Fertility Production Research Articles

Exploring the Potential of Plant Biofertilizers: A Sustainable Approach for Agricultural Nutrient Management

In the face of escalating environmental concerns and the imperative to ensure sustainable agricultural practices, the utilization of plant biofertilizers has emerged as a promising solution for enhancing soil fertility and crop productivity. This paper delves into the burgeoning field of plant biofertilizers, aiming to elucidate their potential as a sustainable approach for agricultural nutrient management. Furthermore, it explores the diverse range of plant-based materials and microbial inoculants utilized in biofertilizer formulations, highlighting their mode of action and application strategies across different agricultural systems. Moreover, the ecological benefits of plant biofertilizers, including reduced reliance on synthetic inputs, mitigation of environmental pollution, and promotion of soil biodiversity, are underscored. Additionally, challenges and constraints associated with the widespread adoption of plant biofertilizers are addressed, offering insights into future research directions and potential solutions. Ultimately, this paper underscores the pivotal role of plant biofertilizers preparation methods in fostering sustainable agriculture practices and ensuring food security in a rapidly changing world.

Interaction of Biochar Addition and Nitrogen Fertilizers on Wheat Production and Nutrient Status in Soil Profiles.

To investigate the responses of crop production and soil profile nutrient status to biochar (BC) application, we conducted a soil column experiment considering two BC addition rates (0.5 and 1.5 wt% of the weight of 0-20 cm topsoil) combined with two nitrogen (N) input levels (low N: 144 kg ha-1, LN; high N: 240 kg ha-1, HN). The results showed that BC application increased the soil pH. The soil pH of the 0-10 cm profile under LN and the 20-40 cm profile under HN were both significantly increased by 0.1-0.2 units after BC addition. Under LN, BC addition significantly increased NH4+-N (17.8-46.9%), total N (15.4-38.4%), and soil organic carbon (19.9-24.0%) in the 0-10 cm profile, but decreased NH4+-N in the 20-30 cm soil profile and NO3--N in the 10-30 cm profile by 13.8-28.5% and 13.0-34.9%, respectively. BC had an increasing effect on the available phosphorus, the contents of which in the 10-20 and 30-40 cm soil profiles under LN and 20-30 cm profile under HN were significantly elevated by 14.1%, 24.0%, and 23.27%, respectively. However, BC exerted no effect on the available potassium in the soil profile. BC had a strong improving effect (15.3%) on the wheat yield, especially the N144 + BC0.5% treatment, which could be compared to the HN treatment, but there was no yield-increasing effect when high N fertilizer was supplied. In summary, BC improved the fertility of agriculture soil (0-20 cm) with wheat. In particular, low N inputs together with an appropriate rate of BC (0.5 wt%) could not only achieve the low inputs but also the high outputs in wheat production. In future study, we will compare the effects of multiple doses of N and BC on soil fertility and crop production.

Evaluation of Organic Sources and Mineral N Fertilizer on Soil Fertility and Coriander Plant (Coriandrum sativum L.) Productivity and Quality under Saline Soil

Two field experiments were carried out at Gelbana, North Sina government during successive winters 2021/2022 and 2022/ 2023 to study the evaluation of organic sources (compost, biochar, and organic farm) combined with or without mineral N different rates on soil fertility and Coriander productivity. Lies coast of Sinai, between 32o_ 350 and 32o_ 450 E and 31o_ 000 and 31o_ 250 N. Lies in the north-western Mediterranean coast of Sinai, between 32o_ 350 and 32o_ 450 E and 31o_ 000 and 31o_ 250 N. Each experiment was carried out in a split-plot design with three replicates in both seasons. Results showed that applying compost combined with or without mineral N fertilizer at different rates improved soil fertility (decreased soil pH, soil salinity, and increase of available macronutrients and micronutrient contents in soil) compared with other treatments. Also, the maximum mean values of Plant height (cm); No. of branches /plant; the weight of seeds /plant (g); the weight of seeds yield (ton/fed), fresh green leaves (ton/fed), and dry yield leaves (ton/fed) for soil treated with compost combined with mineral fertilizer different rate, while the weight of 1000 (g) seeds as affected by organic farm combined with mineral N fertilizer rate. The highest values of N, P, K, Fe, Mn, and Zn concentrations in seeds were treating with compost combined with mineral N fertilizer at a 100 kg N /fed rate than other treatments. As well as, the application of compost combined with mineral N fertilizer at different rates was an increase in protein (%), oil (%), and carbohydrate (%). chlorophyll while the proline was decrease value.

