Comparison of N Mineralization Rate and Pattern in Different Manure- and Sewage Sludge-Amended Calcareous Soil

2019 ◽  
Vol 50 (5) ◽  
pp. 559-569 ◽  
Author(s):  
Leila Zare ◽  
Abdolmajid Ronaghi
Keyword(s):  
Sewage Sludge ◽  
N Mineralization ◽  
Calcareous Soil ◽  
Mineralization Rate

Factors controlling N mineralization, nitrification, and nitrogen losses in an Oxisol amended with sewage sludge

Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 519 ◽  
Author(s):  
J. Sierra ◽  
S. Fontaine ◽  
L. Desfontaines
Keyword(s):  
Sewage Sludge ◽  
Field Experiment ◽  
Water Content ◽  
N Mineralization ◽  
Initial Period ◽  
Factorial Experiment ◽  
Net N Mineralization ◽  
N Losses ◽  
Mineral N ◽  
The Difference

Laboratory incubations and a field experiment were carried out to determine the factors controlling N mineralization and nitrification, and to estimate the N losses (leaching and volatilization) in a sewage-sludge-amended Oxisol. Aerobically digested sludge was applied at a rate equivalent to 625 kg N/ha. The incubations were conducted as a factorial experiment of temperature (20˚C, 30˚C, and 40˚C) soil water (–30 kPa and –1500 kPa) sludge type [fresh (FS) water content 6230 g/kg; dry (DS) water content 50 g/kg]. The amount of nitrifiers was determined at the beginning and at the end of the experiment. The incubation lasted 24 weeks. The field study was conducted using bare microplots (4 m) and consisted of a factorial experiment of sludge type (FS and DS) sludge placement (subsurface, I+; surface, I–). Ammonia volatilization and the profile (0–0.90 m) of mineral N concentration were measured during 6 and 29 weeks after sludge application, respectively. After 24 weeks of incubation at 40˚C and –30 kPa, net N mineralization represented 52% (FS) and 71% (DS) of the applied N. The difference between sludges was due to an initial period of N immobilization in FS. Nitrification was more sensitive than N mineralization to changes in water potential and it was fully inhibited at –1500 kPa. The introduction of a large amount of nitrifiers with FS did not modify the rate of nitrification, which was principally limited by soil acidity (pH 4.9). Although N mineralization was greatest at 30˚C, nitrification increased continuously with temperature. Nitrogen mineralization from DS was well described by the double-exponential equation. For FS, the equation was modified to take into account an immobilization-remineralization period. Sludge placement significantly affected the soil NO-3/NH+4 ratio in the field: 16 for I+ and 1.5 for I–, after 11 weeks. In the I– treatment, nitrification of the released NH+4 was limited by soil moisture because of the dry soil mulch formed a few hours after rain. At the end of the field experiment, the estimated losses of N by leaching were 432 kg N/ha for I+ and 356 kg N/ha for I–. Volatilization was not detectable in the I+ microplots and it represented only 0.5% of the applied N in the I– microplots. The results showed that placement of sludge may be a valuable tool to decrease NO-3 leaching by placing the sludge under unfavourable conditions for nitrification.

scholarly journals Effects of Changing Temperature on Gross N Transformation Rates in Acidic Subtropical Forest Soils

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 894
Author(s):  
Xiaoqian Dan ◽  
Zhaoxiong Chen ◽  
Shenyan Dai ◽  
Xiaoxiang He ◽  
Zucong Cai ◽  
...  
Keyword(s):  
Temperature Change ◽  
N Mineralization ◽  
Organic N ◽  
Mineralization Rate ◽  
Soil N ◽  
Autotrophic Nitrification ◽  
N Transformation ◽  
Gross N Transformation ◽  
Increasing Temperature ◽  
N Pool

Soil temperature change caused by global warming could affect microbial-mediated soil nitrogen (N) transformations. Gross N transformation rates can provide process-based information about abiotic–biotic relationships, but most previous studies have focused on net rates. This study aimed to investigate the responses of gross rates of soil N transformation to temperature change in a subtropical acidic coniferous forest soil. A 15N tracing experiment with a temperature gradient was carried out. The results showed that gross mineralization rate of the labile organic N pool significantly increased with increasing temperature from 5 °C to 45 °C, yet the mineralization rate of the recalcitrant organic N pool showed a smaller response. An exponential response function described well the relationship between the gross rates of total N mineralization and temperature. Compared with N mineralization, the functional relationship between gross NH4+ immobilization and temperature was not so distinct, resulting in an overall significant increase in net N mineralization at higher temperatures. Heterotrophic nitrification rates increased from 5 °C to 25 °C but declined at higher temperatures. By contrast, the rate of autotrophic nitrification was very low, responding only slightly to the range of temperature change in the most temperature treatments, except for that at 35 °C to 45 °C, when autotrophic nitrification rates were found to be significantly increased. Higher rates of NO3− immobilization than gross nitrification rates resulted in negative net nitrification rates that decreased with increasing temperature. Our results suggested that, with higher temperature, the availability of soil N produced from N mineralization would significantly increase, potentially promoting plant growth and stimulating microbial activity, and that the increased NO3− retention capacity may reduce the risk of leaching and denitrification losses in this studied subtropical acidic forest.

scholarly journals Relationship between mineral N content and N mineralization rate in disturbed and undisturbed soil samples incubated under field and laboratory conditions

