Mineral nitrogen in tropical forest soils

1962 ◽  
Vol 59 (2) ◽  
pp. 257-262 ◽  
Author(s):  
R. K. Cunningham
Keyword(s):  
Organic Matter ◽  
Tropical Forest ◽  
Forest Soils ◽  
Mineral Nitrogen ◽  
Surface Layers ◽  
Mineral N ◽  
Total N ◽  
Organic C ◽  
Mineralizable N ◽  
Temperate Soils

1. Δmin-Nad is the most satisfactory measurement for assessing mineralizable-N in the tropical forest soils used; values are treble those for Δmin-Nf and then increase even further on storage. Comparisons of Δmin-Nad are pointless unless methods of sampling, drying, storing and incubating are standardized.2. Δmin-Nad is correlated with total N and organic C but not pH.3. Undisturbed tropical forest soils can produce very large quantities of mineral N, particularly in their surface layers. This probably accounts for the lack of N responses in these soils. More intensive cultivation of these soils is only possible when organic matter is preserved by protecting cleared soils.4. Added nitrogen was leached more rapidly in these soils than in comparable temperate soils but was not fast enough to prevent absorption by plants.

scholarly journals Soil Fertility, N2 Fixation and Yield of Chickpea as Influenced by Long-Term Biochar Application under Mung–Chickpea Cropping System

2020 ◽  
Vol 12 (21) ◽  
pp. 9008
Author(s):  
Shadman Khan ◽  
Zahir Shah ◽  
Ishaq Ahmad Mian ◽  
Khadim Dawar ◽  
Muhammad Tariq ◽  
...  
Keyword(s):  
Organic Matter ◽  
Cropping System ◽  
Mineral Fertilizer ◽  
Mineral Nitrogen ◽  
Control Treatment ◽  
Mineral Fertilizers ◽  
Soil Parameters ◽  
Mineral N ◽  
Total N

A research study was established at the research farm of the University of Agriculture, Peshawar during winter 2018–2019. Commercial biochars were given to the experimental site from 2014 to summer 2018 and received 0.95, 130 and 60 tons ha−1 of biochar by various treatments viz., (Biochar1) BC1, (Biochar2) BC2, (Biochar3) BC3 and (Biochar4) BC4, respectively. This piece of work was conducted within the same study to find the long-term influence of biochar on the fertility of the soil, fixation of N2, as well as the yie1d of chickpea under a mung–chickpea cropping system. A split plot arrangement was carried out by RCBD (Randomized Complete Block Design) to evaluate the study. Twenty-five kilograms of N ha−1 were given as a starter dosage to every plot. Phosphorous and potassium were applied at two levels (half (45:30 kg ha−1) and full (90:60 kg ha−1) recommended doses) to each of the four biochar treatments. The chickpea crop parameters measured were the numbers and masses of the nodules, N2 fixation and grain yield. Soil parameters recorded were Soil Organic Matter (SOM), total N and mineral N. The aforementioned soil parameters were recorded after harvesting. The results showed that nodulation in chickpea, grain yield and nutrient uptake were significantly enhanced by phosphorous and potassium mineral fertilizers. The application of biochar 95 tons ha−1 significantly enhanced number of nodules i-e (122), however statistically similar response in terms of nodules number was also noted with treatment of 130 tons ha−1. The results further revealed a significant difference in terms of organic matter (OM) (%) between the half and full mineral fertilizer treatments. With the application of 130 tons ha−1 of biochar, the OM enhanced from 1.67% in the control treatment, to 2.59%. However, total and mineral nitrogen were not statistically enhanced by the mineral fertilizer treatment. With regard to biochar treatments, total and mineral N enhanced when compared with the control treatment. The highest total N of 0.082% and mineral nitrogen of 73 mg kg−1 in the soil were recorded at 130 tons ha−1 of biochar, while the lowest total N (0.049%) and mineral nitrogen (54 mg kg−1) in the soil were recorded in the control treatment. The collaborative influence of mineral fertilizers and biochars was found to be generally non-significant for most of the soil and plant parameters. It could be concluded that the aforementioned parameters were greater for treatments receiving biochar at 95 tons or more per hectare over the last several years, and that the combination of lower doses of mineral fertilizers further improved the performance of biochar.

