Legume green manure as partial fallow replacement in semiarid Saskatchewan: Effect on carbon fluxes

2000 ◽  
Vol 80 (3) ◽  
pp. 499-505 ◽  
Author(s):  
D. Curtin ◽  
H. Wang ◽  
F. Selles ◽  
R. P. Zentner ◽  
V. O. Biederbeck ◽  
...  
Keyword(s):  
Green Manure ◽  
Carbon Dioxide Emissions ◽  
Fossil Fuels ◽  
C:N Ratio ◽  
C Sequestration ◽  
Triticum Aestivum L ◽  
Soil C ◽  
Residue Decomposition ◽  
Crop Residue Decomposition ◽  
Legume Green Manure

Increasing atmospheric CO2 concentrations, largely due to burning of fossil fuels, may accentuate the risk of global warming. Scientists are optimistic that with appropriate management soils can function as sinks for C and contribute to CO2 abatement strategies. The objective of this study was to determine if soil C can be increased using an annual legume green manure (GM) as partial fallow replacement in a fallow-wheat (Triticum aestivum L.)-wheat (F-W-W) rotation in the Brown soil zone of Saskatchewan. In 1995 and 1996 we measured soil C fluxes in all phases of F-W-W and GM-W-W rotations, which were two of the treatments in an experiment initiated in 1987 on a medium-textured Orthic Brown Chernozem. The GM, Indianhead black lentil (Lens culinaris Medikus) was estimated to add 1800 and 1400 kg C ha−1 in 1995 and 1996, respectively. Annual inputs of C in residues of the wheat crops were two to three times those of GM. Comparison of CO2 emissions from GM with those from the fallow phase of the F-W-W system suggested that GM largely decomposed in the interval between incorporation (mid-July) and freeze-up in fall. Fluxes of CO2 from the wheat phases of GM-W-W closely matched those from the corresponding phases of F-W-W, confirming that there was little carryover of undecomposed GM to the following growing season. Our results suggest that, in a 3-yr rotation, partial fallow replacement with legume GM may have only a minor impact on C sequestration because the increase in C inputs is relatively small (~ 25% in this study) and GM decomposes rapidly in the soil due to its narrow C:N ratio (12–13). Green manuring may, however, play a more significant role in enhancing soil C levels in a F-W system, where relatively large increases in C inputs could be achieved using currently-available legume species. Key words: Carbon sequestration, carbon dioxide emissions, crop residue decomposition, wheat, summerfallow, lentil

Quantifying short-term effects of crop rotations on soil organic carbon in southwestern Saskatchewan

2000 ◽  
Vol 80 (1) ◽  
pp. 193-202 ◽  
Author(s):  
C. A. Campbell ◽  
R. P. Zentner ◽  
F. Selles ◽  
V. O. Biederbeck ◽  
B. G. McConkey ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Green Manure ◽  
Harvest Index ◽  
Crop Residue ◽  
Weather Conditions ◽  
Order Kinetic ◽  
Short Term ◽  
Crested Wheatgrass ◽  
Crop Residue Decomposition ◽  
Legume Green Manure

