Interactions between residues of maize and pigeonpea and mineral N fertilizers during decomposition and N mineralization

2000 ◽  
Vol 32 (5) ◽  
pp. 679-688 ◽  
Author(s):  
Webster D. Sakala ◽  
George Cadisch ◽  
Ken E. Giller
2011 ◽  
Vol 48 (No. 9) ◽  
pp. 389-396
Author(s):  
S. Malý ◽  
B. Šarapatka ◽  
M. Kršková

Parameters characterizing N mineralization and nitrification were measured in soils of ten monitoring areas of the basal soil monitoring carried out by the Central Institute for Supervising and Testing in Agriculture. A remarkable seasonal cycle was found only for nitrate concentrations that reached their maxima in the spring (April–June), and late summer and/or autumn, starting in August. Ammonium ions were nitrified immediately after fertilizer application. Anaerobic N mineralization represented a variable parameter, which was not directly affected by mineral N fertilizers. Nitrification measured by means of one-week incubation was significantly stimulated by N fertilizers confirming that substrate availability was a limiting factor of this process. Short-term nitrification activity (SNA) showed no remarkable seasonal fluctuations, which meant that the potential nitrification rate remained relatively constant during the season. Urease activity was mostly constant during the year and was only slightly related to N mineralization.


Soil Research ◽  
2001 ◽  
Vol 39 (3) ◽  
pp. 519 ◽  
Author(s):  
J. Sierra ◽  
S. Fontaine ◽  
L. Desfontaines

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.


Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1470
Author(s):  
Inmaculada Bautista ◽  
Luis Lado-Monserrat ◽  
Cristina Lull ◽  
Antonio Lidón

In order to assess the sustainability of silvicultural treatments in semiarid forests, it is necessary to know how they affect the nutrient dynamics in the forest. The objective of this paper is to study the effects of silvicultural treatments on the net N mineralization and the available mineral N content in the soil after 13 years following forest clearings. The treatments were carried out following a randomized block design, with four treatments and two blocks. The distance between the two blocks was less than 3 km; they were located in Chelva (CH) and Tuéjar (TU) in Valencia, Spain. Within each block, four experimental clearing treatments were carried out in 1998: T0 control; and T60, T75 and T100 where 60%, 75% and 100 of basal area was eliminated, respectively. Nitrogen dynamics were measured using the resin tube technique, with disturbed samples due to the high stoniness of the plots. Thirteen years after the experimental clearings, T100, T75 and T60 treatments showed a twofold increase in the net mineralization and nitrification rates with respect to T0 in both blocks (TU and CH). Within the plots, the highest mineralization was found in sites with no plant cover followed by those covered by undergrowth. These results can be explained in terms of the different litterfall qualities, which in turn are the result of the proportion of material originating from Pinus halepensis Mill. vs. more decomposable undergrowth residues.


Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 444 ◽  
Author(s):  
Chen-Chi Tsai ◽  
Yu-Fang Chang

Adding biochar to excessive compost amendments may affect compost mineralization rate and nitrogen (N) availability. The objective of this 371-day incubation study was to evaluate the effects of four proportions of woody biochar (0%, 0.5%, 1.0%, and 2.0%) from lead tree (Leucaena leucocephala (Lam.) de. Wit) biochar produced at 750 °C through dynamic mineral N and N mineralization rates in three rural soils (one Oxisol and two Inceptisols). In each treatment, 5% poultry–livestock manure compost was added to serve as an excessive application. The results indicated that the biochar decreased available total inorganic nitrogen (TIN) (NO3−-N+NH4+-N) by on average 6%, 9% and 19% for 0.5%, 1.0% and 2.0% treatments, respectively. The soil type strongly influenced the impact of the biochar addition on the soil nitrogen mineralization potential, especially the soil pH and clay content. This study showed that the co-application of biochar and excessive compost benefited the agricultural soils by improving NO3−-N retention in agroecosystems. The application of biochar to these soils to combine it with excessive compost appeared to be an effective method of utilizing these soil amendments, as it diminished the net N mineralization potential and reduced the nitrate loss of the excessive added compost.


Soil Research ◽  
1992 ◽  
Vol 30 (4) ◽  
pp. 477 ◽  
Author(s):  
J Sierra

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.


1992 ◽  
Vol 72 (1) ◽  
pp. 31-42 ◽  
Author(s):  
D. L. Burton ◽  
W. B. McGill

We compared changes in components of the N-mineralization cascade ranging from the very specific, such as a deaminase, to the highly integrated, such as biomass in a Black Chernozemic seeded to barley (Hordeum vulgare L.) under field conditions at Edmonton. Changes in enzyme content were related to soil [Formula: see text] to determine if the microbial environment changed sufficiently to exert feedback control on N mineralizing reactions and thereby to be detected. Histidase and protease were chosen as model systems for depolymerization and deamination respectively because information exists on their control in pure culture studies, on histidine content and control of histidase in soil, and assay procedures are available for soils. We observed an inverse relationship of labile histidase activity with [Formula: see text] in soils with high [Formula: see text] content and low [Formula: see text] ratio. This relationship provides indirect evidence for [Formula: see text] control of histidase content, but emphasizes that it is only one element of a complex control mechanism. Conversely, enzyme content was not rate limiting to net N mineralization, or sensitive to common control mechanisms. Biomass-C, an integrative measure of substrate supply, potential biological activity and enzymatic activity, describes net mineral-N production better than do indices of any single step. Regular spatial variability is exhibited by [Formula: see text] (and [Formula: see text]). [Formula: see text] is a product of mineralization; a substrate for immobilization, nitrification, plant uptake, and other reactions; and may also be a regulator of activity, or synthesis, of some enzymes. It is intriguing that none of the variables that influence mineral N, such as enzyme activity, biomass, or respiration, varied spatially in a statistically identifiable manner, yet [Formula: see text] did. Key words: Nitrogen mineralization, enzyme content, biomass, protease, histidase, ammonium regulation


