Low Nutrient Concentrations Research Articles

Chemical Fertility of a Ferralitic Soil in a Cropping System Based on Cereals (Fonio and Sorghum) and Legumes (Soya and Mung Bean) on An Experimental Station in Burkina Faso

In Burkina Faso, the low nutrient content of the country's soils has a direct impact on crop yields. The objective of this study is to evaluate the effects of applying organic matter (compost, poultry manure.), and mineral fertilizer Nitrogen-Phosphorus-Potassium (N:14% P:23% K:14%), urea (43% nitrogen) and Burkina Phosphate (BP) on soil fertility in a legume/cereal cropping system. The study was conducted at the INERA Farako-Bâ experimental station from 2018 to 2021. The experimental design was a 4x4 factorial, corresponding to four rotations and four manures, respectively, used as the first and second factors. A split-plot design with three replications was employed. The results obtained indicated that, in comparison to the initial soil, there was an increase of 33% in soil organic carbon and 36% in total nitrogen in the plots where soya and fonio were cultivated in rotation. In comparison to the plots with fonio-sorghum rotation, the plots with mung bean-sorghum and soya-fonio rotations demonstrated increase in assimilable phosphorus of 17% and 15%, respectively. Furthermore, the fertilizer combining compost and poultry manure resulted in a 300% increase in assimilable phosphorus and 28% increase in available potassium compared to the soil without fertilizer inputs and uncultivated for years. Additionally, the fertilizers of compost combined with poultry manure and compost combined with poultry manure and BP resulted in increases in assimilable phosphorus of 131.78% and 116%, respectively. The positive effects obtained on the chemical parameters (phosphorus, potassium and carbon) provide the potential for sustainable soil fertilization in cropping systems, while also valorizing local organic fertilizer.

From subsidies to stressors: Positively skewed ecological gradients alter biological responses to nutrients in streams.

Subsidy-stress gradients offer a useful framework for understanding ecological responses to perturbation and may help inform ecological metrics in highly modified systems. Historic, region-wide shifts from bottomland hardwood forest to row crop agriculture can cause positively skewed impact gradients in alluvial plain ecoregions, resulting in tolerant organisms that typically exhibit a subsidy response (increased abundance in response to environmental stressors) shifting to a stress response (declining abundance at higher concentrations). As a result, observed biological tolerance in modified ecosystems may differ from less modified regions, creating significant challenges for detecting biological responses to restoration efforts. Using the agriculturally dominated Mississippi Alluvial Plain (MAP) ecoregion in Mississippi, USA, as a case study, we tested the hypothesis that macroinvertebrate taxa that typically display a subsidy response to nutrient enrichment in less modified ecoregions (i.e., nutrient-tolerance) shift to a stress response to increasing nutrients in highly modified watersheds with elevated baseline nutrient conditions (i.e., nutrient intolerance). The abundance and diversity of MAP-specific intolerant taxa identified with threshold indicator taxa analysis were either unresponsive or exhibited a subsidy response to increasing nutrients in less modified ecoregions in Mississippi with less land alteration and lower nutrient concentrations, but declined at higher concentrations, providing evidence for a stress response to elevated nutrients in the MAP. Additionally, MAP-specific tolerant and intolerant taxa richness responded to increased nutrients predictably and consistently across space and time within the MAP. However, in MAP streams, elevated specific conductance was predicted to dampen the response of tolerant and intolerant taxa richness to increasing nutrient concentrations, highlighting the importance of considering multistressor interactions when interpreting biological data. Lastly, we demonstrate the efficacy of this approach with sediment bacterial communities characterized with amplicon sequencing, which lack sufficient life history characteristics necessary for the development of multimetric indices. Both macroinvertebrate and bacterial communities responded similarly to increasing nutrient concentrations, suggesting DNA-based approaches may provide an efficient biological assessment tool for monitoring water quality improvements in highly modified watersheds.

