Nematode species composition and ecology of some plants from the Cucurbitaceae Juss. family

Laboratory chronic experiments have determined the effect of the content of petroleum products (PP) in reclaimed alluvial turf heavy loamy and light loamy soil on the growth, yield of green mass and the development of the root system of spring wheat and seed peas. High residual PP content in reclaimed soil resulted in increased seed germination time, with no effect on germination. When growing wheat on reclaimed alluvial turf heavy loamy soil, the toxic effect was manifested only in the early stages of plant development in a variant containing 16.9 g/kg of PP. In the alluvial turf light loamy soil version containing 21.8 g/kg of pollutant, inhibition of plant growth was observed throughout the experiment. In chronic experiments for growing peas on heavy coal soil containing 16.9 g/kg of PP, on light coal soil containing 11.7 g/kg and higher, plant growth inhibition was observed, with a tendency to increase the toxic effect towards the end of the growing experience. Oil contaminants in concentration up to 11-12 g/kg in reclaimed alluvial turf heavy and light-coal soils do not affect the yield of green wheat mass, in concentration 9.7 g/kg and higher inhibit the growth of pea plants, lead to a decrease in the yield of their green mass. The oxidation efficiency of petroleum products when growing plants on reclaimed alluvial turf soil did not exceed 37% and was determined by the initial concentration of pollutant. The presence of PP in the soil led to a change in the structure of the root system of the plants being grown. Tested plants when cultivated on heavy soils are more resistant to negative PP. The findings show that sown peas are more sensitive to the presence of PP in reclaimed soil.

The results of studies on the effect of density, fertilizer and soil type on miscanthus productivity in Western Polesie are presented. It was found that the average yield of dry biomass of 15.5 t/ha was obtained on a dark gray loamy soil for a planting density of 20 pc/ha., and fertilizer application at the rate of N60Р200К200. The application of mineral fertilizers (N60Р200К200) on dark gray light-loamy and sod-podzolic sandy-sandy soil provided the highest increase in dry mass yield (up to control) of 2.9–3.4 t/ha. As the results of research have shown, the dry matter yield varies significantly under the influence of certain factors. Thus, in four years on average the highest dry matter yield was obtained on condition of planting density of 20 thousand pcs./ha and application of N60P200K200 on both dark gray light loamy soil and sod-podzolic sandy soil, 15.5 and 13.1 t/ha respectively. The lowest yields on two types of soils were obtained on condition of planting density of 10 thousand pcs./ha in the trial field without fertilizers (check) – 12.0 t/ha and 9.1 t/ha on dark gray loamy and sod-podzolic light sandy soils, respectively. The application of mineral fertilizers at the rate of N60P100K100 ensured increase in the yield by 1.8 and 2.2 t/ha of dry mass on two types of soils. Increasing the dose of phosphorus and potassium fertilizers up to 200 kg. d. r./ha contributed to an increase in the amount of dry mass to 15.0 and 10.1 t/ha compared to the trial field without fertilizers. The results of the research confirm the fact that with the increase in grain planting density and application of mineral fertilizers, the yield of miscanthus biomass increases, thus, the yield of solid fuel and energy increases as well. Consequently, the highest fuel yield of 17.1 t/ha with the energy yield of 271 GJ/ha was ensured by the application of mineral fertilizers at the rate of N60P200K200 and an increase in planting density to 20 thousand pcs./ha on dark gray light loamy soil. The lowest productivity at this density was characterized by the option without fertilizers (check) - 12.2 t/ha of dry biofuel and 194 GJ/ha of energy. Planting miscanthus plantations with the density of 15 thousand pcs./ha for four years on average reduced the yield of biofuel to 11.0 t/ha and energy to 175 GJ/ha in the trial field without fertilizers (check). However, the lowest amount of biofuel of 10.1 t/ha and energy yield of 159 GJ/ha was obtained in the trial field without fertilizers at the planting density of miscanthus of 10 thousand pcs./ha. The application of mineral fertilizers at the rate of N60P100K100 and N60P200K200 contributed to the increase of the above indices to 13.5 and 14.7 t/ha of dry biofuel and 215 and 235 GJ/ha of energy, respectively. Keywords: miscanthus, dry biomass, solid biofuels, energy, soil.

