Dyck, M.

Leach, D.

Malhi, S.S.

McConkey, B.

Nyborg, N.

Puurveen, D.

Solberg, E.D.

English

eCommons@USASK

Long-term straw management and N fertilizer rate effects on soil organic C and N, and some chemical properties in a Black Chernozem

University of Saskatchewan Research Archive

Long-term Straw Management and N Fertilizer Rate Effects on Soil Organic C and N, and Some Chemical Properties in a Black Chernozem S. S. Malhi1, M. Nyborg2, E. D. Solberg3, B. McConkey4, M. Dyck2, D. Puurveen2 and D. Leach1 1Agriculture and Agri-Food Canada, P.O. Box 1240, Melfort, Saskatchewan, Canada S0E 1A0; 2Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada; 3Alberta Agriculture, Food and Rural Development, Edmonton, Alberta, Canada; 4Agriculture and Agri-Food Canada, Swift Current, Saskatchewan, Canada Introduction • Due to recent developments in Kyoto protocol, there is a great interest to identify management practices that enhance carbon (C) sequestration in soil.  • Because the amounts of annual inputs and outputs of plant residue C are usually much smaller compared to the amounts of organic C present in the soil, it is difficult to detect changes in organic C in soil, especially in the short duration.  • Long-term studies provide such information to determine the best management practices for sustainable soil quality and productivity.  • Crop residues are a source of soil organic matter, which is the primary source and temporary sink of plant nutrients, and energy source for soil microorganisms.  • Crop residue and fertilizer management practices alter some soil properties, but the magnitude of change depends on soil type and climatic conditions.  Objective To determine the effects of 27 years (from 1983 to 2009 growing seasons) of straw management [straw removed (SRem) and straw retained (SRet)] and N fertilizer rate (0, 25, 50 and 75 kg N ha-1) on soil biochemical [total organic C (TOC) and N (TON), light fraction organic C (LFOC) and N (LFON)], and chemical (pH, extractable P, ammonium-N and nitrate-N) properties under conventional tillage. Materials and Methods • Field experiment with mainly barley (and canola, wheat, triticale, or pea in a few years) was conducted on a Black Chernozem (Albic Argicryoll), loam at Ellerslie, Alberta, Canada. • The treatments included two straw management (straw removed [SRem] and straw retained [SRet]) and four N (0, 25, 50 and 75 kg N ha-1) under conventional tillage (tilled twice, once in the autumn and once in the spring, with a chisel cultivator followed by a coil packer) in a RCBD in four replications.  • The crop was harvested every year from 1983 to 2009 for seed and straw yield.  • In autumn 2009, soil samples were taken in eight treatments where N fertilizer urea was broadcast and incorporated into soil in spring just prior to seeding, and then analyzed for various organic C and N fractions. • The calculated data for each parameter were subjected to analysis of variance (ANOVA). Significant (p ≤ 0.05) differences between treatments were determined using least significant difference (LSD0.05) test. Correlations between TOC, TON, LFOC and LFON, and linear regressions for relationships between crop residue C input from 1983 to 2009 growing seasons and soil organic C or N (TOC, TON, LFOC, LFON) stored in soil were calculated using the linear (REG) procedure. Summary • SRet and N fertilizer treatments had higher mass of only LFOC and LFON compared to the corresponding SRem and zero-N control treatments.  • There were strong significant correlations among most soil organic C or N fractions. Linear regressions between crop residue C input and soil organic C or N were significant in most cases.  • There was no effect of residue management on soil pH, but application of N fertilizer reduced pH significantly in the top 7.5 cm soil, on average by 0.28 units. • Extractable P in the 0-15 cm soil layer tended to be higher with SRet than SRem in many cases, but it decreased significantly with N application.  • Residual nitrate-N increased with application of N and also indicated some downward movement in the soil profile up to 90 cm depth.  • There was generally no effect of any treatment on ammonium-N in soil.  Conclusions • Straw retention and N application improved light fraction organic C and N in soil, and generally the differences were more pronounced between the most extreme treatments (SRem0 vs. SRet75).  • Retention of straw tended to increase extractable P in the surface soil, but application of N fertilizer reduced it. Application of N fertilizer reduced pH in the surface soil, and showed accumulation and downward leaching of nitrate-N in the soil profile.  Acknowledgements The authors thank Z. Zhang and K. Strukoff for technical help.                