Environmental Assessment Using Phytoplankton Diversity, Nutrients, Chlorophyll-a, and Trophic Status Along Southern Coast of Jeddah, Red Sea

The objective of this study is to better identify the state of eutrophication of coastal waters along the southern coast of the city of Jeddah in the Red Sea. Thirty-six samples from surface seawater were collected during the spring and autumn of 2021. Water temperature, pH, salinity, dissolved oxygen (DO), nutrients, and chlorophyll-a (Chl-a) content were examined as a guide of water quality indicators. The present data revealed low levels of Chl-a content (in the range of 0.11–0.24 µg L−1). The average concentrations of DIN (dissolved inorganic nitrogen) forms follow the order NO3-N > NH4-N ~ NO2-N (representing about 11.4–29.4% of the total nitrogen). To investigate the trophic status and water quality, numerical indicators were applied to the results of the analysis of chemical variables (NH4-N, NO3-N, and PO4-P) and the biological analysis (Chl-a) in the aqueous environment within the study area. These indicators are simplified based on the specialist, the non-specialist, the decision-maker, and the one responsible for managing the coastal areas. We also obtain through this method a single numerical value that expresses the state of the coastal waters. According to the analysis of phosphorus and nitrogen data and a trophic index (TRIX), the study area’s trophic status was determined as oligotrophic, due to low nutrient concentrations in the seawater. The current study identified a total of 58 species of phytoplankton comprised four classes in the investigated areas; Bacillariophyceae was the dominant algal class (Diatoms 30 species), followed by Chlorophyceae (9 species), Dinophyceae (11 species), and Cyanophyceae (8 species). Seasonally, spring recorded the highest value of total phytoplankton, recording a value of 251 × 103 cells/L with a percentage of 61%, while autumn recorded the lowest value of 186 × 103 cells/L with a percentage of 39%. Phytoplankton classes can be arranged in order of prevalence as follows: Bacillariophyceae >> Dinophyceae > Chlorophyceae > Cyanophyceae.

Physicochemical Characteristics and Soil Suitability for Semi-Irrigated Rice Cultivation in The Tandjile Province of Chad

A study carried out in Tandjilé-Est, a region located in the South-Central part of Chad, aimed to examine the pedoclimatic and socio-economic parameters that cause the variability of rice yield (Oryza sativa) in an irrigated system. Three sites in the Kabalaye canton were chosen for soil sampling; these are Satégui, Mala and Djongo; in each site, five soil samples were taken. To assess the suitability of irrigated areas, two assessment methods were used on the two types of soils in the study area, including a Vertisol and a Planosol. This assessment shows that Vertisols are suitable for growing rice in an irrigated system, while Planosols are marginal. The main limitation in Planosols is the low nutrient content. To overcome this problem, it is necessary to improve the management of field fertility, rotate crops, and train producers in integrated fertility management and provide them with credit and adequate agricultural equipment. Int. J. Appl. Sci. Biotechnol. Vol 12(4): 180-186.

Effects of Straw Management and Nitrogen Application Rate on Soil's Physicochemical Properties and Rice Yield in Saline-Sodic Paddy Fields.

Straw return plays a vital role in crop yield and sustainable agriculture. Extensive research has focused on the potential to enhance soil fertility and crop yield through straw return. However, the potential impacts of straw return on saline-sodic soils have been relatively neglected due to the unfavorable characteristics of saline-sodic soils, such as high salinity, poor structure, and low nutrient contents, which are not conducive to crop growth. Therefore, a two-year field experiment was conducted to assess the effects of straw management (retention or removal) with nitrogen fertilizers (0, 90, 180, 270, and 360 kg N ha-1) on soil aggregates, soil chemical properties, and rice yields in saline-sodic soil. The results showed that straw return with nitrogen fertilization significantly decreased the soil exchange sodium percentage (ESP) and the percentage and organic carbon contribution of silty clay particles and also significantly increased the soil aggregate stability, organic matter (SOM), and percentage and organic carbon contribution of macroaggregates. However, there was no significant difference between 270 kg N ha-1 and 360 kg N ha-1 for all soil indicators under straw return. Straw return significantly increased rice grain yield by 5.77% (two-year average) compared to straw removal. The highest grain yield of 8.01 t ha-1 (two-year average) was obtained from straw return combined with 270 kg N ha-1. However, since this experiment was conducted for only two years, the positive effects of long-term straw return on soil and rice yield could have been greater. Therefore, the application of 270 kg N ha-1 in the early stages of straw return is a promising management practice for improving saline-sodic soils and increasing rice yields.