1990 ◽  
Vol 20 (9) ◽  
pp. 1490-1497 ◽  
Author(s):  
P. J. Smethurst ◽  
E. K. S. Nambiar

The effects of clear-felling and slash removal on the distribution of organic matter and nutrients, fluxes of mineral N, and soil water and temperature were studied in a 37-year-old Pinusradiata D. Don plantation, on a sandy Podzol in southeastern Australia. Slash, litter, and the top 30 cm of soil combined contained 1957 kg N•ha−1, of which slash and litter contained 12 and 25%, respectively. Therefore, loss of slash and litter due to burning or other intensive site preparation practices would substantially reduce the N capital at the site. During the first 18 months after clear-felling, soil water content in the clear-felled area was up to 50% higher than in the uncut plantation, but there were only minor differences in soil temperature. Slash removal decreased the water content of litter, but had little effect on the water content or temperature of the soil. In the uncut plantation, N mineralized in litter and soil was completely taken up by the trees. Following clear-felling, rates of N mineralization increased in litter after 4 months, and in soil after 12 months, but changes were less pronounced with slash removal. After clear-felling, increased mineralization and the absence of trees (no uptake) led to increased concentrations of mineral N in both litter and soil, 64–76% of which was leached below the 30 cm soil depth prior to replanting. Despite leaching, concentrations of mineral N after clear-felling remained higher than those in the uncut plantation for at least 3 years.


1990 ◽  
Vol 20 (9) ◽  
pp. 1498-1507 ◽  
Author(s):  
P. J. Smethurst ◽  
E. K. S. Nambiar

The effects of slash and litter management practices on soil water and temperature, fluxes of mineral N, needle water potential, and tree nutrition and growth were studied in a young Pinusradiata D. Don plantation growing on a sandy Podzol in southeastern Australia. Treatments were slash and litter retained (SL), litter only retained (L), litter ploughed (LP), and slash and litter removed (SLR). Soils without slash or litter cover (LP and SLR) were up to 4 °C warmer on average than soils overlaid by slash or litter and were subjected to greater extremes of temperature. Treatments had relatively little effect on soil water content and needle water potential in trees. Carbon in surface soil increased from 1.14 to 1.83% after incorporation of litter by ploughing, but decreased to 1.37% during the next 40 months. Smaller but significant decreases in C also occurred in other treatments. LP and SLR led to the highest rates of N mineralization in the 1st year. During the first 3 years after clear-felling, rates of N mineralization increased in SL, L, and LP but decreased in SLR. During the 4th year, rates of N mineralization were low (20–30 kg N•ha−1•year−1) in all treatments. Over 4 years, 211, 170, 210, and 147 kg N•ha−1 were mineralized in treatments SL, L, LP, and SLR, respectively. Rates of mineralization and leaching were strongly correlated (R2 = 0.82) and leaching below 30 cm accounted for 75–85% of N mineralized irrespective of treatment. Incorporation of litter by ploughing doubled concentrations of mineral N during the first summer after planting and increased early tree growth. However, rates of N mineralization in the slash and litter treatments, which were high compared with potential rates of uptake, were weakly correlated with tree growth. Factors controlling N supply were of little consequence for tree growth during this early phase of plantation establishment.


2017 ◽  
Vol 9 (2) ◽  
pp. 1123-1128
Author(s):  
Manpreet S. Mavi ◽  
B. S. Sekhon ◽  
Jagdeep Singh ◽  
O. P. Choudhary

An understanding of the mineralization process of organic amendments in soil is required to synchronize N release with crop demand and protect the environment from excess N accumulation. Therefore, we conducted a laboratory incubation experiment to assess nitrogen mineralization potential of crop residues (rice and wheat straw) and organic manures (poultry manure, farmyard manure, cowpea and sesbania) in two benchmark soils (Typic Haplustept and Typic Ustifluvents) of semi-arid region of Punjab, India, varying in textureat field capacity moisture level at a constant temperature of 331°C. Mineralization was faster during first 7 days of incubation in Typic Haplustept and upto 14 days in Typic Ustifluvents which subsequently declined over time. In both soils, net N mineralization continued to increase with increasing period of incubation (expect with crop residues) and was significantly higher in Typic Ustifluvents (54-231µg g-1) than Typic Haplustept (33-203 µg g-1). Compared to unamended soils, percent N mineralized was highest is sesbania (35-40 %) followed by cowpea (32-37 %) and least in wheat (10-11 %) after 42 days of incubation. Thus, sesbania and cowpea may preferably be used to meetthe large N demand during early period of plant growth. Further, mineralization rate constants (k) also indicated that availability of mineral N was significantly higher with application of organic amendments than unamended control treatments in both soils. Therefore, it may be concluded that considerable economy in the use of inorganic N fertilizer can be employed if N mineralization potential of organic inputs is taken into consideration.


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