Commercial Organic Fertilizer Research Articles

Comprehensive Analysis of Antimicrobial, Heavy Metal, and Pesticide Residues in Commercial Organic Fertilizers and Their Correlation with Tigecycline-Resistant tet(X)-Variant Genes.

With the issue of the antimicrobial additive ban in feed in Chinese animal husbandry, it is important to determine the potential drivers of the spread of the newly discovered tigecycline-resistant tet(X)-variant genes. Here, we investigated the correlations between residues of heavy metals, antimicrobials, and pesticides and the relative abundance of tet(X)-variant genes in 94 commercial organic-fertilizer samples collected from 9 Chinese provinces. A total of 5 heavy metals (mercury, lead, arsenic, chromium, and cadmium), 10 antimicrobials, and 18 pesticides were detected. The tet(X)-variant genes, including tet(X)/(X2), tet(X3), tet(X4), tet(X5), and tet(X6) were detected in 39 (41.5%) samples. Although tet(X)-variant-carrying bacteria were not isolated from these samples, the tet(X4)-carrying plasmids could be captured by exogenous Escherichia coli. Correlation analysis revealed that heavy metals, other than antimicrobials, showed a significant positive association with the relative abundance of the tet(X)-variant genes, especially tet(X3) and tet(X4) (R = 0.346 to 0.389, P < 0.001). The correlation was attributed to the coselection of the tet(X3)/tet(X4) gene on the same plasmid and the conjugation-promoting effect of tet(X3)/tet(X4)-carrying plasmids by subinhibitory concentrations of heavy metals. The heavy metals increased the permeability of the bacterial outer membrane and upregulated the transcription of type IV secretion system (T4SS)-encoding genes on tet(X)-variant-carrying plasmids, therefore enhancing the bacterial conjugation rates. Taken together, our findings have indicated that heavy metals may play an important role in spreading tet(X)-variant genes within the animal manure-related environment. IMPORTANCE An antimicrobial resistance gene (ARG) is considered a novel contaminant for the environment. Most animal feces are usually made into commercial organic fertilizers in China and will pose a threat to the farmland soil and agricultural product if fertilizers harboring clinically significant antimicrobial-resistant (AMR) genes are applied on farmland. This study has indicated that heavy metals may play an important role in the transmission of transferable tigecycline resistance genes [tet(X3) and tet(X4)]. The mechanism was that heavy metals posed a coselection effect of the tet(X3)/tet(X4) gene on the same plasmid and could increase the conjugation ability of tet(X3)/tet(X4)-carrying plasmids. The conjugation-promoting concentrations of heavy metals are lower than the maximal limits defined in the national standard for fertilizers, indicating a high transmission risk of tet(X3)/tet(X4) genes within the animal manure-related environment. The findings in this study will provide scientific evidence for the future development of effective measures to reduce AMR dissemination.

Can Agricultural Cooperatives Promote Chinese Farmers' Adoption of Green Technologies?

Green technologies are important for achieving green and high-quality agricultural development. The Chinese government has issued various policies to explicitly encourage the adoption of green technologies. However, incentives for Chinese farmers to adopt green technologies remain insufficient. This study examines whether participation in agricultural cooperatives can help break the barriers to Chinese farmers' adoption of green technologies. It also examines the potential mechanisms by which cooperatives can mitigate the lack of incentives for farmers to adopt agricultural green technologies. Using data from a study on farmers in four Chinese provinces, we found that cooperative participation significantly increases farmers' adoption behavior for both green technologies with effective market incentives (e.g., commercial organic fertilizer technologies) and those without such incentives (e.g., water-saving irrigation technologies).

Effects of partial substitution of chemical fertilizer with organic fertilizer on arbuscular mycorrhizal fungal community of Mangifera indica

Nutrient enrichment caused by fertilization would reduce the diversity of arbuscular mycorrhizal fungi (AMF). To explore whether partial substitution of chemical fertilizer with organic fertilizer would alleviate the negative effects of nutrient enrichment on AMF, we conducted a two-year mango (Mangifera indica) field experiment to examine the effects of different fertilization regimes on AMF communities in roots and rhizospheric soils by using high-throughput sequencing. The treatments included chemical-only fertilization (control), and two kinds of organic fertilizer (commercial organic fertilizer and bio-organic fertilizer) with replacing 12% (low) and 38% (high) chemical fertilizer. The results showed that under equivalent nutrient input, partial substitution of chemical fertilizer with organic fertilizer had positive effects on the yield and quality of mango. The application of organic fertilizer could effectively increase AMF richness. AMF diversity was significantly positively correlated with some indices of fruit quality. Compared with chemical-only fertilization, high replacement ratio of organic fertilizer could significantly change root AMF community, but did not affect AMF community in the rhizospheric soil. Bio-organic fertilizer could enrich more AMF species and form a more complex AMF co-occurrence network than commercial organic fertilizer. In all, replacing chemical fertilizer with a high proportion of organic fertilizer could improve the yield and quality of mango while maintain AMF richness. The changes of AMF community caused by organic fertilizer substitution pre-ferably occurred in roots rather than soils.