Purpose We sought to understand potential legacy impacts of wildfire on loamy soils from karri ( Eucalyptus diversicolor ) forest compared to sandy soils from jarrah ( Eucalyptus marginata ) forests in southwest Australia. Methods We sampled soils (0–5 and 5–10 cm) from forest burned five years previously at high and low severity as well as unburnt forest. Replicate plots for each forest type and burn severity were analysed for particle size analysis (PSA), total carbon (%C), total nitrogen (%N), organic and inorganic phosphorus, nitrate, ammonium, pH, and stable isotope composition (δ 13 C, δ 15 N). Results Loamy soils showed clear evidence of effects of fire on soil properties regardless of fire severity after five years, but these effects were less pronounced in sandy soils. In loamy soils, clay content, % C and %N were significantly lower in burnt sites compared to unburnt sites. Conversely, sandy soils only recorded an increase in inorganic nitrogen and a higher pH in burnt sites. Both loamy and sandy soils burned at high severity had more enriched δ 13 C signatures compared to other sites. Additionally, loamy soils burned at high severity also had more enriched δ 15 N signatures. Conclusion Different legacy effects of fire on the two soil types are likely associated with dissimilarities in soil texture. A higher percentage of clay in unburnt loamy soils contributes to greater retention of soil C and N in burnt soils. This study emphasises the importance of soil texture in carbon and nutrient retention, suggesting that soils in karri forests, while fire-prone, may be more “carbon-sensitive to fire” than previously believed.

Calcareous soil, comprising more than 15% CaCO3, which imposes various physical and chemical challenges to plants, is widespread in arid and semi-arid regions. It was against the stated backdrop that an experiment was carried out to compare growth responses of moringa (Moringa oleifera Lam.) seedlings in calcareous, clayey and sandy soils relative to those in loamy soil during autumn (January-March) 2015 and validated in 2016. Treatments comprised loamy, calcareous, clayey and sandy soils, arranged in randomised complete block design, with 15 replications. Each soil type was steam-pasteurised, with hardened-off six-week-old seedlings transplanted in 10 L plastic bags containing 9.8 L soil for each. At 90 days after transplanting, treatments had significantly (p ≤ 0.05) affected growth variables of M. oleifera seedlings. Relative to loam soil, calcareous soil reduced dry shoot mass (33%), chlorophyll content (36%) and dry root mass (47%), but increased root length (28%). In contrast, clay increased dry shoot mass (66%), leaf number (25%) and root length (26%), whereas sandy soil increased dry shoot mass (42%) and reduced dry root mass (51%). In conclusion, relative to loam soil, marginal soils such as calcareous, clayey and sandy soils had effects on growth of M. oleifera seedlings that included physical and chemical attributes of the soil types. Key words: Calcareous soil, marginal soil, Moringa species, soil pH, soil texture, soil type.

Addition of urease inhibitors is one of the important measures to increase nitrogen (N) use efficiency of crop, due to retardant of urea hydrolysis and reduction of ammonia volatilization loss. An incubation experiment was conducted to investigate the urease inhibition effect of a new phosphoramide urease inhibitor, NPPT (N-(n-propyl) thiophosphoric triamide) in different texture soils under dark condition at 25 ℃, and NBPT (N-(n-butyl) thiophosphoric triamide) was obtained to compare the inhibition effect on urease in different soil textures by different dosages of urea adding. Results showed that the effective reaction time of urea was less than 9 d in the loamy and clay soil. Addition of inhibitors for retardation of urea hydrolysis was more than 3 d. In sandy soil, urea decomposition was relatively slow, and adding inhibitor significantly inhibited soil urease acti-vity, and reduced NH4+-N content. During the incubation time, the inhibition effect of high dosage urea in the soil was better than that of low dosage. At day 6, the urease inhibition rate of NBPT and NPPT (N 250 mg·kg-1) were 56.3% and 53.0% in sandy soil, 0.04% and 0.3% in loamy soil, 4.1% and 6.2% in clay soil; the urease inhibition rate of NBPT and NPPT (N 500 mg·kg-1) were 59.4% and 65.8% in sandy soil, 14.5% and 15.1% in loamy soil, 49.1% and 48.1% in clay soil. The urease inhibition effects in different texture soil were in order of sandy soil > clay soil> loamy soil. The soil NH4+-N content by different inhibitors during incubation time increased at first and then decreased, while soil NO3--N content and apparent nitrification rate both showed rising trends. Compared with urea treatment, addition of urease inhibitors (NBPT and NPPT) significantly increased urea-N left in the soil and reduced NH4+-N content. In short, new urease inhibitor NPPT in different texture is an effective urease inhibitor.

