Bio-organic Fertilizer Research Articles

THE ROLE OF HYDROTHERMAL REGIME OF VEGETATION IN THE FORMATION OF QUALITATIVE INDICATORS OF OILSEED RADISH BIOMASS IN THE SYSTEM OF ITS MULTIDISCIPLINARY USE

During a ten-year cycle of field and laboratory studies, the full biochemical composition of the aboveground leaf mass of oilseed radish was investigated by basic and derived indicators. The evaluation included an additional range of ratios that are taken into account in the system of multidisciplinary evaluation of cover crops with the possibility of their simultaneous involvement in bioorganic fertilization, soilseed restoration, as a raw material for biogas and biofumigation options. The levels of interannual variability of the main parameters of biochemical composition were determined with the detailing of the average biochemical profile of the leaf-stem mass of oilseed radish and the obtained values were compared with similar indicators of common cruciferous species that are traditionally used in the system of bioorganic and soilseed rehabilitation. The possibility of using oilseed radish in variants of intermediate saturation of crop rotations with its subsequent use for green manure, green manure-fodder and raw material-biogas purposes was analyzed on the basis of the assessment of the hydrothermal regime of different-term sowings of oilseed radish in spring and summer variants. The general stress resistance and adaptability of this species to use in variants of different sowing dates against the background of stressful (unfavorable) environmental factors were determined. The role of hydrothermal conditions of the vegetation period on the formation of biochemical components of the formed leaf-stem mass was assessed with the detailing of dependencies based on correlation analysis, the level of average determination of the indicator in the system of paired single dependencies, which allowed to formulate prognostic options for the formation of the indicator depending on the variability of weather conditions and the dynamics of precipitation and average daily temperatures. Conclusions have been developed about the value of oilseed radish for multidisciplinary use on gray forest soilseeds under conditions of unstable moisture, which allows developing agrotechnological solutions in the field of oilseed radish use as both a main and intermediate crop.

Effects of Bio-Organic Fertilizers Substitution on Gaseous Nitrogen Losses in Rice Fields

Traditional practices for managing irrigation and fertilizer in Chinese rice fields have historically consumed large amounts of water resources and caused serious gaseous nitrogen losses (ammonia volatilization and N2O), resulting in low water and fertilizer use efficiency. While both water-saving irrigation and substituting organic fertilizer for chemical fertilizer can impact ammonia volatilization and N2O emissions, the impact of their combined application on gaseous nitrogen loss in rice fields remains unclear. To achieve this goal, we conducted a two-year experiment using two irrigation methods and three bio-organic fertilizer substitution modes. The experiment investigated the effect of different irrigation and fertilizer management techniques on gaseous nitrogen losses in rice fields. The result indicated that controlled irrigation could reduce the peak value of ammonia volatilization by 36.8~75.9% and ammonia volatilization accumulation by 45.8%. However, it also leads to a 71.4% increase in N2O accumulation emissions, resulting in a 43.0% reduction in gaseous nitrogen losses. Compared to full chemical fertilizers, bio-organic fertilizer substitution could effectively reduce the peak of N2O and ammonia volatilization. Cumulative ammonia volatilization and N2O emissions went down by 22.7~60.0% and 38.6~42.6%, respectively. This then led to a 23.4~52.9% drop in total gaseous nitrogen losses. In contrast, the utilization of controlled irrigation and bio-organic fertilizer substitution did not have a significant impact on rice yield. However, it did reduce the intensity of gaseous nitrogen loss from rice fields by 42.7% and 22.5% to 56.5%, respectively. When taken together, the substitution of bio-organic fertilizer in controlled irrigation can effectively reduce gaseous nitrogen losses while maintaining rice yields. This study has significant practical implications for reducing nitrogen loss from paddy fields, improving water and fertilizer utilization, and achieving sustainable agricultural development.