Recycling fertilizers from human excreta exhibit high nitrogen fertilizer value and result in low uptake of pharmaceutical compounds

Recycling nutrients is essential for closing nutrient loops within a circular economy. Using locally available resources such as human excreta to produce bio-based recycling fertilizers can substitute mineral fertilizers and thereby promote environmentally friendly food production. To better understand the fertilizer potential and nitrogen value of human excreta, three novel and safe recycling products were evaluated in a field experiment. Two nitrified urine fertilizers (NUFs) and one fecal compost were applied alone or in combination, and compared against the commercial organic fertilizer vinasse. In addition, the uptake of pharmaceuticals was assessed for treatments with compost application. White cabbage (Brassica oleracea var. capitata f. alba) was cultivated in plots in three different soil types (sand, loam or silt) treated with the fertilizers according to plant needs and mineral soil nitrogen content. The two NUFs resulted in marketable yields similar to those of vinasse in all soil types. Combining fecal compost with a NUF led to increased marketable yield compared to compost alone. The highest yield was recorded from the sandy soil, where vinasse and NUF treatments led to comparable yields, as expected in organic productions systems (up to 72 t ha−1). The cabbage yield and total aboveground fresh biomass followed the following trend in all soils: NUFs ∼ vinasse ≥ compost + NUF ≥ compost. Nitrogen uptake in the cabbage heads and total biomass was significantly higher in sand (69.5–144 kg ha−1) than loam (71.4–95.8 kg ha−1). All compost treatments alleviated the effect of soil type and resulted in comparable nitrogen uptake and yield in all soil types. Plant uptake of pharmaceuticals (Carbamazepin) was higher in sand than in loam, and concentration in the edible part was lower than in the outer leaves. In conclusion, NUF alone appears to be a promising successful fertilizer substitute in horticultural food production. The combined application of NUF and compost led to slightly lower crop yields, but may increase soil carbon content in the long term, promoting climate-friendly food production.

Utilization of compost derived from waste sludge of shrimp raising-ponds for crop cultivation

Compost, an organic fertilizer which is rich of nutrients, safe and environmentally friendly for crop cultivation. In this study, it was aimed at evaluatiton of the effects of the compost derived from shrimp pond waste sludge on plant growth of kohlrabi, white radish, and mustard green. The application of the compost produced in five districts (Quynh Luong, Nghi Hop, Dien Trung, Quynh Di, Hung Hoa) of Nghe An province resulted in remarkably higher plant growth. In which kohlrabi, white radish, and mustard green fertilized by the compost from Quynh Luong district had crop yields of 3.6 kg/m2, 3.4 kg/m2, 3.7 kg/m2 than the control without compost yielding 2.1-2.2 kg/m2. Similarly, other plant growth parameters of number and areas of leaves and survival rate of the plants were all significantly higher than that of the control. Moreover, the mustard greens yields applied the compost produced in the four districts including Nghi Hop, Dien Trung, Quynh Di, Hung Hoa were in the range of 3.1-3.6 kg/m2 all higher than that of the control unapplied fertilization determined as 2.2 kg/m2, but reaching relatively equivalent to that of the commercial organic fertilizer at 3.8 kg/m2, but slightly lower than that of the chemical fertilizer 4.4 kg/m2. The study revealed that the compost from shrimp pond waste sludge can be fertilized for crop cultivattion which was safe and contributing to reducing a large amount of waste sludge discharged from shrimp-raising ponds in Nghe An province.

