No abstract

Digestate contains many valuable nutrients, including nitrogen (N), phosphorus (P), and potassium (K); however, it is characterized by relatively little organic matter. The objective of this study was to assess the four-year impact of digestate (Dig) application, digestate + straw (Dig + St), cattle slurry (Csl), and mineral fertilization (NPK) on soil organic carbon (SOC), total nitrogen (TN), mineral N (Nmin), and the content of plant-available P and K. Fertilization did not have any significant influence on SOC, TN, and SOC/TN parameters. Yet, in comparison with control, there was an upward trend in the concentration of SOC and TN in the topsoil, where fertilizers were applied. In contrast to SOC and TN, fertilizer treatment significantly affected the content of P, K, and Nmin, and the differences depended on the soil depth and the fertilizer used. On average, the highest content of P was obtained in Csl treatment, but the highest content of K was observed in Dig + St. The effect of treatment on Nmin in spring was as follows: NPK = control < Csl = Dig + St < Dig. Straw plowing increased the bio-immobilization of N with digestate and, at the same time, lowered the content level of nitrates in soil.

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.

Fertilization is a key factor for sustaining productivity in agroecosystems. A long-term experiment in cambisol following periodical application of several types of fertilization has been running at the experimental site since 1954. In this study, we determined the impact of applied inorganic and/or organic fertilizers on the activity of soil enzymes and on the structure of microorganisms at depths of 0–30 cm and 30–60 cm. Single-factor comparison showed that use of inorganic and/or organic fertilizer had an insignificant effect on the activities of soil enzymes (at depths 0–30 cm and 30–60 cm) and also on the structure of microbial communities at both depths studied. Only soil respirations exhibited stimulation by combined fertilization. The results, irrespective of sampling depth (0–60 cm), showed that application of combined organic and inorganic fertilization stimulated the activity of glucosidases and use of inorganic fertilizer inhibited the activity of arylsulphatases. Respirations were stimulated by application of organic fertilizer and combined fertilization. Nevertheless, principal component analyses, which calculate with multidimensional data, revealed differences in samples treated by sole mineral fertilizer compared to other variants, especially in the lower layer. In general, our results indicate that use of combined fertilization may improve biological characteristics in deeper parts of soil profile and possibly increase biological activity in agroecosystems.

Soil organic matter (SOM) plays an important role in the terrestrial ecosystems and agroecosystems. Changes in the agricultural sector in the countries of the Central and Eastern Europe (the Czech Republic, Slovakia, Poland, etc.) within the past 25 years have negatively affected the SOM and contributed to the soil degradation. The aim of this chapter is the evaluation of the long-term application of mineral fertilizers and farmyard manure: the Control (without fertilization), farmyard manure (FYM + 0), FYM accompanied with NPK (FYM + N 3 PK), and FYM with mineral nitrogen FYM + N (FYM + N 2), on the essential chemical properties of the soil and yield of the fundamental arable crops in the long-term field experiments, established in different soil and climate conditions (black soils, brown soils, cambisols, altitude ranging from 260 to 650 m a.s.l.) of the Czech Republic in 1955, using the modern multi-criteria statistical methods (PCA, FA, CLU, etc.). The longterm and regular application of organic manure and organic manure with mineral fertilizers (FYM + N 3 PK and FYM + N 2) optimize the soil characteristics, stabilize crop and feedstuff production, and increase the adaptation potential of the soil in the Czech Republic, which is supposed to be weakened due to the expected changes of the environmental conditions in the near future.