Comparison of legume-based cropping systems at Warra, Queensland. 1. Soil nitrogen and organic carbon accretion and potentially mineralisable nitrogen

Soil Research ◽  
1996 ◽  
Vol 34 (2) ◽  
pp. 273 ◽  
Author(s):  
SA Hossain ◽  
RC Dalal ◽  
SA Waring ◽  
WM Strong ◽  
EJ Weston

Effects on soil nitrogen accretion and potentially mineralisable nitrogen were studied as part of a long-term field experiment established in 1986 to test alternative legume-based systems for restoring fertility in a Vertisol. Organic C accretion was also measured to ascertain the changes in organic matter content. The systems, which were studied only during 1989 and 1990, were a grass+legume ley (purple pigeon grass, Rhodes grass, lucerne, annual medics) of 4 years duration followed by wheat; a 2-year rotation of wheat (lucerne undersown) and lucerne; a 2-year rotation of wheat (medic undersown) and medic; a 2-year rotation of chickpea and wheat; and continuous wheat as control. Soil total N and organic C significantly increased in the 0–10 cm soil layer only under the grass+legume ley. There was no significant change in the soil C/N ratio. Plant residues contained from 52 to 104 kg N/ha in 1990 at the end of the legume phase, with high values for root N in the grass+legume ley. A comparison of N accretion versus fixation at the end of the legume-based systems in 1990 showed that net accumulation of N exceeded fixation in soil under lucerne and grass+legume leys; in the latter, net accumulation of 779 kg N/ha over 3.75 years was measured compared with 384 kg N/ha for N2 fixation. Part of the accumulation of N may have been due to uptake of NH4-N from the deep subsoil. Although values for soil mineral N (0–120 cm) were low at the end of all the legume-based systems, a deep subsoil (120–300 cm) accumulation of NH4-N was found in all treatments. The nitrogen mineralisation potentials (No) for 0–10 cm depth samples taken at the end of the legume phase in 1989 were higher in all the legume-based systems (105–182 mg N/kg) than the wheat control (57 mg N/kg). The rapid biological tests of N availability, both waterlogged and aerobic incubation, were more sensitive to treatment differences than No, in the surface and subsoil (range 12–78 mg N/kg for 0–10 cm soil for the waterlogged procedure). The rapid chemical tests, hot KCl extraction and the autoclave index, showed small treatment effects and did not appear to be useful availability indices. The pasture management (graced v. mown and removed) had no significant effect on total N, organic C and N availability indices in this alkaline Vertisol during the study period.


Author(s):  
Željko S. Dželetović ◽  
Nevena Lj. Mihailović

Based on a greenhouse experiment, we evaluated nitrogen availability in the surface mineral layer of soil under various natural meadow stands by analyzing the following soil characteristics: total organic C, total N, initial content of easily available N inorganic forms, mineralized N content obtained by aerobic and anaerobic incubations and A-value. The experiment was performed on a test plant and through the application of urea enriched with 5.4 % 15N. The investigated soils under natural meadows are characterized with comparatively high mineralization intensity and high N availability indices. Contents of mineral N produced by aerobic incubation and the intensity of the mineralization correlate with the total organic C in the soil and the total N in the soil. Correlation of the availability index of the soil N produced by aerobic incubation with the total organic C and the total N in the soil under natural meadows is almost linear (r = 0.9981 and r = 0.9997, respectively). Contents of mineral N produced by anaerobic incubation, as well as the corresponding N availability and mineralization intensity indices correlate poorly with the mentioned parameters. Efficiency of nitrogen utilization from the applied N-fertilizer by the test crop varies within a wide range of values and correlates with the biomass yields of the test crop.



Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 764
Author(s):  
Sharon L. Weyers ◽  
David W. Archer ◽  
Jane M.F. Johnson ◽  
Alan R. Wilts

Application of exogenous N fertilizers provides agronomic benefits but carries environmental liabilities. Managing benefits and liabilities of N-based fertilizers in conventional (CNV) and organic (ORG) cropping systems might be improved with better knowledge of nutrient dynamics, the generation of intrinsic N, and maintenance of soil organic matter. This study evaluated mineral N dynamics, yields, residue inputs, and change in soil organic C (SOC) and total N (TN) in strip-tilled, four-year crop rotations [corn (Zea mays L.)-soybean (Glycine max [L.] Merr.)-wheat under-seeded with alfalfa (Triticum aestivum L./Medicago sativa L.)-alfalfa] over eight years of production under CNV management using mineral-N (NO3NH4) and chemical pesticides or ORG management using organic-N (animal manure) and no chemical treatments. In ORG, N availability increased over time, but did not benefit ORG yields due to poor control of insects and weeds. Corn, soybean, and wheat grain yields were 1.9 to 2.7 times greater in CNV. In general, SOC was lost in CNV but did not change in ORG. Cumulative yield N removals exceeded cumulative fertilizer-N inputs by an average of 78% in CNV and 64% in ORG. These results indicated ORG management supported N availability by generating intrinsic N.



2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ningguang Dong ◽  
Guanglong Hu ◽  
Yunqi Zhang ◽  
Jianxun Qi ◽  
Yonghao Chen ◽  
...  

AbstractThis study characterized the effect of green manures (February orchid, hairy vetch, rattail fescue and a no-green-manure control) and the termination method (flail or disk) on nutrient contents, enzyme activities, microbial biomass, microbial community structure of rhizosphere soil and vegetative growth of walnut tree. All three selected green manures significantly enhanced the water content, organic C, total N and available P. The rattail fescue significantly decreased the mineral N. Total organic C, total N, mineral N and available P were significantly greater under flail than under disk. Hairy vetch and February orchid significantly improved levels of soil β-glucosidase, N-acetyl-glucosaminidase and acid phosphatase activity, whereas rattail fescue improved only β-glucosidase activity. All of the green manures significantly decreased phenoloxidase activity. β-glucosidase, N-acetyl-glucosaminidase and acid phosphatase activities were significantly greater under flail relative to disk. The termination method had no significant effect on phenoloxidase activity. The different types of green manures and termination methods significantly altered the soil microbial biomass and microbial community structure. The green-manure treatments were characterized by a significantly greater abundance of Gram-positive (Gram +) bacteria, total bacteria and saprophytic fungi compared to the control. Hairy vetch significantly decreased the abundance of arbuscular mycorrhizal fungi (AMF) while February orchid and rattail fescue increased their abundance compared to the no-green-manure treatment. The abundance rates of Gram+ bacteria, actinomycetes, saprophytic fungi and AMF were significantly greater in soils under flail than under disk. In terms of vegetative growth of walnut tree, hairy vetch showed the greatest positive effects. The growth of walnut tree was significantly greater under flail relative to disk. Our results indicate that green-manure application benefits the rhizosphere soil micro-ecology, rhizosphere soil nutrient contents and tree growth. Overall, the hairy vetch and flail combined treatment is recommended for walnut orchards in northern China.



2011 ◽  
Vol 35 (6) ◽  
pp. 1985-1994 ◽  
Author(s):  
Carina Rosa Álvarez ◽  
Alejandro Oscar Costantini ◽  
Alfredo Bono ◽  
Miguel Ángel Taboada ◽  
Flavio Hernán Gutiérrez Boem ◽  
...  