Growth Rates and Specific Aminoacyl-tRNA Synthetases Activities in Clupea harengus Larvae

Gaining robust in situ estimates of the growth rate of marine fish larvae is essential for understanding processes controlling year-class success and developing sustainable management strategies to maintain good environmental status. We measured the growth rate of Atlantic herring (Clupea harengus) larvae in the laboratory and compared it to the activity of aminoacyl-tRNA synthetases (AARS). Larvae were reared under controlled conditions for 20 days at three temperatures (7, 12, and 17 °C) using different prey concentrations (0.1, 0.3, and 2 prey·mL−1) of the copepod Acartia tonsa. The relationship between specific growth rates (SGR) and specific AARS activities was best described by a linear function—SGR = −0.1031 + 0.0017 · spAARS, r2 = 0.71, p < 0.05—when only larvae fed ad libitum were considered regardless of the temperature. When larvae fed with low concentrations of food were included in the analysis, the relationship was SGR = −0.0332 + 0.0010 · spAARS, r2 = 0.42, p < 0.05. This latter slope was rather low compared to other studies performed in zooplankton. We suggest protein degradation during the early life stages of fish as the cause of this low slope. We also studied SGR under food deprivation and the effect on specific AARS activities. We found rather high specific AARS activities in small individuals of early stages of fish, also suggesting protein degradation. Further research about protein degradation and turnover rates is needed in order to use AARS activity as a proxy for growth rates in field-caught larvae.

Impacts of phosphate-solubilizing bacterium strain MWP-1 on vegetation growth, soil characteristics, and microbial communities in the Muli coal mining area, China.

Due to the cold climate and low soil nutrient content, high-altitude mining areas are challenging to restore ecologically. Their poor nutrient content may be ameliorated by introducing specific microorganisms into the soil. This study aims to evaluate the effects of a highly efficient phosphate solubilizing bacterium MWP-1, Pseudomonas poae, on plant growth, soil nutrients in remedying the soil of the high-altitude Muli mining area in Qinghai Province, and analyze its impact on microbial communities through high-throughput sequencing soil microbial communities. The results showed that MWP-1 significantly increased the content of soil available phosphorus by >50%, soil organic matter and total nitrogen by >10%, and significantly increased the height, coverage, and aboveground biomass of vegetation by >40% in comparison with the control (p < 0.05). MWP-1 mainly affected the composition of the soil bacterial communities at the taxonomic level below the phylum. Its impact on soil fungal communities occurred at the phylum and below taxonomic levels. In addition, MWP-1 also significantly improved the diversity of soil bacterial and fungal communities (p < 0.05), and changed their functions. It also significantly altered the relative abundance of genes regulating phosphorus absorption and transport, inorganic phosphorus dissolution and organic phosphorus mineralization in the bacterial community (p < 0.05). It caused a significant increase in the relative abundance of the genes regulating nitrogen fixation and nitrification in nitrogen cycling (p < 0.05), but a significant decrease in the genes regulating phospholipase (p < 0.05). Although sequencing results indicated that Pseudomonas poae did not become the dominant species, its dissolved phosphorus elements can promote plant growth and development, enrich soil nutrient content, and affect the succession of microbial communities, enhance ecosystem stability, with an overall positive effect on soil remediation in the mining area.

Nutrient availability explains distinct soil fungal colonization of angiosperm versus gymnosperm wood

Abstract Soil fungi play an essential role in the fungal colonization of deadwood, with consequences for multiple ecosystem functions such as wood decomposition. Nutrient deposition can substantially affect fungal activity, but it is unclear how external nutrient inputs and host plant nutrient content interact to influence soil fungal colonization of deadwood. To advance understanding of fungal dynamics during deadwood decomposition, we conducted a field experiment with eight tree species (four angiosperms and four gymnosperms) under four nutrient additions (no nutrient addition, nitrogen (N)‐addition, phosphorus (P)‐addition and combined N‐ and P‐addition), to investigate fungal colonization and communities in different host plant clades (angiosperms and gymnosperms) over 3 years. The study revealed that host plant clade and nutrient availability interact significantly, which strongly influenced soil fungal colonization of deadwood. The percentage of shared fungi (present in both soil and deadwood) was higher in angiosperms (38.1%–47.3%) than in gymnosperms (26.5%–36.5%). Saprotrophs were the dominant functional group in the shared fungal community, with symbiotrophs as the next most abundant group, and the dominant fungal taxa were mainly K‐strategists, which were more abundant in gymnosperms than in angiosperms. Notably, there was a stronger connection between soil fungi and deadwood fungi in gymnosperms compared to angiosperms, which was likely related to the importance of K‐strategist fungi for decomposing wood with low nutrient content. Overall, the shared fungal community in angiosperms was more sensitive to nutrient addition than in gymnosperms, resulting in greater changes to fungal taxa and functional groups. In angiosperm wood, N‐addition significantly increased α‐diversity but decreased β‐diversity of the shared fungal community, indicating N‐limitation. In gymnosperm wood, P‐addition significantly reduced both α‐diversity and β‐diversity of the shared fungal community, indicating P‐limitation. Synthesis. Our study demonstrates the divergent effect of nutrient addition on fungal colonization in angiosperms versus gymnosperms. Considering interactions between inherent plant traits and exogenous nutrient availabilities thus provides a more comprehensive understanding of the association between soil fungi and deadwood fungi during wood decomposition.

