Bio-organic Fertilizer Research Articles

Microbial community assembly and chemical dynamics of raw brewers’ spent grain during inoculated and spontaneous solid-state fermentation

Solid-state fermentation (SSF) carried out by microbial bioinoculants is an environmentally friendly technology for the sustainable recovery and valorization of agri-food wastes. Particularly, mesophilic SSF processes allows the production of bio-organic fertilizers enriched with beneficial soil microorganisms. However, the establishment of microbial consortia and the interaction with native waste microbiota still require thoughtful investigations. Here, raw brewers’ spent grain (BSG), the main waste from the brewing industry, was subjected to two mesophilic SSF processes (maximum temperature of 35 °C) carried out by a multi-kingdom microbial bioinoculant and the BSG spontaneous microbiota. After 90 days, both SSF processes led to stable organic soil amendments, as indicated by the C:N ratio (10.00 ± 1.4), pH (6.66 ± 0.09), and DOC (8.45 ± 1.2 mg/g) values. Additionally, the fermented BSG showed a high nitrogen content (42.2 ± 3.4 mg/Kg) and biostimulating activities towardLepidium sativumseeds. The monitoring of microbial communities by high-throughput sequencing of 16S and ITS rRNA indicated that BSG samples were enriched in microbial genera with interesting agronomic applications (i.e.,Devosia, Paenibacillum, Trichoderma, Mucor, etc.). Microbial cross-kingdom network analyses suggested that the microbial assembly of BSG was significantly influenced by the bioinoculant, despite the inoculated microbial genera being able to persist in BSG samples only the first week of SSF. This suggests that the study of microbial interactions between exogenous microbial inoculants and waste resident microbiota is required to optimize SSF processes aimed at the recovery and valorization of unprocessed wastes.

Machine learning-based estimation and mitigation of nitric oxide emissions from Chinese vegetable fields

High fertilizer input and nitric oxide (NO) emissions characterize the intensive vegetable production system. However, the amount, geographic distribution, and effective mitigation strategies of NO emissions over Chinese vegetable fields remain largely uncertain. In this study, we developed a data-driven estimate of NO emissions and their spatial pattern in Chinese vegetable fields based on the Random Forest (RF) model. Additionally, we conducted a field experiment in a subtropical vegetable field to investigate the effect of climate-smart practices on NO emissions. The RF model results showed that soil NO emissions from Chinese vegetable fields were sensitive to nitrogen application amount, soil clay content, and pH. The total NO emission from Chinese vegetable fields in 2018 was estimated to be 75.9 Gg NO–N. The urgency to reduce NO emissions in vegetable fields was higher in northern than in southern China. Our meta-analysis and field experiment results suggested that biochar amendment and replacing chemical fertilizers with bio-organic fertilizers were win-win climate-smart management practices for mitigating NO emissions while improving vegetable production. Overall, our study provided new insights into NO emissions in vegetable soil ecosystems and can facilitate the development of regional NO emission inventories and effective mitigation strategies. These findings highlight the importance of adopting sustainable and climate-smart agricultural practices to reduce NO emissions and mitigate their adverse environmental impacts.

Study of the efficiency of growing maize for silage for processing into biogas and digestate

Given the growing area of maize cultivation in Ukraine and globally, research into the possibilities of using silage as a component of biogas plants to produce biogas as an alternative fuel and digestate as a bio-organic fertiliser is of high relevance and production necessity. The purpose of this study was to investigate the chemical composition of green mass of maize and its changes depending on the growing season for its use in biogas production. Field, laboratory, laboratory-field, and statistical research methods were used in the study. The findings of this study showed that the quality of maize silage depends on soil and climatic conditions, elements of growing technology, genetic characteristics of a particular hybrid, its maturity group, harvesting time, etc. The genetic characteristics of the hybrid had the greatest influence on the dry matter content, specifically, the mid-early hybrid Amaros stood out in terms of dry matter content on 10-14 August 2020 (26.61%). The highest crude fibre content was observed in the hybrid P9170 – 6.32% and 26.86%, respectively, in natural and absolutely dry matter. This hybrid belongs to the mid-season ripeness group. The shift in the harvesting time of the green mass of the maize hybrids under study also affected the characteristics of the chemical composition and the carbohydrate-lignin complex of the green mass of the maize hybrids under study. The yield of green mass of maize hybrids substantially depended on the maturity group of maize hybrids and was highest in the mid-season maize hybrids Burito – 78.1 t/ha and P9170 – 73.1 t/ha, while in the group of mid-early hybrids it was 55.3 t/ha and 68.9 t/ha in Amaros and P9071. Hybrids with a long growing season have higher green mass yields and dry matter yields per unit area. The findings can be used by farms that grow silage maize and have the opportunity to use the vegetative mass as a component of biogas plants for biogas production and digestate production

