Nutrient Addition Research Articles

A coral-associated actinobacterium mitigates coral bleaching under heat stress

BackgroundThe positive effects of exposing corals to microorganisms have been reported though how the benefits are conferred are poorly understood. Here, we isolated an actinobacterial strain (SCSIO 13291) from Pocillopora damicornis with capabilities to synthesize antioxidants, vitamins, and antibacterial and antiviral compounds supported with phenotypic and/or genomic evidence. Strain SCSIO 13291 was labeled with 5 (and − 6)-carboxytetramethylrhodamine, succinimidyl ester and the labeled cell suspension directly inoculated onto the coral polyp tissues when nubbins were under thermal stress in a mesocosm experiment. We then visualized the labelled bacterial cells and analyzed the coral physiological, transcriptome and microbiome to elucidate the effect this strain conferred on the coral holobiont under thermal stress.ResultsSubsequent microscopic observations confirmed the presence of the bacterium attached to the coral polyps. Addition of the SCSIO 13291 strain reduced signs of bleaching in the corals subjected to heat stress. At the same time, alterations in gene expression, which were involved in reactive oxygen species and light damage mitigation, attenuated apoptosis and exocytosis in addition to metabolite utilization, were observed in the coral host and Symbiodiniaceae populations. In addition, the coral associated bacterial community altered with a more stable ecological network for samples inoculated with the bacterial strain.ConclusionsOur results provide insights into the benefits of a putative actinobacterial probiotic strain that mitigate coral bleaching signs. This study suggests that the inoculation of bacteria can potentially directly benefit the coral holobiont through conferring metabolic activities or through indirect mechanisms of suppling additional nutrient sources.

Plant biodiversity responds more strongly to climate warming and anthropogenic activities than microbial biodiversity in the Qinghai–Tibetan alpine grasslands

Abstract Biodiversity serves as the fundamental underpinning for ecosystem functions and services. As a result of human‐induced global change, there is a growing awareness of the substantial alterations in terrestrial above‐ground biodiversity, particularly within alpine regions. However, it remains uncertain whether below‐ground biodiversity will exhibit similar responses, both in terms of magnitude and manner, to anthropogenic global changes as above‐ground biodiversity. Here, we conducted a meta‐analysis to assess the impacts of warming, nutrient addition and grazing on plant and soil microbial biodiversity in alpine grasslands on the Qinghai–Tibetan Plateau, which are known to be climate‐sensitive and vulnerable. The analysis included 819 experimental observations from 152 studies, focussing on species richness, Shannon diversity and Pielou's evenness. We found that plant biodiversity exhibited greater sensitivity to climate warming and anthropogenic activities compared with soil microbial biodiversity. Specifically, plant richness and Shannon diversity were reduced by warming and nutrient addition, while plant evenness was increased by grazing. However, only microbial richness was increased by grazing and microbial evenness was increased by warming slightly. The responses of biodiversity to climate warming and anthropogenic activities were modulated by multiple factors. Specifically, the negative effects of warming on plant biodiversity were more pronounced in long‐term experiments under warmer or drier environmental conditions. The negative effects of nitrogen addition on biodiversity were enhanced by the intensity and duration of nitrogen treatment. Appropriate intensity and frequency of grazing were beneficial to sustaining plant biodiversity. Soil microbial biodiversity was weakly regulated, where bacterial Shannon diversity was more sensitive to nutrient addition, while fungal species richness was sensitive to grazing. Synthesis. Our findings reveal a mismatch between above‐ground plant and below‐ground microbial biodiversity in response to climate warming and anthropogenic activities in alpine grasslands, with plant biodiversity being more sensitive. In the context of future global change, plant biodiversity may be at greater risk than soil microbial biodiversity. In addition, biodiversity responses of different experimental and environmental conditions should be distinguished, and more attention is needed on biodiversity conservation in alpine steppe, or areas with warmer and drier environmental conditions, high‐intensity fertilization or heavy grazing.