Effect of Premium Compost on Soil Carbon Microbial Biomass in Pineapple Plants on Marginal Land Central Lampung

Acidic soil reactions, low nutrient content, low organic carbon levels, and low soil biodiversity characterize marginal land. Adding organic matter, such as compost, is expected to rehabilitate these lands. One key biological indicator of successful land rehabilitation by adding organic matter or compost is soil carbon microbial biomass (SCMB). This study aimed to assess the effect of compost on SCMB in pineapple plants. It was designed using a Randomized Completely Block Design with four treatments: Control (P0) = Without compost (Pineapple Cultivation Standard at GGPC), P1 = Cow dung compost (50 Mg ha-1), P2 = Premium compost A (50 Mg ha-1) and P3 = Premium compost B (50 Mg ha-1). Each treatment was replicated four times. The data were analyzed using ANOVA at the 5% significance level, following testing for homogeneity of variance using the Bartlett test and additivity with the Tukey test. Different treatment means were examined using contrast orthogonal tests, and correlation tests were performed to explore relationships among key variables. Results indicated that cow dung and premium compost (A and B) increased SCMB by 89.31% and 84.06%, respectively, at 15 and 16 MAP observations. At 16 MAP observations, soil organic carbon and soil pH were correlated with SCMB; in contrast, at observations 13, 14, and 15 MAP, soil organic carbon, soil pH, soil moisture, and soil temperature did not correlate with SCMB.

Reconstructing Holocene hydroclimate variability and coastal dynamics of the Nile Delta: A diatom perspective

This study analyses diatom assemblages from a Nile Delta core (B-1) to probe Holocene hydroclimate changesand their influence on the ecological habitats of the delta coast, with a further focus on the effects of relative sea-level rise. We found that the freshwater diatom Aulacoseira granulata varied in tandem with hydroclimate pulses in the Nile watershed, driven by the shift of the Intertropical Convergence Zone (ITCZ), therefore serving as a proxy for palaeo-Nile flow. Based on the ecological affinities of diatom taxa, we defined 5 diatom assemblages (I-V). Assemblage I (>10.0-8.5 ka BP) shows high A. granulata abundance (60–80%), implying peak Nile flow during the African Humid Period (AHP), at least 3 times greater than that of the recent past. Assemblage II (8.5-7.5 ka BP) sees decreased A. granulata (20–40%) and emergence of freshwater diatoms with benthic-oligotrophic characteristics (e.g. Epithemia gibba), suggesting reduced Nile flow and a delta estuary where the habitat became shallower with lower nutrient content. Assemblage III (7.5-6.0 ka BP) shows A. granulata resurgence (50–80%), reflecting Nile hydroclimate variability post-AHP due to the migration of the Intertropical Convergence Zone (ITCZ). The high-resolution- diatom spectra of B-1 also revealed major habitat changes, from saline to fluvial-dominated environments, around 6.0 ka BP. Assemblage IV (6.0-3.2 ka BP) indicates a notable Nile flow decline and freshwater community proliferation, coinciding with coastal habitat expansion and delta progradation due to RSL stablisation and basin-wide aridification. Assemblage V (3.2-2.0 ka BP) is marked by drought-tolerant diatoms (Nitzchia amphibia, Hantzschia amphioxys and Cavinula cocconeiformis), indicating intensified aridification.

Hybrid membrane process for nutrient recovery and sodium reduction in aquaculture wastewater

The swift growth of the aquaculture industry has exacerbated nutrient discharge, leading to eutrophication, while low nutrient but high sodium content impedes effective nutrient recovery and reuse. This study presents a novel hybrid membrane-based treatment sequence comprising ammonia stripping (AS), vacuum membrane distillation (VMD), and nanofiltration in diafiltration mode (NF), designed to efficiently recover ammonia and phosphate and reduce sodium from mixed aquaculture effluents. The process achieved ammonia and phosphate recovery efficiencies of 88.74 % and over 99 %, respectively, with a corresponding sodium reduction of 99.04 wt%. The AS stage concentrated ammonia from 20.37 mg/L to 2046.67 mg/L, whereas the subsequent VMD and NF stages produced phosphate-rich (rose from 10.33 mg/L to 50.50 mg/L) and sodium-reduced retentates (decreased from 510 mg/L to 44.50 mg/L). Long-term testing over eight consecutive batches showed robust performance with ammonia flux decline by only 2.81 %, permeate flux reduction by 4.30 %, and minimal inorganic fouling, maintaining consistent permeate quality that met environmental standards. These findings underline the proposed hybrid process's potential for sustainable aquaculture wastewater management, offering substantial enhancement in nutrient and water recycling.