Bio-organic fertilizers from food wastes induce changes in soil microbial community composition and the development of bok-choy (<i>Brassica rapa</i>)

Bio-organic fertilizers from food wastes induce changes in soil microbial community composition and the development of bok-choy (<i>Brassica rapa</i>)

Bio-organic approach for monitoring the Plant growth for Sustainable agriculture

Agriculture plays a critical role in sustaining life and driving the economy of India. The idea of sustainable agriculture is a holistic approach to meet the demands of food supply while protecting our environment. Through various sources, it has been found out that the country is running out of the main reservoirs of water to irrigate the fields. The present study investigated the possibility to prepare different natural hydrogels using Chia seeds, Flax seed, Gond katira, Arrowroot powder, Tapioca, Agar-agar, Corn starch, Gelatin, Aloe vera, and their comparison with a synthetic hydrogel used in sanitary napkins. On successful formation of natural hydrogels and getting valuable results in their water holding capacity, the work continued to test their potential on growth and development of seeds of two plants: Moong beans (Vigna radiata) and Fenugreek (Trigonella sp.) along with bio-organic fertilizers prepared from onion, garlic and banana respectively. Seeds were sown in soil less media (Coco-coir) and the study of various parameters like phytotoxicity test, seed germination, water consumption, number of leaves, root and shoot length indicated promising results in the establishment and healthy growth of the seedlings. Use of natural biodegradable hydrogels therefore may prove as an easy, low cost and eco-friendly way to establish the seedling development and subsequent productivity at the commercial level under conditions of water scarcity for sustainable agriculture.

Portable Disc Granulator Machine

This work presents the design of a portable disc granulator machine to produce granule shape fertilizer from a powdered mixture. The industry demands granular fertilizer made from chemical substances due to the benefits that can be obtained compared to fine powder fertilizer. It has a longer lifespan of up to 9 months and a slow rate of nitrogen absorption from fertilizer because of its granular form. Granular fertilizers are easy to store and do not settle out over time, or salt out in cold weather. Fertilizer plays the role of a plant food element and is crucial to maintaining the health of plants for their growth. The pharmaceutical method is frequently used by farmers to create fertilizer in the form of granules which are wet granulation and dry granulation process. Wet granulation was employed in this project since it involves the addition of liquids like molasses or water. The portable disc granulator machine is designed to turn fertilizer into granule shapes, which are subsequently used as the product's base material. However, the fertilizer must be produced a uniform ±5 mm diameter of granular shape for bio-organic fertilizer. Solidification has been made to improve the fertilizer’s granular shape to create a consistent ±5 mm diameter in the disc that rotates automatically with an angle of 48°. A disc granulator machine should first be filled with bio-organic fertilizer. Then, use brown sugar solution or cornstarch to form a granule shape. The disc will be rotating at a speed of 11 to 15 rpm. To assess the machine's ability to create granules with a diameter of about 5 mm, evaluation, and analysis were performed using a vernier caliper. The result demonstrated that the machine could produce ±5 mm with a tolerance of 1 mm and uniformity will be constant.

PRODUCTION OF BIOFERTILIZER USING GOAT DUNG, CHICKEN DUNG, PINEAPPLE PEELS AND CITRUS PEELS

This study aimed at evaluating the efficacy of composed Biofertilizers from Pineapple and Orange (Citrus) Peels blended with Goat dung and Chicken dung.Organic wastes comprising goatdung, chiken dung, Pineapple waste and Citrus wastes were collected from the Dutsin-Ma vegetable Wednesday market, The agro waste was mixed and put into a digester to which 500 mL of water and 200 g of rumen content were also added. The digester was then tightly closed and a rubber pipe were put on top of the digester so as to allow the gas to escape. Sorghum seeds (10) were then planted using two polythene bags. The organic biofertilizer was applied to one polythene bag at 500 g and the other without treatment (control). The plant length and number of leaves were determined. Results obtained revealed that, the composed Biofertilizer significantly(p<0.05) increased the growth parameters of the test plant considered. The production of organic biofertilizer is an excellent waste processing and recycling method which is cost effective, readily available and ecologically friendly.

