Studies on decomposition of humus in clay-humus complexes
TL;DR: In this article, it has been observed that smaller and more flexible humic molecules are less susceptible to the said decomposition as compared to larger and more rigid structures, and that such decomposition decreases at higher clay concentrations.
Abstract: Decomposition studies with humic acids (HAs) present in HA-clay complexes revealed that such decomposition decreases at higher clay concentrations. At high clay concentration, moreover, it has also been observed that smaller and more flexible humic molecules are less susceptible to the said decomposition as compared to larger and more rigid structures.
Citations
More filters
TL;DR: In this article, Soil organic carbon (SOC), total and plant available soil nutrient stocks and nutrient balances were investigated to assess temporal soil nutrient dynamics in relation to management activities in the Southern Ecuadorian Andes.
25 citations
TL;DR: In this paper, the authors studied the composition and organic carbon distribution of organomineral complexes in a black soil under different land uses and management by means of ultrasonic dispersion and particle assortment.
Abstract: Organomineral complexes form the basis of soil fertility and have significant effects on the soil environment. In this research, we aimed to study the composition and organic carbon (C) distribution of organomineral complexes in a black soil under different land uses and management by means of ultrasonic dispersion and particle assortment. The results showed that the fine sand–size complex (20–200 μm) was dominant under different land uses and management. Silt-size (2–20 μm) and fine sand-size content increased with nitrogen and phosphorus application (NP) and NPM (NP together with organic manure) treatment, whereas clay-size (0–2 μm) content decreased. The content of 20-μm complex showed the opposite trend. The silt-size content increased with the increase of SOC (soil organic C). A negative relationship was observed between the clay-size complex content and SOC content. Land-use change resulted in different dynamics in C sequestration...
11 citations
Cites background from "Studies on decomposition of humus i..."
...Christensen (1987) performed an aerobic incubation experiment and observed that SOM degraded in the order sand > clay > whole soil > silt....
[...]
TL;DR: In this article , the effect of conservation agriculture on soil humic acid content and their stability and abundance of functional groups was investigated using Fourier Transform Infrared (FTIR) spectroscopy under different scenarios.
Abstract: Recently conservation agriculture (CA) using the principles of zero tillage, crop residue management and suitable crop rotation has gained the momentum and quite popular among the farmers. Researchers throughout the globe have shown the potential of CA in enriching soil organic carbon storage in various soil types and cropping systems. But there is very limited study on the effect of CA on soil humic acid content and their stability and abundance of functional groups. An experiment was conducted in an Alfisols with four scenarios (designated as Sc) namely conventional farmers practice (Sc1) of transplanted rice (TPR) followed by conventional tilled broadcasted wheat (CT- wheat) with residue removal, transplanted rice (TPR) followed by zero tillage (ZT) wheat and mung bean with partial residue retention (Sc2), direct seeded rice (DSR) followed by ZT- wheat and mung bean with full residue retention (Sc3), ZT-maize followed by ZT-wheat and mung bean (Sc4) at the research farm of ICAR-Central Soil Salinity Research Institute, Karnal, Haryana, India. The objectives of this study were to assess the humic acid (HA) content and stability of soil carbon through desorption study and to characterize the functional groups of HA by Fourier Transform Infrared (FTIR) spectroscopy under different scenarios. HA was extracted from soil samples collected from 0 to 15 and 15–30 cm depth after rice harvesting in 2018 after nine years of the experiment. Results showed that Sc4 recorded significantly highest HA content at 0–15 depth (4.23 g/kg) and 15–30 cm soil depth (2.08 g/kg). Lower E4/E6 ratio revealed higher stability and humification of humic acid carbon under CA based scenarios. Lowest desorption rate constant (0.20/day) was observed under Sc4 indicating higher organic carbon stability in soil. Higher labile carbon and nitrogen was observed in soils under Sc3 as revealed through desorption study. FTIR spectroscopy results confirmed the prevalence of higher number of functional groups (O C O, C O or CHO) in HA under CA based scenarios with an order of Sc4 >Sc3 >Sc2 >Sc1. Therefore, CA is not only efficient in enriching the organic carbon in soil but also in more stable complex of HA with soil particles having long term implications in soil carbon sequestration for future posterity. • Conservation agriculture (CA) effects on humic acid (HA) content and behaviour was studied. • CA based maize-wheat-mungbean showed highest HA content. • Desorption study reflected higher stable carbon under CA based maize system. • FTIR spectroscopy reveals complex functional groups in HA under CA based systems. • CA has potential to store more carbon in stable forms compared to conventional agriculture.
