Compost Application Research Articles

Site Suitability and Air Pollution Impacts of Composting Infrastructure for California's Organic Waste Diversion Law.

California's organic waste diversion law, SB 1383, mandates a 75% reduction in organics disposal by 2025 to reduce landfill methane emissions. Composting will likely be the primary alternative to landfilling, and 75-100 new large-scale composting facilities must be sited in the state to meet its diversion goal. We developed a strategy for evaluating site suitability for commercial composting by incorporating land-use, economic, and environmental justice criteria. In our Baseline scenario, we identified 899 candidate sites, and nearly all are within a cost-effective hauling distance of cropland and rangelands for compost application. About half of sites, mostly in rural areas, are not within a cost-effective collection distance of enough municipal organics to supply an average-sized facility. Conversely, sites near cities have greater access to organics but cause greater health damages from ammonia and volatile organic compounds emitted during the composting process. The additional required composting capacity corresponds to $266-355 million in annual damages from air pollution. However, this excludes avoided emissions from landfilling, and damages could be reduced by 56% if aerated static piles are used instead of windrows. Siting a higher number of smaller decentralized facilities could also help equally distribute air pollution to avoid concentrating burdens in certain communities.

Co-composting: A Comprehensive Review of Its Potential in Transforming Coir Pith Waste into Nutrient-rich Manure

Coir industries in India generates around 7.5Mt of coir waste yearly, which is unsuitable for agricultural use due to its high C:N ratio, lignin, phenol, cellulose and tannin content. The accumulation of coir pith leads to adverse environmental problems due to the release of phenolic compounds, lignin, tannins etc. Biodegradation or composting is the best way to manage coir waste and thereby the environmental pollution can be avoided. Co-composting is a method of decomposing multiple organic materials, which aims to create stable humus, and overcome the limitations of composting with a single organic source. Co-composting of coir pith reduces the C:N ratio, lignin content, cellulose content and increases the nutrient contents. In co-composting technology more than one feed stock are used for composting. It can be done by treating the coir pith with organic source of nutrients viz., farm yard manure or poultry manure or agro-industrial wastes or green manure crops or leguminous weeds or treating the coir pith with organic wastes and earthworms, or treating the coir pith lignin degrading micro-organisms and or supplementing the coir pith with lime, rock phosphate etc. along with the organic sources of nutrients mentioned above to speed up the composting process. Co-composting of coir pith resulted in the production of nutrient rich organic manure within a short period of time. Application of coir pith compost had significant effect on the growth and yield attributes of crops. Harnessing the potential of coir pith can lead us towards a more sustainable and greener future.

Growth and initiation of third stage of immature oil palm (Elaeis guineensis Jacq.) by giving oil palm frond compost and paclobutrazol

The third stage of immature oil palm is the phase where the plants enter preparation for flowering, so efforts are needed to initiate flowering, one of which is by using plant growth regulators (PGR) such as paclobutrazol. It is expected that the use of oil palm fronds as compost and application to oil palm plants can support sustainable oil palm management activities. Paclobutrazol, as a growth regulator, plays a role in stimulating the flowering of immature oil palm plants. This research aims to determine the response to the growth and development of immature oil palm plants in the third stage by administering palm frond compost and paclobutrazol at certain doses and concentrations. The experiment was carried out from June to December 2020 at the Ciparanje Experimental Garden, Faculty of Agriculture, Padjadjaran University. The experimental design used was a Randomized Block Design (RBD) with 12 treatments and three replications. The experimental results showed that the application of compost to oil palm fronds and paclobutrazol had a significant effect on plant height and stem girth, but there were no significant differences in the number of fronds, leaf area, chlorophyll index, and flowers. All treatments did not produce flower shoots but showed inhibition of vegetative growth in immature oil palm plants in the third stage. The application of 12.8 kg of oil palm frond compost and 150 ppm paclobutrazol had the best effect on the height and girth of the oil palm stem and had an effect that was not significantly different from other treatments on the parameters of a number of fronds, leaf area, leaf chlorophyll, and flower growth.