Effects of Different Conditioners on Soil Microbial Community and Labile Organic Carbon Fractions under the Combined Application of Swine Manure and Straw in Black Soil

The return of straw and manure to agricultural fields can impact soil organic carbon (SOC) and biological properties. However, there is a lack of research on how to use swine manure, maize straw, and various conditioners together affects soil bacterial and fungal populations. This study aimed to investigate six treatments, namely, only maize straw (S00), maize straw combined with swine manure (S0Z), maize straw combined with biochar and swine manure (SCZ), maize straw combined with boron slag and swine manure (SBZ), maize straw combined with biological agent and swine manure (SJZ), and maize straw combined with bio-organic fertilizer and swine manure (SFZ). The results showed that after the two-year return, all treatments increased the SOC content in 2023, which was 12.55–26.89% higher than S00. And the SCZ treatment significantly increased the soil organic carbon (SOC), dissolved organic carbon (DOC), easily oxidizable carbon (EOC), particulate organic carbon (POC), and microbial biomass carbon (MBC) content by 26.89%, 25.44%, 56.88%, 16.08%, and 43.54%, compared to S00. A redundancy analysis (RDA) showed that the continuous application of manure, maize straw, and conditioners has a positive impact on the diversity and abundance of soil microbial communities, enhancing the accumulation of soil carbon. Furthermore, our research revealed that soil fungi exhibited higher sensitivity in soil carbon composition following the addition of manure, straw, and conditioners to agricultural fields than bacteria. In conclusion, the addition of different conditioners to the fields is beneficial to biodiversity conservation from the perspective of achieving soil carbon storage and soil protection. Our findings suggested that the combination of maize straw, biochar, and swine manure was been proven to be the most effective treatment for increasing labile organic carbon fractions and enhancing the microbial community.

Effects of Different Organic Fertilizer Substitutions for Chemical Nitrogen Fertilizer on Soil Fertility and Nitrogen Use Efficiency of Foxtail Millet

Conventional fertilizer management can destroy the structure of soil. Replacing chemical fertilizers with organic fertilizers can improve soil quality and nitrogen use efficiency. We aimed to study the effects of organic fertilizer substitutions for chemical nitrogen fertilizer on soil fertility and nitrogen use efficiency in order to clarify the effectiveness of the available nutrient management measures in improving soil quality and increasing foxtail millet yield. A field experiment was carried out over two consecutive years, and a total of six treatments were set up: no fertilizer (CK), chemical nitrogen fertilizer alone (N), the substitution of 25% of chemical nitrogen fertilizer with bio-organic fertilizer (N25A1), the substitution of 25% of chemical nitrogen fertilizer with fermented mealworm manure (N25B1), the substitution of 50% of chemical nitrogen fertilizer with bio-organic fertilizer (N50A2), and the substitution of 50% of chemical nitrogen fertilizer with fermented mealworm manure (N50B2). The results of this study show the following: (1) Compared with chemical nitrogen fertilizer, the substitution of organic fertilizer for nitrogen fertilizer reduced the bulk density and solid phase of the soil, and it increased the total porosity, water content, liquid phase, and gas phase of the soil. (2) Compared with nitrogen fertilizer, the use of an organic fertilizer increased the contents of nitrate nitrogen, ammonium nitrogen, and total nitrogen in the soil by 13.59~52.56%, 4.47~18.27%, and 4.40~12.09%, respectively. The content of alkaline nitrogen increased by 1.70~32.37%, and the contents of soil available potassium, available phosphorus, and organic matter also increased. (3) The activities of sucrase, urease, glutaminase, and asparaginase were improved by replacing chemical nitrogen fertilizer with organic fertilizer. The N25 treatments performed better than the N50 treatments, and fermented mealworm manure performed better than biological organic fertilizer. (4) A moderate application of organic fertilizer (N25) can increase the grain yield, ear weight, grain weight, and 1000-grain weight of foxtail millet, whereas excessive application of organic fertilizer (N50) can reduce foxtail millet yield. (5) Replacing chemical nitrogen fertilizer with organic fertilizer can improve the agronomic use efficiency, physiological efficiency, biased productivity, harvest index, and apparent use efficiency of nitrogen fertilizer. In this study, the substitution of 25% of chemical nitrogen fertilizer with fermented mealworm manure was the best combination for restoring crop productivity and soil quality.