Isolation and Characterization of Phosphorus Solubilizing Bacteria from Millet Rhizosphere in Lafia metropolis

Phosphorus is an essential, but often unavailable nutrient for plant growth in the soil due to its low solubility. Phosphorus solubilizing bacteria (PSB) convert insoluble forms of phosphorus into soluble forms that can be taken up by plants. The study aimed to isolate and characterize PSB from the rhizosphere of millet plants in Lafia, and to evaluate their potential for improving soil fertility and crop productivity. Soil samples were collected from four different locations and plated on Pikovskaya's agar medium. PSB colonies were identified based on their ability to produce clear zones around them. The PSB isolates were further characterized by morphological, biochemical, and molecular methods. The phosphate solubilizing activity and plant growth-promoting traits of the PSB isolates were also assessed. The PSB isolates were tested for their effect on the growth of millet seedlings in pots. The results showed that 16 PSB isolates belonging to four genera (Bacillus, Pseudomonas, Enterobacter, and Klebsiella) were obtained from the soil samples. The PSB isolates exhibited varying degrees of phosphate solubilizing activity, ranging from 11.2 to 81.6 mg/L. The PSB isolates also showed positive results for the production of indole acetic acid, ammonia, hydrogen-cyanide, and siderophore. The PSB inoculation significantly increased the shoot and root lengths, and fresh and dry weight of the millet seedlings. The study concluded that the PSB isolates from the millet rhizosphere in Lafia could enhance soil phosphorus availability and millet growth. The study recommended further research on the field application and optimization of the PSB inoculation.

Efficiency of neem (Azadirachta indica) as a nitrification inhibitor under laboratory conditions

The use of nitrification inhibitors is a technology that can increase the efficiency of nitrogen fertilization, and synthetic and natural products can be used for this purpose. However, the use of these products is still poorly studied in tropical regions. The objective of this work was to evaluate the nitrification of nitrogen, under laboratory conditions, with urea covered with doses of neem leaf or cake, using DMPP (3,4-dimethylpyrazole phosphate) for comparison. The treatments consisted of a 2 x 4 + 2 factorial scheme, with the first factor represented by neem sources (leaf and cake), used to cover the urea and the second factor by neem doses, these doses being 0, 10 , 20 and 40% of the total applied N (200 mg kg-1, using urea as a N source) and two additional treatments: control (soil without nitrogen fertilizer) and urea + DMPP. Ammonium and nitrate contents were evaluated right after incubation (time 0) and on the 7th, 15th, 30th, 60th and 90th day after the start of incubation. For the ammonium content in the soil, there was influence of source and dose on the fifteenth day of incubation, with linear increments for both sources; and for nitrate levels, there was a significant effect (p<0.01) of neem doses on the 7th and 15th days of incubation, with a reduction in levels depending on the doses for the two sources tested. Significant differences (p<0.01) were found between additional and factorial treatments and between additional treatments for ammonium levels from the 7th to the 90th day of incubation. There was no significant interaction, in any of the dates, between neem sources and doses for ammonium and nitrate contents in the soil. Covering the urea with neem leaf and cake was efficient in reducing the levels of nitrate in the soil up to 15 days after incubation, resulting in higher levels of ammonium in the soil until this date. However, DMPP was more efficient in reducing nitrification, promoting inhibition up to 60 days of incubation.

