Tillage and Soil Amendments Effect on Soil Physical Properties and Yield of Oats (Avena sativa L.) in Organic Farm in Mediterranean Croatia

Organic agriculture represents sustainable and environmentally friendly soil management. Nevertheless, this kind of management requests high level of knowledge due to limitations in use of agrochemicals. Proper agro-technical measures are especially important on organic farms on degraded saline-sodic soils in Mediterranean. In this paper, we study the impact of two tillage managements (disc-harrow – DH and disc-harrow with ripping – DH+RIP) and three selected treatments on soil physical properties in saline-sodic soils of River Raša valley, Croatia. Treatments were: control, G6+OM (6 t ha-1 gypsum + 40 t ha-1 farmyard manure) and G6S2 (6 t ha-1 gypsum + 2 t ha-1 sulphur). Results show that DH+RIP treatment recorded lower bulk density, penetration resistance and higher air filled porosity compared to DH treatment. Soil amendments also show implications on soil physical properties. Lowest compaction was noted at G6+OM, while control treatment recorded the highest. Yields of oat were generally low due weed infestation. DH+RIP treatments showed 15% higher yields compared to DH treatments. Amendments also recorded different response on oat yield. G6+OM treatment recorded 34% higher yields of oats compared to control, while G6S2 treatment recorded 82% of grain yields compared to control. This can be justified by the period between sulphur application into this treatment and sowing date, which was too short. Research should be continued with expanded monitoring of soil hydraulic properties, carbon dynamics, soil structure and aggregate stability in order to find most appropriate and sustainable soil management on saline-sodic soils under organic production in Mediterranean

Land Management Impacts on Soil Properties and Initial Soil Erosion Processes in Olives and Vegetable Crops

This research aims to assess the impacts of soil use management on runoff, soil losses, and their main soil controls in vegetable cropland (CROP), tilled olives (OT), and grass-covered olive orchards (OGC) on Leptosol in Croatia. Soil analysis and rainfall simulation experiments were conducted to quantify runoff (Run), soil, and nutrient losses. Bulk density (BD) was significantly higher at OT plots, in addition to the CROP plots. Water-stable aggregates (WSA), mean weight diameter (MWD), and soil organic matter (OM) were significantly higher in OGC plots compared to the other land uses. Run and soil loss (SL) were significantly higher in CROP and OT plots compared to the OGC plots. The CROP plots showed soil management that can be considered as unsustainable with 52, 68- and 146-times higher losses of phosphorus (P loss), nitrogen (N loss), and carbon (C loss) compared to the OGC plots. The principal component analysis showed that MWD was associated with vegetation cover (VC), water-holding capacity (WHC), WSA, OM, total nitrogen (TN), time to ponding (TP), and time to runoff (TR). These variables were negatively related to P2O5, Run, SL, and P, N, and C loss. Results indicate the need for the adoption of conservation strategies in croplands and olive orchards

Short-range and regional spatial variability of soil chemical properties in an agro-ecosystem in eastern Croatia

Spatial and temporal characterization of soil properties in agro-ecosystems is crucial for monitoring the evolution of soil functions and for understanding the main influential processes. Moreover, the objective mapping of soil properties in agro-ecosystems is urgently needed for regional planning purposes and the proper choice of land management practices. In this work, the geostatistical analysis of a dataset of soil properties, derived from 2411 soil samples collected in Vukovar-Srijem County (Croatia), highlighted the multiple benefits of a spatial-statistical approach. The main aim of this paper is to jointly examine short-range (i.e., within-field) and regional spatial variability of several soil chemical properties: soil pH, organic matter (OM), plant available phosphorus (AP) and potassium (AK). The available sampling network, characterized by a set of 2411 (0\u201330 cm depth) irregularly and field-clustered soil samples, allowed to derivate of two typologies of soil nutrient maps by means of ordinary block kriging: within-field high-resolution maps (block size 250 m) and regional low-resolution maps (block size 2000 m). Soil pH and OM had lower variability compared to AP and AK. The OM content and pH ranged from 1.24% to 5.25% and from 3.69 to 7.84, respectively. Almost 94% of all samples had an OM content below 3%, indicating the need for future adoption of environmentally friendly soil management in this county. The mean values of AP and AK were 173 mg kg 12 1 and 238 mg kg 12 1, respectively, indicating a moderate supply of these nutrients. Geostatistical analysis revealed that the best-fit models were spherical for pH and AP, with moderate spatial dependency, and exponential for OM and AK, with strong spatial dependency. The within-field high-resolution soil property maps can be used as guidance for site-specific fertilization and liming. In addition, the regional maps derived for larger interpolation support provide quantitative information for regional planning and environmental monitoring and protection purposes. Consequently, the multi-resolution mapping of soil properties and the analysis of their spatial variability highlighted possible connections with influential factors and processes, including the relationships with different soil types. Finally, quantification of the spatial variability of soil properties by means of variogram models constitutes a basis for optimizing soil sample spacing for mapping purposes in the studied region

Anomalous cyclic conjugation in benzenoid molecules with a small number of Kekule structures