One of the expected benefits of no-tillage systems is a higher rate of soil C sequestration. However, higher C retention in soil is not always apparent when no-tillage is applied, due e.g., to substantial differences in soil type and initial C content. The main purpose of this study was to evaluate the potential of no-tillage management to increase the stock of total organic C in soils of the Pampas region in Argentina. Forty crop fields under no-tillage and conventional tillage systems and seven undisturbed soils were sampled. Total organic C, total N, their fractions and stratification ratios and the C storage capacity of the soils under different managements were assessed in samples to a depth of 30 cm, in three layers (0-5, 5-15 and 15-30 cm). The differences between the C pools of the undisturbed and cultivated soils were significant (p < 0.05) and most pronounced in the top (0-5 cm) soil layer, with more active C near the soil surface (undisturbed > no-tillage > conventional tillage). Based on the stratification ratio of the labile C pool (0-5/5-15 cm), the untilled were separated from conventionally tilled areas. Much of the variation in potentially mineralizable C was explained by this active C fraction (R² = 0.61) and by total organic C (R² = 0.67). No-till soils did not accumulate more organic C than conventionally tilled soils in the 0-30 cm layer, but there was substantial stratification of total and active C pools at no till sites. If the C stratification ratio is really an indicator of soil quality, then the C storage potential of no-tillage would be greater than in conventional tillage, at least in the surface layers. Particulate organic C and potentially mineralizable C may be useful to evaluate variations in topsoil organic matter.



Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 719 ◽  
Author(s):  
M. T. Moroni ◽  
P. J. Smethurst ◽  
G. K. Holz

Several soil analyses were used to estimate available N in surface soils (0–10 cm) over a 2-year period at 5 sites that supported 1- to 4-year-old Eucalyptus nitens plantations, and once in subsoils (10–120 cm) at 3 of these sites. Soils were derived from basalt (1 site previously pasture, 1 Pinus radiate, and 2 native forest) or siltstone (previously native forest). Soil analyses examined were total N, total P, total C, anaerobically mineralisable N (AMN), hot KCl-extractable N (hot KCl-N), and NH4+ and NO3– in soil solution and KCl extracts. AMN, KCl-extractable NH4+ and NO3–, and soil solution NH4+ and NO3– varied considerably with time, whereas hot KCl-N, total N, total P, and total C were temporally stable except for a gradual decline in total C with time at one site. Only total P was correlated with net N mineralisation (NNM) across all sites (r2 = 0.91, P < 0.05, n = 5). At 2–3 years after planting, soil solution and KCl-extractable NO3– dropped below 0.1 mm N and 1 μg N/g soil, respectively, at sites with NNM ≤24 kg N/ha.year (n = 3). Sites with NNM ≤24 kg N/ha.year also had ≤0.8 Mg P/ha. Although concentrations of indices of soil N availability decreased with depth, the contribution of subsoil (10–120 cm depth) to total profile N availability was estimated to be at least twice that of the top 10 cm. At an ex-pasture site, high concentrations of mineral N were found at 75–105 cm depths (KCl-extractable N, 289.3 μg N/g soil; 2.8 mm mineral N in soil solution), which may have become available to plantations as their root systems developed.



2005 ◽  
Vol 56 (12) ◽  
pp. 1415
Author(s):  
Y. J. Kliese ◽  
R. C. Dalal ◽  
W. M. Strong ◽  
N. W. Menzies

Piggery pond sludge (PPS) was applied, as-collected (Wet PPS) and following stockpiling for 12 months (Stockpiled PPS), to a sandy Sodosol and clay Vertosol at sites on the Darling Downs of Queensland. Laboratory measures of N availability were carried out on unamended and PPS-amended soils to investigate their value in estimating supplementary N needs of crops in Australia's northern grains region. Cumulative net N mineralised from the long-term (30 weeks) leached aerobic incubation was described by a first-order single exponential model. The mineralisation rate constant (0.057/week) was not significantly different between Control and PPS treatments or across soil types, when the amounts of initial mineral N applied in PPS treatments were excluded. Potentially mineralisable N (No) was significantly increased by the application of Wet PPS, and increased with increasing rate of application. Application of Wet PPS significantly increased the total amount of inorganic N leached compared with the Control treatments. Mineral N applied in Wet PPS contributed as much to the total mineral N status of the soil as did that which mineralised over time from organic N. Rates of CO2 evolution during 30 weeks of aerobic leached incubation indicated that the Stockpiled PPS was more stabilised (19.28% of applied organic C mineralised) than the Wet PPS (35.58% of applied organic C mineralised), due to higher lignin content in the former. Net nitrate-N produced following 12 weeks of aerobic non-leached incubation was highly correlated with net nitrate-N leached during 12 weeks of aerobic incubation (R2 = 0.96), although it was <60% of the latter in both sandy and clayey soils. Anaerobically mineralisable N determined by waterlogged incubation of laboratory PPS-amended soil samples increased with increasing application rate of Wet PPS. Anaerobically mineralisable N from field-moist soil was well correlated with net N mineralised during 30 weeks of aerobic leached incubation (R2 = 0.90 sandy soil; R2 = 0.93 clay soil). In the clay soil, the amount of mineral N produced from all the laboratory incubations was significantly correlated with field-measured nitrate-N in the soil profile (0.1.5 m depth) after 9 months of weed-free fallow following PPS application. In contrast, only anaerobic mineralisable N was significantly correlated with field nitrate-N in the sandy soil. Anaerobic incubation would, therefore, be suitable as a rapid practical test to estimate potentially mineralisable N following applications of different PPS materials in the field.