Biocontrol Potential of Bacteria Isolated from Vermicompost against Meloidogyne incognita on Tomato and Cucumber Crops

Root-knot nematodes are the major diseases in protected cultivation around the world. Bio-organic fertilizer has become a research hotspot, with a variety of microorganisms that control various vegetable soil-borne diseases. This study screened nematocidal microorganisms from fresh vermicompost, explored the inhibitory substances produced by biocontrol agents, and evaluated their potential biocontrol ability in the pot and field under greenhouse conditions. The highly effective antagonistic microbes of Meloidogyne incognita (M. incognita) were screened. Strains YL1 and YL31 were identified as Peribacillus frigoritolerans, and strain YL6 was identified as Lysinibacillus fusiformis. The three strains all produced chitinase and protease, which prevented the normal development of eggs and the second-stage juveniles (J2) by destroying their appearance. The three strains all improved potassium-dissolving ability, and the strains YL1 and YL6 also enhanced phosphorus-dissolving ability. Pot experiments showed that tomato root knots were reduced, and plant growth improved. Field tests showed that the root-knot index and nematode population were reduced significantly, and cucumber growth and yield were enhanced. Strain YL1 had the best control effect with 70.6%, and the yield increased by 14.9% compared with the control. Overall, this study showed the ability of antagonistic bacteria YL1, YL6, and YL31 to control root-knot nematodes, and these antagonistic bacteria could be developed as biocontrol agents for sustainable agriculture.

Evaluation of Virgibacillus dokdonensis MCCC 1A00493 as a biological control agent and microbial organic fertilizer against root-knot nematodes

Root-knot nematodes (RKNs) can result in severe losses to crop production and economies. Virgibacillus dokdonensis MCCC 1A00493, a deep-sea bacterium, has demonstrated potent antagonistic effects against Meloidogyne incognita in vitro. However, the control efficacy under greenhouse and field conditions remains unclear. In this study, we investigated the nematicidal effect of MCCC 1A00493 fermentation liquid and its synergism with black soldier fly (BSF) larval frass organic fertilizer both in greenhouse and field experiments. MCCC 1A00493 fermentation liquid demonstrated a significant control efficacy on RKNs both in greenhouse and field experiments, with the highest control efficacy reaching 68.97 % and 74.87 %, respectively. Meanwhile, the synergistic effects of MCCC 1A00493 and BSF larvae frass organic fertilizer was investigated by adding 10 % suspension (1 × 109 CFU/mL) of MCCC 1A00493 into 71.51 kg of chicken manure organic fertilizer produced by co-conversion of BSF larvae and Bacillus subtilis BSF-CL. It was noted that MCCC 1A00493 microbial organic fertilizer reduced disease incidence of RKNs significantly both in greenhouse and field experiments, with the root gall index decreasing by 51.75 % and 63.22 %, respectively. MCCC 1A00493 fermentation liquid and microbial organic fertilizer demonstrated a control efficacy on RKNs exceeded commercial nematicide avermectin and commercial bio-organic fertilizer, respectively. In addition, MCCC 1A00493 fermentation liquid and microbial organic fertilizer had positive effects on the growth of tomato plants. These findings confirmed that V.dokdonensis MCCC 1A00493 as a biological control agent and microbial organic fertilizer have significant effect on RKNs and can be used as potential biocontrol preparations.

Effects of chemical fertilizer reduction combined with bio-organic fertilizer application on growth physiology and nutrient absorption of Chinese cabbage in open fields on plateau in summer

Effects of chemical fertilizer reduction combined with bio-organic fertilizer application on growth physiology and nutrient absorption of Chinese cabbage in open fields on plateau in summer

Effects of Continuous Cropping and Application of Bio-organic Fertilizers on Growth, Yield and Quality of Sugar Beet under Reduced Chemical Fertilizer Application

Effects of Continuous Cropping and Application of Bio-organic Fertilizers on Growth, Yield and Quality of Sugar Beet under Reduced Chemical Fertilizer Application