Long-term experiments to identify response patterns of available soil nitrogen, rice, and soybeans to rice straw compost in a paddy-upland rotation field in Akita, Japan

ABSTRACT Compost application can enhance soil fertility and is consequently presumed to increase crop production in Japan’s paddy-upland rotation fields. This study aimed to evaluate the effects of rice straw compost (RSC) application on available soil nitrogen (Av-N) levels and rice and soybean plants in a paddy-upland rotation field using data obtained from a long-term field experiment. Data collected between 2005 and 2020 were analyzed from a long-term paddy rice – upland soybean rotation field. The experimental design employed a split-plot arrangement, with RSC application (with and without RSC) representing the whole plot, N fertilizer application (no nitrogen vs. standard fertilizer) representing the split-plot, and years representing the replication factor. The datasets included eight years of rice and soybean cultivation, and the chemical properties of postharvest soil spanned 16 years. The data was analyzed via analysis of variance. Applying RSC increased the Av-N concentration significantly by 63%–67%. The RSC application significantly increased the N concentration in rice shoots at the mature stage by 8%–12% but decreased it in soybean shoots after the seed emergence stage by 4%–8%. Consequently, the rice yield displayed clear responses to RSC application, whereas the soybean yield did not. The lack of soybean yield response might be due to an inhibitory effect of the Av-N gain attributable to the RSC application on biological nitrogen fixation. While applying compost can enhance Av-N content as well as rice productivity in paddy-upland rotation fields, its impact on soybean productivity requires careful evaluation.

Amelioration of Soil Fertility by the Application of Different Fruit Waste Composts

The soil health status of Bangladesh decreased day by day, particularly organic matter and major nutrient content. The organic matter content in most of the agricultural soil in Bangladesh is <2%, which indicates poor soil health condition. In Bangladesh, almost every day, an enormous amount of waste material is produced from different kinds of seasonal and unseasonal fruit’s peels. Lack of proper recycling methods, most of these wastes are thrown away in drains, cannels, rivers, etc. which indicates a major threat to environmental safety. Composts derived from the wastes of different fruit’s peels can be an excellent source of organic matter and essential nutrients for soil health improvement. Therefore, the present study was carried out to evaluate the changes in physicochemical properties and nutrient contents of experimental soil treated with compost prepared from different types of fruit’s waste. The compost was prepared accordingly using different types of fruits waste and then the collected compost was thoroughly mixed with the soil and kept for six months. The experimental treatment consisted of three organic composts (jackfruit peel compost, mango peel compost, and banana peel compost) and three rates of application (1000, 1500, and 2000 kg ha-1). The experiment was arranged in a factorial completely randomized design and replicated thrice. The analyzed data showed that, the physicochemical properties and nutrient contents of experimental soil varied significantly with the use of different types of fruit’s wastes compared to no waste added soil, except in the case of particle size. Soil mixed with mango peel compost at a rate of 2000 kg ha-1 resulted in a higher available N content (2520 mg kg-1) and available P content (42.56 mg kg-1), whereas the available K content (219.88 mg kg-1), EC (1.55 dS m-1) and CEC (1209.56 meq 100g-1) were found higher in soil treated with banana peel compost of 2000 kg ha-1. On the other hand, soil treated with jackfruit peel compost of 1500 kg ha-1 showed the higher available Ca content (1533.33 mg kg-1) and the jackfruit peel compost of 2000 kg ha-1 resulted in the higher organic carbon (1.98%) and organic matter (3.41%). The findings of this experiment revealed that, compost prepared from different types of fruit peels can be an excellent source of organic matter and nutrients and among the tested composts, mango peel compost was better to improve the physiochemical properties of soil and supply sufficient nutrients for plant growth.

Open windrow composting of lignocellulosic crop residues and neem litter: Accounting for reactive nitrogen and greenhouse gas emissions

Crop residue management plays a key role in reducing the environmental impact of agriculture, particularly through composting. Compost application to soil replenishes organic matter. A study was conducted to quantify the greenhouse gas emissions (GHG) (carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O)) and reactive nitrogen (Nr) losses (ammonia (NH3) and oxides of nitrogen (NOx)) from the open windrow composting of crop residues from three cereal crops (rice, maize and pearl millet) and neem litter. The windrow moisture was maintained between 50 and 60% with mechanical turning every 25 days. Compost maturity was reached after 137 days, indicated by a germination index (GI) > 80% and the ratio of initial to final C/N ratio, which was <0.4. CO2 and N2O emissions increased after turning, while CH4 emissions declined. The global warming potentials of the composts were 169.71, 184.13, 200.15, and 217.3 g CO2 eq. kg⁻1 initial dry matter (DM) for rice straw, maize stover, pearl millet stover, and neem litter, respectively. NH3 emissions ranged from 1.13 to 2.13 mg kg⁻1 initial DM, with neem litter producing more NH3 and less N2O due to its lower C/N ratio and nitrification inhibitory properties. Rice straw emitted the highest NOx (75.48 mg kg⁻1 DM), while maize stover had the lowest (28.39 mg kg⁻1 DM). Nitrogen losses from compost ranged from 8.16% in paddy straw to 0.53% in neem compost, with carbon losses ranging from 82.35% to 85.57%. The study concluded that careful management of moisture and aeration is critical for minimizing gaseous emissions from open windrow composting.

