Goddard, T.

Malhi, S.S.

Nyborg, M.

Puurveen, D.

English

eCommons@USASK

Long-term tillage, straw, and N rate effects on quantity and quality of organic C and N in a Black Chernozem soil

University of Saskatchewan Research Archive

 1 Long-term Tillage, Straw and N Rate Effects on Quantity and Quality of Organic C and N in a Black Chernozem Soil S. S. Malhi1, M. Nyborg2, T. Goddard3 and D. Puurveen2 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;  3Alberta Agriculture, Food and Rural Development, Edmonton, Alberta, Canada Background • With recent developments, such as the Kyoto protocol, there is a desire to identify best management practices to enhance carbon (C) sequestration.  • Soil organic matter is the primary source and temporary sink for plant nutrients and it maintains soil tilth, aids air and water movement, promotes water retention and reduces soil erosion.  • Soil organic carbon (SOC) reserves in western Canada have diminished considerably since the initial cultivation of native prairie grasslands 100 or more years ago, especially with tilled summer fallow.  • Adoption of better management strategies such as continuous cropping, reduced tillage, improved fertilization, application of organic amendments and crop rotations including perennial forage can increase the amount of organic C and/or N stored in the soil. • Soil, crop and fertilizer management practices alter soil properties, but the magnitude of change depends on soil type and climatic conditions.  Objective • To determine the long-term (19 or 27 years - 1980 to 1998 or 2006) effects of tillage, straw management and N fertilizer on total organic C (TOC) and N (TON), light fraction organic C (LFOC) and N (LFON), macro organic matter C (MOM-C) and N (MOM-N), microbial biomass C (MB-C), and mineralizable C (Cmin) and N (Nmin), pH, extractable P, ammonium-N and nitrate-N in a Black Chernozem (Albic Argicryoll) loam soil.  Materials and Methods • A field experiment was conducted from 1980 to 1998 or 2006 with barley-wheat-canola rotation on a Black Chernozem (Albic Argicryoll) loam (pH 6.0 and initial TOC 5.645%). at Ellerslie, Alberta, Canada.  • Treatments Table 1) included two tillages (zero tillage [ZT] and conventional tillage [CT]), two straw managements (straw removed [SRem] and straw retained [SRet]) and four N fertilizer rates (0, 50 and 100 kg N ha-1 in SRet, and 0 kg N ha-1 in SRem plots).  • Individual plots were 2.8 m x 6.9 m. Plots under CT were tilled twice, once in autumn and once in spring (chisel cultivator). The ZT plots did not undergo any disturbance, except for seeding drill.  • Crop was harvested from 1980 to 2006 for seed and straw yield.   2 • In autumn 1998, and in spring 2007, soil samples were taken from each plot after growing wheat. The soil samples were then analyzed for various organic C and N fractions and some chemical properties. • Total organic C (TOC) and N (TON), light fraction organic C (LFOC) and N (LFON), macro organic matter C (MOM-C) and N (MOM-N), microbial biomass C (MB-C), and mineralizable C (Cmin) and N (Nmin) measured in 0-7.5 and 7.5-15 cm or 0-5, 5-10 and 10-15 cm layers.  • pH, extractable P, ammonium-N and nitrate-N in 0-7.5, 7.5-15, 15-30 and 30-40 cm or 0-15, 15-30, 30-60, 60-90 and 90-120 cm layers.  Summary • The mass of TOC and TON in soil was usually higher in SRet than SRem plots, and tended to increase with ZT and N fertilizer application (Table 2).  • The mass of LFOC and LFON in soil increased with straw retention and N fertilizer application, but LFOC and LFON were higher under CT than ZT especially in the 5-10 cm layer (Table 2).  • Treatments with SRet and N fertilizer generally had higher mass of Cmin, Nmin, MOM-C and MOM-N in soil than the corresponding SRem and zero-N control treatments (Table 3). Tillage, straw and N fertilizer had no consistent effect on MB-C in soil.  • There were close and significant correlations among most soil organic C or N fractions in most cases, except MB-C which correlated with TOC and TON, and also with MOM-N at P ≤ 0.10 (Table 4). Linear regressions between crop residue or C input and soil organic C or N were significant in most cases, except MB-C where it was not significant (Tables 5 and 6).  • Soil pH was depressed with N application in the 0-7.5 or 0-10 cm layer (Table 7).  • Extractable P was higher in ZT than CT plots in the 0-7.5 cm soil layer, but decreased with N fertilizer application after 27 years. Extractable P tended to be higher in SRet than SRem plots (Table 7).  • There was no consistent effect of N fertilization on ammonium-N in soil. Nitrate-N increased with N fertilizer application, and also indicated downward movement in the soil profile especially after 27 years (Table 7).  • The effects of tillage, straw management and N fertilizer on soil properties were more pronounced in the surface layers than the deeper layers.  Conclusion • In conclusion, the findings suggest that elimination of tillage, straw retention and N fertilizer application would improve soil organic C and N, and may be better for the long-term sustainability of soil quality/health/fertility, and subsequently crop production.  Acknowledgements • The authors would like to thank Z. Zhang and K. Strukoff for technical help, D. Leach for preparing and Erin Cadieu for printing the poster.   3 Table 1. Description of treatments sampled in autumn 1998 and spring 2007 at Breton, Alberta, Canada (Gray Luvisol soil, experiment established in autumn 1979)            Table 2. Effect of long-term tillage, straw and N rate on mass of soil total organic C (TOC), total organic N (TON), light fraction organic C (LFOC) and light fraction organic N (LFON) in 0-15 cm soil depth in spring 2007 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1979)              Table 3. Effect of long-term tillage, straw and N rate on mass of mineralizable C and N, microbial biomass C (MB-C), MOM-C, MOM-N in 0-15 cm soil depth in autumn 1998 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn 1979)              Treatment No. ID  Tillage system  Straw management  Rate of N (kg N ha-1) 1 ZTSRem0 Zero Straw removed 0 4 ZTSRet0 Zero Straw retained 0 3 ZTSRet50 Zero Straw retained 50 6 ZTSRet100 Zero Straw retained 100 2 CTSRem0 Conventional Straw removed 0 5 CTSRet0 Conventional Straw retained 0 8 CTSRet50 Conventional Straw retained 50 7 CTSRet100 Conventional Straw retained 100   Mineralizable mass   Microbial Biomass   Cmin Nmin  MB-C  MOM-C  MOM-N  Treatment (tillage/straw/kg N ha-1)  (kg C ha-1) (kg N ha-1)  kg C ha-1) (kg C ha-1) (kg N ha-1) ZTSRem0  554 64.5  1436 659 25.6 ZTSRet0  561 70.8  1424 656 30.2 ZTSRet50  635 77.2  1395 704 31.8 ZTSRet100  600 78.8  1350 935 46.0 CTSRem0  492 52.8  1244 421 17.4 CTSRet0  573 64.7  1354 733 28.8 CTSRet50  655 84.4  1477 931 41.5 CTSRet100  618 72.3  1421 855 38.1 LSD0.05  71 14.9  139 378 14.2 SEM  24.0** 5.06**  47.3• 128.5• 4.83*      (Mg C ha - 1 )     (kg N ha - 1 )   Treatment   (tillage/straw/kg N ha - 1 )     TOC   TON     LFOC   LFON   ZTS Rem 0     86.74   7.469     1277   59.0   ZTS Ret 0     89.88   7.720     1523   67.3   ZTS Ret 50     91.20   7.763     2004   94.0   ZTS Ret 100     92.17   7.833     1886   93.7   CTS Rem 0     84.63   7.269     1508   68.4   C TS Ret 0     88.37   7.514     1831   85.2   CTS Ret 50     93.19   7.909     2650   130.6   CTS Ret 100     89.89   7.657     2503   131.0   LSD 0.05     5.96   0.450     441   24.1   SEM     2.026 •   0.1529 •     149.9 ***   8.2 ***      4 Table 4. Relationships among soil organic C or N fractions (TOC, TON, LFOC, LFON, MOM-C, MOM-N, MB-C, mineralizable C [Cmin] and mineralizable N [Nmin]), or