Aeolian dust and hydro-biological characteristics: Decoding dust storm impacts on phytoplankton in the northern Arabian Gulf

Aeolian dust is an essential source of growth-limiting nutrients for marine phytoplankton. Despite being at the core of the Global Dust Belt, the response of the Arabian Gulf ecosystem to such atmospheric forcing is rarely documented. Here, the hydro-biological effect of mineral dust was studied in the northern Arabian Gulf (NAG) off Kuwait through monthly water sampling (December 2020 to December 2021), dust-storm follow-up sampling, and mineral dust and nutrient addition in-situ experiments. The multivariate analysis of oceanographic data revealed pronounced hydro-biological seasonality. The mineral dust deposition during two severe dust storm events in March and June 2021 showed a spatially varying effect of dust on coastal waters. The dust storms elevated the surface dissolved iron levels by several magnitudes, increased the dissolved inorganic nitrogen and phosphorous levels, changed their stoichiometry, and offset the hydrobiological seasonality. In the microcosms, dust input temporarily reduced phytoplankton phosphorous limitation in a dose-dependent manner when mesozooplankton (copepods) grazing was minimal. The microphytoplankton response to mineral dust inputs was comparable to that with nitrogen and phosphorous treatment. While Both treatments increased diatom size structure and biomass, the abundance of single-celled diatoms was comparatively higher in dust treatment. Multivariate analysis indicated that dust deposition alters the hydrographical properties of the surface ocean during dust storm events. The effects, though transient, were traceable for 3–16 days post-storm in coastal waters. The response of the summer phytoplankton to these changes, if delayed or muted, should be interpreted with caution given the summer water column stratification, the high nitrogen: phosphorous ratio and the low phosphorous solubility of aerosol dust, and the complex pelagic microbial food web interactions in the NAG. This study thus underlines the importance of a multivariate approach in documenting the ecological implications of Aeolian dust storms on marine environments closer to the dust source regions.

Nutrient loading weakens seagrass blue carbon potential by stimulating seagrass detritus carbon emission

Coastal nutrient loading has been linked to a decline in the capacity of seagrass ecosystems to sequester carbon (‘blue carbon’); however, the mechanisms are unclear. Here we investigated how nutrient loading can affect the contribution that seagrass plant material makes to blue carbon stocks by investigating plant quality-decomposition dynamics. Specifically, we used a combination of laboratory and field experiments to account for various changes in biogeochemical cycling from seagrass meadows, ranging from changes in leaf quality to CO2 fluxes. It was found that nutrient loading increased the ‘labile’ content of seagrass (i.e. increased levels of leaf nitrogen, phosphorus and soluble organic carbon (amino acid and soluble sugar content), and at the same time decreased levels of ‘recalcitrant’ carbon (i.e. materials that are harder for microbes to break down, such hemicellulose, cellulose and lignin contents). Nutrient-enriched leaves decomposed ∼ 18 % faster than non-enriched leaves (i.e. greater biomass loss from nutrient-affected seagrass), resulting in ∼ 80 % more CO2 emissions from nutrient-enriched seagrass. We also found that seagrass that naturally contained high levels of labile carbon at the start of the experiment were affected to a greater degree (i.e. higher CO2 emissions) by nutrients addition than seagrass that had high proportions of recalcitrant carbon to begin with. Overall, these findings suggest that nutrient loading can weaken the capacity of seagrass ecosystems to act as blue carbon sinks through its effect on seagrass leaf decomposability.

Current perspective on nutrient solution management strategies to improve the nutrient and water use efficiency in hydroponic systems

Hydroponics, a soilless cultivation technique using nutrient solutions under controlled conditions, is used for growing vegetables, high-value crops, and flowers. It produces significantly higher yields compared to conventional agriculture despite its higher energy consumption. The success of a hydroponic system relies on the composition of the nutrient solution, which contains all the essential mineral elements necessary for optimal plant growth and high yield. This review delves into the discussion of enhancing nutrient solution management strategies across different hydroponic systems. The aim of this review is to discuss various techniques for monitoring nutrient solutions in order to improve nutrient use efficiency (NUE) and water use efficiency (WUE). The conventional approach of monitoring the hydroponic nutrient solution using electrical conductivity measurement may not provide precise information about ion concentrations, potentially resulting in poor yields or excessive fertilizer usage. To overcome these limitations, alternative management strategies have been developed to enable more accurate monitoring and efficient management. One such strategy is the nitrogen-based approach, where nitrogen concentration becomes the primary controlled element in the nutrient solution and leads to WUE and NUE development by prolonging nutrient solution recirculation. Furthermore, various methods have been devised to improve nutrient solution strategies. These include using ion-selective electrodes to measure individual ions in the hydroponic nutrient solution, using sensors to monitor substrate moisture content, estimating water requirements, and implementing programmed nutrient addition methods. In addition to introducing different management techniques to optimize hydroponic performance, this review provides a better understanding of hydroponic systems.