Fertilizer use in conventional cereal production in northern Greece: Mapping gaps for improving sustainability

Summary Optimizing fertilizer use in intensively cropped soils is essential, but knowledge of related issues among farmers is lacking. The present study assessed farmers’ perceptions of fertilizers and practices of fertilizer use in intensive cereal production in rural areas of Evros in northern Greece. In total, 250 cereal farmers were chosen for this study, and more than half of the farmers (53.6%) perceived that chemical fertilizers are hazardous, corroborating a general perception of chemophobia. Nevertheless, almost all farmers (98.8%) stated that they applied fertilization in their cereal production. Among them, 82.8% applied inorganic fertilizers, 9.2% applied green manure, 4.4% applied animal manure, and 3.6% applied commercial organic fertilizers. Most farmers used rates within the recommended rates in cereal production, while 12.9% and 6.2% of the farmers reported fertilization rates that were significantly lower or higher than those recommended for the area, respectively. Almost half of the farmers (48.8%) stated that they often use slow-release fertilizers and 30.8% stated that they frequently use foliar-applied fertilizers in cereals. Most farmers (57.2%) never kept records of annual fertilizations, while two-thirds of the farmers (66.4%) never asked for a soil analysis. Overall, most farmers (52.0%) showed traditional behavior, while only 5.2% showed innovative behavior in fertilizer use. Multiple regression analysis revealed that the innovative behavior was promoted by large-scale farmers, farmers who applied crop rotation, and farmers who perceived inorganic fertilizers as harmful. Moreover, large farm size and favorable attitudes concerning organic fertilizers were significantly associated with organic fertilizers use.

Yield and Nutrient Uptake of T. Aman Rice as Influenced by Fertilizer Management and Preceding Crop Combinations in Vegetable-Vegetable-Rice Cropping Sequence

In recent years awareness of fertility status of soil and the nutrients requirement for crops according to cropping arrangement has increased. In this context, the study was carried out over 2 years (2018 and 2019) at the Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) research farm to assess the influence of fertilizer management and preceding crop combinations on yield and yield contributing attributes of subsequent T. Aman rice; to determine the amount of nutrient concentration and taken up by the subsequent T. Aman rice regarding the preceding crops combinations and fertilizer treatments in vegetable–vegetable–rice cropping sequence. Treatments consisted of three prior crop combinations, i.e., before planting T. Aman rice (Potato-Stem Amaranth, Garlic-Stem Amaranth and Cauliflower-Stem Amaranth) including for each, four replications of two fertilizer treatments: commercial organic fertilizer (N based organic compost) and inorganic fertilizer (Soil test based inorganic fertilizer without cow dung). The subsequent T. Aman rice (BRRI dhan75) yields and yield contributing characters were not significantly affected by the interaction effect of preceding crop combinations and fertilizer application. Furthermore, fertilizer treatments had no significant effect on yields and yield components of T. Aman rice (BRRI dhan75) excluding plant height. Preceding crop combination had significant effect on grain panicle-1 of T. Aman rice (BRRI dhan75). At the end of two years, results clearly indicated that yield contributing parameters of BRRI dhan75 performed better under both preceding crop combinations as P2 (Garlic-Stem Amaranth) and P3 (Cauliflower-Stem Amaranth) with F2 (soil test based inorganic fertilizer management). Whereas yield was found greater under both preceding crop combination, P1 (Potato - Stem Amaranth) with F1 (N based organic compost alone) and P2 (Garlic-Stem Amaranth) using F2 (soil test based inorganic fertilizer). The interaction of preceding crop combination and fertilizer application demonstrated significant effect on nutrient concentration (Nitrogen, Phosphorus and Potassium) in grain and straw of T. Aman. The application of inorganic fertilizer using the soil test-based method significantly increased N uptake by grain under both preceding crop combination as P2 (Garlic-Stem Amaranth) and P3 (Cauliflower-Stem Amaranth) compared with a sole application of N based organic compost. Yet, it is too quick to create a decisive remark based on only these very few numbers of preceding crops combinations and fertilizer treatments in vegetable-vegetable-rice cropping sequence. Therefore, a detailed study with a huge number of organic and inorganic fertilizer treatments applied under large number of vegetable-vegetable-rice cropping sequence is obviously needed to reach a precise conclusion.