1751-1755The currently used Kekule-structure-based models for assessing the extent of cyclic conjugation in benzenoid hydrocarbons predict that there is no or very little cyclic conjugation in the rings possessing "fixed" double and single carbon-carbon bonds. With the example of a suitably chosen class of benzenoid systems with a small number of Kekule structures, we show that the cyclic conjugation in the rings with "fixed" bonds (measured by its energy-effect) may be unexpectedly high, contradicting the results of standard Kekule-structure-based considerations. Consequently, our study reveals that the analysis of the conjugation modes of polycyclic aromatic compounds, based solely on Kekule structures, may sometimes be insufficient and may lead to erroneous conclusions

Short-term responses of soil respiration induced with biochar and lime in acid soil

Biochar amendments have been widely proposed as a conventional and efficient strategy to promote soil organic carbon (SOC) sequestration via negative priming. Unfortunately the extent and biological mechanisms responsible for biochar-induced 193 negative priming are still not fully understood. Despite traditional explanations focused on the environmental filtering mechanisms of biochar amendments on microbial biomass and community composition underlying the priming effect on SOC dynamics whether and how a biochar-induced competitive network structure with keystone taxa determines SOC mineralization in natural ecosystems has been minimally explored. Here we paid particular attention to the relationships between the diversity and network structure of soil bacterial and fungal communities and SOC mineralization. A 3-year field experiment was conducted comprising five treatments: no fertilization conventional fertilization and conventional fertilization with three rates of biochar amendments. Biochar amendments considerably increased soil moisture and pH and subsequently shaped the composition and co-occurrence networks of soil bacterial and fungal communities. Importantly network analysis coupled with stable isotope probing incubations consistently determined that biochar amendments reshaped the competitive modular structure with putative keystone taxa in the bacterial and fungal networks. Structural equation modeling suggested that the biochar-induced competitive modular structure with keystone taxa promoted bacterial and fungal diversity and consequently reduced carbohydrate catabolism and soil metabolic quotient. Our study revealed that biochar-induced competition with keystone taxa stimulated the bacterial and fungal diversity and consequently decreased SOC mineralization. The comprehensive understanding of the unexplored biological mechanisms underlying the biochar-induced negative priming may provide crucial implications for enabling SOC sequestration. Biochar amendments considerably increase

Land management impacts on soil properties and initial soil erosion processes in olives and vegetable crops

This research aims to assess the impacts of soil use management on runoff, soil losses, and their main soil controls in vegetable cropland (CROP), tilled olives (OT), and grass-covered olive orchards (OGC) on Leptosol in Croatia. Soil analysis and rainfall simulation experiments were conducted to quantify runoff (Run), soil, and nutrient losses. Bulk density (BD) was significantly higher at OT plots, in addition to the CROP plots. Water-stable aggregates (WSA), mean weight diameter (MWD), and soil organic matter (OM) were significantly higher in OGC plots compared to the other land uses. Run and soil loss (SL) were significantly higher in CROP and OT plots compared to the OGC plots. The CROP plots showed soil management that can be considered as unsustainable with 52, 68- and 146-times higher losses of phosphorus (P loss), nitrogen (N loss), and carbon (C loss) compared to the OGC plots. The principal component analysis showed that MWD was associated with vegetation cover (VC), water-holding capacity (WHC), WSA, OM, total nitrogen (TN), time to ponding (TP), and time to runoff (TR). These variables were negatively related to P2O5, Run, SL, and P, N, and C loss. Results indicate the need for the adoption of conservation strategies in croplands and olive orchards

Bone morphogenetic protein (BMP)1-3 enhances bone repair

Members of the astacin family of metalloproteinases such as human bone morphogenetic protein 1 (BMP-1) regulate morphogenesis by processing precursors to mature functional extracellular matrix (ECM) proteins and several growth factors including TGFβ, BMP2, BMP4 and GFD8. We have recently discovered that BMP1-3 isoform of the Bmp-1 gene circulates in the human plasma and is significantly increased in patients with acute bone fracture. We hypothesized that circulating BMP1-3 might have an important role in bone repair and serve as a novel bone biomarker. When administered systemically to rats with a long bone fracture and locally to rabbits with a critical size defect of the ulna, recombinant human BMP1-3 enhanced bone healing. In contrast, neutralization of the endogenous BMP1-3 by a specific polyclonal antibody delayed the bone union. Invitro BMP1-3 increased the expression of collagen type I and osteocalcin in MC3T3-E(1) osteoblast like cells, and enhanced the formation of mineralized bone nodules from bone marrow mesenchymal stem cells. We suggest that BMP1-3 is a novel systemic regulator of bone repair

Detection of bone and cartilage-related proteins in plasma of patients with a bone fracture using liquid chromatography–mass spectrometry

Following bone fracture, a large number of growth factors, cytokines, and their cognate receptors involved in the repair process are active at the fracture site. To determine whether they appear in patients’ blood as candidate biomarkers for following the outcome of healing, we analysed the plasma of 25 patients with an acute bone fracture following affinity plasma purification, SDS gel electrophoresis and liquid chromatography - tandem mass spectrometry (LC-MS/MS). Two hundred and thirteen nonredundant proteins were identified in the in-gel analysis of pooled plasma proteins. Gene ontology (GO) analysis indicated that a majority of detected proteins were of extracellular origin, whereas only a small number were of intracellular (cytosol and nucleus) origin. A significant proportion of detected proteins was involved in the cell growth and proliferation, transport and coagulation. Twelve proteins were potentially related to bone and cartilage metabolism, and several have not been previously identified in the plasma, including: TGF-β induced protein IG-H3, cartilage acidic protein 1, procollagen C proteinase enhancer protein and TGF-β receptor III