Reutilization of food industrial waste for lutein production with heterotrophic microalgae Chlorella sorokiniana MB-1-M12

BackgroundLutein is a xanthophyll carotenoid commonly found in photosynthetic organisms, such as microalgae and plants. It serves as a photosynthetic accessory pigment and possesses antioxidant properties. Lutein is recognized for its prophylactic use in preventing Age-Related Macular Degeneration (AMD) and is widely employed in health supplements. The demand for lutein is steadily increasing. This study utilized Chlorella sorokiniana MB-1-M12 for heterotrophic growth and lutein production, employing molasses as a model of food industrial waste as an alternative carbon source. MethodsMolasses was hydrolyzed using acids, and the optimal hydrolysis conditions were determined by varying the types and concentrations of the acids. The resulting hydrolysate, which contains reducing sugars, was then recovered and used to support the heterotrophic growth of C. sorokiniana MB-1-M12 for lutein production. Significant FindingsThe best efficiency in molasses hydrolysis was achieved using 0.15 M sulfuric acid, resulting in a maximum sugar recovery of 0.721 gs of reducing sugar per gram of molasses. When the molasses hydrolysate reached a sugar concentration of 10 g/L, it yielded a biomass of 2.57 g/L and a lutein content of 2.1 mg/g. These findings indicate that molasses can effectively serve as a substitute for glucose as a carbon source, although it cannot provide all the essential micronutrients required for biomass growth. Consequently, the addition of nutrients in BG-11 medium became necessary. This study successfully demonstrates the upcycling of waste resources, such as molasses, into a high-value product like lutein, all achieved in a cost-effective and resource-efficient manner.

Computational modelling to advise and inform optimization for aeration and nutrient-dosing in wastewater treatment: Case study from pulp and paper mill in south-central Sweden

Sweden's pulp and paper sector accounts for a significant proportion of national energy usage, besides generating wastewater that causes eutrophication of nearby sinks. In this paper, the possibility of optimizing biological wastewater treatment at the Stora Enso Skoghall mill south of the city of Karlstad in central Sweden, with respect to electricity usage and the addition of nutrients, has been investigated. A computational model of the treatment process was developed, based on process data obtained from the said mill, and nine different scenarios were compared subsequently, with energy use, environmental impacts and operational expenses, as criteria. The most energy-efficient and cost-effective alternative was a combination of measures such as lowering the oxygen level in the MBBR (Moving Bed Bio-Reactor) from 3 mg/l to 2 mg/l and using the Hyperclassic aerator in the aerated lagoon. This arrangement yielded a 48.5 % reduction in operational expenses, and a 60 % decrease in the energy use, vis-à-vis the reference case, without affecting the efficiency of the treatment process. This also uncovered an opportunity to mitigate the annual global warming and eutrophication impacts, by approximately 100 tons CO2-eq. and 140 kg PO43−-eq. respectively. All attempts to optimise the use of resources and decrease the anthropogenic environmental footprint ought to be made to come closer to the targets set by the United Nations' sustainable development goals (SDGs). The authors' conclusion predicated on the results of the modelling and analysis done in this study is that the potential of seemingly small process modifications, such as lowering the oxygen level in the MBBR, and applying a more optimal dosage of nutrient salts, must not be overlooked by wastewater treatment plants in general (and those in pulp and paper mills in particular).

Pathways linking nutrient enrichment, habitat structure, and parasitism to host-resource interactions.