Assessment of the impact of methods of biologization of the agrocenosis of apple trees (<i>Malus domestica</i> Borkh.) on soil fertility and plant productivity

The influence of methods of biologization of the agrocenosis of the orchard, including soil blackening with cereal-legume mixtures of perennial grasses in combination with the introduction of biofertilizers of various spectrum of action, on soil fertility and productivity of apple trees (Malus domestica Borkh.) has been studied. The study was carried out in a two-factor long-term field experiment on meadow soils of the Salgir River valley (Republic of Crimea). It was revealed that the biologization of the agrocenosis of the apple tree contributed to the enrichment of the soil with organic matter, increased the content of its active components, led to the accumulation of mobile forms of phosphorus and potassium with a slight decrease in the content of nitrate nitrogen in the soil. At the same time, the concentration of nutrients in the leaves of the apple tree, including nitrogen, increased. All this contributed to an increase in the yield of fruits. Quantitative relationships between indicators of soil fertility and productivity of apple trees have been revealed. The obtained dependencies allowed us to build a model of productivity of Golden Delicious apple trees during the biologization of its agrocenosis. The most effective combination of the studied methods of biologization is the use of soil blackening with a cereal-bean mixture 3 (CBM3) with bacterization of the root system of an apple tree with a nitrogen-fixing strain (NFS).

Effect of Natural IAA Produced by Streptomyces Strain ACM37 on Seed Germination and Seedling Growth


 
 
 Biofertilizers play an important role in sustainable agriculture by improving soil fertility, crop tolerance and crop productivity. In this context, exploitation of plant growth promoting rhizobacteria with various beneficial properties is challenging. This study aimed to investigate the plant growth promoting activity of indole-3-acetic acid (IAA)-producing actinomycetes strain, Streptomyces ACM37 on the seed germination and seedling growth at early stage. The ACM37 was grown in starch-casein broth for 7 days at 28° C, 80 rpm and supplemented with 50 mg/l L- tryptophan to induce IAA production. After 7 days, IAA concentration in cell-free culture broth was quantified by following the Salkowski's method and it was 50 mg/l. Seed germination and seedling growth of cowpea (Vigna unguiculata) and rice (Oryza sativa L.) at different concentrations of IAA were estimated as % seed germination, number of roots, primary root length and length of hypocotyl. Initially, seeds were surface sterilized with 10% (v/v) NaOCl and soaked in 10, 20, 30, 40 and 50 mg/l crude IAA preparations for 1 h at 30° C. As controls, seeds were soaked in sterilized distilled water (SDW) and 50 mg/l synthetic IAA. Ten seeds per each treatment with three replicates were placed on 0.8% (w/v) water-agar in Petri plates and incubated in dark at 30° C. The % seed germination of ACM37-IAA-treated cowpea and rice seeds was enhanced at all concentrations compared to SDW and synthetic IAA treatments after 3 days. The highest 100% germination of cowpea was given at 10 mg/l IAA while it was 96.67±3.33% in>30 mg/l IAA in rice. Similarly, there was a significant (P<0.05) increase in primary root length and number of lateral roots in cowpea at 10 mg/l of ACM37-IAA. Overall, ACM37 showed significant plant growth promotion in cowpea at low concentration (10 mg/l) of IAA whereas there was a significant (P<0.05) reduction at high concentrations (>10 mg/l). On the other hand, there was no apparent increase in all growth parameters except seed germination in rice at all concentrations. It appears that high concentrations of ACM37-IAA may be required to promote plant growth in rice. Overall results highlight that plant growth promotion activity of ACM37 varies at different IAA concentrations and different plant species, probably between monocot and dicot species. Therefore, ACM37 has potential application as a plant growth promoting agent in biofertilizers and plant growth inhibiting agent in bioherbicides at certain IAA concentrations.
 Keywords: Actinomycetes, Biofertilizer, Bioherbicide, IAA
 
 

Role of Land Use Dynamic Nature and Their Influence on Soil Physico-Chemical Properties in Various Watersheds in Ethiopia

Land-use changes have remarkable effects on the dynamics of soil properties. The lowest mean of bulk density, the highest fraction of clay, soil pH, soil organic matter, total nitrogen, available phosphorus, cation exchange capacity, and exchangeable base were recorded in forest land. Also, soil depth data might fluctuate with increasing soil depth. This variation might be due to inappropriate land use management led to disturbance of soil nutrient status, indicating that the soil condition in the cultivated land and plantation forest is getting below the condition of soils under natural forest and grazing lands. Therefore, needs immediate intervention to protect the remnant natural forest and to replenish the degraded soil properties proper land use plans and soil water conservations are important to enhance and sustain soil fertility and agricultural productivity.