Effect of Organic and Biofertilization on some Qualitative and Productive Traits of Barley Plant

A field experiment was conducted in a sandy, clay soil loam in Al-Nahrawan region, east of Baghdad. The experiment included two factors: organic fertilizer (compost) at three levels, 15 tons. ha-1 and 30 tons ha-1 without adding organic fertilizer and biofertilizer (mycorrhiza) at two levels, adding 200 g of mycorrhizal inoculation without addition, In a randomized complete split block design with three replicates in order to evaluate the effect of adding different levels of a type of fungal (mycorrhizal) and organic (compost) bio-fertilizers, individually or in an interaction manner, on the qualitative and productive traits of barley plant (plant height (cm), dry weight (kg. ha-1), grain weight (Mg.ha-1) and harvest index (%) The results showed that the treatment of compost and mycorrhizal interactions was significantly excelled on the control treatment for all traits, with values of (82.13, 9018, 4.117, 38.63), respectively.

EFFECT OF AQUEOUS PLANT EXTRACTS AND INORGANIC FERTILIZER ON THE GERMINATION, GROWTH AND DEVELOPMENT OF MAIZE (Zea mays)

This study was conducted to evaluate the effect of Plant extract and inorganic fertilizer on the germination and early seedling growth of maize, Bio-fertilizers have the ability to symbiotically relate to the roots of plants. These living microorganisms help to transform complicated organic material into basic compound, helping the plant to grow and nurture in a natural way. Aqueous extracts of Azadirachta indica was obtained using cold maceration method the experiment was designed in a completely randomize design both in the in vitro and field experiments, the germination rate, plumule and radicle lengths as well as the dry matter accumulations of the maize plant were determined. The extract was diluted using serial dilution method to obtain 100,75,50, & 25% of the extract and an inorganic fertilizer NPK. Aqueous extract of the plant demonstrated ability to stimulate the germination, growth and development of maize crop. The effect of the extracts increases with increase in the concentration of the extracts with the best activity in 100% concentration of the extract, which was as effective as the Inorganic fertilizer in all the parameters considered used in the studies. Application of organic biofertilizer is recommended as it increases the yield and early germination of the plant.

DETERMINATION OF WATER CONSUMPTION OF POTATO UNDER IRRIGATION SYSTEMS AND IRRIGATION INTERVALS BY USING POLYMERS AND BIO-FERTILIZERS IN DESERT SOILS

Two field experiments were conducted during the spring season 2020 in Karbala governorate, to study the effect of sprinkler and surface drip irrigation systems to determine water consumption of potatoes and irrigation intervals using polymers and bio-fertilizers in desert soils. The experiment included three factors: 1-Irrigation system surface drip T1 and sprinkler T2, 2- The Irrigation interval: every 2 days I1, 4 days I2 and 6 days I3, 3- Addition of soil conditioners: control without any addition C, bio-organic fertilizers (seek) B, polymer (zeba) P, and polymer+ bio-organic fertilizers P+B. The experiment was designed according to the nested design with three replicates. Potato tuber class (Hermosa) rank E was planted. The results showed that the operating pressure of 50-150 kPa was drip and sprinkler irrigation, respectively. Irrigation interval treatment I1 also obtained the lowest added water depth of 212.64 and 486.70 mm at the drip and sprinkler irrigation systems, respectively. Moreover, the actual consumptive use ETa values ​​for irrigation interval I1, I2, and I3 at drip irrigation were 276.44, 428.31, and 593.04 mm, respectively. Though at sprinkler irrigation were 550.50, 959.46, and 1385.08 mm for irrigation intervals I1, I2, and I3, respectively. The highest values ​​of crop coefficient at tuber formation and filling stage were 0.66, 0.79, 1.06, 1.86, 3.42, and 4.73 for the irrigation interval I1, I2, and I3, respectively, at the drip and sprinkler irrigation systems.