Human activities simultaneously alter nutrient levels, habitat structure, and levels of parasitism. These activities likely have individual and joint impacts on food webs. Furthermore, there is particular concern that nutrient additions and changes to habitat structure might exacerbate the size of epidemics and impacts on host density. We used a well-studied zooplankton-fungus host-parasite system and experimental whole water column enclosures to factorially manipulate nutrient levels, habitat structure (specifically: mixing), and presence of parasites. Nutrient addition increased infection prevalence, density of infected hosts, and total host density. We hypothesized that nutrients, mixing, and parasitism were linked in multiple ways, including via their combined effects on phytoplankton (resource) abundance, and we used structural equation modeling to disentangle these pathways. In the absence of the parasite, both nutrients and mixing increased abundance of phytoplankton, whereas host density was negatively related to phytoplankton abundance, suggesting a mixture of bottom-up and top-down control of phytoplankton. In the presence of the parasite, nutrients still increased phytoplankton abundance but mixing no longer did, and there was no longer a significant relationship between host density and phytoplankton. This decoupling of host-resource dynamics may have resulted from reduced grazing due to illness-mediated changes in feeding behavior. Overall, our results show that the impact of one human activity (e.g., altered habitat structure) might depend on other human impacts (e.g., parasite introduction). Fortunately, carefully designed experiments and analyses can help tease apart these multifaceted relationships, allowing us to understand how human activities alter food webs, including interactions between hosts and their parasites and resources.

Responses of a common tropical epiphyte, Asplenium nidus, to changes in water and nutrient availability.

Epiphytes are highly dependent on atmospheric inputs of water and nutrients. Reductions in water availability associated with warming and climate change and continual atmospheric nitrogen (N) deposition can affect plant growth but few studies have evaluated the effects of changes in both water and nutrient availabilities on epiphytes. We experimentally tested whether epiphyte growth is more water- or nutrient-limited, if nutrient limitation was stronger for nitrogen or phosphorus, and whether nutrient limitation interacts with water availability. We applied watering (high and low) and nutrient addition (control, +N, +P, +N+P) treatments to greenhouse-grown Asplenium nidus, a common epiphytic fern found in many tropical and subtropical wet forests. We measured leaf area production and leaf elemental concentrations to assess how A. nidus growth and physiology respond to changes in water and nutrient availabilities. We found that leaf growth of A. nidus was more affected by water availability than nutrient addition and the effect of adding nutrients was not fully realized under low-water availability. Among the different nutrient treatments, +N+P had the greatest effects on A. nidus growth and physiology in both watering treatments. Watering treatment changed leaf elemental concentrations but not their ratios (i.e. C:N and N:P). Nutrient addition altered C:N and N:P ratios and increased the concentration of the added elements in leaves, with more pronounced increases in the high-watering treatment. We conclude that the growth of A. nidus is more water- than nutrient-limited. When nutrient limitation occurs (i.e. under high-water availability), nutrient co-limitation is stronger than limitation by N or P alone. This result taken together with studies of other epiphytes suggests greater water than nutrient limitation is likely widespread among epiphytic plants. The limited effects of nutrient addition in the low-water treatment suggest that the effect of atmospheric N deposition on epiphyte growth will be limited when water availability is low.

283 Awardee Talk: Effects of Late Gestational Maternal Nutrient Balance on Nutrient Partitioning to the Gravid Uterus in Beef Cattle