Crop management practices can have a major influence on soil fertility and soil organic C (SOC) sequestration. We need to accurately measure and estimate changes in SOC in the short term (<20 yr). A 10-yr crop rotation experiment, conducted on a medium-textured Orthic Brown Chernozem at Swift Current, in southwestern Saskatchewan, was sampled in 1990 (3 yr after initiation of the study) and in 1993 and 1996, to measure SOC changes under nine crop rotation treatments. Minimum tillage practices were used. The stubble was cut high to enhance snow trap and N and P fertilizer applied based on soil tests. Grain and straw yields of the cereals, and hay yields of the crested wheatgrass (CWG) [Agropyron cristatum (L.) Gaeertn.] were measured annually. An empirical equation which uses two simultaneous first order kinetic expressions, one to estimate crop residue decomposition and the other to estimate soil humus C mineralization was used, together with crop residue (straw and estimated root) C inputs, to estimate SOC changes over the 1987 to 1996 period. The estimated SOC values for the 1990 to 1996 period were generally similar to the measured values (r2 = 0.64, P < 0.0001). Significant (P < 0.10) changes in SOC were not observed below 15 cm depth, perhaps because shallow tillage (10- to 12.5-cm depth) is practiced. A change from cropland to CWG did not increase SOC, and this treatment, chemical fallow-winter wheat (Triticum aestivum L.)-spring wheat (F-WW-W), and F-high-yielding (Hy) Canada Prairie Spring (CPS) wheat-Hy (F-Hy-Hy) rotations, had the lowest SOC gains among the rotations. The CPS wheat had a higher harvest index (0.46) than hard red spring (HRS) wheat (0.39), but it increased SOC less than the comparable HRS wheat rotation between 1990 and 1996 indicating that higher grain yields do not always equate to higher SOC. Weather conditions were favourable for cereals from 1990 to 1996 and we measured significant increases in SOC (up to 5.5 Mg ha−1 in 6 yr). This is encouraging for producers who may be contemplating participating in "C trading", although this also suggests that periods of less favourable weather will limit gains in SOC. Summerfallowing once in 4 yr in this semiarid environment did not reduce SOC gains compared to continuous wheat (Cont W). For example, a F-W-W-W rotation gained 4.88 Mg C ha−1 in 6 yr while continuous wheat gained 5 Mg ha−1. Growing Indianhead lentil (Lens culinaris Medikus) as a legume green manure crop (GM) with wheat in a GM-W-W rotation did not increase SOC more than F-W-W. The efficiencies of conversion of residue C to SOC were high, ranging between 9% for frequently fallowed systems to 29% for continuously cropped systems, likely due to the favourable weather conditions experienced. Key words: Carbon sequestration, legume green manure, crested wheatgrass, harvest index effect, C conversion efficiencies

Effect of crop rotations on NO3 leached over 17 years in a medium-textured Brown Chernozem

2006 ◽  
Vol 86 (1) ◽  
pp. 109-118 ◽  
Author(s):  
C. A. Campbell ◽  
F. Selles ◽  
R. De Jong ◽  
R. P. Zentner ◽  
C. Hamel ◽  
...  
Keyword(s):  
Green Manure ◽  
Health Hazard ◽  
Triticum Aestivum L ◽  
Perennial Grasses ◽  
Rooting Depth ◽  
Net N Mineralization ◽  
No Tillage ◽  
Crested Wheatgrass ◽  
Cropping Frequency ◽  
Legume Green Manure

High NO3 concentration in drinking water can be a health hazard, but properly fertilized rotations containing cereals and pulses or perennial grasses reduce the risk of NO3 leaching. Over fertilization, and sometimes under fertilization, frequent summer fallowing, and use of legume green manure may increase the risk of NO3 leaching in subhumid areas. We used a crop rotation study, initiated in 1987 on a medium-textured Brown Chernozem at Swift Current, Saskatchewan, to determine the influence of cropping frequency, legume green manure, wheat class and grass hay crop on NO3-N leached beyond the rooting depth of cereals (1.2 m) after 17 yr. Nitrate distribution in the soil to 2.4 m was measured in 1987 and again in 2003. All rotations received N and P fertilizer based on soil tests, and were generally managed using no-tillage. The period had 4% more precipitation than the long-term average (367 mm) with 5 yr exceeding the average by >13%. A comparison of NO3-N content below 1.2 m depth in 1987 and 2003 showed no significant (P < 0.05) leaching has occurred, although the legume (Lens culinaris L.) green manure-wheat-wheat (Triticum aestivum L.) system showed evidence it may eventually leach NO3. Contrary to expectations, continuous-wheat, because of higher N applied and possibly because net N mineralization is small under no-tillage, tended to leach more NO3 than fallow-containing rotations (P = 0.09). Crested Wheatgrass (Agropyron cristatum L. Gaertn) reduced NO3 content to 2.4 m because it is a perennial with deep and extensive roots. There was no effect of wheat class on the amount of NO3 leached. Key words: Cropping frequency, wheat class, lentil green manure, crested wheatgrass