Optimized Fertilizer–Water Management Improves Carrot Quality and Soil Nutrition and Reduces Greenhouse Gas Emissions on the North China Plain

In order to improve carrot quality and soil nutrition and reduce the environmental pollution caused by intensive carrot production, more comprehensive combined water–fertilizer management strategies are necessary. This study hypothesizes that optimal management of water and fertilizer can improve carrot yield and quality and reduce greenhouse gas emissions and soil nutrient residues. Thus, coordinated water–fertilizer management strategies were tested for carrot production on the North China Plain over two consecutive growing seasons. Four treatments were tested: local standard fertilization and irrigation practices (FNP); optimized irrigation and chemical nitrogen, phosphorus, and potassium fertilizer (OPT); OPT treatment with partial replacement of chemical fertilizer with peanut shell (PS); and OPT treatment with partial replacement of chemical fertilizer with mushroom residue (M). Compared to the FNP treatment, there were statistically significant increases in soluble sugars (12–27%) and free amino acids (14–26%), and decreases in the nitrate content (7–17%) of fleshy root in the OPT, PS, and M treatments. In autumn carrots, the OPT and M treatments decreased yield, whereas PS increased yield; spring carrot yield was significantly decreased in the OPT, PS, and M groups compared to the FNP group. There were no significant effects of the treatment group on carrot growth rates, nutrient accumulation, or nutrient distribution. However, the OPT, PS, and M treatments were associated with significantly increased partial productivity of phosphate fertilizer (233–363%), reduced residual levels of nitrate and available phosphorus in the top 80 cm of soil, and decreased greenhouse gas emissions by 8–18% compared to the FNP treatment. These results highlight the effectiveness of partial organic fertilizer substitution and integrated water–fertilizer management to produce high-quality carrots with minimal environmental damage.

Resource-Saving Measures to Improve Soil Fertility and Increase Plant Productivity through the Use of Straw

Resource-Saving Measures to Improve Soil Fertility and Increase Plant Productivity through the Use of Straw

Evaluating the role of caretaker‐rated personality traits for reproductive outcomes in a highly endangered Hawaiian corvid

AbstractPersonality studies are increasingly relevant and applicable to a broad range of conservation issues, including a role for selecting compatible mates in conservation breeding programs (CBPs). Choosing compatible breeding pairs is essential for maximizing reproductive success in CBPs, which provide assurance populations for species facing extinction and candidates for translocation to support wild populations. We investigated the value of caretaker‐assessed personality ratings of the critically endangered ‘Alalā (Hawaiian Crow, Corvus hawaiiensis) in predicting reproductive outcomes: nest quality, fertile egg production, and hatchability in the ‘Alalā CBP. Caretakers used well‐defined operational definitions to rate 22 personality traits for 69 male and 59 female ‘Alalā, achieving high inter‐rater agreement (ICC ≥ 0.85) for 8 traits – aggressive, bold/fearless, fearful, imprinted/abnormal, inept, submissive, territorial, and tendency to feather pluck (a stereotypic behavior) – used in a principal components analysis to distill intercorrelated variables into three principal components. While we did not find that personality influences nest quality or hatchability (based on limiting inferences to fixed effects with high relative importance scores; ≥0.8), we found some evidence that pairs with males that were more territorial/aggressive and fearful than their mates had a higher probability of egg fertilization, but there was substantial variability in this relationship, with confidence intervals overlapping zero. These personality traits may influence pair dynamics, enhancing compatibility, may predict better pair coordination on the nest, or both. Our results highlight the ability of caretakers to successfully identify ‘Alalā personality traits and provide some support for integrating personality into the pairing process; however, further research is needed to understand the value of ‘Alalā personality as a mate selection tool. The application of similar approaches to enhance CBP performance in other taxa is promising, but will require overcoming methodological challenges surrounding the complexity of data collection and interpretation of consistency among raters.