Abstract Successful intrauterine growth relies on adequate placental nutrient transfer capacity and is determined by placental size, placental morphology, uteroplacental blood supply, nutrient transporter abundance, and the nutrients available in maternal circulation. The majority of bovine fetal growth occurs during late gestation and must be accompanied by similar exponential increases in uteroplacental development to allow for necessary nutrient delivery. Competition for nutrients in young females between maternal growth and satisfying pregnancy, lactation, and maintenance requirements is still poorly understood. Our current work investigated the relationships between maternal, fetal, and uteroplacental factors and the impacts of late gestational nutrient restriction on prenatal nutrient delivery to the calf. Analysis of 113 full-term expelled placentas revealed that primiparous dams and dams in thin body condition had smaller placentas than their older or fleshier counterparts, suggesting the addition of growth requirements or exhausted nutrient reserves limited placental and fetal development. Calf size at birth and placental weight were positively correlated among all females, but it is still unknown which controls and signals for the growth of the other. Uterine blood flow measured during late gestation was positively correlated with calf birth weight; however, uterine blood flow and placental weight were only positively correlated closer to parturition at 40 and 20 d before calving. Additionally, contralateral uterine blood flow may have a disproportionately greater contribution to placental and fetal growth as it more closely resembled total blood flow associations than did ipsilateral. In 2 experiments, primiparous females fed 70% of energy and protein requirements during late gestation lost body weight and condition, had less metabolites in circulation, and had lower maternal heart rates than those fed to meet requirements. In Exp. 1, nutrient restricted dams had less contralateral placental growth, yet total uterine blood flow and placental weight were maintained and ensured fetal growth similar to control offspring. In Exp. 2, nutrient restriction reduced calf birth weight by 15%. Fetal growth perturbations were largely driven by a 17% reduction in placental size along with less nutrients available from maternal circulation, independent of a concomitant decrease in uterine blood flow. At 48 h of age, calf visceral organs were smaller due to nutrient restriction, but asymmetrical growth allowed for growth of the brain, lungs, and bone to be spared. Ongoing analysis of cotyledonary nutrient transporter and angiogenic factor gene expression will provide crucial insight into another determinant of placental nutrient transfer capacity. These findings demonstrate that pregnant beef females in a negative nutrient balance will attempt to spare fetal growth but at a certain threshold placental adaptation can be compromised, resulting in intrauterine growth restriction. A better understanding of nutrient delivery to the gravid uterus will allow for improved management strategies to ensure optimal fetal growth.

Incubation of ombrotrophic bog litter and mixtures of Sphagnum, Betula and Calluna results in the formation of single litter-specific decomposition patterns

Peat accumulation is the result of an imbalance between the biomass production and the reduced decomposition of organic matter, which has allowed peatlands to accumulate high levels of carbon over time. Sphagnum-dominated peatlands are among the most threatened ecosystems due to increasing anthropogenic pressures and harsher environmental conditions caused by climate change. The resulting changes in vegetation alter litter interactions and change decomposition patterns by altering nutrient cycling, hydrological conditions and carbon sequestration capacity of bogs. The aim of this study was to identify decomposition patterns for different bog litter types and mixtures over time. We sampled litter from an ombrotrophic bog (Sphagnum, Betula, Calluna), prepared mixtures of litter types and incubated our samples under laboratory conditions. We evaluated decomposition proxies and used k-means clustering to detect the formation of litter- and mixture-specific decomposition patterns over time. Sphagnum litter had a consistently low decomposition and its presence in mixtures reduced enzymatic activities. Initially, Betula litter added high amounts of N and labile C compounds to leachates. k-means clustering revealed a typical initial decomposition pattern (i.e. lowest decomposition directly after starting the incubation, followed by highest decomposition rates, and a steady decrease until the end) for most litter types, except for Sphagnum. Litter-specific decomposition patterns emerged after 14 days. Betula litter did not enhance decomposition of other litter types in our short-term incubation, but additional nutrient inputs could alter peat-litter interactions in the long term, increasing the risk of losing the carbon sink function of nutrient-poor bogs.

439 Identifying Forage Efficient Cows

Abstract In recent years, substantial progress has been made in understanding the sources of biological variation and genetic components of feed efficiency in growing animals consuming energy-dense mixed diets during the post-weaning phase. Much less is known about within-animal variation of feed efficiency for beef cows consuming moderate to low-quality forage diets common to most cow/calf production systems and where > 74% of the total feed energy required to produce beef is consumed. Considerable evidence indicates the existence of a genetic by environment interaction for feed efficiency. Therefore, more rapid progress in forage utilization efficiency and reduction in greenhouse gas emissions in the cow herd could be made by studying feed efficiency when cattle consume moderate quality, unprocessed forage diets. Phenotype for feed intake and feed efficiency are most practically and cost effectively determined during the post-weaning growing stage. However, due to the additional nutrient sinks associated with gestation and lactation, little is known about the repeatability of forage utilization efficiency between growing heifers and beef cows. An update of recent advancements to identify forage-efficient cows will be provided during the presentation.