NATIVE MYCORRHIZAE FROM ETHIOPIA IMPROVE TREE GROWTH AND SEEDLINGS SURVIVAL CONTRIBUTING TO THE GREEN LEGACY PROGRAM

&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: A rapid production of tree seedlings in nurseries with a high survival rate after transplanting is important to respond to the current demand for programs of restoration of arid environments by forestation. The low level of seedlings’ survival and establishment, caused by low moisture and nutrient content of soils, has been a bottleneck to reaching the target of the forest national restoration in Ethiopia of last years. It is suggested that, inoculation with root-associated plant growth promoting microorganisms could help to ameliorate this scenario and also respond to the Ethiopia's Green Legacy Program. &lt;strong&gt;Objective&lt;/strong&gt;: To assess the potential of inoculation with arbuscular mycorrhizal fungi (AMF) native to Ethiopia to improve the survival and growth of trees that could be used in afforestation programs in Ethiopia. &lt;strong&gt;Methodology&lt;/strong&gt;: The study was carried out in three stages: (1) soil samples associated with roots of selected acacia species (T&lt;sub&gt;1&lt;/sub&gt;-AMF of&lt;em&gt; A. abyssinica&lt;/em&gt;, T&lt;sub&gt;2&lt;/sub&gt;-AMF of&lt;em&gt; A. seyal&lt;/em&gt;, T&lt;sub&gt;3&lt;/sub&gt;-AMF&lt;em&gt; &lt;/em&gt;of &lt;em&gt;A. tortilis &lt;/em&gt;and&lt;em&gt; &lt;/em&gt;T&lt;sub&gt;4&lt;/sub&gt;-Control) were collected of highland and lowland areas from Ethiopia, (2) Sorghum (&lt;a href="https://www.researchgate.net/publication/342429051_Evaluation_of_sorghum_Sorghum_bicolor_L_Moench_variety_performance_in_the_lowlands_area_of_wag_lasta_north_eastern_Ethiopia"&gt;&lt;em&gt;Sorghum bicolor&lt;/em&gt; (L.), provided by the Melkasa Agricultural Research Center-(MARC) served as a trap plant for &lt;/a&gt;the AMF consortium multiplication and (3) plant growth promotion by AMF was assessed throughout inoculations of seedlings of&lt;em&gt; &lt;/em&gt;&lt;em&gt;Delonix regia&lt;/em&gt; (Hook.) Raf.,&lt;em&gt; Sesbania grandiflora &lt;/em&gt;(L.)&lt;em&gt;, Cassia fistula &lt;/em&gt;L&lt;em&gt;., &lt;/em&gt;and&lt;em&gt; Azadirachta indica &lt;/em&gt;A. Juss., trees&lt;em&gt;. &lt;/em&gt;&lt;strong&gt;Results&lt;/strong&gt;: All inoculated seedlings showed significantly greater responses in all growth and mycorrhizal parameters over the non-inoculated trees. Consortium T&lt;sub&gt;2&lt;/sub&gt;-AMF associated to roots of&lt;em&gt; A. seyal &lt;/em&gt;from lowlands of Batu, showed significantly greater responses in all plant growth and mycorrhizal parameters over the AMF inoculums associated to other tree species evaluated. Significant and positive correlations were found between mycorrhizae and plant-growth parameters&lt;em&gt;. &lt;/em&gt;&lt;strong&gt;Implications:&lt;/strong&gt; Our results suggest that inoculation with native arbuscular mycorrhizal fungi indigenous from Ethiopia has the potential to significantly enhance survival and growth rates of tree seedlings. This could thereby advance national reforestation goals and addressing challenges in seedling establishment in arid environments. &lt;strong&gt;Conclusion&lt;/strong&gt;: The potential for growth promotion and establishment of tree seedlings evidenced, implies that further efforts should be directed towards the in-mass production of AMF-based inoculants, particularly associated with &lt;em&gt;A. seyal&lt;/em&gt; roots.&lt;/p&gt;