Soil bacterial community is influenced by long‐term integrated soil fertility management practices in a Ferralsol in Western Kenya

AbstractIntroductionSoil bacterial community structure, abundance and diversity, important in biogeochemical cycling, are influenced by several anthropogenic and edaphic factors. Numerous agronomic practices have been promoted to improve soil fertility and crop production in western Kenya, but little is known on their impacts on soil microbial diversity in the region.Materials and MethodsIn this study, conducted in 2019, we assessed the influence of various long‐term (17 years) agronomic management practices, involving application of farmyard manure (FYM) either sole or under different combinations with inorganic nitrogen (N), phosphorus (P) and potassium (K), using 12 treatments, on bacterial community composition, relative abundance and diversity. The bacterial community composition was assessed through amplicon sequencing on an Illumina Miseq platform conducted in MR DNA Laboratory, USA.ResultsThe soil bacterial community composition and diversity were predominantly higher under management practices with application of FYM, either sole or in combination with inorganic fertilisers compared to treatments with either sole NPK fertiliser or no input application. Certain bacterial taxa, involving Proteobacteria, Bacteroidetes, Nitrospirae, Fusobacteria, Nitrospinae and Actinobacteria predominated in management practices where FYM was added either solely or in combination with chemical fertilisers. In addition, several soil chemical parameters showed significant influences on bacterial composition, relative abundance and diversity indices. Soil pH, soil organic carbon (SOC), N, K, Ca, Mg, Cu, Zn, Fe and cation exchange capacity consistently showed strong positive correlation with numerous bacterial phyla. Bacterial phyla were significantly affected by treatments. Some bacterial phyla, like Chloroflexi and Acidobacteria, were mostly dominant in treatments applied with organic inputs but were depressed under carbon‐deficient treatments (no‐input control and sole NPK application treatments).ConclusionThis study revealed that long‐term agricultural management practices that seek to improve SOC content and nutrient availability also stimulated bacterial diversity and shifted bacterial composition.

Effect of filter cake and bagasse ash application on selected chemical properties of acidic Nitisol

The rising cost of lime, traditionally used to address soil acidity and its detrimental effects on soil fertility, has prompted the exploration of organic by-products as more affordable alternatives for mitigating soil acidity, particularly for low-income farmers. Therefore, the objective of this study was to investigate effects of filter cake (FC) and bagasse ash (BA) application on soil acidity under greenhouse condition. The experiment was laid out in a completely randomised design with four replications. The FC and BA were investigated separately each with six levels (0, 20, 40, 60, 80, and 100) t/ha-1. The acidic soil was collected from Imdibir area at a depth of 0-20 cm, air dried, ground and passed through 4 mm sieve. Each pot was received 4 kg of soil with respective treatment material after they were well homogenised. The laboratory analysis revealed that the soil had an initial pH of 5.1, while filter cake and bagasse ash had pH values of 8.0 and 10.2, respectively. Application of FC increased soil pH from 5.1 to 7.3, along with improvements in organic matter, nitrogen, phosphorus, sulphur, potassium, calcium, magnesium, and cation exchange capacity. Similarly, BA application raised pH from 5.1 to 7.4 and enhanced organic matter, nitrogen, phosphorus, sulphur, potassium, calcium, magnesium, and cation exchange capacity. The maximum effects for both FC and BA occurred at the highest application rate (100 t/ha-1), while iron and manganese content increased with BA application but decreased as rates increased, and copper and zinc levels were positively affected by both FC and BA applications. Overall, both FC and BA applications significantly improved soil pH and nutrient content. The findings of this study can provide practical and cost-effective solutions for improving soil fertility and crop production