Closing the food waste loop: Analysis of the agronomic performance and potential of food waste disposal products

The recycling of urban food waste (FW) is of great importance to the sustainable and low-carbon urban development. Focusing on the solid residues of FW aerobic composting and anaerobic digestion, this study selects three FW disposal products (FWDPs) and compares their nutrient compositions with the main traditional organic fertilizers in China through a literature review; carries out a seven-season field experiment with 30% of the nitrogen in FWDPs substituted for equal chemical nitrogen to explore the impacts on vegetable yields; and uses a field questionnaire to investigate farmers' awareness of FWDPs. FW aerobic compost and FW digestate solid residue can significantly increase seven-season total yields by 21.5% and 17.2% respectively compared with conventional chemical fertilizer alone, and maintain the same yield level with conventional combined application of chicken manure and chemical fertilizer, proved to be effective on crop yield as organic fertilizers. The case study of Xiamen indicates that FWDPs have great potential to produce organic fertilizers and reduce the application amount of pure chemical fertilizers by 5.6% under current conditions, where around one-third of restaurant FW is disposed of using anaerobic digestion technologies. Measures like formulating supportive regulations, expanding government propaganda, and producing qualified and cost-effective commercial organic fertilizers with FWDPs will improve farmers’ knowledge and acceptance of FWDPs.

Re-utilization of Sub-optimal Used-planting Media to Cultivate Black Rice in the Pot

Beside reducing production cost, re-utilization sub-optimal used planting media was environmentally good practice, especially when the plants were cultivated in the pots. This research incorporated black rice accession that had high economic value. The plants were cultivated in 10-kg pots, arranging in Randomized Block Design with three replications, each consisted of 5 pots. The treatments were weight-based additions of local organic soil and commercial organic fertilizer of 5 %, 10 %, 15 %, and 0 % (no-addition). Result of this research indicated that 10 % addition of local organic soil was considered enough to cultivated black rice in the pots. The plants were observed to grow normal with plant height reached 150 cm, consisted of 70 clumps and produced 56.52 g dry seeds per pot, equivalent to 11.69 ton per ha. In percentage, addition of 5, 10 and 15 % local organic soil, resulted in 33-53 % increase in number of mature panicles, 33-56 % increase in total number of seeds, 123-232 % increase in number pithy seeds, and 106-289 % increase in weight of dry seeds per pot.

Supplemental Effects of Self-extracted Organic Nutrient Solution on the Growth and Yied of Water Spinach (Ipomoea Aquatic F.) in an Aquaponic System

Aquaponics combines two technologies, recirculating aquaculture systems and hydroponics in a closed system. The nutrients recycled from fish tanks supply nutrients for vegetables grown in hydroponics, however in some cases, the nutrient levels may not be sufficient for the optimal growth and yield of plants. In this study, two experiments were conducted to understand the effects of supplemental organic nutrient solutions on plant growth and yield in climbing perch-water spinach aquaponics. Experiment 1 (Exp.1) was conducted to evaluate the effects of three types of leaf-based organic fertilizers on the growth and yield of water spinach, namely self-extracted organic nutrient solution (OE), and two popular commercial foliar organic fertilizers, Hydro Fulvic (OF1) and TCN HUME (OF2), with the dose of 1%. Exp.1 showed that supplementation with the self-extracted solution significantly increased the growth and yield of water spinach but did not change the quality of water spinach in terms of the Brix values and nitrate residue content compared to the control. However, the self-extracted solution showed less effectiveness than the two commercial fertilizers in this experiment. Therefore, we conducted experiment 2 (Exp.2) to determine the suitable concentration and potential use of this extract for water spinach in aquaponics. The results of Exp.2 indicated that the concentration of 2% was the most economical and effective to provide supplemental nutrients for water spinach in the climbing perch-water spinach system. The study suggests that self-extracted organic nutrient solutions can be effectively used for growing water spinach in aquaponic systems.

Substituting Inorganic Fertilizers with Organic Amendment Reduced Nitrous Oxide Emissions by Affecting Nitrifiers’ Microbial Community

