Response of soil nitrogen retention to the interactive effects of soil texture, hydrology, and organic matter

The content of organic matter in the soil, its labile (hot water extractable carbon–HWEC) and stable (soil organic carbon–SOC) form is a fundamental factor affecting soil productivity and health. The current research in soil organic matter (SOM) is focused on individual fragmented approaches and comprehensive evaluation of HWEC and SOC changes. The present state of the soil together with soil’s management practices are usually monitoring today but there has not been any common model for both that has been published. Our approach should help to assess the changes in HWEC and SOC content depending on the physico-chemical properties and soil´s management practices (e.g., digestate application, livestock and mineral fertilisers, post-harvest residues, etc.). The one- and multidimensional linear regressions were used. Data were obtained from the various soil´s climatic conditions (68 localities) of the Czech Republic. The Czech farms in operating conditions were observed during the period 2008–2018. The obtained results of ll monitored experimental sites showed increasing in the SOC content, while the HWEC content has decreased. Furthermore, a decline in pH and soil´s saturation was documented by regression modelling. Mainly digestate application was responsible for this negative consequence across all soils in studied climatic regions. The multivariate linear regression models (MLR) also showed that HWEC content is significantly affected by natural soil fertility (soil type), phosphorus content (−30%), digestate application (+29%), saturation of the soil sorption complex (SEBCT, 21%) and the dose of total nitrogen (N) applied into the soil (−20%). Here we report that the labile forms (HWEC) are affected by the application of digestate (15%), the soil saturation (37%), the application of mineral potassium (−7%), soil pH (−14%) and the overall condition of the soil (−27%). The stable components (SOM) are affected by the content of HWEC (17%), soil texture 0.01–0.001mm (10%), and input of organic matter and nutrients from animal production (10%). Results also showed that the mineral fertilization has a negative effect (−14%), together with the soil depth (−11%), and the soil texture 0.25–2 mm (−21%) on SOM. Using modern statistical procedures (MRLs) it was confirmed that SOM plays an important role in maintaining resp. improving soil physical, biochemical and biological properties, which is particularly important to ensure the productivity of agroecosystems (soil quality and health) and to future food security.

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DOM degradation by light and microbes along the Yukon River-coastal ocean continuum

Scientific Reports ◽

10.1038/s41598-021-89327-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Brice K. Grunert ◽

Maria Tzortziou ◽

Patrick Neale ◽

Alana Menendez ◽

Peter Hernes

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Salinity Gradient ◽

Coastal Ocean ◽

Interactive Effects ◽

The Arctic ◽

Yukon River ◽

Spring Freshet ◽

Dom Composition

AbstractThe Arctic is experiencing rapid warming, resulting in fundamental shifts in hydrologic connectivity and carbon cycling. Dissolved organic matter (DOM) is a significant component of the Arctic and global carbon cycle, and significant perturbations to DOM cycling are expected with Arctic warming. The impact of photochemical and microbial degradation, and their interactive effects, on DOM composition and remineralization have been documented in Arctic soils and rivers. However, the role of microbes, sunlight and their interactions on Arctic DOM alteration and remineralization in the coastal ocean has not been considered, particularly during the spring freshet when DOM loads are high, photoexposure can be quite limited and residence time within river networks is low. Here, we collected DOM samples along a salinity gradient in the Yukon River delta, plume and coastal ocean during peak river discharge immediately after spring freshet and explored the role of UV exposure, microbial transformations and interactive effects on DOM quantity and composition. Our results show: (1) photochemical alteration of DOM significantly shifts processing pathways of terrestrial DOM, including increasing relative humification of DOM by microbes by > 10%; (2) microbes produce humic-like material that is not optically distinguishable from terrestrial humics; and (3) size-fractionation of the microbial community indicates a size-dependent role for DOM remineralization and humification of DOM observed through modeled PARAFAC components of fluorescent DOM, either through direct or community effects. Field observations indicate apparent conservative mixing along the salinity gradient; however, changing photochemical and microbial alteration of DOM with increasing salinity indicate changing DOM composition likely due to microbial activity. Finally, our findings show potential for rapid transformation of DOM in the coastal ocean from photochemical and microbial alteration, with microbes responsible for the majority of dissolved organic matter remineralization.

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Application methods influence biochar‐fertilizer interactive effects on soil nitrogen dynamics

Soil Science Society of America Journal ◽

10.1002/saj2.20170 ◽

2020 ◽

Author(s):

Xiuwen Li ◽

Avishesh Neupane ◽

Sutie Xu ◽

Nourredine Abdoulmoumine ◽

Jennifer M. DeBruyn ◽

...