Quantifying carbon sequestration in a minimum tillage crop rotation study in semiarid southwestern Saskatchewan

2007 ◽  
Vol 87 (3) ◽  
pp. 235-250 ◽  
Author(s):  
C. A. Campbell ◽  
A. J. VandenBygaart ◽  
R. P. Zentner ◽  
B. G. McConkey ◽  
W. Smith ◽  
...  
Keyword(s):  
Crop Rotation ◽  
Green Manure ◽  
Crop Management ◽  
C Sequestration ◽  
Century Model ◽  
Organic C ◽  
Minimum Tillage ◽  
Cropping Frequency ◽  
The Impact ◽  
Legume Green Manure

Scientists and the agricultural community require methods of quantifying C sequestration in soils. This is important in assessing the impact of crop management practices on emission of greenhouse gases and for “C trading”. Using simulation models may be a more effective method of quantification as compared with in situ measurements. A 17-yr crop rotation experiment being conducted on a medium-textured Orthic Brown Chernozem at Swift Current, Saskatchewan, in which soil organic C (SOC) was being monitored periodically, was used to assess the effect on C sequestration of cropping frequency, wheat class, legume green manure (LGM), flexible cropping based on available water, and regrassing of crop land. Prior to the study, the experimental site had been cropped to fallow-wheat (F-W) for the previous 60 yr. Crop management in this experiment involved minimum tillage, snow trapping, and N + P fertilization based on soil tests. Three models [Century, the Introductory C Balance model (ICBM), and the Campbell model] were tested for their effectiveness in simulating SOC trends. Because growing season precipitation was average to above average, yields, and thus C inputs from residue, were also above average, and consequently SOC increased in most systems for the first 10 yr before reaching a new steady state. SOC gains (kg ha-1 yr-1) in the 0- to 15-cm depth in 17 yr were directly proportional to cropping frequency (F-W-W = 135, F-W-W-W = 332, and Cont W = 441); LGM-W-W gained SOC at a much higher rate than F-W-W (329 vs. 135 kg ha-1 yr-1 ); Canada Western Red Spring (CWRS) wheat (Triticum aestivum L.), although it yielded 26% less than Canada Prairie Spring (CPS) wheat, gained SOC at a higher rate than CPS wheat (135 vs. 0 kg ha-1 yr-1). Further, 2 yr of conventionally-tilled fallow in 17 yr (flexible system) markedly suppressed SOC gain by 46% compared with Cont W (441 vs. 236 kg ha-1 yr-1). There was a 282 kg ha-1 yr-1 gain in SOC under crested wheatgrass (Agropyron cristatum L.) (CWG) but most of this gain occurred in the last 7 yr. Though having their inherent weaknesses, the ICBM and Campbell models performed equally well in simulating SOC trends (r2 = 0.55**), but Century was less effective (r2 = 0.21*), in part because of its limited ability to simulate yields. Because C input, and thus yield, is one of the main factors influencing SOC gains, and since measured yields are used in the ICBM and Campbell models, while simulated yields are used by Century, the ICBM and Campbell models have an advantage over the Century model in this comparison. Efficiencies of conversion of input C to SOC increased with cropping frequency, and were higher for LGM-W-W than for F-W-W, and for systems with CWRS wheat rather than CPS wheat. Efficiency of conversion was 8% for F-W-W, 15% for LGM-W-W and 21% for Cont W. Key words: ICBM model, Century model, Campbell model, C sequestration, legume green manure, regrassing

Contrasting  effect of coniferous and broadleaf trees on soil carbon storage during reforestation of mature soils and afforestation of immature soils

