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Soil organic matter (SOM) represents one of the largest and most important reservoirs of organic carbon in terrestrial eco-systems. The quality of SOM (e.g., content of soil organic carbon, humic substances, humic acids, fulvic acids, and HA/FA ratio) is a key factor in determining soil fertility and productivity. The loss of SOM is currently considered a detrimental form of soil degradation. The study aims to evaluate the effect of mineral fertilising (NPK), farmyard manure, cattle slurry, and digestate applications in intensively used permanent grassland. The long-term field experiments were carried out at the locality Jevíčko, region of Boskovice Furrow Malá Haná (the Czech Republic). The effect of amending soil with different organic and mineral fertilisers was studied. Qualitative parameters of SOM, soil reaction, and the content of available nutrients (N, P, K, Ca, Mg) were followed. Results showed that the control (no organic input) and the NPK variants had the lowest SOM quality. Higher SOM quality was after the farmyard manure, Slurry, and Digetsate applications. The highest acidity (indicated by the lowest values of pH/KCl) was determined in the control, NPK, Slurry, and D variants. The most favourable soil reaction and available nutrient content were after the farmyard manure application. Humic substances spectral absorption in the UV-VIS and infrared spectral ranges showed that the highest absorbance and amount of aliphatic hydrophobic components were observed after the application of farmyard manure. The multi-criteria statistical evaluation, including principal component analysis and factor analysis, confirmed that amending soil with farmyard manure and slurry resulted in an increase in humic substances content and improved SOM quality. [ABSTRACT FROM AUTHOR]

Global carbon storage in soils is widely discussed today because of climate uncertainty and maintaining sustainable agricultural production. Human intervention in agricultural or energy production poses many changes in soil management, which highly affects soil quality/health. Permanent grasslands fulfil a wide range of ecosystem functions and have a high potential for increasing arable land. Today, grasslands are becoming more and more intensively used, fertilized and disturbed. Optimizing their management is essential to maintain a resilient and stable ecosystem. The produced biomass is used as a forage or for energy production. We aimed at the impact of long-term grassland liming on the total content of soil organic carbon (SOC), humic substances (CHS), and microbial biomass (Cmic). Furthermore, soil reaction and available nutrient content were evaluated. Soil samples were collected from a split-plot field experiment at Mendel University in Brno (locality Kameničky). The soil was classified as Dystric Planosol Siltic, medium textured, strongly acidic, with high soil organic carbon content. The yearly liming rate was 1.4 t/ha CaO. The linkage between the soil pH, SOC, Cmic, and available nutrient content was evaluated by the multivariate exploratory techniques and regression models. Results showed that long-term liming affects both soil biota and carbon storage. [ABSTRACT FROM AUTHOR]

The present study aims to test and evaluate the efficiency of a new modified method of organic matter evaluation. It allows the assessment of the quality and quantity of the primary soil organic matter and the stable organic fractions separately. The new method was tested in six soil samples of different localities in the Czech Republic. This method is based on observing reaction kinetics during the oxidation of soil organic matter and measuring the cation-exchange capacity of stable organic fractions. The results were compared with classical methods, which rely on the isolation of humic substances, determination of the content of humic acids and fulvic acids and their ratio CHA:CFA, quotient E4/6, and fractionation of soil organic matter according to resistance to oxidation. It turned out that the results of the new modified method are more sensitive in comparison with the results obtained by classical procedures. The linear regression demonstrated the dependence between the amounts of soil organic matter determined by the classical method compared with the modified method. Moreover, the new modified method was found to be faster and not demanding on laboratory equipment. The new method has been improved to be easily repeatable, and some shortcomings of the previous method were eliminated. Based on our results and other recent studies, the modified method may be recommended for the practical evaluation of soil organic matter conditions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]