Soil organic matter is stabilized by organo-mineral associations through two key processes: The role of the carbon to nitrogen ratio

Geoderma ◽  
2020 ◽  
Vol 357 ◽  
pp. 113974 ◽  
Author(s):  
Peter M. Kopittke ◽  
Ram C. Dalal ◽  
Carmen Hoeschen ◽  
Cui Li ◽  
Neal W. Menzies ◽  
...  
Author(s):  
Patarapong Kroeksakul ◽  
Arin Ngamniyom ◽  
Kun Silprasit ◽  
Sakawjai Tepamongkol ◽  
Punnada Teerapanaprinya ◽  
...  

The study aimed to evaluate and correlate acidic soil components to understand the phenomena of this type of soil. The soil samples were collected from 64 locations in 3 provinces of central Thailand and were tested for soil pH, element content, soil organic matter (SOM), and soil organic carbon (SOC). The results show that soil acidity in central Thailand has an average pH of 4.71 ± 0.87. The soil acidity level ranges from very strongly acidic in Phatum Thani and Nakhon Nayok provinces to strongly acidic in Chachoengsao province. Soil bulk density is about 0.34 g/cm3, and the correlation of soil pH to lead (Pb), nickel (Ni), nitrogen (N), carbon-to-nitrogen ratio (C/N ratio), and zinc (Zn) is as follows: principle component 1 (PC1) is carbon-to-nitrogen ratio > pH > zinc (C/N ratio > pH > Zn), and principle component 2 (PC2) is soil organic carbon > bulk density > soil organic matter (SOC > BD > SOM). Soil pH, SOM, and SOC are in similar groups. The soil abundance at the study site was compared with the ideal soil for plants, and heavy metal contamination in the acidic soil of the central region did not exceed the standard limit. The study found a correlation between SOM and SOM (r = 0.715; p < 0.01), indicating soil quality and microbial activity.


Author(s):  
Xiaomeng Wei ◽  
Tida Ge ◽  
Chuanfa Wu ◽  
Shuang Wang ◽  
Kyle Mason-Jones ◽  
...  

1999 ◽  
Vol 79 (1) ◽  
pp. 103-109 ◽  
Author(s):  
F. Courchesne ◽  
J.-F. Laberge ◽  
A. Dufresne

The role of soil organic matter (OM) on SO4 retention was investigated by comparing OM content, SO4 retention, and the distribution of Fe, Al and Si compounds in OM-poor (Grands-Jardins, PGJ) and OM-rich (Hermine, HER) Podzols from Québec, Canada. At both sites, four pedons were sampled by horizon; soil pH in H2O, organic C, phosphate-extractable SO4 and, sodium pyrophosphate, acid ammonium oxalate and dithionite-citrate-bicarbonate (DCB) extractable Fe, Al and Si were measured for each mineral horizon. The mineralogy of the clay (<2 µm) and fine silt (2–20 µm) fractions of selected horizons was determined by X-ray diffraction (XRD) and infrared spectroscopy (IR). Weighted mean organic C and pyrophosphate extractable Fe and Al contents were significantly higher in the HER than in the PGJ sola, while the PGJ soils were richer in amorphous inorganic Al. No trends were observed for inorganic Fe compounds. Chemical dissolution and IR allowed the identification of short-range ordered aluminosilicates, probably allophane, in the OM-poor and slightly acidic to neutral PGJ soils. These materials were absent from the OM-rich and acidic HER soils. Phosphate extractions showed that the weighted mean native SO4 content was five times higher in the PGJ than in the HER soil. Finally, native SO4 was strongly related to inorganic Fe, Al and Si (associated with allophane) at PGJ but only to inorganic Fe at HER. These results indicate that OM indirectly affects SO4 sorption through the influence organic substances exerts on the nature and distribution of pedogenic Fe, Al and Si compounds, such as allophane, in Podzolic profiles. Key words: Organic matter, sulfate, imogolite, allophane, silica, Podzol