2021 ◽  
Author(s):  
Lucie Hublova ◽  
Jan Frouz
Keyword(s):  
Tree Species ◽  
C:N Ratio ◽  
Clay Content ◽  
Common Garden ◽  
C Sequestration ◽  
Soil Development ◽  
Alkaline Soils ◽  
Soil C ◽  
Coniferous Trees ◽  
C Storage

&lt;p&gt;Soils and forest soil in particular represent important pools of carbon (C). Here, we present a quantitative review of common garden experiments in which various tree species were planted alongside each other in European countries to answer following questions: Does soil sequester more C under broadleaf than under conifer trees? and How do the effects of tree species and litter quality on soil C sequestration change with soil development (i.e., maturity) and other soil properties?&lt;strong&gt; &lt;/strong&gt;We found that the effects of broadleaf and coniferous trees on C sequestration differed with the stage of soil development. In mature soils, more C was stored under coniferous trees than under broadleaf trees. In soils in early stages of soil development, on post-mining spoil heaps, the opposite trend was found, i.e., more C was stored under broadleaf. C sequestration under broadleaf trees was highest in immature soils and in soils with high pH. C sequestration was negatively correlated with the litter C:N ratio in post-mining soils but not in other more mature soils. Similarly C sequestration was negatively correlated with the litter C:N&amp;#160; in alkaline soils and in soil with high clay content. These results suggest that C sequestration mechanisms differ in immature vs. mature soils such that C storage is greater under broadleaf trees in immature soils but is greater under coniferous trees in mature soils. The study was supported by LIFE17/IPE/CZ/000005 project&lt;/p&gt;

scholarly journals Effects of Steel Slag and Biochar Incorporation on Active Soil Organic Carbon Pools in a Subtropical Paddy Field

Agronomy ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 135 ◽  
Author(s):  
Weiqi Wang ◽  
Derrick Lai ◽  
Abbas Abid ◽  
Suvadip Neogi ◽  
Xuping Xu ◽  
...  
Keyword(s):  
Paddy Field ◽  
Crop Production ◽  
Activity Index ◽  
C:N Ratio ◽  
Steel Slag ◽  
C Sequestration ◽  
Industrial Wastes ◽  
Organic C ◽  
Soil C ◽  
Early Crop

Industrial wastes and agricultural byproducts are increasingly used in crop production as fertilizers, but their impacts on soil carbon (C) sequestration remain poorly understood. The aim of this study was to examine the effects of applying steel slag (SS), biochar (B), and a combination of these two materials (SS + B) on total soil organic C (SOC), active SOC fractions, and C pool management index (CPMI) in a subtropical paddy field in China. The treatments were applied at a rate of 8 t ha−1 to rice at the two (early and late) crop seasons in 2015. The SOC concentrations in the top 30 cm soils in the SS + B treatments were 28.7% and 42.2% higher in the early and late crops, respectively, as compared to the controls (p < 0.05). SOC was positively correlated with soil C:N ratio across the two crop seasons (r = 0.92–0.97, p < 0.01). As compared to the control, SS + B treatment had significantly higher carbon pool index (CPI) in both early (22.4%) and late (40.1%) crops. In the early crop, the C pool activity index (CPAI) was significantly lower in B and SS + B treatments by over 50% than in the control, while the soil C pool management index (CPMI) in the SS, B, and SS + B treatments was lower than that in the control by 36.7%, 41.6%, and 45.4%, respectively. In contrast, in the late crop, no significant differences in CPAI and CPMI were observed among the treatments. Our findings suggest that the addition of steel slag and biochar in subtropical paddy fields could decrease active SOC pools and enhance soil C sequestration only in the early crop, but not the late crop.