Effects of Compost Application of Green Waste on Soil Properties: A Meta-Analysis

Objective: With the accelerating urbanization process, the garden area is gradually expanding, and the production of green waste is also increasing. Composting green waste can not only reduce environmental pollution caused by incineration and landfill and improve the utilization efficiency of resources but also improve the soil and increase soil productivity. The study aims to investigate the comprehensive impact of green waste compost (GWC) application on soil nutrient conditions. Through comprehensive data analysis, the impact of compost application of green waste on soil properties was revealed as a reference for compost application and fertilizer reduction. Methods: Based on meta-analysis, we quantitatively investigated the response of soil properties to the application of green waste, collected published experimental data, and integrated 25 domestic and international literature to analyze the effects of different soil properties on soil nutrients. Literature was used to analyze the impact of different application rates of GWC on the physicochemical properties of soils with varying pH levels. The results were compared to control conditions with no GWC application. Results: The application of significantly improved soil quality by reducing soil bulk density and increasing the levels of soil organic matter, organic carbon, total nitrogen, available phosphorus, available potassium, and dehydrogenase activity. The increases in available potassium and soil organic carbon were consistently significant across all subgroups. However, the effects on available phosphorus and organic matter varied in significance depending on initial soil pH. Soil bulk density was influenced by the GWC content, while dehydrogenase activity showed significant effects only when initial soil pH was ≥8. Total nitrogen levels were significantly impacted by GWC application in soil with an initial pH of &lt;8 and at GWC contents of ≥50%. Conclusion: The application of green waste compost demonstrates a positive effect on soil improvement. This study provides a comprehensive database that supports the use of GWC in enhancing soil quality and reducing the need for chemical fertilizers.

Exploring compost production potential and its economic benefits and greenhouse gas mitigation in Addis Ababa, Ethiopia

The increasing amount of municipal organic waste (MOW) and human excreta (HE) has led to socio-economic and environmental challenges in the cities of developing countries. This study estimated MOW and HE, compost production potential from MOW and HE, and compost application potential for urban agriculture fertilization, economic benefits, soil carbon sequestration, and greenhouse gas (GHG) mitigation in Addis Ababa, Ethiopia, for the period 2025–2050. MOW was forecasted using the Holt-Winters forecasting model. HE was estimated using the daily average rate of HE generation. The compost production potential was estimated using the forecasted MOW and HE. Compost fertilization was determined by considering compost nitrogen (N), phosphorus (P), and potassium (K) and the fertilizer requirements of cereals and vegetables. The economic benefits of compost were determined by considering the price of compost-equivalent urea, NPS, and potassium chloride fertilizers. The mitigation of GHG emissions from compost application was estimated using the IPCC Tier 1 method. The forecasted quantities of MOW, HE, and compost for 2050 are 301, 462, and 343 Gg, respectively. The compost could supply 5 Gg of N and 2.2 Gg of P in 2050, sufficient to fertilize 14,129 ha of vegetable fields. The economic benefits of using compost as a substitute for synthetic fertilizers could reach 10 million USD in 2050. Compost production and application could offset the total GHG emissions of Addis Ababa by 13.1 % (10,241Gg CO2-eq year−1) in 2050. The application of compost generated from MOW and HE in Addis Ababa can substitute synthetic fertilizers, provide economic benefits, and mitigate GHG emissions.

Partial replacement of inorganic fertilizer with organic inputs for enhanced nitrogen use efficiency, grain yield, and decreased nitrogen losses under rice-based systems of mid-latitudes