Nitrogen and phosphorus addition mediate soil priming effects via affecting microbial stoichiometric balance in an alpine meadow

Priming effect (PE) plays a crucial role in regulating the decomposition of soil organic matter (SOM). Multiple empirical results have shown that nitrogen (N) and phosphorus (P) addition can significantly alter the direction and intensity of PE, which may significantly affect carbon turnover in grasslands, especially in alpine meadows that are sensitive to N and P enrichment. To evaluate the PE responses to N and/or P addition, we conducted an incubation experiment by adding 13C-labeled glucose and nutrient additions (+N, +P, and +NP) in soils collected from an alpine meadow. The soils were incubated for 30 days and soil/microbial properties and enzyme activities were measured. Partial correlation and linear regression analyses were then performed to investigate their correlations with PE. The results showed that mean PE intensity among all treatments was 0.61 mg C g−1 soil or 1.35 (ratio). Nitrogen addition increased PE intensity, which was attributed to the better match between soil resources and microbial demands and enhanced enzyme activities. However, the PE intensity in P-addition soils was lower than that in control soils. This discrepancy may be related to the P-induced decrease of N availability and stronger microbial C/N imbalance. No significant response of PE intensity to NP addition was detected, and this could be explained by the offset of positive N effects and negative P effects on microbial decomposition. In this experiment, N or P addition altered the PE intensity by mediating the match between soil C:N:P ratio and microbial demands, which supported the stoichiometric decomposition hypothesis. Overall, our study highlights the importance of considering the C, N and P coupling in regulating PE, and underscores the need for further investigation into the effects of soil P on microbial activity and SOM decomposition.

Validation of Diacetyl Monoxime Method for Quantification of Urea in Sea Water

Urea is widely used in agriculture and aquaculture as a major source of nitrogenous fertilizer. Therefore, urea exists in dissolved form in the marine/freshwater ecosystem. However, if the concentration in waterbodies is higher than a threshold limit, it can be toxic to fish and prawns. Therefore, accurate measurement of urea is a must even in marine water systems. Estimation of urea from freshwater samples using colorimetric method is well established. The well-known diacetyl monoxime method is widely used for accurate estimation of urea from fresh water as well as various biological samples. The presence of various interfering ions in sea water affects the estimation and limits the adaptability of any new methods directly into sea water. The accurate and precise estimation of urea are essential to optimize the nutrient addition. In this study, the diacetyl monoxime method was considered for urea estimation in sea water (3.5% salinity) and the method was validated for specificity, linearity, robustness, ruggedness and sensitivity as per International Council for Harmonization guidelines. During this study, urea showed maximum absorbance at 524 nm wavelength in both the samples. This method was found linear up to 100 ppm of urea in fresh and sea water samples. The variations of wavelength by 5-10%, reagent volumes by 2.5-5%, sample storage, analysis did not show any significant impact on the estimation of urea from both the samples. However, the method was found more sensitive and showed the limit of detection of 0.5 ppm in fresh water and 1.5 ppm in sea water. The overall results indicate that this method is accurate and robust for sea water samples and therefore can be used for estimation of urea in sea water samples.

Effect of Deficiency-adjusted Macronutrients to Cure Brown Bast Syndrome in Rubber Tree (Hevea brasiliensis)

The brown bast (BB) syndrome causes a 15-20% loss of annual rubber (Hevea brasiliensis) production in Malaysia, and no sustainable remedy has been developed yet. Initial investigation showed a macronutrients deficiency in the bark of affected plants compared to non-affected plants. Therefore, this study was undertaken to know the effect of spraying the deficient macronutrients in curing BB syndrome and increasing latex productivity. The treatments were selected by adjusting deficient nutrients, especially in N, K, and S, compared to healthy plants. The treatments consisted of 13 combinations of nutrient concentrations and a control (no application on healthy rubber trees). One liter of individual treatment per tree was applied on the trunk of BB-affected trees once a week for one month. Data on latex production was collected one week after the last application and continued for up to three months. The results showed that the treatment T9 (0.5% N, 0.8 mg/L K, and 0.2% S), in addition to other prescribed nutrients, made a 100% cure of BB syndrome after three weeks of application, and the nutrient contents of the bark of the affected plants appeared to be similar to the healthy plants. Applying these additional nutrients enhanced the latex production at the rate of 51.85 g/tapping/tree after two months of treatment application under the agro-ecosystem of FELCRA, Simpang Renggam, Johor, Malaysia. It is a new finding to 100% cure BB syndrome and to increase the latex productivity in sustaining the rubber industry in Malaysia.

