Commercial Organic Fertilizer Research Articles

Study of Steroid Estrogen Loss in Soil after the Application of Composted Manure as a Fertilizer

Steroid estrogens (SEs) play a significant role as endocrine-disrupting substances, and one of their major sources is animal manure. However, there is limited information available regarding the loss of SEs in farmland soil after the application of commercial composted animal manure or fertilizers. To address this gap, our study aimed to simulate rainfall and flood irrigation scenarios and investigate the loss characteristics of SEs, as well as Chemical Oxygen Demand (COD), Total Nitrogen (TN), and Total Phosphorus (TP) in runoff from soil–manure mixtures. The results demonstrated that the loss concentrations of SEs (73.1 ng/L of the mean E2β active equivalent factor) presented a potential environmental risk. Additionally, substituting composted manure with commercial organic fertilizers lead to a significant reduction in TP (maximum 56%) and TN (maximum 24%) loss. Consequently, the application of commercial organic fertilizers offers considerable advantages in maintaining nitrogen and phosphorus fertilization efficiency while controlling SEs loss. Furthermore, our study explored the synergistic pollution mechanism among these pollutants and observed significant correlations between SEs and TN, TP, and COD loss concentrations, indicating the simultaneous occurrence and migration of these pollutants in agricultural non-point source pollution. These results provide valuable insights into the environmental risk associated with SEs from agricultural non-point sources.

Assessing intracellular and extracellular distribution of antibiotic resistance genes in the commercial organic fertilizers

Compost-based organic fertilizers often contain high levels of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs). Previous studies focused on quantification of total ARGs and MGEs. For a more accurate risk assessment of the dissemination risk of antibiotic resistance, it is necessary to quantify the intracellular and extracellular distribution of ARGs and MGEs. In the present study, extracellular ARGs and MGEs (eARGs and eMGEs) and intracellular ARGs and MGEs (iARGs and iMGEs) were separately analyzed in 51 commercial composts derived from different raw materials by quantitative polymerase chain reaction (qPCR) and metagenomic sequencing. Results showed that eARGs and eMGEs accounted for 11–56% and 4–45% of the total absolute abundance of ARGs and MGEs, respectively. Comparable diversity, host composition and association with MGEs were observed between eARGs and iARGs. Contents of high-risk ARGs were similar between eARGs and iARGs, with high-risk ARGs in the two forms accounting for 6.7% and 8.2% of the total abundances, respectively. Twenty-four percent of the overall ARGs were present in plasmids, while 56.7% of potentially mobile ARGs were found to be associated with plasmids. Variation partitioning analysis, null model and neutral community model indicated that the compositions of both eARGs and iARGs were largely driven by deterministic mechanisms. These results provide important insights into the cellular distribution of ARGs in manure composts that should be paid with specific attention in risk assessment and management.

A Study of the Relationship between Initial Grape Yield and Soil Properties Based on Organic Fertilization

Increasing the use of organic fertilizers is an effective measure to improve, increase soil fertility and maintain crop yields. The aim of this study was to investigate the influence of different types of organic fertilizers on the early yield of grapes and soil parameters, as well as the relationship between soil parameters and grape yield under fertilization conditions. The ‘Shine Muscat’ grape was used as the material, with early maturing cultivation in the solar greenhouse. From the time of grape planting, three-year continuous fertilization management was carried out using five types of base fertilizers: chemical fertilizer (CK), fermented corn stalk residue (A1), mature sheep manure (A2) and two types of commercial organic fertilizers (B1 and B2). In the third year, berry and soil samples were collected to determine grape yield and evaluate soil physicochemical properties, nutrient status and changes in enzyme activity, studying the relationship between grape yield and soil indicators. The results show that compared to CK, the grape yields with B1 and B2 increased by 19.04% and 16.26%, respectively, while A1 and A2 decreased by 24.09% and 18.97%. Organic fertilizer application reduced soil bulk density, increased soil porosity, enhanced soil organic matter content and effectively buffered soil pH levels. Two types of commercial fertilizers (B1 and B2) improved soil total nitrogen, total phosphorus, total potassium, available nitrogen and available phosphorus content to varying degrees. All organic fertilizer treatments effectively increased soil enzyme activity, except for soil sucrase activity. Through correlation and regression analyses, it was found that in this study, the levels of available nitrogen, available potassium and soil saccharase activity were most closely related to early grape yield. Their influence on grape yield was in the order of available nitrogen > soil saccharase activity > available potassium. Therefore, with a combined organic and inorganic basal fertilization system, the fertilizer nutrients are more comprehensive and help to increase the productivity of grapes at the beginning of the fruiting period. Nitrogen and phosphorus are very important in the maintaining of grape yields and improving sucrose activity in the soil through the application of organic fertilizers cannot be ignored when increasing yields.

