.182.037.557.671.484.169.165.4 71.071.101020304050607080901000 25 50 75 0 25 50 75 ESN Urea ESN UreaSRem SRet SRem SRetStraw X Rate of N Straw X Source of NUptake of N in [seed + straw] (kg N ha-1 )1983 to 1996 1997 to 2009

Long-term straw management and N fertilizer rate effects on crop yield, N uptake and N balance sheet in a Gray Luvisol

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Long-term straw management and N fertilizer rate effects on crop yield, N uptake and N balance sheet in a Gray Luvisol

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