Comparative analysis of different bio-organic fertilizers on growth and rhizosphere environment of grapevine seedlings

Grapevine seedlings need to absorb a lot of nutrients from the soil during the growth process, and appropriate fertilizer can greatly promote the growth of seedlings. The purpose of this study was to investigate the effects of different bio-organic fertilizers (BOF) on shoot and root growth, soil biochemical characteristics, and bacterial communities of ‘Shine Muscat’ and ‘Kyoho’ seedlings. Four treatments were established: no fertilizer (CK), chemical fertilizer + organic fertilizer (T1), chemical fertilizer + bio-organic fertilizer 1 (T2, containing Bacillus amyloliquefaciens), chemical fertilizer + bio-organic fertilizer 2 (T3, containing Trichoderma). The results showed that BOF had better effects on growth and rhizosphere environment of grapevine seedling than organic fertilizer (OF) treated group. The shoot growth, chlorophyll content, and root growth with BOF of grapevine seedlings were generally better than those treated with OF. Compared with T1, T2 and T3 made grapevine seedlings meet the fixed drying requirement (main shoot 0.8 m) 1–4 weeks earlier. The expansion of roots and the improvement of root activity under BOF treatment were also beneficial to plant growth. Moreover, transcriptome analysis showed that BOF enhanced the phytohormones and cell wall processes in grapevine root, and up-regulated the expression of cell wall-related genes such as XTH23, EXPs, PME17, and auxin related genes such as ABCBs and GH3. In addition, BOF increased soil organic matter content, available nitrogen, available potassium, available phosphorus, and enzyme activity (soil catalase, urease, sucrase, and nitrate reductase). The Shannon and Chao values of T2 were higher than those of T1 and CK, which improved the diversity and richness of soil microbial community. As compared to CK, T2 treatment increased the symbiotic nitrogen fixing Proteobacteria by 4.10 %, and reduced Acidobacteria by 9.79 %. Actinobacteria, which is related to the degradation of stubborn polymers, was the dominant group in T2 treatment, accounting for 10.17 %. As compared to CK and T1, Actinobacteria was increased by 6.89 % and 5.66 %. In summary, BOF could promote the growth of grapevine seedlings by improving phenotypic traits, soil fertility, bacterial diversity, richness abundance, and provide theoretical and technical support for grapevine garden construction and tree management.

Substitution of organic and bio-organic fertilizers for mineral fertilizers to suppress nitrous oxide emissions from intensive vegetable fields

To gain insight into the microbial mechanisms associated with the replacement of chemical fertilizers with organic or bio-organic fertilizers to mitigate soil nitrous oxide (N2O) emissions, we measured N2O emissions from greenhouse vegetable soils through field observations and pot experiments. Results showed that organic substitution suppressed N2O emissions by reducing soil mineral N content and stimulating the abundance of the nosZII gene. The trade-off effect of bio-organic substitution on N2O emissions may be due to the stimulated activity of the AOA-amoA gene, resulting in unfavorable conditions for N2O production and thus reduced N2O loss. We also linked the inhibitory effect of organic and bio-organic substitution on N2O emissions to the increased abundance of key species in bacterial co-occurrence networks represented by Patescibacteria as they were significantly and negatively correlated with N2O emissions. However, the mitigation effect of bio-organic substitution on N2O emissions was conteracted by an increase in Bacillus abundance due to the direct negative effect of Bacillus on the nosZII gene abundance. These findings suggest that conventional or bio-organic substitution is a promising strategy for alleviating the environmental costs of crop production.

The effect of bio-organic fertilizers the productivity of potatoes and vegetable root crops in the conditions of the south-east of Kazakhstan