SPENT BLEACHING EARTH: SYNTHESIS, PROPERTIES, CHARACTERISATION, AND APPLICATION

Spent bleaching earth (SBE) is hazardous solid waste generated from the edible oil industry through the oil bleaching process, as it is used to purify the edible oil to accomplish the strict standards required for edible oil on colour, taste and hence oil’s shelf-life. It has diverse applications for energy, construction, and agriculture, which are attributed to its remarkable physical and chemical properties. Waste generation can be reduced by utilising SBE for applications that include biogas production, bio-organic fertiliser, lubricating grease, and foamed concrete incorporating SBE. In line with this background, this paper compiled and reviewed the literature on the synthesis of SBE through the activation of bentonite, edible oil bleaching process, properties of SBE and characterisation techniques for SBE. Finally, the merits and demerits of the application of SBE are expounded. The overall performance of SBE in their respective applications is enhanced by free cations and residual oil present. Finally, future research considerations are also discussed for the co-pyrolysis application of SBE and other biomass substrates as an economically significant prospect. It is noted that reusing SBE appears to improve the oil refining industry’s sustainability and in turn the cities and communities.

Enhancing pakchoi (Brassica chinensis L.) agriculture with magnetized-ionized brackish water and organic fertilizers: A sustainable approach to soil quality and crop yield optimization

The scarcity of freshwater, the increasing use of brackish water (B) for irrigation, and the judicious application of organic fertilizers have significant research and practical value for environmental science, water resource management, and clean production. This study investigated the combined impact of B, magnetized-ionized brackish water (MIB), and organic fertilizer on pakchoi (Brassica chinensis L.) growth, yield, and soil quality. Over a two-year period (2022–2023), this study explored the impacts of two types of irrigation water (B and magnetized-ionized brackish water, MIB) in combination with varying rates of water-soluble bio-organic fertilizer (0, 20, 40, 60, and 80 kg/ha, corresponding to treatments 0 through 4, respectively). The findings indicated that the application of 60 kg/ha of organic fertilizer greatly improved the growth rate of pakchoi in terms of plant height, leaf area index, and fresh weight. Moreover, under MIB irrigation, the fresh weight growth rate of pakchoi was superior to that observed under B irrigation. Notably, B irrigation necessitated additional fertilizer to maintain elevated levels of alkali-hydrolyzed nitrogen (AN) and soil quality. Furthermore, the use of organic fertilizer substantially enhanced soil quality, with AN, available phosphorus (AP), organic matter (OM), and soil quality index (SQI) demonstrating a strong positive correlation (P < 0.05). Mantel test analysis showed significant correlations (P < 0.05) between soil OM, SWC, AP, and pakchoi growth and yield. According to the partial least squares path modeling analysis, the use of organic fertilizer had a relatively minor effect on the yield and quality of pakchoi under B irrigation, with path coefficients of 0.088 and 0.298, respectively. However, under MIB irrigation, organic fertilizer enhances yield and quality by improving soil quality (path coefficients of 0.914). In conclusion, the application of MIB irrigation coupled with organic fertilizer contributed to sustainable soil fertility, enhanced crop productivity, and mitigated the environmental impacts associated with conventional irrigation and fertilization methods. Our research underscores the importance of supporting agricultural research and development focused on sustainable irrigation and fertilization methods for farmers and policymakers. This integrated approach offers a harmonious solution for optimizing crop yields and enhancing water use efficiency, and the reduction of in chemical pollutants within agricultural production systems.

Soil aggregate stability helps construct a stable nitrogen fixation system in lignite-based amendment-driven saline-sodic soil remediation

