Effect of Potassium Budget on Evolution of Soil Potassium in Different Crop Sequences and Site Conditions

The influence of six different crop sequences on the dynamics of topsoil available and fixed potassium (Kavail and Kfix) was studied within a 4-year period at 6 sites of different soil and climatic conditions. The highest K off takes were recorded for 3-year alfalfa / clover cropping followed by winter wheat (-151 kg K/ha/year) and for the crop sequence including one year of sugar beet / potato (-0124 kg K/ha/year). Kavail and Kfix were significantly decreased especially at crop sequence with alfalfa / clover cropping, compared to other crop sequences. At three sites of lower Kfix content (340-830 mg K/kg), differences in Kavail and Kfix between crop sequences were more frequent, whereas almost no significant differences between treatments were observed at sites of higher Kfix content (1,000-1,380 mg K/kg). Changes of both K forms and K budget correlated significantly at sites of lower Kfix content. At these sites, Kavail decreased at the rate of 0.045 mg K per 1 kg/ha of K offtake; the rate of Kfix decrease was 0.059 mg K per 1 kg/ha of K offtake. At sites of higher Kfix, no significant relation between K forms and K budget was observed. The results show an importance of Kfix as a K source in intensive agricultural systems with low or no K inputs

Chemical and Spectroscopic Parameters Are Equally Sensitive in Describing Soil Organic Matter Changes After Decades of Different Fertilization

The composition and dynamics of soil organic matter (SOM) are decisive factors in soil quality. In this work, total organic C (Ctot), hot water extractable C (Chwl), and aliphatic and aromatic SOM components detected by Fourier transform infrared (FTIR) spectroscopy were determined to evaluate SOM quantity and quality in soil samples taken between 2004 and 2017 from 13 field experiments established in different soil and climatic conditions of the Czech Republic. In addition, the C pool index (CPI), lability index (LI), C management index (CMI), and SOM decomposition index (DI) were assessed. Treatments were selected as follows: Unfertilized control (Nil), mineral fertilized treatment (NPK), farmyard manured treatment (FYM), and organic and mineral fertilized treatment (FYM+NPK). Both organic and combined fertilization significantly increased soil Ctot, Chwl, CPI, LI, CMI, and labile aliphatic SOM components (FTIRaliph) in most of the experiments compared to unfertilized treatments (p ≤ 0.05). In contrast, the highest content of recalcitrant aromatic SOM components (FTIRarom) and increased DI were determined in majority of unfertilized soils. Our results show that: (1) fertilization regimes increased both labile and total C pools; the highest increase was nearly uniformly observed for NPK+FYM treatment; (2) SOM chemical and FTIR spectral detection had equal sensitivity to the changes; and (3) none of the parameters or indices tested can be used as a stand-alone SOM quality descriptor

Assessing soil aggregate stability by measuring light transmission decrease during aggregate disintegration

Advancements in technology have recently enabled to assess soil aggregate stability (SAS) using digital devices. To address the need for a faster and more efficient method of measuring SAS, we have developed a simple yet effective approach using a specialized device. The innovative method named SlakeLight involves measuring the changes in light transmittance as aggregates undergo slaking. The device consists of the measuring chamber, which is placed on a LED light source with a surface-homogeneous distribution of luminosity. During the disintegration process of aggregates immersed in water, reduction in the light emitted to the photodiodes is proportional to SAS. The functionality of the device was tested using topsoil samples from two field fertilization trials. The recorded SAStrans values were compared with the wet sieving method (WSA) and SLAKE test. The new method showed a strong correlation with both reference methods (r = 0.89 for WSA, r = -0.86 for SLAKE). The device was able to detect a statistically significant differences in SAS between the grassland and the cropland at both sites. Although differences in SAStrans were not significant between different fertilization treatments unlike WSA, the simplicity and speed of the measurement increase the potential of the method for practical implementation in agriculture, surpassing the limitations of traditional and labor-intensive laboratory techniques

Long-term field experiments and their contribution to environmentally balanced agriculture:Abstract proceedings of the international colloquium and of the workshop Unbalanced potassium plant nutrition: causes, consequences and threats

Proceedings of the scientific conference on long-term field experiments and their contribution to environmentally balanced agriculture with focus on unbalanced potassium nutrition

Long-term field experiments and their contribution to soil quality research:Abstract proceedings of the colloquium and workshop Crop and soil simulation models

Proceedings of the scientific conference with international guests. The conference was devoted to long-term experiments and soil quality assessment

Organic fertilization improves soil aggregation through increases in abundance of eubacteria and products of arbuscular mycorrhizal fungi

Abstract An important goal of sustainable agriculture is to maintain soil quality. Soil aggregation, which can serve as a measure of soil quality, plays an important role in maintaining soil structure, fertility, and stability. The process of soil aggregation can be affected through impacts on biotic and abiotic factors. Here, we tested whether soil management involving application of organic and mineral fertilizers could significantly improve soil aggregation and if variation among differently fertilized soils could be specifically attributed to a particular biotic and/or abiotic soil parameter. In a field experiment within Central Europe, we assessed stability of 1–2 mm soil aggregates together with other parameters of soil samples from differently fertilized soils. Application of compost and digestates increased stability of soil aggregates. Most of the variation in soil aggregation caused by different fertilizers was associated with soil organic carbon lability, occurrence of aromatic functional groups, and variations in abundance of eubacteria, total glomalins, concentrations of total S, N, C, and hot water extractable C. In summary, we have shown that application of compost and digestates improves stability of soil aggregates and that this is accompanied by increased soil fertility, decomposition resistance, and abundance of total glomalins and eubacteria. These probably play significant roles in increasing stability of soil aggregates

Impacts and Uncertainties of +2∘C of Climate Change and Soil Degradation on European Crop Calorie Supply

Even if global warming is kept below +2°C, European agriculture will be significantly impacted. Soil degradation may amplify these impacts substantially and thus hamper crop production further. We quantify biophysical consequences and bracket uncertainty of +2°C warming on calories supply from 10 major crops and vulnerability to soil degradation in Europe using crop modeling. The Environmental Policy Integrated Climate (EPIC) model together with regional climate projections from the European branch of the Coordinated Regional Downscaling Experiment (EURO-CORDEX) was used for this purpose. A robustly positive calorie yield change was estimated for the EU Member States except for some regions in Southern and South-Eastern Europe. The mean impacts range from +30 Gcal ha−1 in the north, through +25 and +20 Gcal ha−1 in Western and Eastern Europe, respectively, to +10 Gcal ha−1 in the south if soil degradation and heat impacts are not accounted for. Elevated CO2 and increased temperature are the dominant drivers of the simulated yield changes in high-input agricultural systems. The growth stimulus due to elevated CO2 may offset potentially negative yield impacts of temperature increase by +2°C in most of Europe. Soil degradation causes a calorie vulnerability ranging from 0 to 50 Gcal ha−1 due to insufficient compensation for nutrient depletion and this might undermine climate benefits in many regions, if not prevented by adaptation measures, especially in Eastern and North-Eastern Europe. Uncertainties due to future potentials for crop intensification are about 2-50 times higher than climate change impacts