Effect of superphosphate addition on N mineralization in some Australian forest soils

Soil Research ◽  
1993 ◽  
Vol 31 (3) ◽  
pp. 285 ◽  
Author(s):  
RA Falkiner ◽  
PK Khanna ◽  
RJ Raison
Keyword(s):  
Pinus Radiata ◽  
Forest Soils ◽  
N Mineralization ◽  
Net N Mineralization ◽  
Mineral N ◽  
Undisturbed Soil ◽  
Total N ◽  
Organic C ◽  
Forest Sites ◽  
P Content

Pinus radiata stands are reported to accumulate increased N on addition of phosphatic fertilizers. Field and laboratory studies were initiated to determine if addition of superphoshate increases soil N mineralization in forest soils. In a field experiment, application of 200 kg P ha-1 as superphosphate to trenched plots in a Pinus radiata stand increased accumulated soil mineral-N contents by 122% and 82% above the control on two occasions. Application of 500 kg P ha-1 as superphosphate either alone or in combination with lime (10 Mg ha-1) increased in situ soil net N mineralization in a dry sclerophyll eucalypt forest from 20.7 (control) to 28.3 (+P) and 30.2 (+P+lime) kg N ha-1 yr-1 20 cm-1. Uptake by the vegetation accounted for all of the mineralized nitrogen. In a 180 day laboratory incubation using undisturbed soil columns (0-20 cm) from nine forest sites, seven soils showed a positive response to superphosphate (100 kg P ha-1) addition, with increases in N mineralization ranging from 14% to 117%. The response of N mineralization to superphosphate addition was not related to initial soil organic C, total N or P content in the 0-20 cm layer. However, soil pH and organic C combined to account for 76% of the variation in N mineralization response (P < 0.01). In the 0-5 cm layer of untreated soils, soil organic P content could explain 71% of the variation in net N mineralization. Addition of superphosphate appears to increase N mineralization in several Australian forest soils and the improved availability of N will enhance tree growth rates. The mechanisms underlying the response are still poorly understood and thus also our ability to predict its significance for tree nutrition on specific forest sites.

scholarly journals Effects of green-manure and tillage management on soil microbial community composition, nutrients and tree growth in a walnut orchard

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ningguang Dong ◽  
Guanglong Hu ◽  
Yunqi Zhang ◽  
Jianxun Qi ◽  
Yonghao Chen ◽  
...  
Keyword(s):  
Microbial Community ◽  
Green Manure ◽  
Rhizosphere Soil ◽  
Green Manures ◽  
Hairy Vetch ◽  
Mineral N ◽  
Total N ◽  
Organic C ◽  
Nutrient Contents ◽  
Walnut Tree

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.

Sulfur forms in bulk soils and alkaline soil extracts of tropical mountain ecosystems in northern Thailand

Soil Research ◽  
2002 ◽  
Vol 40 (1) ◽  
pp. 161 ◽  
Author(s):  
A. Möller ◽  
K. Kaiser ◽  
N. Kanchanakool ◽  
C. Anecksamphant ◽  
W. Jirasuktaveekul ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Tropical Soils ◽  
Forest Site ◽  
Alkaline Soil ◽  
Northern Thailand ◽  
Total N ◽  
Soil Extracts ◽  
Organic C ◽  
Organic S

Sulfur, besides phosphorus, is crucial for the nutrition of plants on tropical soils. Its availability is closely related to the turnover of soil organic matter. To get a better insight into transformation of soil S forms during the decomposition of organic matter, we studied inorganic and organic S pools in bulk samples and alkaline extracts of soils under different land uses representative of the tropical highlands of northern Thailand. Samples were taken from a cabbage cultivation, a Pinus reforestation, a secondary forest, and a primary forest. Total S ranged from 483 549 mg&sol;kg in the subsoil to 1909 376 mg&sol;kg in the organic layers, which is relatively high for tropical soils. The major S component in soil was organic S, comprising 75–99&percnt; of total S. Organic S was significantly correlated with total S, organic C, and total N, indicating that there is a close relationship between C, N, and S cycling in soil. C-bonded S was the predominant form in the topsoils (35–99&percnt; of total S) but its presence decreased with soil depth. The maximum concentrations of ester SO4-S were found in the A horizons (128 49 mg&sol;kg), whereas the concentrations of inorganic SO4-S were small in all horizons. Compared with the forest site, the cabbage cultivation site was strongly depleted in S. C-bonded S was more depleted than ester SO4-S. A comparison of the S forms in NaOH extracts with S forms in bulk soil and C forms as indicated by 13C-NMR spectroscopy showed (i) that the extracts were very representative of soil organic S fractions and (ii) that ester SO4-S was mainly associated with O-substituted aliphatic C. In contrast, C-bonded S seemed to be connected to more-or-less all C binding types. transformation of soil organic matter, sulfate.