Influence of Acetylene Concentration on N2O and N2 Emissions from an Intensive Vegetable Soil under Anoxic and Oxic Conditions

Acetylene (C2H2) is often employed to assess soil total denitrification (N2O + N2) due to its ease of implementation. However, this technique underestimates soil denitrification in soils with low nutrient contents, particularly those supporting grain yields. To our knowledge, there are limited studies that have specifically investigated the impact of C2H2 on nutrient-rich vegetable soils, especially concerning the emissions of N2 and N2O and the nitrogenous gas product ratio (i.e., N2O/(N2O + N2)). In this study, we conducted both anoxic and oxic incubations at various C2H2 concentrations (0%, 0.01%, and 10%, v/v) and utilized a robotized sampling and analysis system to quantify soil N2, N2O, and CO2 emissions. Our findings revealed that the cumulative N2O production in soil treated with 10%C2H2 was significantly lower than that in soil treated with 0.01%C2H2 and soil without C2H2. Contrarily, high concentrations of C2H2 (10%, v/v) led to increased N2 production. Similar trends were observed under oxic conditions, where 10%C2H2 concentration did not enhance N2O production but markedly increased N2 and CO2 emissions. Moreover, the N2O/(N2O + N2) product ratio was notably higher in soils treated with 0%C2H2 compared to the 10%C2H2 treatment under anoxic conditions. These findings indicate that high concentrations of acetylene could facilitate the reduction of N2O to N2 and lead to underestimated soil total denitrification in vegetable soil, regardless of anoxic or oxic conditions. This discovery underscores the drawbacks when employing high concentrations of acetylene to evaluate actual total denitrification in intensive greenhouse vegetable soils, highlighting the necessity for further investigation into alternative methodologies.

Farmland Degradation in the Czech Republic: Drivers and Barriers of Mitigation Strategies in Agricultural Soils

ABSTRACTIn line with Sustainable Development Goal (SDG) 15.3, which aims to restore degraded land and soil, and the priorities of the Common Agriculture Policy (CAP) to mitigate environmental issues caused by intensive agriculture, understanding the factors influencing farmers' adoption of soil conservation practices (SCPs) is crucial. However, there is still a limited understanding of these specific factors, particularly in the context of the Czech Republic. This study investigates the perceptions and determinants influencing the adoption of SCPs among farmers in the Czech Republic. We analyzed 358 randomly selected farm households using probit and multivariate probit models. Our results show that a significant number of farmers perceive soil degradation as an important problem, attributing it to factors such as low soil nutrient content, declining soil humus, water and wind erosion. The results of our analysis showed positive associations for perceived effectiveness and profitability, indicating that farmers tend to adopt practices such as minimum tillage, mulching, mixed cropping, cover cropping, and continuous soil cover when these methods are perceived to be effective and profitable. Conversely, negative associations are found for perceptions of soil degradation and education, suggesting potential barriers to adoption with higher levels of perceived soil degradation and education. The study also highlights the complex interplay of information sources on adoption, with both positive and negative trends. In light of these findings, we propose recommendations, including that awareness campaigns should be tailored to address perceptions of soil degradation, and that the use of peer networks and information dissemination from research institutions can bridge the gap between scientific recommendations and on‐farm practices. Policy makers and agricultural extension services should work together to develop targeted strategies that take into account regional differences in the factors influencing adoption and ultimately promote widespread adoption of SCPs.

Assessment of the chemical composition of buriti (Mauritia flexuosa Liliopsida) and cassava (Manihot esculenta Crantz) residues and their possible application in the bioproduction of coconut aroma (6 pentyl-α-pyrone).

