Assessing biogas digestate,pot ale,wood ash and rockdust as soil amendments: effects on soil chemistry and microbial community composition

Applying by-products as soil amendments to agricultural systems is growing in popularity. We aimed to assess the efficacy of some contemporary by-products to provide nutrients to crops as well as the potential harm of adding toxic elements to the environment. Four different by-products widely available in Northern Europe were tested for their effects on two nutrient-poor agricultural soils in terms of increasing available macro- and micro-nutrients as well as toxic elements. Assessing soil microbial community as a sensitive tool for evaluating soil quality was conducted with the focus on microbial activity, carbon metabolism and on Rhizobium/Agrobacterium. Wood ash increased pH and Ca_EDTA, K_EDTA and Mg_EDTA in the soils. The only increase in EDTA-extractable micronutrients in the soils was observed by applying pot ale, increasing Cu. None of the amendments increased the availability of Pb and Cd in the soils. Soils amended with the by-products thus remained similar to the unamended control but were quite different from fully mineral fertilised soils. There were no detectable adverse effects on the physiological and genetic profiles of microbial communities. The by-products were moderately beneficial and did not change the soil microbial community as much as the fully fertilised treatment with mineral fertilisers. Changes in the microbial community profiles were probably due to direct effects on microbes limited by K, Ca and N as opposed to indirect effects on plant growth. This is potentially significant in understanding how to improve impoverished and marginal soils as microbial activity affects many other ecosystem functions.     

The effect of different nitrogen levels on yield and quality of stevia (Stevia rebaudiana bert.)

In the present work, the efficiency of different nitrogen doses (0, 50, 100, 150, and 200 kg ha^?1) on growth, yield, and quality of stevia (Stevia rebaudiana Bert.) was investigated in 2011–2013. The study was conducted in Antalya located in the Mediterranean Region of Turkey. Terra rossa type soil (LVx, FAO) characteristics of the experimental field were clay loam, with high amounts of lime (33,9%) and slightly alkaline (pH 7.7). The experiment was carried out in randomized block design with four replications. All the results were summarized as mean of three years. The highest fresh and dry biomass yields (26.75 t ha^?1 and 7.5 ha^?1, respectively) were obtained from 150 kg ha^?1 N dose and followed by 100 kg ha^?1 N dose (26.29 t ha^?1 and 7.24 ha^?1, respectively). Whereas the highest fresh and dry leaf yields (13.27 t ha^?1 and 3.82 t ha^?1, respectively) were realized in 100 kg ha^?1 N dose. Actually, all nitrogen doses gave higher biomass and leaf yields compared to the control. On the hand, major steviol glycosides (stevioside and rebaudioside A) in the leaf were not influenced by nitrogen levels. In conclusion, 100 kg ha^?1 N dose was found to be suitable for cultivation of stevia under field conditions.     

Plant-derived CO2 flux from cultivated peat soils

Abstract

Methods used to estimate the CO₂ emission from soil commonly measure the total CO₂ flux. To be able to quantify the net CO₂ emission from cultivated peat soils there is a need to distinguish between soil organic matter-derived CO₂ respiration and plant-derived respiration. In this investigation we used the root exclusion method to separate the plant-derived respiration from total CO₂ emission. The plant-derived contribution was estimated to be between 27 and 63% of total CO₂ emission depending on soil type and season. We also found a relationship between soil temperature, biomass growth and CO₂ efflux, which can be used to estimate plant-derived respiration. Due to the priming effect the root exclusion method is less reliable late in the season.     