A statistical model predicts N mineralization of various organic amendments for paddy fields

ABSTRACT To predict the mineralization of nitrogen(N) in organic amendments in paddy fields, we applied data obtained from incubation experiments under waterlogged conditions by a hierarchical Bayesian model using acid-detergent-soluble organic N (ADSON) as a model input. Each of 20 organic amendments (6 cattle manure composts, 3 swine manure composts, 3 poultry manure composts, 2 oil cakes, 2 rice brans, 1 fish meal, 1 sludge fertilizer, and 2 mixed commercial organic fertilizers) was mixed with paddy soil, and the N mineralization curves obtained after 1, 2, 4, 8, and 12 weeks of waterlogging were incorporated into the model to obtain values of the model parameters k i , α1, and Q 10. All model parameters converged with a mean absolute error (MAE) of 0.044 g N kg−1, a root mean square error (RMSE) of 0.060 g N kg−1, and a model efficiency (EF) of 0.96. These values were comparable to or slightly better than those of a previous model for upland soil conditions. Most of the observed values were within the 95% Bayesian prediction interval, indicating that the model performed well with the observed data. Although it is generally believed that livestock manure composts decompose more slowly than organic fertilizers such as oil cake, the livestock manure composts had a large value of the rate constant k i , presumably because of the initial rapid decomposition of the small amounts of organic N present in them. In paddy fields, the soil conditions are aerobic between the application of organic amendments and water entry. In such a case, we propose the use of the upland field model to predict the mineralization of organic N during the period of aerobic soil conditions and of this study’s model during the period of waterlogging, subtracting the amount of already mineralized N from the parameters N in and ADSON. The model devised here is expected to be useful for fertilization design in organic agriculture and in the reduction of the use of inorganic fertilizer.

Fertilisation strategies and their influence on nutrient flows in organic apple orchards

AbstractIn organic fruit production, permitted fertilisers contain multiple nutrients with stoichiometries differing from the nutrient offtakes of the fruit trees. Furthermore, some pesticides contain nutrients resulting in additional inputs. These conditions may cause unbalanced nutrient supplies and thereby influence the long-term sustainability of the system. An analysis of nutrient management practices in organic apple farms was conducted in three Southern and one Northern German apple-growing region. Data on nutrient inputs (via fertilisers and pesticides) and outputs (via fruit) per orchard were collected along with soil samples from up to five orchards per farm on 19 farms. On average, farmers fertilised 37 kg N and harvested 23 Mg apples per ha and year. Nutrient budgets showed imbalances for N (+ 25 kg ha−1 year−1), P (+ 3 kg), K (− 4 kg), Ca (+ 37 kg), Mg (+ 4 kg), S (+ 53 kg), Na (+ 4 kg) and Cl (+ 3 kg). Base fertilisers like compost or manure contributed to higher nutrient inputs due to a larger P and K-to-N-ratio. Commercial organic fertilisers such as keratins or vinasse contained much lower ratios. The main S input sources were pesticides (46 kg). N inputs by base (p = 0.06) and commercial (p = 0.37) fertilisers had no significant effect on the yield. Balanced nutrition can best be achieved by applying a combination of 20% of the total N demand via base fertilisers, complemented with commercial fertilisers with low element-to-N-ratios (e. g. keratin fertilisers, vinasse or biological N2 fixation). No correlation was found between soil nutrient status and nutrient budgets. Site conditions and internal field nutrient flows (transfer of the inter-row biomass via mulching into the tree row) had a stronger influence on the soil nutrient content than fertilisation strategy. In addition, fruit orchards showed a spatial differentiation of soil nutrient contents. Elevated P and K contents above the recommended range in the tree row were found in 67% of the orchards, while tendencies of depletion were found in the inter-row area. Mulching schemes which transfer biomass from the inter-row area to the tree row need to be adapted to this condition.