Table 1 Relationships among soil organic C or N fractions (TOC, TON, LFOC, LFON), or between crop residue C input from 1983 to 2009 growing seasons and organic C or N stored in soil sampled in autumn 2009 at Ellerslie (Black Chernozem) Alberta, Canada (experiments established in autumn, 1983)    Correlation coefficients    Parameter  TOC TON LFOC LFON Relationships among soil organic C or N fractions   TOC   0.952*** 0.6710.07 0.832ns  TON    0.751* 0.6620.07  LFOC     0.965***  LFON                Table 2 Linear regressions for relationships between crop residue C input from 1983 to 2009 growing seasons and organic C or N (TOC, TON, LFOC, LFON) stored in soil sampled in autumn 2009at Ellerslie Black Chernozem), Alberta, Canada (experiments established in autumn, 1983)   Crop parameter (X) Soil C or N parameter (Y) zLinear regression   (Y = a + bX) R2  Crop residue C input TOC Y = 87.929 +0.0886X 0.079ns   TON Y = 7.2739 + 0.0132X 0.252ns   LFOC Y = 379.17 +63.199X 0.882*   LFON Y = -4.169 + 3.9408X 0.938** zY = Soil organic C or N fraction (TOC and TON as Mg C or N ha-1; and LFOC, LFON as kg C or N ha-1; a = Intercept on Y, origin of the line; b = Regression coefficient of Y on X, slope of line; X = Crop residue C input (Mg ha-1).  *, ** and ns refer to significant treatment effects in ANOVA at P ≤ 0.05, P ≤ 0.01 and not significant, respectively.              Table 3 Linear regressions for relationships between the amount of N applied in various treatments from 1983 to 2009 (0, 675, 1350 and 2025 kg N ha-1)) and organic C or N (TOC, TON, LFOC, LFON) stored in soil sampled in autumn 2009 at Ellerslie Black Chernozem), Alberta, Canada (experiments established in autumn, 1983)   Amount of N applied (X) Soil C or N parameter (Y) zLinear regression  (Y = a + bX) R2  Amount of N applied in SRem TOC Y = 90.22 + 0.0004X 0.005ns   TON Y = 7.642 + 0.0012X 0.080ns   LFOC Y = 1929.2 + 9.528X 0.650ns   LFON Y = 90.385 + 0.765X 0.884*       Amount of N applied in SRet TOC Y = 89.42 + 0.0555X 0.543ns   TON Y = 7.5163 + 0.006X 0.717ns   LFOC Y = 2073.5 + 15.27X 0.985**   LFON Y = 103.7 + 0.8018X 0.982** zY = Soil organic C or N fraction (TOC and TON as Mg C or N ha-1; and LFOC, LFON as kg C or N ha-1; a = Intercept on Y, origin of the line; b = Regression coefficient of Y on X, slope of line; X = Amount of N applied in various treatments from 1983 to 2009 (kg ha-1).  *, ** and ns refer to significant treatment effects in ANOVA at P ≤ 0.05, P ≤ 0.01 and not significant, respectively.                 89.47 92.49 87.92 91.03 89.1492.31 89.9994.540102030405060708090100SRem0 SRem25 SRem50 SRem75 SRet0 SRet25 SRet50 SRet75             Figure 1. Effect of long-term straw management and N fertilizer rate on mass of total organic C (TOC) in soil (0-15 cm) in autumn 2009 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1983; SEM = 2.082ns).                       Figure 2. Effect of long-term straw management and N fertilizer rate on mass of total organic N (TON) in soil (0-15 cm) in autumn 2009 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1983; SEM = 1.476ns).     TOC mass (Mg C ha-1 )7.603 7.809 7.541 7.79 7.516 7.751 7.6448.049012345678910SRem0 SRem25 SRem50 SRem75 SRet0 SRet25 SRet50 SRet75TON mass (Mg N ha-1 ) 18102481 2404254020252554282132380500100015002000250030003500SRem0 SRem25 SRem50 SRem75 SRet0 SRet25 SRet50 SRet75    -1 )ha           Figure 3. Effect of long-term straw management and N fertilizer rate on mass of light fraction organic C (LFOC) in soil (0-15 cm) in autumn 2009 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1983; SEM = 179.0***).                       Figure 4. Effect of long-term straw management and N fertilizer rate on mass of light fraction organic N (LFON) in soil (0-15 cm) in autumn 2009 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1983; SEM = 8.67***).   LFOC mass (kg C 86.8121.6129.7143.0100.4127.6145.6161.20102030405060708090100110120130140150160170SRem0 SRem25 SRem50 SRem75 SRet0 SRet25 SRet50 SRet75-1) hag N mass (kONLF 5.43 5.415.15 5.13 5.355.37 5.22 5.17012345678SRem0 SRem25 SRem50 SRem75 SRet0 SRet25 SRet50 SRet75               Figure 5. Effect of long-term straw management and N fertilizer rate on pH soil (0-7.5 cm) in autumn 2009 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1983; SEM = 0.056**).                       Figure 6.  Effect of long-term straw management and N fertilizer rate on extractable P in soil (0-90 cm) in autumn 2009 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1983; SEM = 6.68ns).   pH in soil depth 0-7.5 cm60.445.4 45.3 46.065.053.3 55.249.50102030405060708090100SRem0 SRem25 SRem50 SRem75 SRet0 SRet25 SRet50 SRet75Extractable P  (kg P ha-1 ) 17.533.639.877.815.526.542.660.40102030405060708090100SRem0 SRem25 SRem50 SRem75 SRet0 SRet25 SRet50 SRet75     N (kg N ha-1 )   Nitrate-      Figure 7. Effect of long-term straw management and N fertilizer rate on nitrate-N in soil (0-90cm) in autumn 2009 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1983; SEM = 8.01***). 

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Long-term straw management and N fertilizer rate effects on soil organic C and N, and some chemical properties in a Black Chernozem

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