between crop residue or crop residue C input from 1980 to 1998 or 2006 growing seasons and soil organic C or N stored in soil sampled in autumn 1998 and in spring 2007at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn, 1979)                    Table 5. Relationships among soil organic C or N fractions (TOC, TON, LFOC, LFON, MOM-C, MOM-N, MB-C, mineralizable C [Cmin] and mineralizable N [Nmin]), or between crop residue or crop residue C input from 1980 to 1998 or 2006 growing seasons and soil organic C or N stored in soil sampled in autumn 1998 and in spring 2007at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn, 1979)                     Parameter  Correlation coefficients Relationships among soil organic C or N fractions 1998 soil samples  TOC TON LFOC LFON MOM-C MOM-N MB-C Cmin Nmin TOC   0.979*** 0.759* 0.753* 0.866** 0.891** 0.714* 0.846** 0.956*** TON    0.867** 0.863** 0.936*** 0.948*** 0.703* 0.897** 0.969*** LFOC     0.988*** 0.965*** 0.948*** 0.494ns 0.775* 0.788* LFON      0.931*** 0.945*** 0.463ns 0.756* 0.783* MOM-C       0.967*** 0.611• 0.843** 0.873** MOM-N        0.511ns 0.806* 0.895** MB-C         0.709* 0.700* Cmin          0.932*** Nmin                      2007 soil samples  TOC TON LFOC LFON      TOC   0.991*** 0.699* 0.675•      TON    0.633• 0.610•      LFOC     0.992***      LFON            Parameter  Correlation coefficients  Relationships between crop residue or crop residue C input and soil organic C or N fractions 1980 to 1998  TOC TON LFOC LFON MOM-C MOM-N MB-C Cmin Nmin Crop residue  or C input  0.535ns 0.670• 0.795* 0.819* 0.720* 0.755* 0.268ns 0.782* 0.713*            1980 to 2006  TOC TON LFOC LFON      Crop residue  or C input  0.726* 0.669• 0.889** 0.910**        5 Table 6. Linear regressions for relationships between crop residue C input from 1980 to 1998 or 2006 growing seasons and soil organic C or N (TOC, TON, LFOC, LFON, MOM-C, MOM-N, MB-C, mineralizable C [Cmin] and mineralizable N [Nmin]) stored in soil sampled in autumn 1998 and in spring 2007at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn, 1979)                     Table 7. Effect of long-term tillage, straw and N rate on nitrate-N in 0-15 and 15-30 cm soil depths, extractable P in 0-15 cm soil depth and pH in 0-5 and 5-10 cm soil depths in spring 2007 at Ellerslie, Alberta, Canada (Black Chernozem soil, experiment established in autumn, 1979)             Crop parameter (X) Soil C or N parameter (Y) Linear regression (Y = a + bX) R2 1980  to 1998    Crop residue C input TOC Y = 89.74 + 0.1575X 0.2857ns  TON Y = 7.834 + 0.0166X 0.4495•  LFOC Y = 981.3 + 27.301X 0.6321*  LFON Y = 39.86 + 1.7065X 0.6710*  MOM-C Y = 323.9 + 12.912X 0.5186*  MOM-N Y = 9.161 + 0.7276X 0.5707*  MB-C Y = 1323 + 2.0163X 0.0718ns  Cmin Y = 449.2 + 4.2783X 0.6112*  Nmin Y = 46.89 + 0.7444X 0.5083* 1980  to 2006    Crop residue C input TOC Y = 82.13 + 0.0708X 0.5271*  TON Y = 7.135 + 0.0110X 0.4478•  LFOC Y = 365.3 + 33.285X 0.7901**  LFON Y = 1.396 + 1.9494X 0.8291**   Nitrate-N (kg N ha-1)  Extractable P (kg P ha-1)  pH Treatment (tillage/straw/kg N ha-1)  0-15 cm 15-30 cm  0-15 cm  0-5 cm 5-10 cm ZTSRem0  6.20 4.04  37.27  5.63 5.42 ZTSRet0  5.01 3.53  39.70  5.50 5.34 ZTSRet50  5.77 5.37  20.90  5.27 5.18 ZTSRet100  8.80 7.35  23.24  5.20 5.13 CTSRem0  5.71 4.71  37.40  5.48 5.50 CTSRet0  6.28 4.49  39.76  5.50 5.46 CTSRet50  5.60 5.66  17.47  5.33 5.26 CTSRet100  6.77 7.99  21.37  5.18 5.06 LSD0.05  2.54 2.19  7.37  0.13 0.16 SEM  0.862• 0.744**  2.895***  0.044*** 0.053***  

https://harvest.usask.ca/bitstream/10388/9162/1/S.S.%20Malhi%20et%20al.%2c%202010c.pdf

Long-term tillage, straw, and N rate effects on quantity and quality of organic C and N in a Black Chernozem soil

Abstract

Similar works

Full text

Available Versions

eCommons@USASK

University of Saskatchewan Research Archive