Residual brewer’s Saccharomyces cerevisiae yeasts as biofertilizers in horticultural seedlings: towards a sustainable industry and agriculture

The food industry generates substantial amounts of organic waste often underutilized within the system. Craft beer production, experiencing global rapid expansion, contributes to this waste stream with byproducts such as spent grain, trub, and yeast. Many craft beer industries discharge yeast residue directly into public water bodies. In recent years, yeasts have garnered attention for their potential to enhance plant growth and contribute to sustainable agriculture. This study focuses on characterizing Saccharomyces cerevisiae yeast collected at the end of the craft beer fermentation process. Biomass characterization was conducted, and the yeast’s effect on lettuce and tomato seeds and seedlings was evaluated at four concentrations (105, 106, 107, and 108 cells mL−1) in sterile substrate. After 28 days, plant height, leaf number, fresh and dry weights of both aboveground and root parts, as well as chlorophyll content, were analyzed. The most effective concentration (107 cells mL−1) was applied to tomato seedlings in sterile substrate, compared with a commercial organic fertilizer. After 21 days, growth parameters were assessed. The study demonstrated that increasing yeast doses up to 108 cells mL−1 positively affects seed germination and seedling development. Notably, a dose of 107 cells mL−1 proved effective for application in seedlings as an organic amendment and substitute for commercial products. This integrated approach showcases the potential of yeasts in sustainable agriculture, utilizing byproducts from the food industry to enhance crop performance and mitigate environmental pollution.

Effects of Different Agricultural Waste Composts on Cabbage Yield and Rhizosphere Environment

The return of agricultural waste to the field is one of the most effective strategies of increasing crop yield, improving the soil’s physicochemical properties, and improving the soil rhizosphere environment. In the present study, sheep manure (SM), cow manure (CM), tail vegetable (TV), mushroom residue (MR), and corn straw (CS) were used as raw materials, and no fertilization (CK1) and local commercial organic fertilizer (CK2) treatments were used as controls. Eight composts were set up using specific mass ratios of different compost materials. After fermentation, field experiments were conducted to determine the cabbage yield, soil’s physicochemical properties, and soil rhizosphere conditions. The eight composts increased the soil organic matter and nutrient contents significantly. Among the eight fermentation formulas, T6 (CM:CS:TV:SM = 1:1:2:6), T7 (MR:CS:TV:SM = 1:1:2:6), and T8 (CM:MR:CS:TV:SM = 1:1:1:2:5) were relatively effective. Therefore, high-throughput sequencing was performed on T6, T7, T8, CK1, and CK2. T6, T7, and T8 exhibited increased relative abundance of Proteobacteria, Actinomycetes, and Firmicutes, while the Acidobacteria abundance was decreased. In addition, Ascomycota’s and Basidiomycetes’ relative abundance decreased, and the oil chytrid and mortierella increased. The microbial community structure was affected significantly by pH, electrical conductivity, available potassium, available nitrogen, and organic matter. In general, the three composts increased yield by improving the soil’s physicochemical properties, fertility, and microbial community structure. Among them, T6 had the most significant effect and is the optimal formula for use as a local organic cabbage fertilizer, and it could facilitate sustainable agricultural development.

