Indices of soil nitrogen availability in five Tasmanian Eucalyptus nitens plantations

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.


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.



2013 ◽  
Vol 59 (No. 6) ◽  
pp. 235-240 ◽  
Author(s):  
Bordoloi LJ ◽  
Singh AK ◽  
Manoj-Kumar ◽  
Patiram ◽  
S. Hazarika

Plant&rsquo;s nitrogen (N) requirement that is not fulfilled by available N in soil has to be supplied externally through chemical fertilizers. A reliable estimate of soil N-supplying capacity (NSC) is therefore essential for efficient fertilizer use. In this study involving a pot experiment with twenty acidic soils varying widely in properties, we evaluated six chemical indices of soil N-availability viz. organic carbon (C<sub>org</sub>), total N (N<sub>tot</sub>), acid and alkaline-KMnO<sub>4</sub> extractable-N, hot KCl extractable-N (KCl-N) and phosphate-borate buffer extractable-N (PBB-N), based on their strength of correlation with available-N values obtained through aerobic incubation (AI-N) and anaerobic incubation (ANI-N), and also with the dry matter yield (DMY), N percentage and plant (maize) N uptake (PNU). In general, the soils showed large variability in NSC as indicated by variability in PNU which ranged from 598 to 1026 mg/pot. Correlations of the N-availability indices with AI-N and ANI-N decreased in the order: PBB-N (r = 0.784** and 0.901**) &gt; KCl-N (r = 0.773** and 0.743**) &gt; acid KMnO<sub>4</sub>-N (r = 0.575** and 0.651**) &ge; C<sub>org</sub> (r = 0.591** and 0.531**) &ge; alkaline KMnO<sub>4</sub>-N (r = 0.394** and 0.548**) &gt; N<sub>tot</sub> (r = 0.297** and 0.273*). Of all the indices evaluated, PBB-N showed the best correlations with plant parameters as well (r = 0.790** and 0.793** for DMY and PNU, respectively). Based on the highest correlations of PBB-N with biological indices as well as plant responses, we propose PBB-N as an appropriate index of N-availability in the acidic soils of India and other regions with similar soils.



2016 ◽  
Vol 14 (4) ◽  
pp. e0806 ◽  
Author(s):  
Ramón Isla ◽  
Mónica Guillén ◽  
Montserrat Salmerón

There are limited studies about the effect of nitrogen (N) deficiency on leaf growth, N status, and photosynthetic capacity of maize grown under field conditions in a Mediterranean climate. The objective of this work was to evaluate the effect of different levels of mineral N availability on leaf gas exchange parameters of sprinkler irrigated maize. The experiment was conducted in a conventional maize field located in the central part of the Ebro valley (Spain) during two seasons. Using a portable LICOR-6400 equipment, instantaneous measurements and light response curves to gas exchange were conducted in plots with different levels of N supply ranging from deficient (no fertilized) to over-fertilized (300 kg N/ha). In addition to gas exchange measurements, mineral soil N content, chlorophyll meter readings (CMR), leaf N content, and grain yield were measured in the different plots. Results showed that grain yield reached a plateau (14.5 Mg/ha) when the mineral N available was about 179 kg/ha. CMR were linearly and highly related to total N in ear leaves. The relationship between light-saturated leaf photosynthesis measurements and CMR was significant but very weak (R2=0.13) at V8 and V14 stages but increased later in the growing season (R2=0.52). Plants with intermediate levels of N supply (48<CMR<54) tended to have slightly higher assimilation rates than plants with higher CMR readings. As the available N increased, the saturation point, the light compensation point and significant increases of dark respiration rate were observed. Under the conditions of the study, leaf N contents of 1.9% in the ear leaf were enough to maximize leaf assimilation rates with no need to over-fertilize the maize crop.



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.