Excessive inorganic fertilizers are one of the main causes of nitrous oxide (N2O) emissions. Organic fertilizers can not only reduce the use of nitrogen (N) fertilizers by increasing soil organic matter but are also safe for the environment. The partial replacement of nitrogen (N) fertilizers with organic fertilizers can potentially reduce N2O emissions. To illuminate the best ratio for the nitrogen replacement of inorganic fertilizer, the present experiment was conducted in dryland areas of central Gansu Province and different portions of inorganic N fertilizers (200 kg ha−1); i.e., 0, 50, 37.5, 25, and 12.5% were replaced with commercial organic fertilizers to test their effects on soil physicochemical properties, the grain yield of maize, N2O emissions, and the diversity of ammonia-oxidizing archaea (AOA) and bacterial (AOB) communities. Results showed that the maximum N2O emission was obtained by 100% inorganic fertilizers and the lowest was obtained at the control (no fertilizer). Substituting inorganic fertilizers with organic manure not only reduced N2O emissions but also improved soil organic carbon content and soil moisture and typically improves grain yield and biomass. The highest reduction in N2O emissions was recorded by 50% substitution. Furthermore, 37.5% and 12.5% substitutions did not reduce the grain yield and biomass compared to 100% inorganic fertilizer, and a 37.5% substitution performed better in improving soil fertility. Organic fertilizer increased the amoA copy number of AOA but decreased that of AOB. Nitrososphaera (AOA) and Nitrosospira (AOB) were the most dominant ammonia-oxidizing communities. Structural equation modeling indicated that AOB contributes more N2O emissions than AOA and is more sensitive to changes in pH, moisture, and NO3−−N, and the input of organic fertilizers may affect AOB by influencing soil physicochemical traits. In summary, replacing a reasonable proportion (37.5%) of inorganic fertilizers with organic manure improves soil fertility, reduces N2O emissions, and stabilizes production.

Effects of Two Kinds of Commercial Organic Fertilizers on Growth and Rhizosphere Soil Properties of Corn on New Reclamation Land.

Due to the development of urbanization and industrialization, a large amount of cultivated land resources has been occupied, while new reclamation land could expand the supply of usable land for food security. Organic fertilizers, such as crop residues, biosolids, sheep manure, mushroom residue, and biogas liquid, have been considered as an effective amendment in immature soil to improve its quality. Recently, two kinds of commercial organic fertilizers, pig manure and mushroom residue organic fertilizer (PMMR-OF), and sheep manure organic fertilizer (SM-OF), have been more regularly applied in agriculture production. However, the information available on effect of the two kinds of fertilizers on plant growth and rhizosphere soil properties in immature field is very limited. In order to evaluate PMMR-OF and SM-OF on immature soil, the soil quality and microbial community structure of corn rhizosphere soil samples under the two kinds of organic fertilizers at different concentrations was investigated. The results revealed a significant difference between commercial organic fertilizers (especially SM-OF) and chemical compound fertilizers (CCF) in soil properties and microbial community structure. Indeed, compared with the control based on16S and ITS amplicon sequencing of soil microflora, SM-OF caused a 10.79–19.52%, 4.33–4.39%,and 14.58–29.29% increase in Proteobacteria, Actinobacteria, and Ascomycota, but a 5.82–20.58%, 0.53–24.06%, 10.87–16.79%, 2.69–10.50%, 44.90–59.24%, 8.88–10.98%, and 2.31–21.98% reduction in Acidobacteria, Gemmatimonadetes, Bacteroidetes, Verrucomicrobia, Basidiomycota, Mortierellomycota, and Chytridiomycota, respectively. CCF caused a 24.11%, 23.28%, 38.87%, 19.88%, 18.28%, and 13.89% reduction in Acidobacteria, Gemmatimonadetes, Bacteroidetes, Verrucomicrobia, Basidiomycota, Chytridiomycota, but a 22.77%, 41.28%, 7.88%, and 19.39% increase in Proteobacteria, Actinobacteria, Ascomycota, and Mortierellomycota, respectively. Furthermore, redundancy discriminant analysis of microbial communities and soil properties of PMMR-OF, SM-OF, CCF, and the control treatments indicated that the main variables of bacterial and fungal communities included organic matter content, available P, and available K. Overall, the results of this study revealed significant changes under different fertilizer conditions (PMMR-OF, SM-OF, CCF, under different concentrations) in microbiota and chemical properties of corn soil. Commercial organic fertilizers, particularly SM-OF, can be used as a good amendment for the new reclamation land.

Development and validation of a solid phase extraction-UPLC-MS/MS method for the determination of fifty-nine antimicrobials in commercial organic fertilizers and amended soils