Restoring organic matter in a cultivated, semiarid soil using crested wheatgrass

2000 ◽  
Vol 80 (3) ◽  
pp. 429-435 ◽  
Author(s):  
D. Curtin ◽  
F. Selles ◽  
H. Wang ◽  
R. P. Zentner ◽  
C. A. Campbell
Keyword(s):  
Organic Matter ◽  
Carbon Dioxide Emissions ◽  
C Sequestration ◽  
Mitigation Strategies ◽  
Organic C ◽  
Crested Wheatgrass ◽  
Soil C ◽  
Sequestration Potential ◽  
C Stocks

Planting of cultivated land with perennial forages may increase C sequestration in soil organic matter and contribute to atmospheric CO2 mitigation strategies. However, little is known of the effectiveness of introduced grasses in restoring organic C in cultivated soils of the Canadian prairies. Our objective was to evaluate the C sequestration potential of crested wheatgrass (CWG) (Agropyron cristatum L. Gaertn.), a widely introduced, early-season grass. In 1995 and 1996, we measured soil CO2 fluxes, C inputs in plant material and total soil C under CWG and a fallow-wheat (Triticum aestivum L.)-wheat rotation (F-W-W). These were two of the treatments in a replicated crop rotation experiment initiated in 1987 in southwestern Saskatchewan on a medium-textured soil that had previously been under long-term wheat production. Average to above-average growing season (1 May to 31 July) precipitation in 1995–1996 resulted in annual inputs of C in wheat residues of 3000–4500 kg ha−1. Growth of CWG, which was hayed and removed, was relatively poor in both years, but especially in 1995 when dry matter yield was only 1300 kg ha−1. For the 1988–1996 period, there was a strong correlation (R2 = 0.81; P < 0.001) between CWG yield and precipitation received in May, showing the importance of early spring rains determining CWG yield and C inputs to the soil. Carbon inputs under CWG (1200 kg ha−1 in 1995 and 2400 kg ha−1 in 1996) were less than under wheat but CO2-C emissions were similar under CWG and wheat. Soil C measurements in fall 1996 confirmed that CWG did not gain C relative to the F-W-W rotation. Although failure of CWG soil to store more C than cultivated soil may be partly because weather conditions during the experiment were more favourable for wheat than CWG, our results cast doubt on the ability of CWG to restore C stocks in prairie soils degraded by long-term cropping. Key words: Carbon sequestation, carbon dioxide emissions, wheat, crested wheatgrass, fallow

Soil fertility effects on carbon fluxes under two spring wheat rotations in a semiarid agroecosystem

2002 ◽  
Vol 82 (2) ◽  
pp. 155-163 ◽  
Author(s):  
D. Curtin ◽  
H. Wang ◽  
F. Selles ◽  
C. A. Campbell ◽  
R. P. Zentner
Keyword(s):  
Soil Fertility ◽  
Spring Wheat ◽  
Management Practices ◽  
Crop Residues ◽  
C Sequestration ◽  
Triticum Aestivum L ◽  
Soil Fertility Management ◽  
Soil C ◽  
C Storage ◽  
Fertility Treatments