Impacts of one-time large amounts of leafy vegetable waste incorporated into dryland fields on soil fertility and forage maize production

A large amount of vegetable waste is often dumped into the environment, causing serious pollution in major market distribution areas. This paper explores the feasibility and optimization of incorporating vegetable waste into dryland fields to improve soil fertility and crop productivity. The experimental design included three quantities of fresh leafy vegetable waste (QVW) buried into the soil: 800, 1600, and 2400 t·ha−1 and three covering soil thicknesses (CST): 10, 20, and 30 cm. Zero QVW was the control NW. By planting forage maize for two consecutive years, the variations of soil parameters and aboveground dry biomass (ABM) of maize plants were observed. Compared with the NW, the incorporation led to a distinct decline in soil bulk density (BD) by 2.00–17.41%, an increase in soil moisture (SM), organic carbon (SOC), total nitrogen (TN), and microbial carbon (MBC) by 5.84% −29.72%, 5.93% −50.17%, 16.98% −245.71% and 19.66% −304.08%, respectively. Topsoil conductivity (EC) and soil inorganic nitrogen (IN) were 3.81–9.43 fold and 19.02–88.29 fold that of NW. BD was significantly negatively correlated with the QVW and CST. SM, SOC, TN, and IN increased significantly with the increase of QVW and CST. The topsoil EC was significantly positively correlated with QVW, and negatively correlated with CST. The sequestration rates of SOC and nitrogen were significantly positively correlated with CST. The ABM in the incorporating vegetable waste treatment was 1.59–2.74 fold that of NW. The ABM showed a parabolic relationship with QVW (R2 = 0.97 **), and a linear relationship with CST (R2 = 0.91 **). Conclusively, the optimal QVW was 1346 t·ha−1, and the corresponding CST was 30 cm. Excessive QVW can cause topsoil salinization and constrain crop growth. Increasing CST contributes to sequestrating more water and nutrients and mitigating secondary salinization of the soil.

Prevalence of Abomasum Nematode infection in Sheep from North of Iran

Abstract
 In many countries, small ruminants provide the primary source of human protein and play an important role in livestock production. Parasitic infections, especially gastrointestinal parasites, cause economic losses such as reduced fertility and milk production, damage to the leather industry, weight loss, treatment costs, and losses in severe infections. Thus, identifying and classifying these parasites, including the above cases, is essential for scientific research in any country. This study aimed to Prevalence of Abomasum Nematode infection in Sheep from North of Iran. In the present cross-sectional descriptive study, we have studied the prevalence of infection with abomasum nematodes in sheep in northern Iran from April 2020 to September 2021 in 2400 abomasum sheep slaughtered in industrial slaughterhouses in Gilan and Mazandaran provinces (1200 sheep from each province). With three age groups of below two years, two to four years, and above four years and gender segregation of hosts, after necropsy and preparation of sheep abomasal mucosa chip and isolation and segregation of samples, we studied the morphologic and morphometric characteristics of the samples. The actions were performed according to the taxonomic keys and using SPSS software V.16 and Paired Sample T-Test statistical test to determine the level of significance of the data (p <0.05) to classify and compare the obtained data and examine the ratio. The sex of the host was determined by the age of the animal and the prevalence of the parasite at the mentioned ages. The present study results and comparison of the prevalence of infection in Gilan and Mazandaran provinces showed that Marshallagia marshalli had the highest prevalence of 94.6% and 91.9% in Mazandaran and Gilan province, respectively. The prevalence of Ostertagia circumcincta was 87.2% and 77.2% in Gilan and Mazandaran provinces. The prevalence of Ostertagia occidentalis was 86.9% in Gilan province and 78% in Mazandaran province, while the prevalence of Parabronema skrjabini was 86.6% in Gilan province and 61.2% in Mazandaran province. The prevalence of Haemonchus contortus was 66.8% and 60.5% in Gilan and Mazandaran, the lowest prevalence in these two provinces. The present study results showed the importance of combating the spread of parasitic infections with strategic treatment methods and biological control of these parasites. Also, various reports of drug resistance in abomasal nematodes should be emphasized more and more by competent bodies.
 Keywords: Abomasum, Nematodes, North of Iran, Parasitic infections, Sheep.