This work aimed to define strategies to increase the bioproduction of 6 pentyl-α-pyrone (bioaroma). As first strategy, fermentations were carried out in the solid state, with agro-industrial residues: Mauritia flexuosa Liliopsida. and Manihot esculenta Crantz in isolation, conducting them with different nutrient solutions having Trichoderma harzianum as a fermenting fungus. Physicochemical characterizations, centesimal composition, lignocellulosic and mineral content and antimicrobial activity were required. Fermentations were conducted under different humidification conditions (water, nutrient solution without additives and nutrient solutions with glucose or sucrose) for 9days. Bioaroma was quantified by gas chromatography, assisted by solid-phase microextraction. The results showed the low production of this compound in fermentations conducted with sweet cassava (around 6ppm (w/w)). The low bioproduction with sweet cassava residues can probably be related to its starch-rich composition, homogeneous substrate, and low concentration of nutrients. Already using buriti, the absence of aroma production was detected. Probably the presence of silicon and high lignin content in buriti minimized the fungal activity, making it difficult to obtain the aroma of interest. Given the characteristics presented by the waste, a new strategy was chosen: mixing waste in a 1:1 ratio. This fermentation resulted in the production of 156.24ppm (w/w) of aroma using the nutrient solution added with glucose. This combination, therefore, promoted more favorable environment for the process, possibly due to the presence of fermentable sugars from sweet cassava and fatty acids from the buriti peel, thus proving the possibility of an increase of around 2500% in the bioproduction of coconut aroma.

Improving sugarcane productivity on marginal soil in Takalar, Indonesia, through the application of sugarcane factory waste

Marginal soil with low nutrient content is a crucial problem in reducing crop productivity, including sugarcane. This study aimed to elucidate the possible improvement of the physical and chemical properties of marginal soil through the application of organic waste from sugar factories, namely kettle ash and press mud. Nine treatment combinations of 0, 10, and 20 t ha-1 of each kettle ash and press mud were arranged in a two-factor randomized factorial design with three replications. Soil organic matter, N, P, and K, soil aggregate stability, and sugarcane productivity were measured after planting sugarcane for five months. The results showed that the application of kettle ash and press mud, especially with a ratio of 20 t ha-1 kettle ash and 10 t ha-1 press mud, was able to reduce the leaching of organic matter and improve sugarcane growth, particularly increasing the number of tillers by 16%, stem height by 14%, and diameter by 16%. The sugarcane productivity obtained was 58.02 t ha-1. Other portions of kettle ash and press mud did not have a favorable effect on sugarcane productivity. This study provided practical insights for increasing agricultural productivity, especially in sugarcane plantations.

Inoculation with Arbuscular Mycorrhizal Fungi Supports the Uptake of Macronutrients and Promotes the Growth of Festuca ovina L. and Trifolium medium L., a Candidate Species for Green Urban Infrastructure.

Green roofs and walls play an important role in promoting biodiversity, reducing the urban heat island effect and providing ecosystem services in urban areas. However, the conditions on green walls/roofs (low nutrient and organic matter content, drought, high temperatures) are often unfavorable for plant growth. Arbuscular mycorrhizal fungi (AMF) can improve the growth and development of plants under stress conditions as they can increase nutrient and water uptake. In a 6-month pot experiment, we investigated the effect of AMF inoculation on the growth and NPK uptake of Festuca ovina L. and Trifolium medium L., which are used for green roofs and walls. Two variants of mycorrhizal inoculation were used in the experiment: a commercial mycorrhizal inoculant AM Symbivit (Symbiom Ltd., Lanskroun, Czech Republic) and a mycorrhizal inoculant collected from calcareous grassland in the Silesia region (Poland). Funneliformis mosseae was the most abundant species in the roots of F. ovina and T. medium with IM inoculum. In the CM variant, a dominance of F. mosseae was observed in the roots of F. ovina. In contrast, Archaeosporaceae sp. node 317 dominated in the roots of T. medium. Both inoculations had a positive effect on the increase in dry weight of the shoots of T. medium, but only the commercial inoculum had a positive effect on the growth of F. ovina. Both inoculations improved the P uptake by the roots and the P and K uptake into the shoots of T. medium. In addition, both inoculations improved the K uptake by the roots of F. ovina and the N, P and K uptake into the shoots. In conclusion, both AMF communities included in the inoculations had a positive effect on plant growth and nutrient uptake, but the effect depends on the plant and the mycorrhizal fungus species.

Stable phytoplankton community compositions in Lake Mead (Nevada-Arizona, USA) during two decades of severe drought

