Carbon In Different Fractions Research Articles

Predicting the Stability of Organic Matter Originating from Different Waste Treatment Procedures.

Recycling organic wastes into farmland faces a double challenge: increasing the carbon storage of soil while mitigating CO2 emission from soil. Predicting the stability of organic matter (OM) in wastes and treatment products can be helpful in dealing with this contradiction. This work proposed a modeling approach integrating an OM characterization protocol into partial least squares (PLS) regression. A total of 31 organic wastes, and their products issued from anaerobic digestion, composting, and digestion-composting treatment were characterized using sequential extraction and three-dimension (3D) fluorescence spectroscopy. The apportionment of carbon in different fractions and fluorescence spectra revealed that the OM became less accessible and biodegradable after treatments, especially the composting. This was proven by the decrease in CO2 emission from soil incubation. The PLS model successfully predicted the stability of solid digestate, compost, and compost of solid digestate in the soil by using only the characterized variables of non-treated wastes. The results suggested that it would be possible to predict the stability of OM from organic wastes after different treatment procedures. It is helpful to choose the most suitable and economic treatment procedure to stabilize labile organic carbon in wastes and hence minimize CO2 emission after the application of treatment products to the soil.

Сравнительная структура углеродного пула в надземной фитомассе культур сосны и ели

Forests are the active stabilizers of the carbon cycle. Therefore, the global academic com-munity pays a great attention to the study of carbon deposit function of forest lands. Progress in the accuracy of carbon stock estimates can be achieved through the creation of a database on carbon stocks in phytomass of forest areas. Periodic researches of Scots pine and Norway spruce crops are carried out in Arkhangelsk region in order to determine the accumulated carbon in different fractions of above-ground phytomass. It has been found that 36-years-old pine crops phytocenosis accumulate carbon 4 times more actively (119.3 t/ha) than spruce crops phytocenosis (30.08 t/ha). Deposited carbon stocks increase with plants growth, regardless of breed, in all above-ground phytomass fractions. The largest share of carbon accumulation was observed in the stem wood fraction both in pine and spruce plantations. The second largest carbon deposit fraction in spruce crops is leaves and branches; in pine crops – branches. The lowest share of carbon pool is concentrated in the fraction of pine dead branches (4.3 %), and spruce branches (4.4 %). A set of experimental data on carbon pool in forest crops will give a boost to the database formation of carbon stocks in the above-ground phytomass of forests; which must be considered in assessing the ecological functions of forests and organization of effective measures for the forest resources rational use.For citation: Sungurova N.R., Khudyakov V.V., Strazdauskas S.E. Comparative Carbon Pool Structure in Above-Ground Phytomass of Pine and Spruce Crops. Lesnoy Zhurnal [Forestry Journal], 2019, no. 3, pp. 159–165. DOI: 10.17238/issn0536-1036.2019.3.159

Climate‐sensitive ecosystem carbon dynamics along the soil chronosequence of the Damma glacier forefield, Switzerland

AbstractWe performed a detailed study on the carbon build‐up over the 140‐year‐long chronosequence of the Damma glacier forefield, Switzerland, to gain insights into the organic carbon dynamics during the initial stage of soil formation and ecosystem development. We determined soil carbon and nitrogen contents and their stable isotopic compositions, as well as molecular‐level composition of the bulk soils, and recalcitrance parameters of carbon in different fractions. The chronosequence was divided into three age groups, separated by small end moraines that resulted from two glacier re‐advances. The net ecosystem carbon balance (NECB) showed an exponential increase over the last decades, with mean annual values that range from 100 g C m−2 yr−1 in the youngest part to over 300 g C m−2 yr−1 in a 60–80 years old part. However, over the entire 140‐year chronosequence, the NECB is only 20 g C m−2 yr−1, similar to results of other glacier forefield studies. The difference between the short‐ and long‐term NECB appears to be caused by reductions in ecosystem carbon (EC) accumulation during periods with a colder climate. We propose that two complementary mechanisms have been responsible: 1) Reductions in net primary productivity down to 50% below the long‐term mean, which we estimated using reconstructed effective temperature sums. 2) Disturbance of sites near the terminus of the re‐advanced glacier front. Stabilization of soil organic matter appeared to play only a minor role in the coarse‐grained forefield. We conclude that the forefield ecosystem, especially primary productivity, reacts rapidly to climate changes. The EC gained at warm periods is easily lost again in a cooling climate. Our conclusions may also be valid for other high mountain ecosystems and possibly arctic ecosystems.

Quantificação do carbono das substâncias húmicas em diferentes sistemas de uso do solo e épocas de avaliação

A quantificação do carbono nas diferentes frações da matéria orgânica do solo (MOS) torna-se necessária devido ao interesse de se conhecer o potencial de captura e armazenamento do carbono nos diferentes sistemas de uso do solo. O objetivo deste trabalho foi quantificar o carbono das substâncias húmicas em diferentes sistemas de uso do solo e épocas de avaliação e correlacioná-lo com algumas propriedades químicas e físicas do solo. Os sistemas selecionados foram: preparo convencional (PC-milho/feijão), plantio direto (PD-berinjela/milho), consórcio maracujá/Desmodium sp, cultivo com figo e sistema agroflorestal. As amostras de solo foram coletadas em duas profundidades (0-5 e 5-10 cm) e épocas (17/11/2005-verão e 23/6/2006-inverno). Foi determinado o carbono orgânico total (COT) e realizado o fracionamento químico da MOS, quantificando-se o carbono da fração humina (C-HUM), fração ácido húmico (C-FAH) e fração ácido fúlvico (C-FAF). O C-HUM constituiu a maior parte do COT, havendo correlação significativa com o COT em todos os sistemas avaliados e estações. Analisando o C-FAH foi possível identificar alterações no solo relacionadas aos sistemas de uso, na profundidade de 0-5 cm e no verão, destacando-se o PD com os maiores teores. Com o C-FAF ocorreu este mesmo comportamento, mas na profundidade de 5-10 cm e no inverno, destacando-se o PC com maiores valores. Foram verificadas correlações significativas entre Valor S, Valor T e DMP em todos os sistemas, com exceção da área de PC. O PD aumenta os teores de C-FAH, nas duas profundidades e nas duas estações, quando comparado ao PC do solo.

Influence of a carbamate pesticide on growth, respiration (14C)-carbon metabolism and symbiosis of aRhizobium sp.

Addition of aldicarb (2 methyl-2(methyl thio) propionaldehyde-0-methyl carbamoyl oxime) in the growth medium enhanced the growth ofRhizobium sp. (cowpea group) at 2 ppm level while an inhibition was observed at the normal (5 ppm) and higher (10 ppm) concentrations. Respiration of the cells was also inhibited by 5 and 10 ppm levels of the chemical eventhough a stimulation was observed at 2 ppm (lower) concentration. The insecticide, when incorporated at 5 and 10 ppm levels in the medium increased the14C-glucose incorporation and considerably altered the assimilation of the radioactive carbon in different fractions of rhizobium cells. Soil application of this insecticide (Temik 10 G) reduced the number of nodules formed and the total nitrogen content in cowpea plants inoculated with theRhizobium sp. but enhanced the dry matter production of cowpea plants.