Lignite−based amendments are promising soil conditioners for improving crop yield and nitrogen use efficiency, but there is limited knowledge regarding the potential effects of lignite−based amendment on nitrogen cycling−related microbial communities and their impacts on NH3 volatilization and crop nitrogen uptake in saline−sodic farmland. Here, we investigated the influences of lignite bioorganic fertilizer (LBF) on NH3 volatilization, nitrogen uptake, and microbial communities containing nifH, amoA, and nirS genes through a two−year field experiment. Three treatments were considered in the experiment, i.e., a control treatment with no organic fertilizer application (CK), a farmyard manure treatment (FYM) involving the application of sheep manure at a rate of 21 t ha−1, and a LBF treatment with optimal application rates of 3.0 and 4.5 t ha−1. Results showed that compared with the control treatment (CK), the LBF treatment reduced the total NH3 volatilization by 22.3% and 13.5% in 2019 and 2020, respectively. In addition, the LBF treatment significantly increased sunflower nitrogen uptake by 52.5% and 114.2% in 2019 and 2020, respectively, in comparison with the CK treatment. Moreover, the LBF treatment not only increased the absolute abundance of the nifH gene by 111.5% and altered the core microbes in the nifH−containing community, but it also enhanced the complexity, stability, and cooperation of co−occurrence network of the nifH−containing community, which were positively related to the sunflower nitrogen uptake. The LBF and FYM treatments reduced NH3 volatilization by improving the soil aggregate stability and saturate hydraulic conductivity. These results indicated that LBF may offer a feasible measure to improve the sunflower nitrogen uptake by constructing a complex, stable, and cooperative nitrogen fixation system, without the risk of NH3 volatilization in saline−sodic farmland.

Substituting Partial Chemical Fertilizers with Bio-Organic Fertilizers to Reduce Greenhouse Gas Emissions in Water-Saving Irrigated Rice Fields

Conventional water and fertilizer management practices have led to elevated greenhouse gas emissions from rice fields and decreased the efficiency of water and fertilizer utilization in agricultural land. The implementation of water-saving irrigation and the substitution of chemical fertilizers with organic alternatives can influence CH4 and N2O emissions in rice fields. However, it remains unclear how the simultaneous application of both methods will affect the CH4 and N2O emissions in rice fields. Therefore, two irrigation methods (F: flooded irrigation; C: controlled irrigation) and three fertilization modes (A: full chemical fertilizer; B: bio-organic fertilizer replacing 15% chemical nitrogen fertilizer; C: bio-organic fertilizer replacing 30% chemical nitrogen fertilizer) were set up through field experiments to explore the effect of greenhouse gas emission reduction in rice fields by combining controlled irrigation and bio-organic fertilizers. Substituting some chemical fertilizers with bio-organic fertilizers can lower the peak CH4 and N2O fluxes in rice fields, leading to a decrease in the cumulative CH4 and N2O emissions by 11.9~29.7% and 10.8~57.3%, respectively. The reductions led to a considerable decrease in the global warming potential (GWP) and the greenhouse gas emission intensity (GHGI) by 16.1~48.1% and 16.3~48.1%, respectively. Controlled irrigation significantly reduced CH4 emissions by 55.2~69.4% compared with flooded irrigation in rice fields. However, it also increased N2O emissions by 47.5~207.9%, considerably reducing their GWPs by 11.8~45.5%. Neither bio-organic fertilizer substitution nor controlled irrigation significantly affected rice yield. Replacing 15% of chemical nitrogen fertilizers with bio-organic fertilizers in controlled irrigation rice fields can minimize rice GWP and GHGI. The study’s results are of significant importance for enhancing the regulation of greenhouse gases in farmland and achieving sustainable agriculture through cleaner production.

A novel biochar-augmented enzymatic process for conversion of food waste to biofertilizers: Planting trial with leafy vegetable

The present study developed a novel biochar-augmented enzymatic approach for fast conversion of food waste to solid and liquid biofertilizers. By augmented with 10 % of biochar and mediated with 5 % of food waste-derived hydrolytic enzymes mixture (i.e. fungal mash), 100 kg of food waste could be converted into 22.3 kg of solid biofertilizer with a water content of 30 % and 55.0 kg of liquid biofertilizer, which fulfilled Chinese national standards for solid and liquid organic biofertilizers, respectively. Field plantation results showed that the Pak Choi grown on food waste-derived biofertilizers was comparable with that on commercial ones, in terms of the vegetable productivity and nutrient contents. It was further revealed that the application of food waste-derived biofertilizers did not change soil chemical properties but enriched microbial diversity. This study clearly indicated that the biochar-augmented enzymatic approach for food waste conversion to biofertilizers was technically feasible and economically viable towards circular agriculture economy.