Changes in soil C storage due to management practices are important in relation to soil quality and to the broader issue of atmospheric C sequestration. Our objective was to evaluate the effects of soil fertility management on C fluxes under two spring wheat (Triticum aestivum L.) rotations in semiarid southwestern Saskatchewan, i.e., continuous wheat (Cont W) and a rotation that included summerfallow every third year (F-W-W). Continuous wheat was grown under two fertility regimes since initiation of the experiment in 1967, i.e., fertilization with N+P (no nutrient limitation) or with P only. In F-W-W there were three fertility treatments: N+ P, N only, and P only. We measured soil CO2 emissions under all fertility treatments and rotation phases during the 1995 and 1996 cropping seasons (emissions were measured at about weekly intervals between spring and freeze-up in autumn). Inputs of C in straw were measured and a root:straw ratio of 0.59 was used to estimate root C inputs. Alleviation of nutrient limitations generally had a positive effect on wheat growth (and thus on C inputs), particularly in 1995, the wetter of the 2 yr (precipitation 14% greater than average). For example, C inputs in 1995 under Cont W were estimated at 2700 kg ha-1 in the N+P treatment compared with 1500 kg ha-1 in the P only treatment. Fertility treatments had little effect on CO2 emissions; e.g., for Cont W the mean flux for the 1995 monitoring period was 2.7 mmol CO2 m-2s-1 where N + P was applied and 2.6 mmol CO2 m-2s-1 where P only was applied. Greater C inputs, but similar outputs of CO2-C for the N + P treatment vs. the systems receiving N or P only, suggest that proper fertilization resulted in a gain in soil C. However, quantifying the fertility-induced C gain is problematic because of uncertainty regarding effects of fertility on several components of the C budget, particularly root-C inputs and the contribution of rhizosphere respiration to the measured CO2 flux. Key words: Carbon sequestration, N and P fertilization, CO2 emissions, C inputs in crop residues, spring wheat, summerfallow

EFFECTS OF CROP ROTATIONS AND FERTILIZATION ON YIELDS AND QUALITY OF SPRING WHEAT GROWN ON A BLACK CHERNOZEM IN NORTH-CENTRAL SASKATCHEWAN

1990 ◽  
Vol 70 (2) ◽  
pp. 383-397 ◽  
Author(s):  
R. P. ZENTNER ◽  
C. A. CAMPBELL ◽  
K. E. BOWREN ◽  
W. EDWARDS
Keyword(s):  
Spring Wheat ◽  
Green Manure ◽  
Triticum Aestivum L ◽  
Crop Rotations ◽  
Organic N ◽  
Silty Clay ◽  
Total N ◽  
Crop Sequence ◽  
Legume Green Manure

Effects of rotation length, crop sequence, and fertilization on yields and quality of spring wheat (Triticum aestivum L.) were examined for eight crop rotations over a 27-yr period (1960-1986) on an Orthic Black Chernozem at Melfort, Saskatchewan. The silty clay loam soil had an initial organic N content of about 0.55% (0-to 15-cm depth). During 1960-1971, fertilized plots received N and P based on general recommendations for the region; thereafter, fertilizer was applied based on soil tests. Yields of wheat grown on fertilized fallow were similar for fallow-wheat, fallow-wheat-wheat (F-W-W), and a 6-yr fallow-wheat-legume hay rotation (avg. 2519 kg ha−1 in 1960-1971 and 3036 kg ha−1 in the wetter 1972-1986 period). In contrast, yields of wheat grown on fertilized stubble in a F-W-W rotation (avg. 2113 kg ha−1 in 1960-1971 and 2775 kg ha−1 in 1972-1986) averaged 34% higher than yields of continuous monoculture wheat due to fewer observed weed and disease problems. Fertilized stubble wheat yields in F-W-W averaged 88% of comparable fallow wheat yields, while continuous wheat averaged only 66%. Fertilizer increased fallow wheat yields by 14-18%. Stubble wheat yields were increased 11–16% for 3-yr rotations and 26% for continuous wheat during 1960-1971 when relatively low rates of N fertilizer were applied, and 22–31% and 49% for these same rotations, respectively, during 1972-1986 when moisture was more favorable and soil test criteria were used. Inclusion of grass-legume hay or legume green manure crops in the rotations provided no yield benefit for subsequent wheat crops in this fertile soil. The yields of wheat from fertilized rotations increased significantly with years of study reflecting the higher fertilizer rates used in later years and use of improved production technologies. Wheat yields of unfertilized treatments generally increased or showed no trend with time, thus providing no evidence of declining soil fertility. Crude protein concentration and total N yield of the grain were significantly increased by fertilization and inclusion of a grass-legume hay crop in the rotation. Total grain P yield of wheat was also influenced by fertilizer and by rotation, while volume weight of grain was unaffected by treatment.Key words: N and P fertilizer; grass-legume hay; legume green manure; crop sequence; protein

scholarly journals Carbon stocks and soil sequestration rates of riverine mangroves and freshwater wetlands