Spatial pattern and scale of soil N and P fractions under the influence of a leguminous shrub in a Pinus canariensis forest

Free-living nematodes from littoral benthic sediments of four lakes, two rivers and a hot spring in Ethiopia are studied. Populations of nematodes encountered are identified to the species level. The general nematode (generic and species) composition of the lakes, rivers and hot spring are appraised by giving special emphasis to the nematodes from L. Tana, i.e. three sites where different environmental factors come into play were considered. Gelda is a site close to a river inlet (River Gelda), Gedero is a site exposed to strong wind action while Zegie is a secluded site protected by a land mass from any strong wind action. Nematode communities were identified using classification and ordination techniques. The identified communities are then characterised with respect to species composition, biomass, density, diversity, size structure, feeding type and maturity index. Also, the vertical distribution of nematodes is examined at the community and species level. An attempt has been made to associate these variations with the considered environmental factors viz. site, water depth, sediment depth, median grain size and percentage of mud in the sediment. Median grain size and percentage of mud varied over the three sites with the lowest grain size and the highest percentage of mud in Gelda. The incoming river is regarded responsible for the high mud content at this site. The composition of the nematode communities from the lakes, rivers and hot spring by and large was typically freshwater. The highest number of species (40 species) was recorded from L. Tana (a lake relatively intensively sampled) whereas the lowest number was recorded from the saline lake, Abiyata (2 species). Both species in the latter belong to the genus Monhystrella. The complete dominance of species of this genus in L. Abiyata and its presence in the saline lakes and hot spring is argued to be associated with their opportunistic nature and their high temperature dependency and their capacity to withstand high osmotic stress conditions. The role played by salinity in the distribution of nematodes in inland water bodies is considered vital. The occurrence of two species of the genus Udonchus in River Abbay where an outlet of a waste disposal scheme of a textile factory is situated, and their absence in any other site coupled with the habitual presence of one of the two species in mineral waters are used to argue that the genus may be an indicator of some kind of environmental (chemical ?) stress. Five nematode communities are identified in L. Tana, viz. Gelda at 0.5 m, Gelda at 1.5 m, Zegie at 0.5 m, Zegie at 1.5 m and Gedero. The vulnerability of Gedero to strong wind action is maintained to be the main reason for the absence of a significant difference in nematode community at the two water depths at this site. The presence of few dominant species characterised four of the five communities. Factors that account for differences in species composition and abundance are discussed. Local conditions are thought to be important in the different communities in L. Tana. A strategy in niche partitioning is suggested to be the main driving force behind the composition of few most dominant species which (in L. Tana and other reviewed lakes) invariably was a combination of a deposit feeder(s) and an omnivore/predator(s) species. In general, nematode diversity in L. Tana was comparable to that found in oligotrophic and mesotrophic freshwater lakes. Nematode diversity varied over the different communities

Plant parasitic nematode populations on upland and hydromorphic rice in Côte d’Ivoire: relationship with moisture availability and crop development on a valley slope