Soil Research ◽  
1996 ◽  
Vol 34 (6) ◽  
pp. 937 ◽  
Author(s):  
ZH Xu ◽  
JN Ladd ◽  
DE Elliott

Assessments of soil nitrogen (N) availability were undertaken using soils sampled at 0-10 and 10-20 cm depths from 123 experimental sites where the responses of cereal crops to N fertilisers were tested, throughout the cereal zone of South Australia. Rates of N mineralisation and percentage N mineralisation, as determined by a laboratory aerobic incubation method, were related to soil properties. Mineralisable N (N mineralised during a Li-week incubation) of 0-10 cm soil varied from 14 to 121 kg N/ha with a median of 50 kg N/ha, and that of 10-20 cm soil, from 5 to 42 kg N/ha (median 19 kg N/ha). Mineralisable N in 0-10 cm soil accounted for 90% of total mineralisable N in 0-20 cm soil. The percentages of N mineralised were generally higher in 0-10 cm soil (0.8-12.5%, median 3.4%) than in 10-20 cm soil (0.4-8.3%, median 2.3%). Soil organic carbon (OC) and total N could be well estimated from each other, and fron! soil pH, bulk density, and held capacity, with coefficients of determination (R2) ranging from 0.64 to 0.78. Overall, either mineralisable N or percentage N mineralisation rate in the surface soils could be well estimated from soil OC, total N, C to N ratio, bulk density, field capacity, and pH (R2, 0.78-0.86 for mineralisable N, and 0.67-0.91 for percentage N mineralisation rate).



2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Craig G. Cogger ◽  
Andy I. Bary ◽  
Elizabeth A. Myhre

As heat-dried biosolids become more widely produced and marketed, it is important to improve estimates of N availability from these materials. Objectives were to compare plant-available N among three different heat-dried biosolids and determine if current guidelines were adequate for estimating application rates. Heat-dried biosolids were surface applied to tall fescue (Festuca arundinaceaSchreb.) in Washington State, USA, and forage yield and N uptake measured for two growing seasons following application. Three rates of urea and a zero-N control were used to calculate N fertilizer efficiency regressions. Application year plant-available N (estimated as urea N equivalent) for two biosolids exceeded 60% of total N applied, while urea N equivalent for the third biosolids was 45%. Residual (second-year) urea N equivalent ranged from 5 to 10%. Guidelines for the Pacific Northwest USA recommend mineralization estimates of 35 to 40% for heat-dried biosolids, but this research shows that some heat-dried materials fall well above that range.



Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2419
Author(s):  
Anastasios Gatsios ◽  
Georgia Ntatsi ◽  
Luisella Celi ◽  
Daniel Said-Pullicino ◽  
Anastasia Tampakaki ◽  
...  

Information about the availability of soil mineral nitrogen (N) in organic greenhouse tomatoes after the application of mobile green manure (MGM), and its impact on plant nutrient status and yield is scarce. Considering this knowledge gap, the effects of legume biomass from faba beans that are cultivated outdoors (FAB), or from feed-grade alfalfa pellets at two different doses (AAL = 330 g m−2; AAH = 660 g m−2) that were applied as MGM on the nutrition and yield of an organic greenhouse crop of tomatoes were evaluated. All of the MGM treatments increased the mineral N concentrations in the soil throughout the cropping period, and the total N concentration in tomato leaves when compared to the untreated control. FAB and AAH treatments had a stronger impact than AAL in all of the measured parameters. In addition, AAL, AAH, and FAB treatments increased the yield compared to the control by 19%, 33%, and 36%, respectively. The application of MGM, either as faba bean fresh biomass or as alfalfa dry pellets, in organic greenhouse tomatoes significantly increased the plant available soil N, improved N nutrition, and enhanced the fruit yield. However, the N mineralization rates after the MGM application were excessive during the initial cropping stages, followed by a marked decrease thereafter. This may impose an N deficiency during the late cropping period.