Influence of Soil Type and Temperature on Nitrogen Mineralization from Organic Fertilizers

Organic vegetable producers in Georgia, USA, utilize a range of amendments to supply nitrogen (N) for crop production. However, differences in soil type, fertilizers and environmental conditions can result in variability in N mineralization rates among commonly utilized organic fertilizers in the region. In this study, the effects of temperature on N mineralization from three commercial organic fertilizers [feather meal (FM), pelleted poultry litter (PPL) and a mixed organic fertilizer (MIX)] in two soil types from Georgia, USA (Cecil sandy clay loam and Tifton loamy sand) were evaluated for 120 d. Net N mineralization (Net Nmin) varied with soil type, fertilizer and temperature. After 120 d, Net Nmin from the FM fertilizer ranged between 41% and 77% of total organic N applied, the MIX fertilizer ranged between 26% and 59% and the PPL fertilizer ranged between 0% and 22% across all soil types and temperatures. Incubation at higher temperatures (20 °C and 30 °C) impacted Net Nmin of FM fertilizer in the Tifton series soil. Temperature and soil type had a relatively minor impact on the potentially mineralizable N of the PPL and MIX fertilizers after 120 d of incubation; however, both factors impacted the rate of fertilizer release shortly after application, which could impact the synchronicity of N availability and plant uptake. Temperature-related differences in the mineralization of organic fertilizers may not be large enough to influence a grower’s decisions regarding N fertilizer inputs for vegetable crop production in the two soils. However, organic fertilizer source will likely play a significant role in N availability during the cropping season.

Effects of Different Cover Crops and Amendments on Soil and Crop Properties in Organic Vegetable Production

The impacts of two different cover crop (CC) strategies, as well as compost, silicon (Si), and biocontrol (BC) soil amendments were evaluated on soil chemical and biological properties, crop development and yield, and disease and pest issues in organic vegetable production, as represented by legume (green snap bean), cucurbit (green zucchini squash), and solanaceous (sweet pepper) vegetable crops, in a three-year field trial in Maine, USA. A multi-species CC mixture (6 crops, including legumes, grasses, and brassicas) was compared with a standard winter rye CC for potential benefits on soil properties and biomass production. Soil amendments included a commercial organic fertilizer alone, composted dairy manure, compost plus BC (commercial formulations of Trichoderma and Streptomyces spp.), and compost plus Wollastonite, a natural source of Si. Poor stand establishment of some components of the multi-species CC mixture resulted in lower biomass and ground cover relative to winter rye, but had no effect on crop development or yield. Compost amendments increased soil pH, organic matter, and nutrient contents, as well as yields of bean, zucchini, and peppers relative to a fertilizer-only treatment. Additions of Si increased Si content in plant leaves and reduced powdery mildew on squash and leaf necrosis of beans. In the absence of substantial soilborne disease, BC provided only marginal reductions in powdery mildew and leaf necrosis and no effects on yield. These results help define specific management practices to improve organic vegetable production and provide useful information and options for growers.

Impacts of selected Climate Smart Agricultural Practices on African Indigenous Vegetables in Kenyan drylands

Climate change has had significant impacts on the cultivation of African Indigenous Vegetables (AIVs) resulting in insufficient yields and food insecurity. African indigenous vegetables are important food crops used in combating malnutrition and food insecurity. The AIVs have the potential to provide nutrition and sustain smallholder farmers’ livelihoods. However, little is known about the impacts of Climate-Smart Agriculture Practices (CSAPs) on the yield levels in AIVs. This study was therefore conducted to evaluate the impacts of selected CSAPs on the yield levels in cowpeas (Vigna unguiculata. L) and black nightshade (Solanum nigrum. L) in Kenyan drylands. Six treatments consisting of organic manure, commercial organic fertilizers, irrigation, mulching, inorganic fertilizers and controls were used. Research plots measuring 3m by 3m were set out in a randomized complete block design and sowed with certified cowpeas seeds and well-established black nightshade seedlings. Treatments were applied at land preparation and at 7 days after crop germination. Data was collected on plant height at vegetative stage and the overall primary yield at crop maturity. Analysis of variance (ANOVA) was conducted on the quantitative data collected and analyzed using Genstat software. Post hoc analysis was carried out for significant means using Tukey’s Honest Significant Difference (HSD) test at p≤0.05. The results revealed significant differences in both the plant height and primary yield across all treatments (p≤0.05). The AIV yield levels were significantly influenced by the CSAPs products used. Plots treated with organic manure, mulching and commercial organic fertilizers had significantly higher yields. Control plots had the least amount of yields. Key words: ANOVA, Climate change, food security, malnutrition and soil degradation.