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 Integrated Nutrient Management of an Acid Paddy Soil in Karang Tanjung Village, Padang Ratu, Central Lampung

2017 ◽  
Vol 22 (2) ◽  
pp. 97-106
Author(s):  
Antonius Kasno ◽  
Irawan Irawan ◽  
Husnain Husnain ◽  
Sri Rochayati
Keyword(s):  
Organic Matter ◽  
Nutrient Management ◽  
Soil Nutrient ◽  
Nutrient Status ◽  
Inorganic Fertilizer ◽  
Soil Nutrient Status ◽  
Inorganic Fertilizers ◽  
Total N ◽  
Organic C ◽  
Set Up

Balanced fertilization is the key factor to improve the efficiency and effectiveness of fertilization.The dosage of inorganic fertilizers applied can be determined based on the nutrient status of P, K and rice productivity. The research aims to improve balance fertilization that combines inorganic fertilizers, which is set up based on soil nutrient status, and organic fertilizers. The research was conducted in Karang Tanjung Village, Padang Ratu District, Central Lampung, in the dry season of 2009 until 2012. An experimental plot of one hectare was set up in the farmer’s paddy fields. Generally, the plot for every treatment was owned by two or more farmers. The treatments consisted of the dose of fertilizer applications for lowland rice, namely (1) dose of fertilizers based on farmer practice, (2) dose of fertilizers proposed by Petrokimia, (3) 75% of fertilizer dose that was set up based on soil analysis plus straw compost, and (4) 75% of inorganic fertilizer combined with manure and biofertilizer. At the fourth growing season, each plot was applied with 100% inorganic fertilizer (NPK fertilizer). The results showed that the limiting factor of the soil used in the current study is the content of organic-C, N, K, and CEC. The compost of rice straw used as organic matter in the current study contains higher organic-C and total-N in comparison to manure. Organic matter application in the form of straw compost or manure can reduce 25% of NPK application, while the production of rice remains high. Fertilization on paddy soils based on soil nutrient status can improve fertilization efficiency. Rice production in the treatment of 100% NPK is similar to that in the fertilization treatments based on farmer practice and Petrokima rate. Keywords: Nutrient management, acid soil, fertilization efficiency

Free light fraction carbon and nitrogen, a physically uncomplexed soil organic matter distribution within subtropical grass and leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (8) ◽  
pp. 820 ◽  
Author(s):  
K. A. Conrad ◽  
R. C. Dalal ◽  
D. E. Allen ◽  
R. Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Depth ◽  
Light Fraction ◽  
Grass Species ◽  
Pasture Grass ◽  
Total N ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
C And N

Quantifying the size and turnover of physically uncomplexed soil organic matter (SOM) is crucial for the understanding of nutrient cycling and storage of soil organic carbon (SOC). However, the C and nitrogen (N) dynamics of SOM fractions in leucaena (Leucaena leucocephala)–grass pastures remains unclear. We assessed the potential of leucaena to sequester labile, free light fraction (fLF) C and N in soil by estimating the origin, quantity and vertical distribution of physically unprotected SOM. The soil from a chronosequence of seasonally grazed leucaena stands (0–40 years) was sampled to a depth of 0.2m and soil and fLF were analysed for organic C, N and δ13C and δ15N. On average, the fLF formed 20% of SOC and 14% of total N stocks in the upper 0.1m of soil from leucaena rows and showed a peak of fLF-C and fLF-N stocks in the 22-year-stand. The fLF δ13C and fLF δ15N values indicated that leucaena produced 37% of fLF-C and 28% of fLF-N in the upper 0.1m of soil from leucaena rows. Irrespective of pasture type or soil depth, the majority of fLF-C originated from the accompanying C4 pasture-grass species. This study suggests that fLF-C and fLF-N, the labile SOM, can form a significant portion of total SOM, especially in leucaena–grass pastures.

Soil nitrogen mineralisation and organic matter composition revealed by 13C NMR spectroscopy under repeated prescribed burning in eucalypt forests of south-east Queensland

Soil Research ◽  
1999 ◽  
Vol 37 (1) ◽  
pp. 123 ◽  
Author(s):  
D. F. Guinto ◽  
Z. H. Xu ◽  
P. G. Saffigna ◽  
A. P. N. House ◽  
M. C. S. Perera
Keyword(s):  
Organic Matter ◽  
Nmr Spectroscopy ◽  
13C Nmr ◽  
Prescribed Burning ◽  
13C Nmr Spectroscopy ◽  
High Ratio ◽  
N Mineralisation ◽  
Total N ◽  
Organic C ◽  
Organic Matter Composition

The effects of burning on in situ extractable nitrogen (NH+4-N+NO-3-N) and net Nmineralisation following scheduled fuel reduction burns in repeatedly burnt dry and wet sclerophyll forest sites in south-east Queensland were assessed. In addition, soil organic matter composition in the wet sclerophyll site was assessed by 13C NMR spectroscopy. The results showed that at the dry sclerophyll site, extractable N and net N mineralisation for 1 year were largely unaffected by burning, while at the wet sclerophyll site, these parameters decreased. 13C NMR analysis of soil samples from the wet sclerophyll site revealed that there was a significant reduction in the proportion of O-alkyl (alkoxy/carbohydrate) C with increasing burning frequency. Statistically significant effects on the other chemical shift regions were not detected. The ratio of alkyl C to O-alkyl C, a proposed index of organic matter decomposition, increased with increasing burning frequency. A high ratio of alkyl C to O-alkyl C suggests low amounts of carbohydrates relative to waxes and cutins, which could in turn lead to slower mineralisation. The findings are in accord with this hypothesis. There were significant linear relationships between cumulative N mineralisation for 1 year and the proportions of alkyl C and O-alkyl C, and the ratio of alkyl C/O-alkyl C. Thus, in addition to reductions in substrate quantity (low organic C and total N for burnt soils), there was also an alteration of substrate quality as revealed by 13C NMR spectroscopy which is reflected in low N mineralisation.