Perspektif ◽  
2016 ◽  
Vol 14 (1) ◽  
pp. 61
Author(s):  
Djajadi Djajadi

<p class="Default">ABSTRACT</p><p class="Default">Organik matter has an important role in determining soil health of sugarcane, i.e. soil capacity to support sugarcane to produce sustainable high yield. Soil organic matter influences soil physical, chemical, and biological properties, so that a consequence of declining soil organic matter is poorer soil fertility and lower yield. This paper has an objective to elucidate the important role of organic matter on sustainable farming of sugarcane. The important role of organic matter in soil fertility has been known for a long time before Green Revolution concept was introduced. With more intensity in sugarcane farming and more increasing of sugar demand, application of organic fertilizer started to be substituted by chemical fertilizer. Using green manure and/or biofertilizer has a chance to be spread out to the farmers due to more practical and more efficient than solid organik fertilizer, such as dung manure or compost. Future research should be focusing on the efectivity of green manure and or biofertilzer sources in improving soil fertility and cane yield, minimizing soil pathogen, reducing soil erosion of sugar cane land monoculture, and improving awareness of farmers about soil degradation as consequences of sugarcane monoculture planting for years.</p><p class="Default">Keywords: Organic matter, sugarcane, soil health sustainable farming</p><p class="Default"> </p><p class="Default"><strong>Bahan Organik: Peranannya dalam Budidaya Tebu Berkelanjutan</strong></p><p class="Default">ABSTRAK</p><p class="Default">Bahan organik tanah berperan penting dalam menentukan kesehatan tanah tebu, yaitu kapasitas tanah yang dapat mendukung produksi tebu yang tinggi secara berkelanjutan. Kadar bahan organik tanah mempengaruhi sifat fisik, kimia dan biologi tanah. Paper ini bertujuan untuk menguraikan tentang peranan bahan organik dalam memperbaiki sifat fisik, kimia dan biologi tanah pertanaman tebu. Pentingnya peran bahan oganik tersebut sudah disadari dari dulu, sehingga sebelum revolusi hijau penggunaan pupuk organik sudah umum dilakukan petani. Dengan semakin intensifnya budidaya tebu dan semakin meningkatnya kebutuhan gula, pemanfaatan pupuk organik sudah jarang dilakukan. Diperlukan usaha untuk meningkatkan dan mempertahankan kadar bahan organik pada lahan tebu, antara lain berupa gerakan masal dalam bentuk gerakan nasional melalui program aplikasi bahan organik. Pemanfaatan pupuk hijau dan/atau pupuk hayati berpeluang untuk diterapkan karena lebih praktis dan efisien daripada penambahan pupuk organik padat. Penelitian ke depan perlu difokuskan untuk mengkaji jenis-jenis pupuk organik dan pupuk hayati yang efektif memperbaiki kesuburan, dalam menekan serangan penyakit, meminimalkan erosi pada lahan-lahan tebu monokultur, dan meningkatkan kesadaran petani tebu tentang terjadinya degradasi lahan akibat penanaman tebu yang terus menerus.</p><p class="Default">Kata kunci: Bahan organik, tebu, kesehatan tanah, budidaya berkelanjutan</p><p class="Default"> </p>


2019 ◽  
Vol 85 (10) ◽  
Author(s):  
Tao Wang ◽  
Zhaomo Tian ◽  
Anders Tunlid ◽  
Per Persson

ABSTRACT The interactions between dissolved organic matter (DOM) and mineral particles are critical for the stabilization of soil organic matter (SOM) in terrestrial ecosystems. The processing of DOM by ectomycorrhizal fungi contributes to the formation of mineral-stabilized SOM by two contrasting pathways: the extracellular transformation of DOM (ex vivo pathway) and the secretion of mineral-surface-reactive metabolites (in vivo pathway). In this study, we examined how changes in nitrogen (N) availability affected the formation of mineral-associated carbon (C) from these two pathways. DOM was extracted from forest soils. The processing of this DOM by the ectomycorrhizal fungus Paxillus involutus was examined in laboratory-scale studies with different levels of ammonium. At low levels of ammonium (i.e., under N-limited conditions), the DOM components were slightly oxidized, and fungal C metabolites with iron-reducing activity were secreted. Ammonium amendments decreased the amount of C metabolites, and no additional oxidation of the organic matter was detected. In contrast, the hydrolytic activity and the secretion of N-containing compounds increased, particularly when high levels of ammonium were added. Under these conditions, C, but not N, limited fungal growth. Although the overall production of mineral-associated organic C was not affected by ammonium concentrations, the observed shifts in the activities of the ex vivo and in vivo pathways affected the composition of organic matter adsorbed onto the mineral particles. Such changes will affect the properties of organic matter-mineral associations and, thus, ultimately, the stabilization of SOM. IMPORTANCE Nitrogen (N) availability plays a critical role in the cycling and storage of soil organic matter (SOM). However, large uncertainties remain in predicting the net effect of N addition on soil organic carbon (C) storage due to the complex interactions between organic matter, microbial activity, and mineral particles that determine the formation of stable SOM. Here, we attempted to disentangle the effects of ammonium on these interactions in controlled microcosm experiments including the ectomycorrhizal fungus P.involutus and dissolved organic matter extracted from forest soils. Increased ammonium levels affected the fungal processing of the organic material as well as the secretion of extracellular metabolites. Although ammonium additions did not increase the net production of mineral-adsorbed C, changes in the decomposition and secretion pathways altered the composition of the adsorbed organic matter. These changes may influence the properties of the organic matter-mineral associations and, thus, the stabilization of SOM.


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