Purpose. To identify ways to increase the productivity of willow plantations on low-productive soils of Western Polissya and to improve the technology of their cultivation.Methods. Field, laboratory, statistical.Results. On dark gray light loamy soil, the highest height of the plants of energetic willow was with a planting density of 20 thousand pcs./ha. The application of mineral fertilizers from the calculation of N60P100K100 contributed to an increase in height by 8 cm, relative to the option without fertilizers (control). An increase in the dose of phosphorus and potassium fertilizers by another 100 kg against the background of N60 ensured an increase in shoots by 32 cm in comparison with the control. With a planting density of 15 thousand pcs./ha, the height of the shoots was slightly less – from 290 cm in the variant without fertilizers to 319 cm in the variants with the introduction of mineral fertilizers. The largest average shoot diameter was in the rarest variants (10 thousand units/ha) – from 14.4 mm, in the variant without fertilizers, to 17.5 mm, in the variant with the introduction of mineral fertilizers at the rate of N60P200K200. Similar data were obtained on sod-podzolic cohesively sandy soil. There were also higher plantations with a planting density of 20 thousand pcs./ha (from 219 cm to 240 cm). On average, over three years of growing willow, the highest yield of dry biomass of 18.2 t/ha was obtained on dark gray light loamy soil with a planting density of 20 thousand pcs./ha and fertilizing at the rate of N60 P200 K200. The application of mineral fertilizers (N60P200K200) on the dark gray light loamy and sod-podzolic cohesive-sandy soil in 2018 ensured an increase in the yield of dry willow mass of energetic by 4.0–5.5 t/ha. Increase in landing density from 10 thousand pcs./ha up to 20 thousand pcs./ha contributed to an increase in the yield of three-year dry willow mass from 11.6–15.6 t/ha to 18.2–23.7 t/ha and from 7.8–10.3 t/ha to 9.8–12,5 t/ha, when grown on dark gray light loam and sod-podzolic beef-edible soil, respectively. Conclusions. During the first three years of growing willow energy plantations in the conditions of West Polesie, the application of mineral fertilizers (N60P200K200) on dark gray light loamy and sod-podzolic cohesive-sandy soil ensured the largest increase in dry crop yield – 4.0–5.5 t/ha and 2.5–2.7 t/ha, respectively. An increase in yield was also facilitated by an increase in planting density from 10 to 20 thousand/ha. The highest yield of dry biomass (18.2 t/ha per year) was obtained on dark gray light loamy soil with the highest planting density (20 thousand units/ha) and a maximum dose of fertilizers (based on N60P200K200).

Aims: This experiment was carried out to study the effects of soil type and seasonal variation on growth, yield, essential oil and artemisinin content of Artemisia annua plant. Methods: Two field experiments were carried out during two successive seasons in two different types of soil, loamy clay soil and sandy loam soil. Artemisia seeds were cultivated in nursery plots at 15th December then transplanted at age of 90 days in a distance of 60cm in apart and 50cm in between plants under organic system then plant samples were collected every 30 days through growth season. Results: Significant increases in vegetative growth characters were observed for plants cultivated in clay loamy soil comparing to those cultivated in sand loamy soil. The plant essential oil percentage of those cultivated in sand loamy soil were increase more than those cultivated in clay loamy soil while essential oil yield of plants grown in clay loamy soil was more than those grown in sand loamy soil. Essential oil % of A. annua aerial parts in the two soils increased with increasing plant age to reach its maximum values at full flowering stage then this tended to decrease towards the end of plant life. The major compound in the essential oil was found to be artemisia ketone followed by 1,8 cineole in both soils. A change in the order of the followed compounds according to the soil type was observed. Artemisinin % and artemisinin yield (kg/fed) of plants cultivated in sand loamy soil was increased in comparing to plants cultivated in clay soil and showed the maximum values of artemisinin % at the flowering stage in August in both types of soil. Conclusion: Cultivation of A. annua in sandy loam soil resulted in increasing essential oil percentage whereas clay loam soil increased oil yield as it increased all vegetative parameters. Artemisia ketone and 1,8 cineole are major compounds in essential oil and their percentage in essential oil for sandy loam soil plants were more than of clay loam plants.