Effects of Soil-Applied Materials on the Dry Weight and Boron Uptake of Maize Shoots (Zea Mays L.) Under High Boron Conditions

High concentrations of boron (B) in the soil, reduces plant growth, crops’ yield and quality. Regarding such problem, synergistic and antagonistic relations between the nutrients can be used to ameliorate the B toxicity. Therefore, a greenhouse experiment was conducted to evaluate effects of soil-applied zinc (Zn), nitrogen (N), calcium (Ca), lime (CaCO₃), potassium (K), humic acid (HA), and humus on the dry weight and B uptake of maize shoots (Zea mays L.) under high-B containing soil conditions. Increasing doses of B (0, 2.5, 5, and 10 mg kg^?1 B) were applied to soil as borax (Na₂B₄O₇10H₂O), and boric acid (H₃BO₃). Positive correlations were found between B doses and the uptake amounts (r = 0.934**; – 0.964**). However, the correlations between the dry weight and B doses (r = ?0.314**; – r = ?0.495**) and between the dry weight and the uptake amounts (r = ?0.294*; – r = ?0.497**) were negative. Among the materials, Zn and humus exhibited positive correlations with dry weight values (r = 0.249*; r = 0.525**), and an effective increase (p < 0.01) in the dry weight amounts of maize shoots was observed under toxic B conditions.     

Inferring spatial structure from population genetics and spatial synchrony in demography of Baltic Sea fishes: implications for management

The spatial structure of species is important for their dynamics and evolution, but also for management and conservation. There are numerous ways of inferring spatial structures, and information from multiple methods is becoming more common to examine how different processes shape the spatial structures of species to improve fish management. Here, we investigate the spatial structure of a suite of Baltic Sea fish species based on the following: (i) spatial (presumably neutral) genetic differentiation, reviewed from the literature, and (ii) spatial synchrony in abundance changes from time series of fishery‐independent surveys, which we currently find to be underused given the amount of data available. For each of these two methods, species were classified as having a distinct, continuous or no/weak spatial structure. In addition, based on each source of information, we estimated the spatial scale of management units for species. The results show that only among species confined to the coastal zone the two sources of information yielded a congruence of the spatial structure (displaying a continuous spatial structure). In contrast, offshore species show weak spatial genetic structure but stronger spatial structure of synchrony in abundance. Based on this, we suggest that population genetic structure and synchrony in abundance should be used as complementary information as they reflect different spatial processes and suggest that management actions should differ with respect to scale depending on the management targets applied. We propose similar analysis should be applied to areas outside the Baltic Sea, and other stock identification methods, to improve management of fish resources.     

Effects of Pressurized Low Polarity Water Extraction Parameters on Antioxidant Properties and Composition of Cow Cockle Seed Extracts

Antioxidant activity of pressurized low polarity water (PLPW) extracts of cow cockle seed and extraction residues were determined using DPPH, ABTS, and FRAP assays. The effect of extraction conditions (temperature (125, 150 and 175 °C) and time) on the antioxidant activity and the relationship amongst the antioxidant activity and extract composition (total phenolics and saponin content) were determined. The antioxidant activity of PLPW extracts increased with extraction temperature. Increasing activity with time was also observed at 175 °C. PLPW extraction residues had the highest activity suggesting antioxidant compounds were not completely extracted by PLPW. Antioxidant activity correlated well with total phenolics content of samples (R ² ≥ 0.94), however no correlation was observed with the saponin content. A strong correlation was observed between the antioxidant activity values obtained using different methods (R ² ≥ 0.94). These results point to the potential of PLPW extraction as a method to modify the activity of biological materials for the production of customized extracts.     

Erratum: Chemical composition of cabbage (Brassica oleracea L. var. capitata) grown on acid sulfate soils