Influence of Decomposed Stubble Return on the Soil Microbial Community Under Perennial Crop Rotation

The aim of this study was to understand how the application of decomposed stubble return (DSR), a type of bio-organic fertilization, affects soil microbial communities under crop rotation. The changes in microbial composition and diversity related to DSR were investigated based on metagenomic sequencing and comparative analysis of two groups of soil samples after a 3-year tomato-pepper-papaya rotation: the DSR and no-DSR (i.e., without DSR) groups, with the soils before crop rotation as the control group. Inter-group comparisons of the crop performance (growth and yield) and physicochemical soil properties (pH value, nutrient elements, and heavy metals) were also conducted to reveal the effects of DSR application on the soil. The relative abundance of bacteria was higher than 90% in all soil samples. Proteobacteria and Actinobacteria in the DSR group and Proteobacteria and Firmicutes in the no-DSR group, whereas Acidobacteria and Proteobacteria in the control, were the two most abundant phyla. The abundance of Proteobacteria decreased, whereas that of Actinobacteria increased, in the DSR-amended soil compared to the no-DSR soil. At genus level, Acidobacterium dominated in the control and genera Pseudomonas, Burkholderia, and Bacillus in the no-DSR group, while Burkholderia, Pseudomonas, and Bacillus in the DSR-amended soil comprised the majority of their microbiomes. The DSR soil had higher microbial diversity and relative abundance of Ascomycota fungi than the no-DSR group after the crop rotation. Along with higher diversity of microbial community, more favorable soil pH, better crop growth, higher crop yields, higher abundance of soil nutrient elements, and lower accumulation of heavy metals in the soil were found in the DSR group compared to the no-DSR one. Furthermore, the DSR soil had more similarities with the control than with the No-DSR soil, in aspects of microbial composition and microbe-derived potential gene functions. It was indicated that decomposed stubble return may improve soil conditions or prevent them from degradation incurred by long-term crop cultivation. It was suggested that the application of the compost derived from fermented post-harvest plant residue may be a general strategy for developing more sustainable agricultural systems.

Integration of mycorrhiza hyphae into organic fertilizer granules on the growth of sugarcane crops

Arbuscular mycorrhizae fungi (AMF) are important for tropical soils where soil phosphorus (P) availability is low so that plants can use P with higher efficiency. AMF can increase the P concentration in the plant root area, by releasing the bonds of fixed P into available P. One of the obstacles in utilizing AMF fertilizer is the limited availability of AMF inoculant in the form of AMF spores. In addition, AMF spore production takes a long time. AMF in the form of hyphae is an alternative as an inoculant because it has a faster infection capacity than AMF spores and does not break apart like AMF spores when made in the form of granular organic biofertilizer. The aim of this research was to analyze the effectiveness of various doses of AMF hyphae granule organic fertilizer on sugarcane plants. This research was conducted using a randomized block design. The treatment doses used were control (without AMF), 750 kg/ha, 1000 kg/ha, 1500 kg/ha, and 2000 kg/ha AMF hyphae granule organic fertilizer which was repeated five times. The results of the research showed that the application of AMF hyphae granule organic fertilizer at a dose of 1500 kg/ha could increase plant height, stem diameter, number of tillers and root infections of sugarcane plants. The P status of sugarcane plants increased from medium to high with a plant P content of 0.442% P2O5. This effect was seen more clearly in sugarcane plants grown in the field than grown in the greenhouse.

Horticultural Innovations Elevating Crop Yields and Agricultural Sustainability for a Flourishing Future

Advancements in horticultural technologies and practices are critical for meeting global food security needs while ensuring environmental sustainability. This paper examines recent innovations that enhance crop yields and resource efficiency in horticulture. Key areas explored include high-tech greenhouse agriculture, precision agriculture techniques, improved irrigation systems, biofertilizers and biopesticides, breeding of resilient cultivars, and vertical farming. Intensive greenhouse production with supplemental lighting, climate control, hydroponics and automation enables year-round vegetable and fruit yields up to 20 times higher than open-field methods. Precision agriculture leverages data analytics, sensors and AI for optimized inputs and cultivation decisions per sub-field zone. Upgraded irrigation systems like drip lines and computerized scheduling curtail water usage. Organic biofertilizers and biopesticides derived from microbes, plants and minerals boost soil health and impede pests while avoiding chemical residues. Newly bred cultivars feature accelerated growth, improved taste and nutrition, and resistance to biotic and abiotic stresses. Meanwhile, vertical farms multilayer indoor cropping to magnify yields in small footprints. Further integration of these and other cutting-edge horticultural technologies can increase global food production without environmental sacrifice. This necessitates greater public and private sector investments paired with institutional support.