Organic vegetables and potatoes are not produced in Kazakhstan. In this regard, the development of organic agricultural technologies is very important. Mineral fertilizers cannot be used in organic production. There are difficulties in preserving and increasing soil fertility, providing vegetables with all the necessary elements of nutrition. Therefore, the role of organic fertilizers and biological stimulators increases in soil and plant formation. Organic fertilizers are an important factor in preserving and increasing soil fertility, increasing yields, and improving quality, including the ecological purity of products, potatoes, and vegetables. The influence of local organic fertilizers, a new bio-organic fertilizer Baraebong Organic Fertilizer (Republic of Korea), and biological products on the nutritional regime of the soil and the productivity of potatoes and root crops (carrots and beets) was studied on the dark chestnut soil of the foothill zone of the south-east of Kazakhstan. Scientific research was carried out at the experimental station of the Regional branch "Kainar" LLP "Kazakh Scientific Research Institute of Fruit and Vegetable Growing". The research uses “The Methodology of Agrochemical Research”, “The Methodology of Experimental Work in Vegetable Growing and Melon Growing”, ‘The Methodology of Field Experience in Vegetable Growing”, and the methodological recommendations "Transition from Traditional to Bioorganic Farming in the Republic of Belarus". The positive effect of different types of bioorganic fertilizers on the nutritional regime of the soil was established such as the content of mobile forms of nitrogen, phosphorus, and potassium increased in it. The yield of potatoes from the introduction of bio-organic fertilizers into the soil increased by 17.4-87.5 %, carrots by 12.8-38.3 %, and beets by 14.0-46.2 %. Bio-organic fertilizers did not adversely affect the quality of potatoes in terms of nitrate content. The level of nitrates in tubers was at the level of 65-215 mg/kg with a MPC of 250 mg/kg. Carrots grown with the use of various bio-organic fertilizers contained 47-136 mg/kg of nitrates at MPC 400 mg/kg, and beet contained 132-429 mg/kg of nitrates at MPC 1400 mg/kg.

Mineral nitrogen content in light serozem soils and the size of nitrogen emission under fertilizer appliciation

The article presents the results of studies on the impact of bioorganic fertilizers on the cultivation of winter wheat, sugar beet, and soybeans in irrigated light sierozems of southeastern Kazakhstan. The study focuses on the effects of these fertilizers on the mineral forms of nitrogen content and the size of N2O emissions from the soil. When applying leaf treatments of mineral and bioorganic fertilizers to cultivated crops, the nitrogen content in light sierozems is enhanced. The main sources of nutrition are easily hydrolyzable and nitrate nitrogen, which accounts for more than 80 %. The contribution of ammonium forms to plant nutrition is insignificant. The size of nitrous oxide emissions was recorded at the beginning of the experiment and after the initial leaf treatment. Under winter wheat crops, the initial concentration of nitrous oxide was 440.3 µg/m³. In the field prepared for sowing sugar beet and soybean in 2023, the concentrations were 373.7 µg/m³ and 557.7 µg/m³, respectively. After the initial treatment, the vegetation on the leaves showed that, on average, the indicator in the different experimental variants for winter wheat crops was 679 µg/m³, for sugar beet crops was 576.8 µg/m³, and for soybean crops was 637.2 µg/ m³. In agroecosystems, N2O emissions are higher under winter wheat compared to row crops such as sugar beet and soybean.

Effect of bio-organic fertilizer derived from agricultural waste resources on soil properties and winter wheat (Triticum aestivum L.) yield in semi-humid drought-prone regions

Water stress, improper fertilization practices, and agricultural waste pollution severely reduce soil fertility and limit agricultural sustainability on the Loess Plateau. Organic fertilizer application is an efficient method for improving soil water and nutrient availability and grain yield in semi-arid and arid areas. However, the impact of bio-organic fertilizer derived from agricultural waste on soil characteristics and wheat yield and the optimum bio-organic fertilizer substitution rate in semi-humid drought-prone areas remain unclear. A two-year field study was conducted to explore the effect of combined bio-organic and chemical fertilizer application on soil moisture, hydraulic properties, soil structure, soil organic carbon (SOC), total nitrogen (TN), grain yield, and water productivity (WP). Six different treatments were designed: no fertilization (CK), conventional chemical fertilization (CF), and bio-organic fertilizer treatments substituting 25% (OF25%), 50% (OF50%), 75% (OF75%), and 100% (OF100%) of the chemical N fertilizer. From the seedling to over wintering stage, the OF75% and OF100% treatments generally improved soil water storage (SWS) and soil water content (SWC) within the 0–100 cm soil layer compared to the CK and CF treatments across both growing seasons. Bio-organic fertilizer substitution significantly reduced soil bulk density by 4.0–5.6% and enhanced soil porosity by 4.2–5.9% in the 0–40 cm soil layer. Moreover, bio-organic fertilizer substitution significantly increased soil saturated hydraulic conductivity and water content, improved aggregate size distribution, and enhanced SOC and TN contents in both years. The OF75% treatment produced the highest aboveground biomass, yield components, grain yields, and WP, attributed to the improved soil physical environment and nutrient contents. Notably, the OF75% treatment increased the average wheat yield and WP by 21.1% and 24.9%, respectively, relative to the CF treatment across both growing seasons. The measured soil properties strongly correlated with wheat yield, yield components, and WP. Thus, the OF75% treatment is an appropriate and promising fertilization management strategy to alleviate water stress, improve soil properties, and promote crop production in semi-humid drought-prone regions.