Commercial organic fertilizers often contain high levels of antimicrobials that can be released into agricultural soils and pose potential ecological risks, and there is a significant need to quantify their occurrence in these products. However, the presence of high contents of organic matter, nutrient salts, and trace metals in commercial organic fertilizers pose significant challenges for the extraction and analysis of antimicrobials, especially when multiple compounds are targeted. This study developed a robust and sensitive multi-residue method for the determination of fifty-nine antimicrobials, belonging to four different classes, in commercial organic fertilizers and amended soils. The method was based on ultrasonic extraction with a mixture of EDTA-McIlvaine buffer/methanol/acetonitrile/acetone (5:2:2:1 by volume), solid phase extraction (SPE) using SAX and HLB cartridges in series, followed by UPLC–MS/MS analysis in the dynamic multiple reaction monitoring (MRM) mode. The performance of the optimized extraction method was good for fifty-nine antimicrobials with a median recovery rate of 46 and 84 % in commercial organic fertilizers and amended soils, respectively. The matrix effects were between 105 and 109 % in commercial organic fertilizers and 102–140 % in amended soils, which are indicative of the effectiveness of pretreatment procedures and the accuracy of instrumental analysis. The method had good linearity (R2 > 0.99), and the detection limits and method quantification limits for fifty-nine antimicrobials in commercial organic fertilizers were 0.002–0.206 ng/g (median 0.026 ng/g) and 0.006–0.684 ng/g (median 0.086 ng/g), respectively. This robust and practical method effectively eliminates the matrix effects of commercial organic fertilizer and could be used for routine determination of multiple classes of antimicrobial residues in commercial organic fertilizers and amended soils.

Effect of organic and mineral fertilizers applications in pasture and no-tillage system on crop yield, fractions and contaminant potential of Cu and Zn

Organic wastes, fertilizers, organominerals, and minerals contain nutrients essential to crops and contribute to increase productivity. However their use can also lead to the accumulation of copper and zinc, which changes the distribution of their fractions and enhances the risk of toxicity to plants and the environment, thereby working against the sustainable development goals. However, the effect of manure applications on clayey soils and the effects of increasing Cu and Zn contents over the years on crop productivity remain unknown. This study aimed to evaluate the distribution and the potential for contamination of heavy metals in clayey soil with a history of the application of different types and amounts of fertilizers under Cynodon spp. grazing and no-tillage system for soybeans. In Experiment 1, Cynodon spp. were cultivated for hay production and submitted to applications of the following treatments: 0, 200, and 400 kg ha−1 of total-N in the form of pig slurry and urea. In experiment 2, the soybean was grown and subjected to the following treatments: control, pig slurry, commercial granulated solid organic fertilizer, organomineral fertilizer blended with granules, and mineral fertilizer blended with granules. The dose of each nutrient source was determined based on the soil analysis and the recommendations of the liming and fertilization manual. The experiments were conducted for four agricultural crops where soil samples were collected in the layer of 0.00–0.10 m layer and submitted to chemical fractionation of Cu and Zn. The use of pig manure increased the availability of Cu and Zn in the soil, causing an increase in the distribution of copper organic (40.73% and 57.64% for PS200 and PS400 treatments, respectively, in Experiment 1; 67.33% for PS treatment, in Experiment 2) and residual fractions (10.01% and 7.60% for PS200 and PS400 treatments, respectively, in Experiment 1; 9.80% for PS treatment, in Experiment 2), while zinc was predominant in clay-mineral (61.04% and 92.01% for PS200 and PS400 treatments, respectively, in experiment 1; 278.90% for PS treatment, in Experiment 2) and residual fractions (2.36% for PS200 treatment in experiment 1; 9.90% for PS treatment, in Experiment 2). Additionally, the use of swine manure increased the Cu and Zn contents in the exchangeable fraction, which may potentiate the toxicity to plants and increase the potential for contamination of subsoil water. However, the increased bioavailability of Cu and Zn did not caused a loss of crop productivity but instead increased dry mass production and crop yield.

Application of a Nano-Enhanced Fertilizer in the Development of Agricultural Low-Carbon Economy in the Yangtze River Economic Belt

The application of fertilizers can increase the yield of crops. Nano-fertilizer is a nano-organic fertilizer, which is an organic fertilizer with very fine particles. The effect of chemical fertilizers is better than that of general chemical fertilizers, which can effectively improve soil organic matter and is beneficial to the growth of crops. Organic fertilizers mainly refer to commercial organic fertilizers produced by high-temperature composting and fermentation of organic solid wastes such as livestock and poultry manure, crop straw, etc., eliminating toxic and harmful substances and being rich in nutrients including organic acids and peptides. Low-carbon economy refers to an economic model that uses various means to reduce greenhouse gas emissions and achieve good ecological operations under the guidance of the concept of sustainable development. With the increase in the global population and the continuous growth of the economic scale, environmental problems and consequences caused by the use of conventional energy such as fossil energy are constantly recognized by people. Under this background, the low-carbon economy emerges as the times require. This paper aims to study the application of nano-enhanced fertilizers in the development of agricultural low-carbon economy in the Yangtze River Economic Belt. In today’s low-carbon economy, the combination of nano-efficiency fertilizers and agricultural production is conducive to improving the utilization rate of chemical fertilizers and reducing carbon emissions. This paper analyzes the carbon sink capacity of farmland ecosystems and the elements affecting the growth of LCA. This provides a basis for the exploration of farmland ecosystems. It expounds the relevant concepts of low-carbon economy and briefly discusses the agricultural carbon emissions in the Yangtze River Economic Belt. The experimental results in this paper show that the enteric fermentation of dairy cows will produce 60 kg of methane and 15 kg of feces. Sheep enteric fermentation produces 4 kg of methane and fecal emissions of 0.13 kg. According to the data, the carbon emission of dairy cows is much greater than that of sheep.