This study aimed to assess whether the fertilizing effects of compost (Com) and vermicompost (VCom) applied to a preceding wheat crop, either alone or in combination with microbial biofertilizers (MBF; arbuscular mycorrhizal fungi and nitrogen-fixing bacteria), could sustain forage maize yield across contrasting soil textures. A split–split plot trial was conducted in 2023 in sandy, loamy, and clay soils. Treatments included Com, VCom, standard mineral nitrogen fertilization, and unfertilized control, each tested with or without MBF inoculation. Maize was harvested at the milk–dough stage and assessed for biomass yield, dry matter partitioning, chemical composition, and in vitro digestibility. Interactions among factors were frequent, particularly with soil texture, but overall, Com and VCom sustained biomass yield and forage quality, especially when combined with MBF. Notably, in loamy soil, VCom coupled with MBF (38.4 t ha−1) outperformed mineral fertilization (32.9 t ha−1). Across soils, loam produced the highest dry matter yield (27.0 t ha−1) and sand the lowest (23.7 t ha−1), while clay showed variable responses depending on the amendment–MBFs combination. All plots treated with the MBFconsistently exhibited higher yields compared to their respective controls, with an average increase of 52.6% across texture and fertilization strategies. Fertilization strategy and soil texture slightly yet significantly affected maize chemical composition, while digestibility remained largely preserved. Crude protein concentration peaked under mineral fertilization in loamy soil (8.3% dry matter). These findings highlight the potential of bio-based fertilizers, especially when integrated with microbial inoculants, to reduce mineral nitrogen dependency and support the sustainable intensification of forage maize.

Simple SummaryThe investigation of insect attachment ability in relation to plant mechanical barriers can shed light on the different steps driving host plant selection in phytophagous insects and help to better understand the complex antagonistic coevolution between insects and plants. In this context, we investigated the attachment ability of the oligophagous melon ladybird beetle Chnootriba elaterii at different developmental stages (adult, larva, eggs) to leaves of several Cucurbitaceae species (watermelon, melon, cucumber, zucchini, pumpkin, squirting cucumber, calabash and loofah) characterized by the presence of glandular and non-glandular trichomes with different characteristics (density, length). We used different techniques (scanning electron microscopy, traction force experiments and centrifugal force tests) to characterize the plant leaf surface and insect attachment devices and measure insect attachment ability to the leaf of the different plant species. Data regarding morphological leaf traits of Cucurbitaceae associated with their resistance against phytophagous insects, combined with data regarding the chemical cues involved in the host plant selection, can help to develop environmentally friendly pest control methods.This study investigates the attachment ability of the oligophagous melon ladybird beetle Chnootriba elaterii to leaves of several Cucurbitaceae species. Using cryo-SEM, we described adult and larva tarsal attachment devices and leaf surface structures (glandular and non-glandular trichomes) in Citrullus lanatus, Cucumis melo, Cucumis sativus, Cucurbita moschata, Cucurbita pepo, Ecballium elaterium, Lagenaria siceraria and Luffa aegyptiaca. Using traction force experiments and centrifugal force tests, we measured the friction force exerted by females and larvae on plant leaves. We observed that Cucurbitaceae glandular trichomes do not affect insect attachment ability at both developmental stages, suggesting some adaptation of C. elaterii to its host plants, while non-glandular trichomes, when they are dense, short and flexible, heavily reduce the attachment ability of both insect stages. When trichomes are dense but stiff, only the larval force is reduced, probably because the larva has a single claw, in contrast to the adult having paired bifid dentate claws. The data on the mechanical interaction of C. elaterii at different developmental stages with different Cucurbitaceae species, combined with data on the chemical cues involved in the host plant selection, can help to unravel the complex factors driving the coevolution between an oligophagous insect and its host plant species.

The host range of Hishimonus concavus Knight was studied in the greenhouse and insectory by determining the suitability of various plants species to this vector of Loofah Witches'-broom for food, oviposition, and development. Fourteen test species of Cucurbitaceae were found to be suitable for oviposition, thirteen for development of nymphes, and thirty three for foods. Adult survival well on Cucurbitaceae, poorly on Convolvulaceae, Portulacaceae; and Amaranthaceae, but differed between the sezes on the same plant species. Females in general survival longer than males. Percent adult survival (females only) after 15 days was 80-100% on 13 species of Cucurbitaceae, 60-79% on 2 species. In the Cucurbitaceae, only Momordica charantia L. was found no eggs to he laid, Cucurbita moschata Duchesne was alto to be unsuitable for development of nymphs. Luffa cylindrica Roem, Lagenaria siceraria Standl, Citrullus vulgaris Schrad and Solena heterophylla (Lour.) Cogn. were more suitable for food, oviposition, and development of Hishimonus concavus Knight.