NO3- uptake and C exudation – do plant roots stimulate or inhibit denitrification?

2020 ◽  
Author(s):  
Pauline Sophie Rummel ◽  
Reinhard Well ◽  
Birgit Pfeiffer ◽  
Klaus Dittert ◽  
Sebastian Floßmann ◽  
...  
Keyword(s):  
Soil Moisture ◽  
N Uptake ◽  
Root Exudation ◽  
Soil Surface ◽  
N Fertilization ◽  
Plant N Uptake ◽  
Mineral N ◽  
Double Labeling ◽  
Total N ◽  
Organic C

&lt;p&gt;Growing plants affect soil moisture, mineral N and organic C (C&lt;sub&gt;org&lt;/sub&gt;) availability in soil and may thus play an important role in regulating denitrification. The availability of the main substrates for denitrification (C&lt;sub&gt;org&lt;/sub&gt; and NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;) is controlled by root activity and higher denitrification activity in rhizosphere soils has been reported. We hypothesized that (I) plant N uptake governs NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; availability for denitrification leading to increased N&lt;sub&gt;2&lt;/sub&gt;O and N&lt;sub&gt;2&lt;/sub&gt; emissions, when plant N uptake is low due to smaller root system or root senescence. (II) Denitrification is stimulated by higher C&lt;sub&gt;org&lt;/sub&gt; availability from root exudation or decaying roots increasing total gaseous N emissions while decreasing their N&lt;sub&gt;2&lt;/sub&gt;O/(N&lt;sub&gt;2&lt;/sub&gt;O+N&lt;sub&gt;2&lt;/sub&gt;) ratios.&lt;/p&gt;&lt;p&gt;We tested these assumptions in a double labeling pot experiment with maize (Zea mays L.) grown under three N fertilization levels S / M / L (no / moderate / high N fertilization) and with cup plant (Silphium perfoliatum L., moderate N fertilization). After 6 weeks, all plants were labeled with 0.1 g N kg&lt;sup&gt;-1&lt;/sup&gt; (Ca(&lt;sup&gt;15&lt;/sup&gt;NO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;, 60 at%), and the &lt;sup&gt;15&lt;/sup&gt;N tracer method was applied to estimate plant N uptake, N&lt;sub&gt;2&lt;/sub&gt;O and N&lt;sub&gt;2&lt;/sub&gt; emissions. To link denitrification with available C in the rhizosphere, &lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;2&lt;/sub&gt; pulse labeling (5 g Na&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;13&lt;/sup&gt;CO&lt;sub&gt;3&lt;/sub&gt;, 99 at%) was used to trace C translocation from shoots to roots and its release by roots into the soil. CO&lt;sub&gt;2&lt;/sub&gt; evolving from soil was trapped in NaOH for &amp;#948;&lt;sup&gt;13&lt;/sup&gt;C analyses, and gas samples were taken for analysis of N&lt;sub&gt;2&lt;/sub&gt;O and N&lt;sub&gt;2&lt;/sub&gt; from the headspace above the soil surface every 12 h.&lt;/p&gt;&lt;p&gt;Although pots were irrigated, changing soil moisture through differences in plant water uptake was the main factor controlling daily N&lt;sub&gt;2&lt;/sub&gt;O+N&lt;sub&gt;2&lt;/sub&gt; fluxes, cumulative N emissions, and N&lt;sub&gt;2&lt;/sub&gt;O production pathways. In addition, total N&lt;sub&gt;2&lt;/sub&gt;O+N&lt;sub&gt;2&lt;/sub&gt; emissions were negatively correlated with plant N uptake and positively with soil N concentrations. Recently assimilated C released by roots (&lt;sup&gt;13&lt;/sup&gt;C) was positively correlated with root dry matter, but we could not detect any relationship with cumulative N emissions. We anticipate that higher C&lt;sub&gt;org&lt;/sub&gt; availability in pots with large root systems did not lead to higher denitrification rates as NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; was limited due to plant uptake. In conclusion, plant growth controlled water and NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt; uptake and, subsequently, formation of anaerobic hotspots for denitrification.&lt;/p&gt;

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