Commercial organic fertilizer substitution increases wheat yield by improving soil quality

Traditional organic fertilizer substitution is an effective measure for increasing crop yield and soil quality while reducing chemical fertilizer input. However, the effects of commercial organic fertilizer substitution (COFS) on soil quality and wheat yield, and the underlying mechanisms, are unknown. In this study, agricultural fields with low fertility (LF) and high (HF) fertility soils were selected for a two-year (2018–2019) field experiment in the oasis region of Northwest China. Three fertilization treatments with three replications (no fertilization, CK; local conventional chemical fertilizer application, LCF; and 20 % of inorganic nitrogen (N) was substituted by commercial organic fertilizer, COFS) were established to study the effects of COFS on wheat growth, yield, nutrient-use efficiency and soil quality. The results showed that compared with LCF in 2018 and 2019, COFS in LF and HF promoted wheat growth, improved nitrogen use efficiency (NUE) and phosphorus use efficiency (PUE), and increased yield (by 1.52 %–3.05 % and 1.16 %–1.39 %) and soil quality (by 15.09 %–28.63 % and 22.53 %–64.82 %) by improving most soil indicators (e.g., soil organic matter (SOM) and available nutrients). Moreover, SOM and available nutrients significantly affect soil quality and wheat yield, which can monitor changes in soil quality and wheat yield. In conclusion, our study revealed that the mechanism of COFS in HF and LF increased wheat yield by improving soil quality. COFS is recommended for agricultural production, but its continuous application requires monitoring changes in SOM and available nutrients to adjust fertilization to guarantee soil quality and crop yield. This study provides guidance for the scientific application of COFS to improve farmland productivity and soil quality and helps to promote healthy and sustainable agricultural development.

Impact of soil amendments on nitrous oxide emissions and the associated denitrifying communities in a semi-arid environment.

Denitrifying bacteria produce and utilize nitrous oxide (N2O), a potent greenhouse gas. However, there is little information on how organic fertilization treatments affect the denitrifying communities and N2O emissions in the semi-arid Loess Plateau. Here, we evaluated how the denitrifying communities are responsible for potential denitrification activity (PDA) and N2O emissions. A field experiment was conducted with five fertilization treatments, including no fertilization (CK), mineral fertilizer (MF), mineral fertilizer plus commercial organic fertilizer (MOF), commercial organic fertilizer (OFP), and maize straw (MSP). Our result showed that soil pH, soil organic carbon (SOC), and dissolved organic nitrogen (DON) were significantly increased under MSP treatment compared to MF treatment, while nitrate nitrogen (NO3−−N) followed the opposite trend. Organic fertilization treatments (MOF, OFP, and MSP treatments) significantly increased the abundance and diversity of nirS- and nosZ-harboring denitrifiers, and modified the community structure compared to CK treatment. The identified potential keystone taxa within the denitrifying bacterial networks belonged to the distinct genera. Denitrification potentials were significantly positively correlated with the abundance of nirS-harboring denitrifiers, rather than that of nirK- and nosZ-harboring denitrifiers. Random forest modeling and structural equation modeling consistently determined that the abundance, community composition, and network module I of nirS-harboring denitrifiers may contribute significantly to PDA and N2O emissions. Collectively, our findings highlight the ecological importance of the denitrifying communities in mediating denitrification potentials and the stimulatory impact of organic fertilization treatments on nitrogen dynamics in the semi-arid Loess Plateau.

Humic Acid Improves Greenhouse Tomato Quality and Bacterial Richness in Rhizosphere Soil.