1998 ◽  
Vol 78 (3) ◽  
pp. 551-562 ◽  
Author(s):  
G. Roloff ◽  
R. de jong ◽  
C. A. Campbell ◽  
R. P. Zentner ◽  
V. M. Benson

The Environmental Policy Integrated Climate (EPIC) model is an important support tool for environmental management. Previous tests of the model have determined that it is suitable for long-term yield estimation, but it is less precise in assessing annual yield variability. To determine the reasons for the discrepancies between estimated and measured yields, we tested the ability of EPIC version 5300 to predict soil water and soil nitrogen dynamics, using data from a long-term spring wheat (Triticum aestivum L.) rotation experiment in the semiarid prairie region of Canada. Potential evapotranspiration (PET) estimates varied among methods tested: Priestley-Taylor and Penman-Monteith methods resulted in PET means that were about twice those obtained with the Hargreaves and Baier-Robertson methods. The higher PET means were associated with an excessive estimation of net radiation. We used the Baier-Robertson method to generate the other estimates reported herein. EPIC generally overestimated total soil water, but it still allowed clear differentiation among rotation phases and times of the year, and provided adequate estimates of water during the critical shot-blade stage. Water estimates by soil layer were also generally overpredicted, especially at depths from 0.15 to 0.60 m, but we were able to differentiate among rotation phases and times of the year. Precision of these latter estimates was generally low, accounting at most for 27% of the variability, and varied by soil layer, rotation phase and time of the year. Nitrate-N estimates tended to be lower than measured values, especially at depths below 0.3 m and during vegetative growth phases. However, the estimates also allowed us to distinguish among the rotation phases and times of the year. Total N and organic C were satisfactorily estimated by EPIC. In general, EPIC provided adequate long-term estimates of the environmental quality indicators tested. Key words: Environmental quality, environmental modelling, sustainability, spring wheat, fallow, potential evapotranspiration methods



2008 ◽  
Vol 23 (03) ◽  
pp. 250-259 ◽  
Author(s):  
Derek H. Lynch ◽  
Zhiming Zheng ◽  
Bernie J. Zebarth ◽  
Ralph C. Martin