Adsorption of phosphate onto agricultural waste biochars with ferrite/manganese modified-ball-milled treatment and its reuse in saline soil

Agricultural waste biochar was widely used to absorb phosphorus (P) from eutrophicated water and soil remediation. However, the research on the reuse of the sorbed P on biochar in infertile saline soil is insufficient. Biochars derived from four kinds of agricultural wastes (cotton straws from two origins, maize stalk, and rice husk) were modified and applied to adsorb phosphate in waste water and then be reused in saline soil in this study. The co-modified method combining ball milling and metal coated treatment obtained the higher specific surface area (SSA) of ferrite/manganese modified-ball-milled biochars (Fe/Mn-BMBCs) (226.5–331.5 m2 g−1) than that of pristine biochars (14.02–30.35 m2 g−1) and ferrite/manganese modified biochar (Fe/Mn-BC) (223.7 m2 g−1), which could improve the pore structure of metal modified biochar. The phosphate adsorption capacity (qmax) of Fe/Mn-BMBCs with rich functional groups and high SSA were 44.0–53.8 mg g−1, which was 4.47–5.82 times higher than that of pristine biochars. Fe/Mn-BMBCs showed efficiently adsorption performance at low pH and high temperature. The application of BC to saline soil could promote the availability of P in saline soil. P-loaded biochars could afford P as a nutrient to promote the growth of lettuce (Lactuca sativa L.) in saline soil. The lettuce fresh weight in Fe/Mn-BMBC-P2 treated soil was 8.21 times higher than that grew in control check (CK) treatment. As a P element provider, P-loaded biochars not only improve saline soil fertility and crop productivity, but also convert the agricultural wastes and P in eutrophicated waters to the sustainable resource.

Development of Limpet aquaculture: Advances on settlement and early growth of Patella aspera Röding, 1798

The limpet Patella aspera is an endemic species to the Macaronesian Islands. Its high economic value and vulnerability to exploitation has triggered the interest in the development of its aquaculture. Significant progress has been made in recent years, with the establishment of artificial fertilization and larval production protocols. However, there are at least two major challenges that need to be addressed before a commercial production can be achieved: larval settlement and juvenile grow-out. The aim of this research was to study the effect of different algae substrates (Ulvella lens, Amphora sp., Entomoneis sp., Navicula salinicola and Nitzschia sp.) on P. aspera settlement and to test the effect of two diets on juvenile growth: a mono diet based on U. lens versus a mixed diet composed by U. lens and the diatoms Nitzschia sp. and Navicula salinicola. Results showed that U. lens was the most efficient settlement cue, given that 84.6% of the post-larvae obtained were found on this algae substrate. In the following trial, U. lens was selected as the base diet for the grow-out phase. The rearing system used ensured juvenile survival percentages above 80%. The regular supply of the diatom mixture, as a dietary supplement, significantly enhanced juvenile growth performance. After 220 days post fertilization, limpets that grew on the mixed diet (U. lens plus diatoms) presented an average shell length of 19.280 ± 5.296 mm. Additionally, developed gonads were observed in females with less than 8 months. This study presents the first record of P. aspera juvenile grow-out, born from artificial fertilization, which represents a major step toward the development of limpet aquaculture.