2015 ◽  
Vol 12 (2) ◽  
pp. 1015-1045 ◽  
Author(s):  
M. F. Adame ◽  
N. S. Santini ◽  
C. Tovilla ◽  
A. Vázquez-Lule ◽  
L. Castro
Keyword(s):  
Carbon Dioxide Emissions ◽  
Biosphere Reserve ◽  
C Sequestration ◽  
Freshwater Wetlands ◽  
Soil N ◽  
Riverine Wetlands ◽  
Soil C ◽  
C Stocks ◽  
Soil Accumulation ◽  
Soil C Sequestration

Abstract. Deforestation and degradation of wetlands are important causes of carbon dioxide emissions to the atmosphere. Accurate measurements of carbon (C) stocks and sequestration rates are needed for incorporating wetlands into conservation and restoration programs with the aim for preventing carbon emissions. Here, we assessed whole ecosystem C stocks (trees, soil and downed wood) and soil N stocks of riverine wetlands (mangroves, marshes and peat swamps) within La Encrucijada Biosphere Reserve in the Pacific coast of Mexico. We also estimated soil C sequestration rates of mangroves on the basis of soil accumulation. We hypothesized that riverine wetlands have large C stocks, and that upland mangroves have larger C and soil N stocks compared to lowland mangroves. Riverine wetlands had large C stocks with a mean of 784.5 ± 73.5 Mg C ha-1 for mangroves, 722.2 ± 83.4 Mg C ha-1 for peat swamps, and 336.5 ± 38.3 Mg C ha-1 for marshes. C stocks and soil N stocks were in general larger for upland (833.0 ± 7.2 Mg C ha-1; 26.4 ± 0.5 Mg N ha-1) compared to lowland mangroves (659.5 ± 18.6 Mg C ha-1; 13.8 ± 2.0 Mg N ha-1). Soil C sequestration values were 1.3 ± 0.2 Mg C ha-1 yr-1. The Reserve stores 32.5 Mtons of C or 119.3 Mtons of CO2, with mangroves sequestering (via soil accumulation) 27 762 ± 0.5 Mg C ha-1 every year.

scholarly journals Short-Term Effect of Nitrogen Fertilization on Carbon Mineralization during Corn Residue Decomposition in Soil

Nitrogen ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 444-460
Author(s):  
Tanjila Jesmin ◽  
Dakota T. Mitchell ◽  
Richard L. Mulvaney
Keyword(s):  
Microbial Biomass ◽  
C:N Ratio ◽  
Carbon Mineralization ◽  
N Fertilization ◽  
Co2 Production ◽  
Microbial Biomass C ◽  
N Availability ◽  
Soil C ◽  
Residue Decomposition ◽  
C And N

The effect of N fertilization on residue decomposition has been studied extensively; however, contrasting results reflect differences in residue quality, the form of N applied, and the type of soil studied. A 60 d laboratory incubation experiment was conducted to ascertain the effect of synthetic N addition on the decomposition of two corn (Zea mays L.) stover mixtures differing in C:N ratio by continuous monitoring of CO2 emissions and periodic measurement of microbial biomass and enzyme activities involved in C and N cycling. Cumulative CO2 production was greater for the high than low N residue treatment, and was significantly increased by the addition of exogenous N. The latter effect was prominent during the first month of incubation, whereas N-treated soils produced less CO2 in the second month, as would be expected due to more rapid substrate depletion from microbial C utilization previously enhanced by greater N availability. The stimulatory effect of exogenous N was verified with respect to active biomass, microbial biomass C and N, and cellulase and protease activities, all of which were significantly correlated with cumulative CO2 production. Intensive N fertilization in modern corn production increases the input of residues but is not conducive to soil C sequestration.

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