The purpose of this study was to investigate the influence of soil geochemistry on the concentrations of Ca, K, Mg, P, Co, Ni, Zn, Mn, Cu, and Fe in cabbage (Brassica oleracea L. var. capitata) grown on acid sulfate (AS) soils in Western Finland. A total of 11 topsoil (0–20 cm) and corresponding cabbage samples and three whole‐soil profiles (≈ 0–260 cm) were collected on three agricultural fields. The concentrations of Co and Zn in cabbage were correlated with the NH₄Ac‐extractable (easily available) concentrations in the topsoil, indicating that the uptake of these elements in cabbage is largely governed by soil geochemistry. Yet, the concentrations of Co and Zn in cabbage were not in general elevated relative to that of Finnish average values, although some AS soils showed enriched concentrations of these metals in the soil and cabbage. Significant geochemical differences (e.g., oxidation depth, organic‐matter and S content, pH) were observed among the studied AS soils, while, on the other hand, the concentrations of Ca, K, Mg, P, Ni, Mn, Cu, and Fe in cabbage were relatively similar. The hydroxylamine‐extractable concentrations of these elements in the topsoil were not correlated to those in cabbage, suggesting that uptake is not governed by the oxide‐bound fraction of these elements in the soil. Similarly, the easily available concentrations of Ca, P, Ni, Mn, Cu, and Fe in the topsoil were not correlated to those in cabbage, indicating that uptake is independent of the easily available concentrations in the soil. Hence, it is suggested that cabbage can regulate and thus optimize its concentrations of Ca, P, Ni, Mn, Cu, and Fe. Oxidation depth affected neither the easily available concentrations of Co, Ni, Zn, and Mn in the topsoil nor the concentrations in cabbage. However, the subsoil with a lower oxidation depth, which is to a smaller extent affected by leaching, may partly be enriched in these metals. Nevertheless, these showed no increased concentrations in cabbage. Based on these findings, it is suggested that the large amounts of metals mobilized in AS soils are easily lost to drains, subsequently contaminating nearby waterways and estuaries whereas they are only partly enriched in cabbage and other previously studied crops (oat).     

A new pest on soybean in Turkey: Melanagromyza sojae Zehntner (Diptera: Agromyzidae)

Melanagromyza sojae Zehntner (Hemiptera: Agromyzidae) is known as a pest of several leguminous plants, especially Glycine max, soybean, in several countries worldwide. As a result of an alert raised by soybean producers in the province of Adana, which has a large share of soybean production in Turkey, plant samples in which pupae were observed were collected from two soybean fields in Çukurova in the production season in 2018. The samples were kept in the laboratory and the emerging adults were identified morphologically as M. sojae. Observations made in soybean fields in Turkey are presented. A review of the situation for this pest and its control methods are is presented. This is the first report of M. sojae in Turkey. It is therefore recommended to perform a close monitoring of this pest to investigate more in detail the extent of the damage caused by this pest in soybean crops in Turkey, to identify its variety preferences, other other hosts, natural enemies and control methods to be used.     

Phyllonorycter apparella, a new record and a new pest of trembling aspen (Populus tremula) in Turkey

Phyllonorycter apparella (Herrich-Schäffer, 1855) (Lepidoptera: Gracillariidae) is a new record for the Turkish fauna and a new trembling aspen(Populus tremula L.) pest for Turkey. Its biology, damage and infestation ratio were studied in Sankami?. (Kars), Turkey, during 1996 and 1997.P. apparella has one generation a year. The developmental stages of the pest are described briefly. P.apparella hibernates in the adult stage. At the beginning of June, the adults appear. Females deposit their eggs on both leaf surfaces, generally one by one, 7–10 days after emerging. The early instars (sap-feeding larvae) start to mine mostly from the underside of leaves. Each mine has one larva, and each leaf may have up to 26 mines. The last instar (tissue-feeding larva) begins to pupate in the mine after mid August. The adults emerge from mid September to the beginning of October, and move to the trunks of old pine trees, where they hibernate in bark crevices. The infestation level may be as high as 90% of the leaves on some trees.     

Effect of some organic amendments on onion bulb rot

The effect of soil amended with stalks of sunflower (Helianthus annuus L.), alfalfa (Medicago sativa L.) and Hungarian vetch (Vicia pannonica Crantz) on onion bulb rot caused byFusarium oxysporum Schlecht. f.sp.cepae (Hanz.) Snyder Hansen andAspergillus niger v. Tieghem was tested in a soil naturally infested with the pathogens under field conditions. All treatments significantly reduced bulb rot incidence. The fungal and antibacterial populations varied among all of the amended tested soils. Heterotrophic fungal populations were more effective than heterotrophic bacterial populations in the suppression of disease. The highest population of fungal microflora was found in plots amended with sunflower stalks. The carbon-to-nitrogen ratio and available moisture content of amended soils have an indirect suppressive role on disease, by increasing the heterotrophic fungal population. http://www.phytoparasitica.org posting June 18, 2002.