2012 ◽  
Vol 524-527 ◽  
pp. 2139-2142
Author(s):  
Shu Li Wang ◽  
Chao Ma ◽  
Wei Bin Yuan

The soil physical and chemical properties of four densities (A:2500/hm2,B:3300/hm2,C:4400/hm2,D:6600/hm2) of hybrid Larch plantations, Larix olgensis plantation(E) and Quercus mandsurica forest(F) were studied in Jiangshanjiao forest farm of Heilongjiang province of China. Soil bulk density, soil porosity, total N, total P, available N and available P were affected significantly by plantation density in hybrid Larch plantations. The lowest surface soil bulk density was in density 2500/hm2. Soil porosity of density 2500/hm2and 3300/hm2was bigger than that of density 4400/hm2and density 6600/hm2. Total N, total P and available N of density 4400/hm2and 3300/hm2were higher than that of density 6600/hm2and density 2500/hm2. Total N, total P, available N and available P of hybrid Larch plantations were not lower than that of Larix olgensis plantation. The results of the soil physical and chemical properties under different densities of hybrid Larch plantations and different types of forest seems to confirm that hybrid Larch plantation did not decreased the soil fertility, and the hybrid Larch plantation with densities of 3300/hm2and 4400/hm2could be conductive to improving the soil quality. The results would provide the theories basis for manage the hybrid Larch plantations.



Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 235 ◽  
Author(s):  
X. Y. Liu ◽  
M. Rezaei Rashti ◽  
M. Esfandbod ◽  
B. Powell ◽  
C. R. Chen

Liming has been widely used to decrease soil acidity, but its effects on soil nitrogen (N) availability and microbial processes in sugarcane fields are largely unknown. Adjacent sugarcane soils at 26 months after liming (26ML), 14 months after liming (14ML) and with no lime amendment (CK) in Bundaberg, Australia, were selected to investigate the effect of liming on soil N bioavailability and microbial activity in a long-term subtropical sugarcane cropping system. Liming in both 14ML and 26ML treatments significantly increased soil pH (by 1.2–1.4 units) and exchangeable Ca2+ (>2-fold) compared with the CK treatment. The lower concentrations of hot water extractable organic carbon (C) and total N and ammonium-N in the 14ML, compared with the CK and 26ML treatments, can be attributed to the absence of trash blanket placement in the former. Enhanced microbial immobilisation due to improved soil pH by liming (14ML and 26ML treatments) led to increased soil microbial biomass C and N, particularly in the presence of a trash blanket (26 ML treatment), but decreased soil respiration and metabolic quotient indicated that acidic stress conditions were alleviated in the liming treatments. Soil pH was the main factor governing soil enzyme activities, with an overall decrease in all enzyme activities in response to liming. Overall, liming and trash blanket practices improved sugarcane soil fertility. Further study is warranted to investigate the shifts in soil microbial community composition and the diversity and abundance of N-associated functional genes in response to liming in sugarcane fields.



2019 ◽  
Vol 9 (21) ◽  
pp. 4481 ◽  
Author(s):  
Figueiredo ◽  
Coser ◽  
Moreira ◽  
Leão ◽  
Vale ◽  
...  

Biochar has been presented as a multifunctional material with short- and long-term agro-environmental benefits, including soil organic matter stabilization, improved nutrient cycling, and increased primary productivity. However, its turnover time, when applied to soil, varies greatly depending on feedstock and pyrolysis temperature. For sewage sludge-derived biochars, which have high N contents, there is still a major uncertainty regarding the influence of pyrolysis temperatures on soil carbon mineralization and its relationship to soil N availability. Sewage sludge and sewage sludge-derived biochars produced at 300 °C (BC300), 400 °C (BC400), and 500 °C (BC500) were added to an Oxisol in a short-term incubation experiment. Carbon mineralization and nitrogen availability (N-NH4+ and N-NO3−) were studied using a first-order model. BC300 and BC400 showed higher soil C mineralization rates and N-NH4+ contents, demonstrating their potential to be used for plant nutrition. Compared to the control, the cumulative C-CO2 emissions increased by 60–64% when biochars BC300 and BC400 were applied to soil. On the other hand, C-CO2 emissions decreased by 6% after the addition of BC500, indicating the predominance of recalcitrant compounds, which results in a lower supply of soil N-NH4+ (83.4 mg kg−1) in BC500, being 67% lower than BC300 (255.7 mg kg−1). Soil N availability was strongly influenced by total N, total C, C/N ratio, H, pore volume, and specific surface area in the biochars.



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