Bio-organic fertilizer facilitated phytoremediation of heavy metal(loid)s-contaminated saline soil by mediating the plant-soil-rhizomicrobiota interactions

Bio-organic fertilizer (BOF) was effective to promote the phytoremediation efficiency of heavy metal(loid)s-contaminated saline soil (HCSS) by improving rhizosphere soil properties, especially microbiome. However, there existed unclear impacts of BOF on plant metabolome and plant-driven manipulation on rhizosphere soil microbiota in HCSS, which were pivotal contributors to stress defense of plants trapped in adverse conditions. Here, a pot experiment was conducted to explore the mechanisms of BOF in improving alfalfa (Medicago sativa)-performing phytoremediation of HCSS. BOF application significantly increased the biomass (150.87–401.58 %) to support the augments of accumulation regarding heavy metal(loid)s (87.50 %–410.54 %) and salts (38.27 %–271.04 %) in alfalfa. BOF promoted nutrients and aggregates stability but declined pH of rhizosphere soil, accompanied by the boosts of rhizomicrobiota including increased activity, reshaped community structure, enriched plant growth promoting rhizobacteria (Blastococcus, Modestobacter, Actinophytocola, Bacillus, and Streptomyces), strengthened mycorrhizal symbiosis (Leohumicola, Funneliformis, and unclassified_f_Ceratobasidiaceae), optimized co-occurrence networks, and beneficial shift of keystones. The conjoint analysis of plant metabolome and physiological indices confirmed that BOF reprogrammed the metabolic processes (synthesis, catabolism, and long-distance transport of amino acid, lipid, carbohydrate, phytohormone, stress-resistant secondary metabolites, etc) and physiological functions (energy supply, photosynthesis, plant immunity, nutrients assimilation, etc) that are associated intimately. The consortium of root metabolome, soil metabolome, and soil microbiome revealed that BOF facilitated the exudation of metabolites correlated with rhizomicrobiota (structure, biomarker, and keystone) and rhizosphere oxidative status, e.g., fatty acyls, phenols, coumarins, phenylpropanoids, highlighting the plant-driven regulation on rhizosphere soil microbes and environment. By compiling various results and omics data, it was concluded that BOF favored the adaptation and phytoremediation efficiency of alfalfa by mediating the plant-soil-rhizomicrobiota interactions. The results would deepen understanding of the mechanisms by which BOF improved phytoremediation of HCSS, and provide theoretical guidance to soil amelioration and BOF application.

How Does Bio-Organic Fertilizer Combined with Biochar Affect Chinese Small Cabbage's Growth and Quality on Newly Reclaimed Land?

The cultivated land area in China is approaching the red line for farmland protection. Newly reclaimed land possesses a large exploratory potential to become a reserved land resource. Identifying a fertilization strategy is vital for improving the poor properties and weak fertility of newly reclaimed land. An experiment was conducted to study the effects of traditional compound fertilizer (Fc) or bio-organic fertilizer (Ft), alone or in combination with biochar addition (6.85 t·ha-1 and 13.7 t·ha-1) on the growth, photosynthesis, yield and quality of Chinese small cabbage (CSC) plant. The results showed that compared to single compound fertilizer application, bio-organic fertilizer application promoted the plant's growth, indicated by the plant height, stem diameter and leaf area index (LAI), and significantly enhanced the yield and dry matter accumulation of CSC. In terms of the combination with biochar, the promoting effects were positively related to the biochar addition rate in the compound fertilizer group, while it was better to apply bio-organic fertilizer alone or in combination with biochar at a low rate of 6.85 t·ha-1. The highest yield was obtained under B2Fc and B1Ft with 29.41 and 37.93 t·ha-1, respectively, and the yield under B1Ft was significantly higher than that under B2Fc. The water productivity (WP) significantly improved in response to both kinds of fertilizer combined with biochar at 6.85 t·ha-1. There was a significant difference between the photosynthetic characteristics of plants treated with single-compound fertilizer and those treated with bio-organic fertilizer. The photosynthetic characteristics increased under compound fertilizer combined with biochar, while they regressed under bio-organic fertilizer combined with biochar. The quality of CSC, especially that of soluble sugars and total phenolics, improved under single bio-organic fertilizer application compared with that under single-compound fertilizer. The nitrite content of the plants increased with increasing biochar addition rate in both fertilizer groups. In conclusion, there is a significant promoting effect of applying bio-organic fertilizer to replace chemical fertilizer alone or combining compound fertilizer with low-rate biochar addition on newly reclaimed land. It is a recommended fertilization strategy to substitute or partially substitute chemical fertilizer with bio-organic fertilizer combined with biochar in newly reclaimed land, and it is of great significance to achieve fertilizer reduction.