Different organic farming systems under greenhouse do not improve soil C storage but affect microbial functions across soil aggregates

AbstractVegetable crops production is usually based on organic fertilizers purchased off‐farm while the care of soil fertility based on the maintenance of adequate level of soil organic matter receives few attentions. Organic production in plastic tunnel‐greenhouses represents the most intensified organic production system. Therefore, we compared four alternative organic production systems mainly characterized by the combination of fertilizer application practices based on compost, cover crops and commercial organic fertilizers. The systems were: input substitution organic method (BAU), biodynamic method (BIODYN), organic‐agroecological (AGROEC) and a not fertilized but organically managed control (CNT). The objective of this study was to explore in a 3‐year long trial, the effects of different organic systems on soil organic carbon (SOC) balance and the possible effects on soil chemical–physical characteristics, enzymatic activities involved in the C, N and P cycling, total bacterial biomass (16S rRNA), and the microbial functional genes cbbL and amoA in bulk soil and in three aggregate size fractions (macroaggregates >250 μm, free microaggregates 250–53 μm and free silt plus clay (free‐SC) < 53 μm). The conducive microclimatic conditions for soil microbial activities under the greenhouse, together with the transition toward a more intensive rotation and tillage, determined a decrease of the SOC stock (from 5.9 Mg C ha−1 in BIODYN to 10.8 in CNT) that was only partially balanced by C input distributed to soil (from 4.6 Mg C ha−1 in CNT to 31.6 in AGROEC). The different organic systems did not seem to directly affect chemical and microbial properties in the bulk soils. The higher SOC decline in CNT, however, resulted in the degradation of soil structure but at same time led to the increase of the FDAse in the bulk soil. At aggregate level, instead, more evident effects of organic systems were observed on both chemical–physical and microbial properties. The impact of organic systems on enzymatic activities differed in the different aggregate size classes while the effect on bacterial biomass and functional genes was the same in all aggregate size classes. Interestingly, the cbbL gene abundance in soil aggregates, especially in macroaggregates, was correlated positively to OC inputs (r = .82; p < .001). The amoA gene and bacterial biomass, instead, put in evidence for BIODYN, a significant decrease in soil aggregates that seemed to be related, particularly in macro and free microaggregates, to the low amount of total N content. In soil aggregates, only AGROEC compared with CNT, determined the increment of the phosphatase in macroaggregates, while BIODYN and BAU highlighted even lower values of β‐d‐glucosidase, β‐d‐glucosaminidase and phosphatase in free‐SC. In conclusion in high‐input organic systems under tunnels, the misleading notion that a high supply of OC and TN through green manuring, compost amendment etc., improves per se soil health is challenged.

Effects of Organic Fertilizers on the Quality, Yield, and Fatty Acids of Maize and Soybean in Southeast Kazakhstan

This paper presents the effects of organic fertilizers on the yield, quality, and fatty acid composition of maize and soybean in 2022 in Southeast Kazakhstan. Maize and soybean yields were improved by commercial organic fertilizers. In general, the yield, quality, and fatty acid (FA) parameters of both crops were influenced by various types of organic fertilizers. The application of HansePlant fertilizer allowed for an increase in the yield of maize seed by 47% and soybean by 31%. Organic fertilizers improved the quality parameters fat, protein, fiber, and starch in maize by 35%, 22%, 14%, and 8%, respectively, compared to control samples. In soybean, the parameters fat, protein, and fiber were improved by 20%, 3%, and 11%, respectively. The FA compositions of maize and soybean were analyzed via gas chromatography and with tandem mass spectrometer using a polarity column. Compared with no fertilization conditions, the omega-6/omega-3 ratio showed the lowest value in maize (22.40–123.96) and soybean (3.26–4.07). A study of the fatty acid composition groups compared with different fertilizer treatments was performed.