Growth and yield responses of two chili varieties on liquid bio-organic fertilizer

One of the horticultural commodities that often causes price fluctuations is chili. The main problem is plant productivity which is low and unstable from one growing season to another, as a result of the application of cultivation technology that is not optimal, especially the use of types and doses of fertilizers. This research was carried out with the main objective of increasing the productivity of two varieties of chili plants by using liquid bio-organic fertilizers. The research was conducted in April-November 2022, in Sidera Village, Sigi-Biromaru District, Sigi Regency. In this study a split plot design was used. The main plot was chili varieties, consisting of: (V1) Bara and (V2) Ozil. The sub plot was the concentration of liquid bio-organic fertilizer (LBO), consisting of: (K0) without LBO, (K1) 2 ml/L water, (K2) 4 ml/L water, (K3) 6 ml/L water, (K4) 8 ml/L water, and (K5) 10 ml/L water. Each treatment was repeated 3 times, so there were 12 experimental units. The results showed: (i) the Ozil variety was more responsive to the application of bio-organic fertilizer, where with a concentration of 8-10 ml/L of water it could produce taller plants, length and larger fruit diameter, compared to the Bara variety with a concentration of bio-organic fertilizer other (ii) The Ozil variety produced taller plants, the number of leaves and the number of branches was higher, the weight per 10 fruits and the weight per fruit were higher, the number of fruits and fruit weight per plant as well as the fruit weight per plot and fruit weight per hectare were higher compared to Bara variety and (iii) The number of branches, weight per 10 pods, weight per pod, number of pods and pod weight per chili plant were obtained higher by the application of herbafarm bio-organic fertilizer 8-10 ml/L of water.

The effect of liquid bio-organic fertiizer on the productivity of ironwood (Eusideroxylon zwageri) leaf biomass

Ironwood (Eusideroxylon zwageri) is an endemic species in East Kalimantan known as ulin by the local community. Ironwood is a protected and slow-growing species. It is essential to look for an alternative use in less period. Ironwood young leaves have been used traditionally as a decoction with diuretic and hair-blackening properties. Such usage provides an opportunity to utilize ironwood without cutting down trees. As a reason for leaves sustainability, it is necessary to stimulate the formation of leaves, one of which is to use liquid bio-organic fertilizer. This study aimed to determine the effect of liquid bio-organic fertilizer on increasing the growth and yield of young ironwood leaves in nurseries. Fifty ironwood seedlings were given 5 ml of liquid bio-organic fertilizer every month, and the other 50 seedlings were not given any fertilizer. The number of young leaves was recorded in the third and ninth months, while the young leaves were harvested in the sixth and twelfth months. This research showed that liquid bio-organic fertilizer increased height increments by up to 107.58%, diameter increment by up to 20.36%, the number of iron wood shoots up to 184.62%, and it also increased the weight of young leaves that can be harvested by up to 588.89%. There were any differences effects of liquid bio-organic fertilizer applied with and without bio-organic fertilizer on the growth and yield of young ironwood leaves. Ironwood shoots’ growth and yield by application of liquid bio-organic fertilizer are better than nonliquid bio-organic fertilizer.

Mitigation of N2O emission from granular organic fertilizer with alkali- and salt-resistant plant growth-promoting rhizobacteria.