The Effect of Nitrogen Reduction and Applying Bio-Organic Fertilisers on Soil Nutrients and Apple Fruit Quality and Yield

In this study, we investigated the effect of partially substituting inorganic nitrogen with bio-organic fertiliser on the ‘Tianhong2’ Fuji apple planting in Xinjiang. Bio-organic fertiliser was applied, and nitrogen was reduced by 20% (T2), 40% (T3), and 60% (T4) during the blooming and fruit expansion periods with conventionally fertilised fields used as control (T1); soil nutrient, soil enzyme activity, leaf nutrients, fruit quality, and yield were measured. The total nitrogen (TN), total phosphorus (TP), total potassium (TK), total calcium (TCa), available phosphorus (AP), available potassium (AK), and soil organic matter (SOM) contents, as well as the soil catalase (S-CAT), soil uretrase (S-UE), soil saccharase (S-SC), and soil nitrate reductase (S-NR) activities, significantly increased in the experimental soils compared with those in T1. In addition, TP, TCa, and total magnesium (TMg) content in apples significantly increased. Compared to T1, the T2 and T3 treatments significantly improved the fruit yield and quality, increasing the sugar–acid ratio, soluble protein, soluble sugar, peel carotenoid, and anthocyanin content and reducing peel chlorophyll content. The brightness (L*), red–green axis (a*), yellow–blue axis (b*), colour intensity (C), and tone (h°) values changed. The yield per hectare and nitrogen fertiliser partial productivity values were significantly increased. Overall, the T2 treatment resulted in the best outcome for the Yili area. In conclusion, partially substituting inorganic nitrogen with bio-organic fertiliser can effectively increase soil and leaf nutrient content and improve fruit yield and quality.

PRODUCTIVITY OF ELEPHANT GRASS (Pennisetum purpureum) PLANTED WITH LEGUMINOSE AT VARIOUS DOSAGES OF BIOORGANIC FERTILIZER

&#x0D; &#x0D; &#x0D; The purpose of this study was to determine the productivity of elephant grass (Pennisetum purpureum) planted with leguminosae at various doses of bioorganic fertilizers. This study used a completely randomized design with two factorial patterns. The first factor was the type of leguminosae (T= without leguminosae; R= Arachi pintoi; L= Alysicarpus vaginalis; and the second factor was the dose of bioorganic fertilizer (D0= 0 kg Nha-1; D1= 100 kg Nha-1; D2= 200 kg Nha-1; and D3= 300 kg Nha-1) There were 12 treatment combinations, each treatment was repeated 5 times so that it consisted of 60 experimental units. The observed variables included growth, yield and growth characteristics variable. The results showed that there was no interaction between leguminous species and fertilizer dosage, both leguminous species only increased leaf area per pot, bioorganic fertilizer D1 and D2 doses tended to increase, while D3 dose increased leaf dry weight, total forage dry weight, and leaf area per pot of elep- hant grass (Pennisetum purpureum). It was concluded that the type of leguminous did not affect the productivity of elephant grass, the dose of bioorganic fertilizer increased crop yields, the highest yields at a dose of 300 kg Nha-1 bioorganic fertilizer.&#x0D; &#x0D; &#x0D;