Charcoal, a byproduct resulting from incomplete combustion of biomass in fire events, can modify the physical properties of soil due to its high porosity and large surface area. To evaluate the impact of fire-deposited charcoal on soil hydraulic characteristics, soil–charcoal mixtures were analyzed to investigate the effects of different application doses (wt%: 0, 1%, 3%, 5%, 10% and 20%) of charcoal on soil bulk density (BD), porosity (total, capillary, and non-capillary), residual moisture after free drainage (RM), saturated water content (SC), and saturated hydraulic conductivity (Ks) of loamy and sandy soils collected from subtropical forests in south China. The results showed that the impact of charcoal on soil’s physical and hydraulic properties depends on the soil type and the application dose. The incorporation of charcoal significantly decreased the BD of sandy soil (p < 0.001), while a significant decrease in BD in loamy soil was only observed as a result of the higher application doses (10% and 20%) (p < 0.001). Charcoal application doses of 5% or higher led to a significant increase in the total porosity (TP) of sandy soil (p < 0.001) and doses of 3% and 20% resulted in a significant increase in the TP of loamy soil (p < 0.001). The capillary porosity (CP) of both sand and loamy soils significantly increased when charcoal was applied at doses of 3% or higher (p < 0.001). The minimum charcoal application dose that significantly increased the RM in sandy soil was 5%, while for loamy soil, the minimum effective dose was 10%. Charcoal applied at a dose of 3% significantly increased the Ks of sandy soil (p < 0.001), while no significant effect on Ks was observed for loamy soil (p > 0.05). Collectively, our findings suggest that fire-derived charcoal enhances the soil water-retention capacity in subtropical forests, with the effects becoming more pronounced at higher application doses and being particularly notable in sandy soil compared to loamy soil.

Maize is one of the main fodders and food source and even staple food in different countries. The presence of arsenic (As) in the soil has been reported to affect the growth and productivity of agricultural crops. The plant uptake of As from soil might depend on the composition and type of soil texture. In this study, we assessed the effect of four levels (0, 25, 50 and 100 mg As kg-1 of soil) of As on As uptake as well as the growth and physiology of maize (Zea mays) grown in three soils varying in texture in a pot experiment conducted at Government college university Faisalabad in February-March, 2018. Results revealed that the growth parameters significantly decreased in response to increasing concentrations of As in all three types of soil. The most prominent effects of As treatments on maize were shown under sandy loam soil followed by loamy soil and then clayey soils. At highest level of As application, the maximum As concentration in plant shoot and root were found in sandy loam soil (45.1 and 93.4 mg kg-1) followed by that in loamy soil (39.9 and 86.2 mg kg-1) and clayey soils (34.9 and 81.1 mg kg-1). Similarly, the maximum Diethylenetriamine Pentaacetic Acid (DTPA) extractable As (2.4 mg kg-1) was detected in sandy loam soil, whereas, the lowest (2.1 mg kg-1) was observed in clayey soil. Antioxidant enzyme activities and protein contents were maximum in the soils amended with 25 mg as kg-1, and were significantly decreased in the soils containing higher levels of As. However, these values were relatively higher in the clayey soils followed by the loamy soil and least in the sandy loam soil. The reactive oxygen species (ROS) including hydrogen peroxide (H2O2), superoxide (O2-) and melondialdehyde (MDA) were found to increase with increasing level of As in the soils. The effects of As on ROS were also maximum in sandy loam soil followed by the loamy soil and minimum in clayey soil. Conclusively we can say that the presence of As significantly affected the growth and physiological parameters of the maize crop. However, the effects of As were more severe in sandy loam soil as compared to the other ones. Keywords: Arsenic, Maize, Soil texture, DTPA extractable As, Growth, Antioxidants.