Humic acid (HA) has attracted increasing attention as a new type of organic fertilizer in horticultural production, such as greenhouse-planted cherry tomato. However, we need more information to evaluate the effects of HA on soil rhizosphere bacteria and tomato performance under greenhouse conditions. In this study, greenhouse-planted cherry tomato was observed with HA added at dosages of 1500, 3000, 4500, and 6000 kg·ha–1, respectively. The other two organic fertilizers [farmyard manure (FM) and commercial organic fertilizer (COF)], were used as comparison with a dosage of 3000 kg·ha–1. Illumina MiSeq sequencing was conducted for bacterial diversity analysis, and tomato quality analysis based on total soluble solids, titratable acid, and sugar–acid ratio was performed for different fertilizer treatments. The results revealed that HA application resulted in the best flavor, compared to CK without the organic fertilizer used and with the other two organic fertilizers. The Chaol estimator and Shannon index showed that fertilizer addition decreased microbial diversity but increased species richness. At a dosage of 3000 kg·ha–1, the effects of different fertilizers were ranked as HA > FM > COF. Our findings offered suggestions to reasonably optimize cherry tomato organic fertilizer application.

Effects of Different Organic Fertilizers on Sweet Potato Growth and Rhizosphere Soil Properties in Newly Reclaimed Land

It is well known that soil fertility is poor in most newly reclaimed land, which has been developed as an effective way to compensate farmland occupation. In order to ameliorate the soil quality of the newly reclaimed land, this study investigated the effect of commercial organic fertilizer (COF) (0.45, 0.90, 1.35 and 1.80 kg/m2), sheep manure (SM) (0.45, 0.75, 1.05 and 1.35 kg/m2), mushroom residue (MR) (1.50, 2.25, 3.00 and 3.75 kg/m2), and chemical compound fertilizer (CCF) (0.075 kg/m2) on the growth of sweet potato, soil pH, organic matter content (OMC), available phosphate, total nitrogen, available potassium, exchangeable Ca and Mg, as well as bacterial and fungal microbial composition during 2019–2021. The results from this study indicated that the COF, SM, MR, and CCF did not significantly change the soil pH, but significantly increased the OMC, which has been regarded as the most significant soil quality parameter. This suggests that the soil amendments used in this study have great potential to improve the soil quality in newly reclaimed land. However, these soil amendments exhibited a differential effect on sweet potato biomass, nutrient elements and the microbial community of the newly reclaimed soil, which depend on the kind and concentration of organic/chemical fertilizer, the application time, as well as the plant and soil parameters. The change was also observed on the bacterial and fungal soil microbial community, which provides us with a microbial basis to understand why organic fertilizer has a great effect on soil improvement. Overall, our results suggest that soil amended with organic fertilizers has great potential for the production of sweet potato in immature soil from the new reclamation land.

Nitrogen Reduction Combined with Organic Materials Can Stabilize Crop Yield and Soil Nutrients in Winter Rapeseed and Maize Rotation in Yellow Soil

Objective: To investigate the effect of nitrogen reduction combined with organic materials on crop growth of winter rapeseed and maize rotation in yellow soil. Methods: A 2-year, four-season winter rapeseed and maize rotation experiment using three organic materials (biochar (B), commercial organic fertilizer (O) and straw (S), 3000 kg·hm−2) and three nitrogen application rates (100%, 85% and 70%) was carried out from 2018 to 2020 in Guizhou Province, China. By comprehensively analyzing the crop yield, biomass and nutrient absorption, soil nutrients indicators, and the efficiency of nitrogen fertilizer was calculated. Results: All organic materials could increase the yield of both crops, and 100% N + O treatment was the best, and the 2-year winter rapeseed and maize yields reached 3069 kg·hm−2, 3215 kg·hm−2 and 11,802 kg·hm−2, 11,912 kg·hm−2, respectively. When nitrogen application was reduced by 15%, the addition of the three organic materials could stabilize or increase the yield and biomass, and nitrogen, phosphorus and potassium absorption in both crops showed an increasing trend, which could improve or maintain soil nutrients. When nitrogen application was reduced by 30%, the yields of two crops with organic materials addition were lower than those of 100% N treatment. Through the interaction, it was found that nitrogen and organic material were the main reasons for the increase in yield, respectively. Conclusions: The addition of three organic materials can replace 15% of nitrogen fertilizer. It is recommended to apply 153.0 kg·hm−2 and 127.5 kg·hm−2 of nitrogen fertilizer in winter rapeseed and maize seasons, respectively, in the rotation area of Guizhou yellow soil, with the addition of 3000 kg·hm−2 organic materials, most appropriately commercial organic fertilizer.