Effects of Nutritional and Culture Medium-based Approaches for Aquaponics System with Bio-floc Technology on Pak Choi and Catfish Growth Rates

Aquaponics with bio-floc can potentially offer sustainable food production with zero waste as it allows farming plants and fish simultaneously, whereby the former use fish waste as their nutrient sources, while the latter receives cleaner water from the plants in a closed-loop system. In the aquaponics system, additional nutrients are usually added to support optimal plant growth, but it is suggested that the amount of such chemical nutrients should be controlled to prevent any harm to the fish. Furthermore, the plant and fish growth rates are influenced by the nutrients and the culture media used. This study aims to examine the effect of nutrition (full-nutrient and half-nutrient treatments) and different types of culture mediums (rockwool, rockwool-perlite, and rockwool-husk) on the growth rates of pak choi (Brassica rapa) and catfish (Clarias gariepinus) using split-plot design. Findings show that the half-nutrient treatment yielded a 17.12% higher plant growth rate and 23.87% heavier catfish weight than the full-nutrient treatment, but these treatments did not affect the fish survival rate. It was also observed that using different culture mediums did not result in any significant difference.

A critical review on integrating bio fortification in crops for sustainable agricultural development and nutritional security

Numerous developing nations face epidemics that are characterized by nutritional deficiencies in both humans and animals. A further threat to nutritional quality is posed by the lack of dietary diversity, which consists predominantly of cereal-based crops lacking in essential mineral nutrients. Cereals and pulses are major food crops in backward countries; however, they often lack essential compounds, macronutrients, and micronutrients, resulting in imbalanced nutrition. Widespread malnutrition, characterized by ailments such as anemia, rickets, and scurvy, is a direct consequence of this nutritional imbalance. It is crucial to bio-fortify cereals and pulses to provide the population with balanced diets and reduce malnutrition. New breeding techniques (NBTs) such as gene editing, gene overexpression, and gene transfer from wild relatives offer alternative avenues to obtain crops with optimal nutritional profiles. This review delves into the significance of bio fortification in enhancing food crops and explores the utilization of advanced breeding methods for the development of novel bio fortified crop varieties, thereby tackling nutritional security within the realm of agriculture. It conveys a message to researchers regarding the considerable potential of bio fortification to enhance crop productivity while enriching crops with additional nutrients.

Obtaining phosphate fertilizer with additional nutrients

In order to obtain phosphorus fertilizer enriched with additional nutrients, the decomposition process of apatite concentrate with sulfuric acid was carried out with an additive, in the first variant – ammonium hydrophosphate, and in the second variant - ammonium and potassium hydrophosphates. Experimental studies have studied the effect of additives on the interaction of sulfuric acid with fluorapatite, as well as X-ray phase and IR spectroscopic analyses have studied the structural composition of the resulting product. It was found that with the use of additives, the resulting phosphorus fertilizer contains, along with calcium dihydrophosphate, also ammonium dihydrophosphate. A distinctive feature is the decomposition of sulfuric acid phosphates, resulting in a poorly soluble calcium sulfate that passes into the solid phase, which has traces of its presence in the resulting fertilizer, and may also not be part of the solution. The process of decomposition of fluorapatite with sulfuric acid using an additional part (NH4)2HPO4, the optimal amount of the additional part should be considered 12-18% (by weight of sulfuric acid) additive, while the highest degree of decomposition of apatite concentrate is achieved, which is 95-97%. The conducted studies have established that the introduction of an additive - ammonium and potassium hydrophosphates - into the process of sulfuric acid decomposition of apatite concentrate also has a positive effect on the duration of the superphosphate maturation period. To clarify the structural composition of the finished product, X–ray phase studies and IR spectrometric analysis of the powdered product were carried out. Thus, mineral fertilizers obtained with the use of additives having an additional nutrient element in their composition, namely nitrogen - in the first variant, and nitrogen and potassium - in the second variant.