AbstractThe market for certified organic potatoes in Canada is growing rapidly, but the productivity and dynamics of soil N under commercial organic potato systems remain largely unknown. This study examined, at two sites in Atlantic Canada (Winslow, PEI, and Brookside, NS), the impacts of organic amendments on Shepody potato yield, quality and soil mineral nitrogen dynamics under organic management. Treatments included a commercial hog manure–sawdust compost (CP) and pelletized poultry manure (NW) applied at 300 and 600 kg total N ha−1, plus an un-amended control (CT). Wireworm damage reduced plant stands at Brookside in 2003 and those results are not presented. Relatively high tuber yields (~30 Mg ha−1) and crop N uptake (112 kg N ha−1) were achieved for un-amended soil in those site-years (Winslow 2003 and 2004) when soil moisture was non-limiting. Compost resulted in higher total yields than CT in one of three site-years. Apparent recovery of N from CP was negligible; therefore CP yield benefits were attributed to factors other than N availability. At Winslow, NW300, but not NW600, significantly increased total and marketable yields by an average of 5.8 and 7.0 Mg ha−1. Plant available N averaged 39 and 33% for NW300 and NW600, respectively. Soil (0–30 cm) NO3−-N at harvest was low (&lt;25 kg N ha−1) for CT and CP, but increased substantially both in season and at harvest (61–141 kg N ha−1) when NW was applied. Most leaching losses of NO3−-N occur between seasons and excessive levels of residual soil NO3-N at harvest, as obtained for NW600, must be avoided. Given current premiums for certified organic potatoes, improving yields through application of amendments supplying moderate rates of N or organic matter appears warranted.



2021 ◽  
Author(s):  
Vito Abbruzzese

In many farm systems, both inorganic and organic fertilisers, including manure and slurry, are applied to the soil to replenish nutrient offtake in agricultural products and additional nutrient losses to soil as well as surface water and groundwater. With respect to sole reliance on inorganic fertilisers, the use of manure/slurry as a nutrient resource offers important benefits, including the reuse and recycling of nitrogen (N) and phosphorus (P) within farming systems as well as a reduction in the reliance on agricultural production on finite inorganic fertiliser reserves. There is increasing interest in the extent to which additives can enhance the nutrient value of slurry/manure. However, little is known about the impacts of these amended slurries/manures on the quantity and composition of N and P within agricultural and pasture soils. We report data from incubation experiments in which soils received a range of treatments, including the application of livestock slurry that had received a mixture of commercial additives. Our experiments were designed to understand how slurry that has received additives ultimately affects nutrient availability in organic, clay-loam and sandy-loam grassland soils. The addition of the additives to slurry resulted in a slight increase or no difference in total solids, pH, total N, ammonium-N, total P, total potassium, total magnesium and total sodium compared to the untreated counterpart. We considered the effects of our treatments on a range of agronomically important soil parameters, including Olsen-P, mineral-N, available-K, pH and organic matter content. This experiment aimed to understand the extent to which soil fertility could be enhanced through the application of slurries/manures that have received additives. The application of both amended and unamended slurry treatments on soil led to higher values of NH4-N, available-K, available Mg and pH than the addition of inorganic fertiliser. In addition, no substantial differences were observed between the treatment of the three soils with unamended and amended slurry.



2002 ◽  
Vol 32 (5) ◽  
pp. 892-902 ◽  
Author(s):  
T I Little ◽  
D J Pluth ◽  
I G.W Corns ◽  
D W Gilmore

After wildfire in the boreal forest, storage of organic carbon (C) begins with the accumulation of forest floor material. Soil properties of Gray Luvisols were studied to determine the differences in development along three toposequences. Our central hypothesis is that slope position does not influence the amount of accumulated organic C and total nitrogen (N) in the forest floor. Organic C and the C/N ratio in the forest floor and in A and B horizons increased from the crest to the toe of the slope. The forest floor contributed 2.0 ± 0.4 kg C·m–2 (mean ± SE) at the crest to 3.5 ± 0.5 kg C·m–2 at the toe. Throughout the solum, the C/N ratio was lower at the top of the slope compared with the toe (p < 0.05), and there were no differences among slope positions for in situ net N mineralization rates. Leaf area index, used as a proxy for net primary productivity, was greater (p < 0.05) at the toe compared with the crest position, and it was negatively correlated with forest floor total N concentration (r = –0.35, p = 0.027). These results, from mixedwood stands approximately 90 years after the last major fire disturbance, indicate that slope position does influence forest floor organic C by horizon volume (p = 0.02), but not total N concentration (p = 0.07). Despite the apparently lower N availability at the toe position, it exhibited the greatest potential productivity.



Sign in / Sign up

Export Citation Format

Share Document