7 citations
TL;DR: In this paper, a study on the effect of conservation agriculture on soil humic acid content and their stability and abundance of functional groups was conducted in an ICAR-Central Soil Salinity Research Institute, Karnal, Haryana, India.
Abstract: Recently conservation agriculture (CA) using the principles of zero tillage, crop residue management and suitable crop rotation has gained the momentum and quite popular among the farmers. Researchers throughout the globe have shown the potential of CA in enriching soil organic carbon storage in various soil types and cropping systems. But there is very limited study on the effect of CA on soil humic acid content and their stability and abundance of functional groups. An experiment was conducted in an Alfisols with four scenarios (designated as Sc) namely conventional farmers practice (Sc1) of transplanted rice (TPR) followed by conventional tilled broadcasted wheat (CT- wheat) with residue removal, transplanted rice (TPR) followed by zero tillage (ZT) wheat and mung bean with partial residue retention (Sc2), direct seeded rice (DSR) followed by ZT- wheat and mung bean with full residue retention (Sc3), ZT-maize followed by ZT-wheat and mung bean (Sc4) at the research farm of ICAR-Central Soil Salinity Research Institute, Karnal, Haryana, India. The objectives of this study were to assess the humic acid (HA) content and stability of soil carbon through desorption study and to characterize the functional groups of HA by Fourier Transform Infrared (FTIR) spectroscopy under different scenarios. HA was extracted from soil samples collected from 0 to 15 and 15–30 cm depth after rice harvesting in 2018 after nine years of the experiment. Results showed that Sc4 recorded significantly highest HA content at 0–15 depth (4.23 g/kg) and 15–30 cm soil depth (2.08 g/kg). Lower E4/E6 ratio revealed higher stability and humification of humic acid carbon under CA based scenarios. Lowest desorption rate constant (0.20/day) was observed under Sc4 indicating higher organic carbon stability in soil. Higher labile carbon and nitrogen was observed in soils under Sc3 as revealed through desorption study. FTIR spectroscopy results confirmed the prevalence of higher number of functional groups (O C O, C O or CHO) in HA under CA based scenarios with an order of Sc4 >Sc3 >Sc2 >Sc1. Therefore, CA is not only efficient in enriching the organic carbon in soil but also in more stable complex of HA with soil particles having long term implications in soil carbon sequestration for future posterity.
7 citations
TL;DR: In this paper, a chemical method based on batch desorption of adsorbed humus on clay-humus complex by sodium hydroxide-sodium pyrophosphate solution was used to assess the stability of humus C through the Desorption rate constant using simple first order exponential equation in a toposequence of Western Himalaya region of India.
Abstract: A chemical method based on batch desorption of adsorbed humus on clay-humus complex by sodium hydroxide-sodium pyrophosphate solution was used to assess the stability of humus C through the desorption rate constant using simple first order exponential equation in a toposequence of Western Himalaya region of India. The rate constant values were significantly (p < 0.0001) higher in hill top (0.305 day−1) and narrow valley (0.184 day−1) than side slope (0.125 day−1) and broad valley (0.11 day−1) suggesting higher stability of soil C in side slope and broad valley. This variation implies that clay particles are active in binding humus C and soil texture plays an important role in stabilizing soil C.
3 citations
References
More filters
01 Jan 1975
TL;DR: The processes of humification occur mainly under aerobic conditions as mentioned in this paper, where animals that live in the soil may initially reduce the size of the fresh organic residues, and further transformations are promoted by the activity of the enzymes of the bacteria and fungi living in soil.
Abstract: The processes of humification occur mainly under aerobic conditions. Animals that live in the soil may initially reduce the size of the fresh organic residues. Further transformations are promoted by the activity of the enzymes of bacteria and fungi living in the soil. Cellulose, proteins and fats are readily available carbon sources for the microorganisms, whereas such compounds as lignin and other phenolic plant constituents are decomposed more slowly. These, as well as some of the new substances that are formed through oxidation of phenolic units, are toxic to different degrees. They can therefore serve as carbon sources only for special species of microorganisms. Besides the organic residue derived from higher animals and plants, many substances synthesized by microorganisms can serve as carbon sources.
406 citations
Book•
01 Jan 1973
TL;DR: The fundamental principles of bacteriology are studied in detail in the context of drug discovery and their applications in medicine and bacteriology.
Abstract: Fundamental principles of bacteriology , Fundamental principles of bacteriology , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
128 citations
42 citations