Partial organic substitution for synthetic fertilizer improves soil fertility and crop yields while mitigating N2O emissions in wheat-maize rotation system

Excessive synthetic N fertilization has resulted in severe soil degradation and high greenhouse gas emissions in agroecosystems. As a promising approach for achieving sustainable agriculture, partial organic substitution for synthetic fertilizer can affect the stoichiometric balance between organic C and inorganic N, thereby regulating nitrous oxide (N2O) fluxes. However, the responses of soil N2O emissions and crop productivity to different ratios of organic fertilizer (OF) to synthetic fertilizer (SF) are still unclear, making the optimal fertilization scheme less accurate. A 2-year field experiment was conducted to measure soil properties, N2O emissions, and crop yields in a wheat-maize rotation system. Six fertilization managements were included: no fertilization (CK); total SF; and 15%, 30%, 45%, and 100% of organic substitution for synthetic fertilizers (LO, MO, HO, and OF), respectively. Compared to SF, soil annual cumulative N2O emissions in LO, MO, HO, and OF were significantly reduced by 16.2–20.5%, 28.9–33.9%, 33.2–42.2%, and 70.2–74.9% in two years, respectively. The mitigation of N2O emission with organic substitution was mainly attributed to the decreasing NO3- and NH4+ contents and increasing soil pH. Meanwhile, soil organic C and total N were considerably higher in HO and OF than other treatments, with the lowest in CK in wheat season and in SF in maize season. Synthetic fertilizer and partial organic substitution increased the annual yield of wheat and maize compared with OF and CK in the first year, and HO increased the annual yield by 9.7% and 37.6% compared with SF and OF in the second year, respectively. The beneficial yield effects were mainly due to the enhanced synchronization of nutrient availability and soil fertility with partial organic substitution. Finally, the yield-scaled N2O emissions were reduced with increasing ratios of organic substitution in two years. Our study suggested that partial organic substitution for synthetic fertilizer, especially 45% organic substitution would be feasible fertilization strategy to improve soil fertility and crop productivity while mitigating N2O emissions in wheat-maize rotation systems.

Effects of Biochar Amendment on N2O Emissions from Soils with Different pH Levels

Biochar application has the potential for mitigating N2O emissions from agricultural soils and has been suggested as a management practice to ameliorate soil fertility and increase crop productivity. Nevertheless, the influence of biochar addition on N2O emissions from soils with different pH levels is not yet clear, which results in a poor understanding of the mechanisms regarding biochar application to soil N2O mitigation. A 40-day incubation experiment was carried out in the present study to investigate the impact of biochar on N2O emissions from soils with different natural pH. Four treatments (control, nitrogen fertilizer application, biochar amendment, and N plus biochar amendment) were set up separately in soils with three different natural pH levels (acidic vegetable soil, neutral rice soil, and alkaline soil). Our results showed that adding biochar significantly decreased N2O emissions by 20.8% and 47.6% in acidic vegetable soil for both N and no N addition treatments, respectively. For neutral and alkaline soils, the reduction of N2O emissions by biochar amendment was only significant for N addition treatments in alkaline soil. Soil pH and NO3−-N concentration were significantly affected by biochar amendment (soil pH increased by 1.43–1.56, 0.57–0.70, and 0.29–0.37 units for acidic vegetable soil, neutral rice soil, and alkaline soil, respectively). Thus, biochar amendment could be used as an effective management practice for mitigating N2O emissions from acidic and alkaline soils.

Distillers' grains organic fertilizer alters soil bacterial composition and co-occurrence patterns in a tobacco-growing field.

In recent years, numerous studies have indicated that the combination of organic and inorganic fertilizers can effectively improve soil fertility and soil productivity. Distillers' grain (DG), the primary by-product of Chinese spirits production, has a high utilization value for producing organic fertilizer. We investigated the effects of distillers' grain organic fertilizer (DGOF) on soil chemical properties and microbial community composition, as well as the effects of chemical properties on the abundance of keystone species. The results indicated that the application of DGOF significantly increased tobacco yield by 14.8% and mainly affected the composition rather than the alpha diversity of the bacterial community. Ten amplicon sequence variants (ASVs) were identified as keystone species in the bacterial communities, and most of their relative abundance was influenced by the DGOF addition through affecting soil chemical properties. Our results elucidated the alterations in soil chemical properties and microbial community composition resulting from DGOF application, which is of great importance to better understand the relationship between DGOF and soil microorganisms in the flue-cured tobacco cultivation field.