Keyword(s):

Soil Nitrogen ◽

Nitrogen Dynamics ◽

Interactive Effects ◽

Soil Nitrogen Dynamics ◽

Application Methods

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Soil texture affects the coupling of litter decomposition and soil organic matter formation

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2021.108302 ◽

2021 ◽

pp. 108302

Author(s):

Gerrit Angst ◽

Jan Pokorný ◽

Carsten W. Mueller ◽

Isabel Prater ◽

Sebastian Preusser ◽

...

Keyword(s):

Organic Matter ◽

Soil Organic Matter ◽

Litter Decomposition ◽

Soil Texture ◽

Soil Organic Matter Formation

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Soil Texture Alters the Impact of Salinity on Carbon Mineralization

Agronomy ◽

10.3390/agronomy11010128 ◽

2021 ◽

Vol 11 (1) ◽

pp. 128

Author(s):

Ruihuan She ◽

Yongxiang Yu ◽

Chaorong Ge ◽

Huaiying Yao

Keyword(s):

Soil Texture ◽

Clay Soil ◽

Sandy Loam ◽

Microbial Community Composition ◽

Clay Content ◽

Interactive Effects ◽

Silty Clay ◽

C Mineralization ◽

Negative Effect ◽

Silty Clay Soil

Soil salinization typically inhibits the ability of decomposer organisms to utilize soil organic matter, and an increase in soil clay content can mediate the negative effect of salinity on carbon (C) mineralization. However, the interactive effects of soil salt concentrations and properties on C mineralization remain uncertain. In this study, a laboratory experiment was performed to investigate the interactive effects of soil salt content (0.1%, 0.3%, 0.6% and 1.0%) and texture (sandy loam, sandy clay loam and silty clay soil with 6.0%, 23.9% and 40.6% clay content, respectively) on C mineralization and microbial community composition after cotton straw addition. With increasing soil salinity, carbon dioxide (CO2) emissions from the three soils decreased, but the effect of soil salinity on the decomposition of soil organic carbon varied with soil texture. Cumulative CO2 emissions in the coarse-textured (sandy loam and sandy clay loam) soils were more affected by salinity than those in the fine-textured (silty clay) soil. This difference was probably due to the differing responses of labile and resistant organic compounds to salinity across different soil texture. Increased salinity decreased the decomposition of the stable C pool in the coarse-textured soil, by reducing the proportion of fungi to bacteria, whereas it decreased the mineralization of the active C pool in the fine-textured soil through decreasing the Gram-positive bacterial population. Overall, our results suggest that soil texture controlled the negative effect of salinity on C mineralization through regulating the soil microbial community composition.

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Effect of starch on the utilization by sheep of a straw diet supplemented with urea and minerals

Australian Journal of Agricultural Research ◽

10.1071/ar9760139 ◽

1976 ◽

Vol 27 (1) ◽

pp. 139 ◽

Cited By ~ 19

Author(s):

JG Mulholland ◽

JB Coombe ◽

WR McManus

Keyword(s):

Organic Matter ◽

Nitrogen Retention ◽

Nitrogen Excretion ◽

Digestible Organic Matter ◽

Cellulose Digestibility ◽

Oat Straw ◽

Total Body ◽

Body Energy ◽

Urinary Nitrogen Excretion ◽

Urinary Nitrogen

Individually penned Border Leicester x Merino wethers, aged 11 months, were fed ad lib. for 16 weeks on a basal ration of ground, pelleted oat straw, urea and minerals, supplemented with 0, 5, 10, 15, 20, 30 or 40% starch. The diets contained equal percentages of nitrogen and minerals. Dry matter intake reached a maximum of 2000 g/day with 30% starch; above this starch level, digestive disturbances were observed. Organic matter digestibility was increased by the addition of starch, but cellulose digestibility was depressed by as much as 18 units with the addition of 30% starch. Up to 10% the starch level had little effect on cellulose digestibility. Liveweight change was significantly correlated with digestible organic matter intake, mean daily weight gains varying from 22 g with no starch to 104 g with 30% starch. However, a large percentage of the liveweight gain was as total body water, and body energy storage increased appreciably only when the diet contained at least 20% starch. The inclusion of 5% starch slightly depressed both intake and liveweight gain. Daily clean wool production was significantly increased at starch levels higher than 20% and ranged from 5.3 to 7.5 g/day with 0 and 40% starch respectively. Increasing levels of starch had little effect on apparent nitrogen digestibility, but resulted in a substantial increase in nitrogen retention through a reduction in urinary nitrogen excretion. Serum urea levels fell from a mean of 42 mg/100 ml during the first week to 31 mg/100 ml during subsequent periods, with no significant differences between diets. With the general exception of potassium, mineral balances were positive or close to zero throughout the experiment.