Effect of nutrient management and soil type on stoichiometric imbalances across the Yangtze River Basin pear districts, China

AbstractNutrition management affects soil carbon (C), nitrogen (N), and phosphorus (P) cycles, as well as their stoichiometry, causing further stoichiometric imbalances. However, research on the effect of nutrient management on soil stoichiometric imbalance is restricted to a single soil type, limiting our understanding of the interactions between these parameters. Therefore, we conducted a study comprising 212 sites throughout the Yangtze River Basin pear districts, for which nutrient management and soil properties were available under different soil types. Soil stoichiometric imbalances varied widely among the districts, with an average C:P imbalance value (C:Pim) of 6.67, higher than that of C:N imbalance (C:Nim; 6.43) and N:P imbalance (N:Pim; 2.83). Meanwhile, soil and microbial biomass stoichiometry, particularly for soil C:P and soil microbial biomass carbon and phosphorus (MBC:MBP), were significantly influenced by nutrient addition. Large N and P fertilizer inputs altered soil C:N and C:P in yellow–brown earth, while soil C:P was influenced by organic nutrient management in purplish soil. Moreover, adding organic nutrients altered the MBP, which further influenced MBC:MBP and MBN:MBP in saline–alkaline soil and yellow–brown earth. Furthermore, C:Pim increased with increasing organic nutrient input in purple soil and decreased with a large chemical fertilizer input in red soil. N:Pim and C:Nim were weakly associated with nutrient management in different soil types. In addition, nutrition management, soil type, soil properties, and microbe content collectively accounted for 45%, 32%, and 38% of the C:Pim, C:Nim, and N:Pim variation, respectively. Nutrient management also exerted a positive direct impact on C:Pim, while soil type elicited a negative direct impact on C:Nim and N:Pim. Meanwhile, all three stoichiometric imbalances were indirectly influenced by soil type. Taken together, our results indicate that soil stoichiometric imbalances, especially for C:Pim, are sensitive to nutrient management and soil type, providing novel insights into these imbalances that can inform the development of potential remedial strategies.

Sustainable Production of Tomato Using Fish Effluents Improved Plant Growth, Yield Components, and Yield in Northern Senegal

Aquaculture and agriculture integration is essential for maximizing water and land productivity in arid and semi-arid regions. Thus, the increase in global water scarcity and the dual use of water for crop and fish production has the potential to optimize water use, dispose of aquaculture wastes, provide additional nutrients to crops, and reduce inorganic fertilizer usage, thus maximizing farm productivity. This greenhouse study was conducted to determine the effects of fish effluents on the growth, yield parameters, and yield of tomatoes (Solanum lycopersicum L.). The experiment was carried out in a randomized complete block design with six replications. The 13 treatments consisted of three irrigation water types (river water—control, Nile tilapia—Oreochromis niloticus, African sharptooth catfish—Clarias gariepinus), four fertilizers (chicken manure, cow manure, sheep manure; recommended rate of NPK—280 kg ha−1 of 10-10-20), and six mixed treatments with fish effluent and 50% of the applied rate of manure alone. Results showed that irrigation with C. gariepinus effluent increased the stem diameter by 21%, the number of flowers by 88%, the fruit number by 50%, the fruit diameter by 24%, the mean fruit weight by 34%, and total fruit weight of tomato by 96% compared to NPK treatments. These effects were more evident when C. gariepinus was mixed with poultry, cow, and sheep manures, which resulted in significantly greater values than recommended rates of NPK. The higher productivity observed from the combined use of C. gariepinus and manure treatments (133% increase, on average) compared to NPK treatments was related to the continuous supply of nutrients and the increase of yield parameters. Therefore, the combined use of C. gariepinus effluent and manure can be a viable alternative for smallholder farmers, for whom inorganic fertilizers are often neither affordable nor available.