Lake Mead, a large reservoir on the Colorado River and a critical drinking water source for the southwestern United States, typically exhibits high water quality, characterized by low nutrient and chlorophyll-a concentrations. This stability persists despite the inflow of highly treated wastewater since the 1960s and significant water level declines since 2000, driven by the ongoing Megadrought and basin-wide consumptive use. Such environmental changes may alter phytoplankton communities, potentially leading to increased cyanobacteria abundance, which could negatively impact water quality and the aquatic ecosystem through harmful algal blooms and toxin production. Here we analyzed 17 years of phytoplankton community structure and chlorophyll-a concentrations in Lake Mead, alongside quantitative water quality data, including nutrients, temperature, and water clarity, to assess the effects of environmental changes on phytoplankton communities. Contrary to the hypothesis that cyanobacteria abundance would have increased throughout the reservoir, our results indicate that phytoplankton community structures have remained largely stable, except for shallow areas where increases in temperature or phosphorus levels were observed. Additionally, we evaluated machine learning models for predicting changes in phytoplankton community structures. While the models confidently predicted changes in total phytoplankton biovolume and chlorophyll-a concentrations within the input parameter boundaries, predictions of peak biovolume showed considerable uncertainty, emphasizing the importance of incorporating uncertainty analysis in forecasting and communicating results. This study underscores the current buffering capacity of large, oligotrophic reservoirs like Lake Mead to maintain stable phytoplankton communities despite environmental changes. However, it also highlights the potential for significant community shifts if this buffering capacity is exceeded.

Differential salt stress resistance in male and female Salix linearistipularis plants: insights from transcriptome profiling and the identification of the 4-hydroxy-tetrahydrodipicolinate synthase gene.

Lysine plays an essential role in the growth differences between male and female S. linearistipularis plants under salt stress. Furthermore, SlDHDPS is identified as a vital gene contributing to the differences in saline-alkali tolerance between male and female plants of S. linearistipularis. Soil salinization is a significant problem that severely restricts agricultural production worldwide. High salinity and low nutrient concentrations consequently prevent the growth of most plant species. Salix linearistipularis is the only woody plant (shrub) naturally distributed in the saline-alkali lands of the Songnen Plain in Northeast China, and it is one of the few plants capable of thriving in soils with extremely high salt and alkaline pH (>9.0) levels. However, insufficient attention has been given to the interplay between salt and nitrogen in the growth and development of S. linearistipularis. Here, the male and female plants of S. linearistipularis were subjected to salt stress with nitrogen-starvation or nitrogen-supplement treatments, and it was found that nitrogen significantly affects the difference in salt tolerance between male and female plants, with nitrogen-starvation significantly enhancing the salt stress tolerance of female plants compared to male plants. Transcriptional analyses showed 66 differentially expressed nitrogen-responsive genes in female and male roots, with most of them showing sexual differences in expression patterns under salinity stress. RNA-seq and RT-qPCR analysis demonstrated that six genes had an opposite salt-induced expression pattern in female and male roots. The expression of the 4-hydroxy-tetrahydrodipicolinate synthase encoding gene (SlDHDPS) in female roots was higher than that in male roots. Further treatment with exogenous lysine could significantly alleviate the inhibitory effect of salt stress on the growth of female and male plants. These results indicate that the SlDHDPS in the nitrogen metabolism pathway is involved in the resistance of S. linearistipularis to salt stress, which lays a foundation for further exploring the mechanism of nitrogen on salt tolerance of S. linearistipularis, and has a significant reference value for saline-alkali land management and sustainable agricultural development.

Impact of run-of-river damming on increasing phytoplankton biomass and species shift in a large Amazonian river

Run-of-river (ROR) dams, often perceived as having minimal environmental impact, can induce significant hydrodynamic changes that alter aquatic ecosystems. We investigated the impacts of an ROR dam on the Madeira River, the largest Amazon tributary, focusing on phytoplankton communities, their ecological implications, and related environmental factors. Our study examined changes in biomass and environmental factors (using General Linear Mixed Models - GLMM), species composition (using PERMANOVA) before and after damming, in both the main channel and tributaries (N = 549 samples). We also identified indicator species associated with different damming phases and regions through an indicator value analysis. The results showed that, following dam construction, the phytoplankton community changed in both the main channel and tributaries, with a shift from lotic diatoms to lentic phytoflagellates. This transition was likely facilitated by altered hydrodynamics and possibly influenced by the decomposition of flooded vegetation in the dam's influence zone. The decomposition of this vegetation could explain both the observed increase in oxygen consumption and the subsequent rise in phytoflagellate biomass after damming. However, despite the overall increase in phytoplankton biomass, the values remained within oligotrophic to mesotrophic conditions, consistent with the low nutrient concentrations recorded. However, we caution that the dam-created hydrodynamic conditions are optimal for phytoplankton growth, potentially exacerbating nutrient-related issues in the future. We recommend proactive management strategies to prevent nutrient enrichment from activities such as agriculture and livestock in isolated Amazon areas affected by dams, thereby mitigating potential degradation of water quality linked to increased phytoplankton biomass.