Rice (Oryza sativa L.) response with the Application of Manure and Liquid Organic Fertilizer

Organic fertilizers are necessary for environmentally friendly agriculture. The study aimed to determine rice response to manure and liquid organic fertilizer application ratio. The study was conducted by experimental method with a Complete Randomized Design with five replications. The treatment consists of 6 treatments, namely organic fertilizer, 25% goat manure + 75% commercial liquid organic fertilizer, 50% goat manure + 50% commercial liquid organic fertilizer, 75% goat manure organic + 25% commercial liquid organic fertilizer, 100% goat manure, and 100% manure goats + 100% commercial liquid organic fertilizer. The results showed that plant height during the middle of the vegetative phase treatment of 25% goat manure + 75% commercial liquid organic fertilizer was higher than the treatment of 50% solid organic fertilizer goat manure + 50% commercial liquid organic fertilizer and 100% treatment of goat manure solid organic fertilizer. The root length and volume of treatment 25% goat manure + 75% commercial liquid organic fertilizer is longer and higher than the combined treatment of manure and other liquid organic fertilizers. The grain weight per clump of mixed manure and liquid organic fertilizer treatment is no different. In the future, treatment of 25% goat manure + 75% commercial liquid organic fertilizer can be applied to increase the rice roots.

Eco-enzyme enhanced the growth of rice cultivars

Organic farming has been increasingly lately to support healthy food for consumers. Organic rice is already produced in Bali for local rice cultivars (red, white, and black color of rice) at Jatiluwih Village, Tabanan Regency using manure, compost and biopesticide. Nowadays, eco-enzyme can be applied as liquid organic fertilizer for increasing soil fertility. Eco-enzyme are produced by fermentation process from kitchen waste, such as rind of fruit and vegetables. The experiment was conducted to observed the used of eco-enzyme for rice growth using modification of SRI (System of Rice Intensification). The method initially started from seeds germination at media consist of soil, compost and manure (1:1:1). Three rice cultivars (Red Rice Jatiluwih, Red Rice Pulagan and White Rice ‘Mentik Susu’) seeds were growth using two solutions (commercial liquid organic fertilizer namely LOF (10%) and eco-enzyme (0.1%) for spraying with 5 replications. Seeds germinated almost 90-95% for both solution after four days. Red Rice from Jatiluwih showed significance increase using eco-enzyme on plant height about 25% higher than spraying by liquid organic fertilizer. Red Rice from Pulagan, Gianyar and White rice ‘Mentik Susu’ only enhanced 10% and 5%, higher using eco-enzyme respectively. Rice paddy that treated by eco-enzyme can be harvested (2-3 weeks) faster than using commercial liquid organic fertilizer. White rice ‘Mentik Susu’ showed positive response with eco-enzyme treatment because had more tillers to increase harvest product than other cultivars. The use of eco-enzyme can assist plant growth by enzyme activity in soil, therefore more availability of nutrients for root uptake.

Microplastic pollution in organic farming development cannot be ignored in China: Perspective of commercial organic fertilizer

Commercial organic fertilizer, an essential fertilizer for developing organic farming in China, has been identified as a potentially important source of microplastics (MPs) on farmland. However, little is known about the occurrence of MPs in commercial organic fertilizers and their potential ecological risks nationwide. Here, stereoscopy and laser-infrared imaging spectrometry were used to comprehensively investigate the abundance, size, type and morphology of MPs in commercial organic fertilizers collected from mainland China, assess the ecological risks, and predict MP contamination. Commercial organic fertilizers contained many MPs (8.88 ×103 to 2.88 ×105 items/kg), especially rich in small-size MPs (<100 µm), accounting for 76.53%. The highest MP pollution load value was observed in fertilizers collected from East China. Chlorinated polyethylene, polyurethane, polyethylene and polypropylene were the dominant MPs with the shape of film and fragment, concentrated in small sizes (<100 µm). The risk index (H-index) of the MPs was used to quantify the ecological risk of the MPs in the different samples, and most of the fertilizers were at level Ⅲ with high risk. Predictably, 2.32 × 1013 - 2.81 × 1016 MPs will accumulate in orchard soils after five years of fertilization, especially in South, Southwest and East China. This study provides primary scientific data on MP pollution in commercial fertilizer and the health development of organic farming.