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Utilization of grass-silage nitrogen by growing sheep

The Journal of Agricultural Science ◽

10.1017/s0021859600032433 ◽

1983 ◽

Vol 100 (1) ◽

pp. 43-62 ◽

Cited By ~ 5

Author(s):

Elisabeth Grenet

Keyword(s):

Organic Matter ◽

Formic Acid ◽

Nitrogen Balance ◽

Crude Protein ◽

Nitrogen Loss ◽

Nitrogen Retention ◽

Protein Digestibility ◽

Water Soluble ◽

Nitrogen Intake ◽

Green Fodder

SUMMARYThe digestibility, the voluntary intake and the nitrogen balance of 108 diets corresponding to 94 silages prepared from 20 fresh crops were measured in growing sheep. Series of silages were made from the same fresh forage. Each series included two controls: a direct-cut silage without additive and a direct-cut silage with formic acid, with a variable number of experimental silages with different additives.Rumen ammonia concentration, measured on rumen-fistulated sheep, decreased when an additive was used. It increased with nitrogen intake and was inversely related to the organic-matter digestibility and the crude-fibre digestibility. It varied with the silage composition.The crude-protein digestibility of direct-cut silages without additives was similar to or slightly higher than the crude-protein digestibility of the fresh crops. The addition of formic acid depressed the digestibility, but the addition of formaldehyde decreased it even more. The urinary nitrogen loss was higher for silages without additive than for the fresh crops and was decreased by the addition of formic acid. The addition of formaldehyde to formic acid had an additive effect.Retained nitrogen was lower in silages without additives (12% of nitrogen intake) than in parent crops (15·7%). It increased when formic acid (15·8%) was added. The addition of formaldehyde at a low rate (1·5 l/t green fodder) to the formic acid did not increase the nitrogen retention whether expressed in g/day or as percentage of nitrogen intake, but the addition of formaldehyde at a high rate (3·5 l/t green fodder) to formic acid decreased nitrogen retention. The other additives based on cereals or whey did not improve the nitrogen balance compared with formic acid. Nitrogen retention differed according to plant species.Retained nitrogen increased with digestible organic-matter intake and nitrogen intake. It increased with the silage water-soluble carbohydrate content. The higher the silage fermentation product content (ammonia, lactic acid, propionic acid), the lower the retained nitrogen. It appears that the nitrogen value of silages can be high provided that the silages are well preserved and that excessive protein breakdown is avoided.

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A generally applicable pedotransfer function that estimates field capacity and permanent wilting point from soil texture and bulk density

Canadian Journal of Soil Science ◽

10.4141/cjss07120 ◽

2008 ◽

Vol 88 (5) ◽

pp. 761-774 ◽

Cited By ~ 23

Author(s):

J. A. P. Pollacco

Keyword(s):

Organic Matter ◽

Soil Moisture ◽

Bulk Density ◽

Soil Texture ◽

The United States ◽

Pedotransfer Functions ◽

Pedotransfer Function ◽

Data Set ◽

Wide Range ◽

Fitting Parameters

Hydrological models require the determination of fitting parameters that are tedious and time consuming to acquire. A rapid alternative method of estimating the fitting parameters is to use pedotransfer functions. This paper proposes a reliable method to estimate soil moisture at -33 and -1500 kPa from soil texture and bulk density. This method reduces the saturated moisture content by multiplying it with two non-linear functions depending on sand and clay contents. The novel pedotransfer function has no restrictions on the range of the texture predictors and gives reasonable predictions for soils with bulk density that varies from 0.25 to 2.16 g cm-3. These pedotransfer functions require only five parameters for each pressure head. It is generally accepted that the introduction of organic matter as a predictor improves the outcomes; however it was found by using a porosity based pedotransfer model, using organic matter as a predictor only modestly improves the accuracy. The model was developed employing 18 559 samples from the IGBP-DIS soil data set for pedotransfer function development (Data and Information System of the International Geosphere Biosphere Programme) database that embodies all major soils across the United States of America. The function is reliable and performs well for a wide range of soils occurring in very dry to very wet climates. Climatical grouping of the IGBP-DIS soils was proposed (aquic, tropical, cryic, aridic), but the results show that only tropical soils require specific grouping. Among many other different non-climatical soil groups tested, only humic and vitric soils were found to require specific grouping. The reliability of the pedotransfer function was further demonstrated with an independent database from Northern Italy having heterogeneous soils, and was found to be comparable or better than the accuracy of other pedotransfer functions found in the literature. Key words: Pedotransfer functions, soil moisture, soil texture, bulk density, organic matter, grouping

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