Organic fertilizer application significantly stimulates nitrous oxide (N2O) emissions from agricultural soils. Plant growth-promoting rhizobacteria (PGPR) strains are the core of bio-fertilizer or bio-organic fertilizer, while their beneficial effects are inhibited by environmental conditions, such as alkali and salt stress observed in organic manure or soil. This study aims to screen alkali- and salt-resistant PGPR that could mitigate N2O emission after applying strain-inoculated organic fertilizer. Among the 29 candidate strains, 11 (7 Bacillus spp., 2 Achromobacter spp., 1 Paenibacillus sp., and 1 Pseudomonas sp.) significantly mitigated N2O emissions from the organic fertilizer after inoculation. Seven strains were alkali tolerant (pH 10) and five were salt tolerant (4% salinity) in pure culture. Seven strains were selected for further evaluation in two agricultural soils. Five of these seven strains could significantly decrease the cumulative N2O emissions from Anthrosol, while six could significantly decrease the cumulative N2O emissions from Cambisol after the inoculation into the granular organic fertilizer compared with the non-inoculated control. Inoculating alkali- and salt-resistant PGPR into organic fertilizer can reduce N2O emissions from soils under microcosm conditions. Further studies are needed to investigate whether these strains will work under field conditions, under higher salinity, or at different soil pH.

Effect of soil bioremediation on soil microbial community structure aimed at controlling tobacco bacterial wilt

Rebuilding soil healthy microbiota is very important for preventing bacterial wilt. A 3-year-long field trial was conducted in China as follows: T1 (conventional fertilization), T2 (T1 + liming), T3 (T1 + bioorganic fertilizer), and T4 (T2 + bioorganic fertilizer). Fluorescence quantitative PCR and high-throughput sequencing were employed to study the dynamics of Ralstonia solanacearum population, microbial community, and network organizations between bacteria and quality-related variables. After 3 years of bioremediation, the control efficacy of tobacco bacterial wilt reached 61.30% and the occurrence delayed by approximately 40 days in T4, which had the highest tobacco yield and output value. The pathogen population of T4 remained below 106 copies/g soil during the entire growth period. Role-shifts prevailed among the network members. Microbes were unipathically associated with variables in T1 but multiplex in T4. In conclusion, soil bioremediation rebuilds a healthy soil microbiota and forms a more interactive and relevant micro-system, thus effectively controlling tobacco bacterial wilt.Key points• This is the first time to effectively bio-control tobacco bacterial wilt in practical production in China, as well as to high-efficiently use the organic waste, thus promoting the organic cycling of the environment.• Soil bioremediation can effectively control soil-borne disease by rebuilding soil healthy microbiota and reducing abundance of pathogenic bacteria, thereby to prevent the soil borne disease occurrence.• After the soil remediated, microbes associated with soil and tobacco characteristics changed from unipathical to multiplex, and the keystone species play different roles compared with the original soil, thus signifying the complexity of multi-species interactions and achieving a closely relevant micro-system, which was ecologically meaningful to the environment.

Long-term bioorganic and organic fertilization improved soil quality and multifunctionality under continuous cropping in watermelon

Continuous cropping has can majorly damage the soil ecosystem, leading to an increased prevalence of pathogenic microorganisms and severe yield losses for watermelons. Multiple prevention strategies have been adopted to overcome this obstacle, among which the application of bioorganic fertilizer can improve microbiome deterioration. However, the response of soil ecosystem multifunctionality and soil quality to fertilizer regimes under continuous cropping remains poorly understood. In this study, based on an 8-year field experiment, we evaluated soil health and ecosystem multifunctionality under different fertilization treatments. Long-term bio-organic fertilization preserved soil electrical conductivity and increased total Cu, Zn, Fe, Mn, Ca, and Mg, total and available nutrients, and enzyme activities compared with those in unfertilized control (CK) and chemical fertilizer treatments. Enzyme activities and yield rapidly changed, indicating their sensitivity to these management practices. Conversely, soil pH, biodiversity, medium/trace elements, and total NPK content were more resistant to change than enzyme activities, suggesting higher stability over time. The area of soil quality index under bio-organic fertilization was 1.2–2.9 times larger than that under CK treatment. Applying biological organic fertilizer and a mixture of chemical and organic fertilizers improved the multifunctionality decline caused by continuous cropping by 1.1–1.4 times, whereas the effect of the chemical fertilizer was weak. Soil health was positively correlated with ecosystem multifunctionality. These findings suggest that long-term bioorganic and organic fertilization is an effective strategy for improving soil quality and multifunctionality in continuous watermelon crops while also contributing toward a more sustainable agricultural system.