Phosphorus availability and corn (Zea mays L.) response to application of P‐based commercial organic fertilizers to a calcareous soil

AbstractRecycling of organic wastes for agricultural production has been recommended as a sustainable way to close the phosphorus (P) cycle. This study seeks to characterize the P forms in organic fertilizers derived from agricultural and nonagricultural source materials to understand how these organic fertilizers will affect corn growth and soil available P. Organic fertilizers including turkey litter compost (TLC), biosolid pellets (BSP), and source separated organic compost (SSO) were applied to a sandy loam soil and compared to controls that received no nutrients or chemical fertilizer. Results from sequential chemical extractions and X‐ray absorption near edge structure spectroscopy revealed that most of the P species are inorganic, with SSO and TLC containing primarily Ca‐P and Mg‐P forms, while the P in the BSP treatments was mostly associated with aluminium (Al). The two chemical fertilizer treatments had the greatest impact on corn height at the initial growth stage; however, after 42 days, corn height was similar for the organic fertilizers and chemical treatment. This initial slow response from the organic fertilizer treatments reduced the grain yield compared to chemical treatment. The results of this study suggest that priority should be given to sufficient P availability at the initial growth stage. Overall, organic fertilizer is a promising P source for grain crop production, but calibration and correlation studies are needed to ensure optimum supply of P for the initial growth stage.

Adaptation of agriculture to extreme weather events: evidence from apple farmers' organic fertilizer use in China.

Overcoming the challenge of more frequent and extreme weather events holds importance in agricultural production. We take spring frost disasters as a representative extreme weather event to identify how perennial economic crop farmers adjust the quantity of organic fertilizer used in response to extreme weather events and their adjustment mechanism. In this study, we establish a conceptual framework for the adaptation mechanism of apple growers under extreme weather events. This article draws and verifies five hypotheses through on-site investigations of apple growers in Shaanxi Province, China. Empirical evidence shows that farmers increase the quantity of commercial organic fertilizer materials in the year and in the following year when spring frost occurs, indicating that their adaptative behavior can be subdivided into repair and prevention. Mechanism analysis shows that liquidity constraints impact farmers' adaptive behavior. Liquidity constraints limit the ability of farmers to increase the quantity of commercial organic fertilizer materials to adapt to a spring frost disaster. Furthermore, for farmers not constrained by liquidity constraints, household resource endowment conditions still affect their adaptive behavior. Significantly, the household labor force size mainly influences farmers to increase commercial organic fertilizer to adapt to a spring frost disaster. Our findings highlight the differences between the adaptive behavior mechanism of perennial crop farmers and food crop farmers. Moreover, we reconfirm the stimulating effect of organic fertilizer on crop production.

Compost tea supplied by partial root-zone drying irrigation affected growth and productivity of eggplants and cucumbers grown in succession