Soil Research ◽  
1992 ◽  
Vol 30 (4) ◽  
pp. 477 ◽  
Author(s):  
J Sierra
Keyword(s):  
N Mineralization ◽  
Negative Relationship ◽  
Feedback Mechanism ◽  
Soil Samples ◽  
Mineralization Rate ◽  
Mineral N ◽  
Undisturbed Soil ◽  
N Content ◽  
Undisturbed Samples

An investigation of in situ N mineralization, using undisturbed soil samples, indicated a negative relationship between the mineral N content [(NO3+NH4)-N] at the beginning of the experiment and the mineral N produced during it. This suggests that a maximum value of mineral N accumulation in intact soil cores could be calculated from the relationship between mineral N content and N mineralization rate. This value would be related to the size of the mineralizable N pool. If this hypothesis is true, the amount of mineralizable N could be estimated from in situ incubations and utilized in the modelling of N mineralization in the field. The aim of this work was to verify this hypothesis. The relationship between the mineral N content and the N mineralization rate was analysed for in situ and laboratory incubations of disturbed and undisturbed soil samples. A negative relationship between the two variables was only obtained for the experiments carried out with undisturbed samples (in the field and laboratory incubations) when the soil moisture content was not limiting for N mineralization. Futhermore, in undisturbed samples, a negative relationship between mineralization rates of consecutive incubation periods was observed, i.e. the soil sample producing relatively more, during a given period, produced relatively less in the following period. This relationship suggests a feedback mechanism operating in N mineralization which would be related to a mineralization-immobilization process in soil microsites. Thus, the N mineralization pattern was more complex than that described by initial hypothesis. The possible consequence of this feedback mechanism on in situ N dynamics is discussed.

Nitrogen-mineralization potential of meadow soils

1993 ◽  
Vol 73 (1) ◽  
pp. 27-38 ◽  
Author(s):  
Régis R. Simard ◽  
Adrien N'dayegamiye
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
N Mineralization ◽  
Mineralization Rate ◽  
Total N ◽  
Available N ◽  
Gompertz Equation ◽  
Mineralizable N ◽  
Mineralization Potential ◽  
Potential Mineralization

An understanding of the mineralization factors in contrasting cultivated soils is necessary for accurate predictions of plant-available N. The objective of this work was to determine the N-mineralization potential and mathematical models that can properly describe the dynamics of the mineralization process in 20 meadow soils from Quebec. The mineralization was monitored over 55.4 wk in a laboratory incubation at 20 °C with intermittent leaching. The cumulative mineralization curves in most soils were characterized by definite lags or a sigmoidal pattern and near-linear release with time after 20 wk. The data were best described by the Gompertz equation; first-order models were inadequate. The total amount of mineralizable N and the potential mineralization rate were very closely correlated with the total amounts of C or N (r > 0.73; P < 0.01). The clay content was also correlated with these mineralization parameters and significantly improved the prediction of the cumulative and potential N-mineralization rate estimated from the total N or C content of soils. The relationships with other soil characteristics such as soil pH and available nutrient contents were weak but significant. The results of this study suggest that textural classes be added in the correction for organic matter content to improve the precision in N-fertilizer recommendation and in soil-quality classifications based on potential mineralization rate. Key words: Soil quality, potentially mineralizable N, Gompertz equation, soil organic matter, soil texture, C, N

scholarly journals Seasonal variations in available N and N-mineralization in relation to fine roots in landslide damaged sites in the sal forest ecosystem of Nepal Himalaya

2013 ◽  
Vol 1 ◽  
pp. 114-124
Author(s):  
Tej Narayan Mandal
Keyword(s):  
N Mineralization ◽  
Root Biomass ◽  
Fine Root ◽  
Fine Root Biomass ◽  
Summer Season ◽  
The Other ◽  
Mineralization Rate ◽  
Available N ◽  
Nepal Himalaya ◽  
Sal Forest

Seasonal dynamics of available nitrogen and N-mineralization in relation to fine root biomass was studied in five landslide damaged (1 to 58 years old) sites in the moist tropical sal (Shorea robusta) forest ecosystem of Nepal Himalaya. Comparisons were made with an undisturbed mature sal forest site located in the same region. Concentrations of soil available-N (NH4+ and NO3-) increased with the age of site till 40-year old sites and then declined. However, the proportion of NH4+ in total available N increased distinctly with increase in the age of sites. The NH4+: NO3- ratio increased considerably from 1.15 in 1-year site to 2.4 in mature sal forest. On the other hand, the net N-mineralization rate increased consistently until 58 years of age but the proportion of nitrification rate relative to ammonification rate distinctly decreased beyond 40 years indicating the dominance of ammonification over nitrification in the older sites. Fine root biomass and N- mineralization rate both increased but available-N decreased during rainy season. On the other hand fine root biomass and N-mineralization rate both decreased and available N increased during summer season. During the summer season, fine root biomass decreased by 57 - 68% indicating a rapid turnover. High turnover of fine root at the younger sites (1 to 15 yrs old) add more organic matter for the developing vegetation. Fine root biomass was positively correlated with the concentration of available-N and N-mineralization rate. It is concluded that fine root development was facilitated by higher amounts of available-N. DOI: http://dx.doi.org/10.3126/njbs.v1i0.7478 Nepalese Journal of Biosciences 1: 114-124 (2011)

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