ABSTRACT Partial root-zone drying irrigation techniques and application of compost tea are practices that, when used separately, have demonstrated beneficial effects on crop productivity in organic farming, with efficient use of natural resources. The aim of this work was to investigate effects of the combination of applying compost tea and using partial root-zone drying irrigation on the growth of eggplants (Solanum melongena L.) and cucumbers (Cucumis sativus L.) grown in succession, on the quantity and quality of the fruits produced, and on soil nutrients after the two growing seasons. The objective was to assess how the two factors, irrigation technique and fertilising method, and the combination of the two, influenced the parameters investigated. Application of compost tea via partial root-zone drying irrigation resulted in well-developed plants and high yields with good quality fruit for both eggplants and cucumbers and did not lead to depletion of soil nutrients, compared with the use commercial organic fertilizers or standard irrigation. Most of the investigated parameters were affected by the interaction of the two factors, though the yield of both crops was more affected by the irrigation technique, while the fertilising approach had a greater effect on the quality of the cucumber fruit. Nevertheless, the combination of compost tea with partial root-zone drying irrigation resulted in competitive performance against the other treatments, whilst reducing the use of resources. The findings showed the effectiveness of applying compost tea by partial root-zone drying irrigation and this was recommended for organic agriculture systems.

Influence of Organic Fertilizer Sources and Application Rates on Onion Production in Georgia, USA

A range of organic fertilizers are available for vegetable crops; however, there is a lack of information regarding the performance and rates of organic fertilizers commonly used in the production of Vidalia onion (Allium cepa). Two commercial organic fertilizers, a mixed source organic fertilizer [MIX (10N–0.9P–6.6K)] and a pelleted poultry litter [PPL (5N–1.8P–2.5K)], were evaluated in two soil types at application rates of 0, 100, 150, 200, 250, and 300 lb/acre nitrogen (N) to determine their impact in the production of Vidalia onions in Georgia, USA, with the objective of determining an optimal fertilizer source and application rate. Field trials were conducted in the 2019–20 and 2020–21 growing seasons in Watkinsville, GA, USA (Cecil series sandy clay loam soil) and Tifton, GA, USA (Tifton series loamy sand soil) on certified organic land. There were significant interactions among location, year, and fertilizer application rate for total marketable yield. In Watkinsville, total marketable yields of onions at different N rates ranged between 1320 and 4565 lb/acre in 2019–20, and between 9951 and 28,749 lb/acre in 2020–21. In Tifton, total marketable yields ranged from 3776 to 9264 lb/acre and 7094 to 14,066 lb/acre in the 2019–20 and 2020–21 seasons, respectively. Aboveground onion N accumulation at harvest was affected by an interaction among location, study year, and fertilizer rate. The largest plant N accumulation was in Watkinsville in 2020–21, ranging from 26 to 50.8 lb/acre N in the 0- and 300-lb/acre N treatments, respectively. In 2020, there were no differences in soil inorganic N at harvest between plots receiving the MIX (9 lb/acre N) or PPL (9.8 lb/acre N) in either location. In 2021, soil inorganic N was greater in plots receiving the MIX fertilizer (14.8 lb/acre N) compared with the PPL fertilizer (11.2 lb/acre N). Yields increased linearly with additional fertilizer; therefore, an optimal application rate for organic fertilizers was not determined.

Removal Rule, Ecological Risk, and Full-Scale Assessment of Antibiotics in Three Organic Fertilizer Production Methods

The occurrence of antibiotic residues present in organic fertilizers produced by diverse techniques is largely unknown. Large-scale evaluation and standardization are imperative to identify the concentration and risks of residual antibiotics during different treatment techniques of livestock manure (i.e., compost, carbonization, and anaerobic treatment). In this study, we assessed the concentration and ecological risks of 30 antibiotics in three types of commercial organic fertilizers by the risk quotient (RQ) method. The highest levels of residual antibiotics in the organic fertilizers produced by composting, carbonization, and anaerobic treatment were 142.58 μg/kg (dry weight) oxytetracycline, 2.53 μg/kg (dry weight) oxytetracycline, and 341.86 mg/L chlortetracycline. We observed that the compost and carbon-based organic fertilizers had an RQ of less than 0.1, indicating a low risk. In contrast, liquid organic fertilizer had an RQ of 0.93, indicating a medium risk. After a comprehensive comparison and evaluation, the “carbonization + anaerobic treatment” mode was found to be more appropriate for most cases. Moreover, the preparation method of organic fertilizers needs further optimization to minimize the concentration of residual antibiotics within the range of low ecotoxicity.