In the rice-based system of mid-latitudes, mineral nitrogen (N) fertilizer serves as the largest source of the N cycle due to an insufficient supply of N from organic sources causing higher N losses due to varying soil and environmental factors. However, aiming to improve soil organic matter (OM) and nutrients availability using the best environmentally, socially, and economically sustainable cultural and agronomic management practices are necessary. This study aimed to enhance nitrogen use efficiency (NUE) and grain yield in rice-based systems of mid-latitudes by partially replacing inorganic N fertilizer with organic inputs. A randomized complete block design (RCBD) was employed to evaluate the effects of sole mineral N fertilizer (urea) and its combinations with organic sources—farmyard manure (FYM) and poultry compost—on different elite green super rice (GSR) genotypes and were named as NUYT-1, NUYT-2, NUYT-3, NUYT-4, NUYT-5, and NUYT-6. The study was conducted during the 2022 and 2023 rice growing seasons at the Rice Research Program, Crop Sciences Institute (CSI), National Agricultural Research Centre (NARC), Islamabad, one of the mid-latitudes of Pakistan. The key objective was to determine the most effective N management strategy for optimizing plant growth, N content in soil and plants, and overall crop productivity. The results revealed that the combined application of poultry compost and mineral urea significantly enhanced soil and leaf N content (1.36 g kg− 1 and 3.06 mg cm− 2, respectively) and plant morphophysiological traits compared to sole urea application. Maximum shoot dry weight (SDW) and root dry weight (RDW) were observed in compost-applied treatment with the values of 77.62 g hill− 1 and 8.36 g hill− 1, respectively. The two-year mean data indicated that applying 150 kg N ha⁻1, with half provided by organic sources (10 tons ha⁻1 FYM or poultry compost) and the remainder by mineral urea, resulted in the highest N uptake, utilization, and plant productivity. Thus, integrated management of organic carbon sources and inorganic fertilizers may sustain the productivity of rice-based systems more eco-efficiently. Further research is recommended to explore root and shoot morphophysiological, molecular, and biochemical responses under varying N regimes, aiming to develop N-efficient rice varieties through advanced breeding programs.

Effect of Integrated Application of Vermicompost and Inorganic Fertilizers on Yield and Yield Components of Bread Wheat in Adami Tulu Jido Kombolcha District of East Showa Zone, Ethiopia

A field experiment was conducted at Adami Tulu Agricultural Research Center during 2022 cropping season to evaluate the responses of vermin compost and inorganic fertilizers on bread wheat (Triticum aestivum). The experiment consists of eight treatments: T1= Control (without fertilizer), T2=50% RNP+4t/ha VC, T3= 50% RNP+ 8t/ha VC, T4=100% RNP, T5= 4t/ha VC, T6= 8t/ha VC, T7= 100% RNP+ 4t/ha VC, T8=100% RNP+8t/ha VC. The result revealed that grain yield affected by combined application of these two fertilizes. There are gradual changes in some major soil parameters have statistically affected by combined application of vermin compost and inorganic fertilizer. Accordingly maximum grain yield (4596.3kg/ha) was recorded from T2 where 50% recommended NP+4t/ha VC where as the lowest grain yield (2109.3kg/ka) was from control plot. Lastly partial budget analysis was also calculated to determine best treatment combination for future farther use. Accordingly maximum net benefit (155,870.50ETB) was obtained from T2 where 50% recommended NP+4t/ha VC was combined. Therefore this treatment was used as best treatment combination for this area, for this crop, it needed for large scale soil fertility management and increasing land productivity.

Different organic composts application in dryland Mollisol:Residual effect and soil CO2 emission.

Organic compost application plays an important role in improving the fertility of Mollisol. However, the effects of different organic composts on carbon sequestration varies greatly and its internal mechanism are unclear. We conducted a field experiment to explore the residual proportion of different organic composts and their effects on carbon emissions in dryland Mollisol in Northeast China. There were a total of seven treatments, including chemical fertilizer control (SNF), organic composts from cattle excreta (CRH), sheep excreta (SHP), chicken excreta (CKN), residue after corn starch production (BCS), residue with crop straws (HRS) and mushroom residue (WMC). We monitored annual soil CO2 flux by static chamber method, as well as the changes of environmental factors and soil dissolved carbon and nitrogen. The regulatory mechanism of organic component characteristics on carbon residual porprotion of organic composts were examined by neural network analysis. The results showed that compared with the SNF treatment, soil dissolved organic carbon (DOC) and extractable organic nitrogen increased by 26.3%-103.5% and 21.4%-150.0%, respectively. The aromaticity of soil DOC was significantly reduced. Heterotrophic respiration flux was mainly affected by soil temperature and DOC content, while its temperature sensitivity was significantly reduced in the CKN treatment. Annual accumulation of heterotrophic respiration increased from 203 g·C·m-2 of the control to 234-334 g·C·m-2 under treatments with organic composts applications, with the CKN and HRS treatments showing the strongest impact. The annual carbon residual proportion of different organic composts in Mollisol was in an order of CRH (91.2%)> WMC (82.9%)> BCS (82.6%)> SHP (78.1%)> CKN (70.2%)> HRS (69.3%). Hemicellulose content and C/N of organic composts were the key factors, which explained 58.8% and 32.9% of the total variations of carbon residual proportion. Organic compost from cattle excreta had higher residual proportion due to lower C/N, hemicellulose content and soluble polyphenol content, and thus did not significantly affect Mollisol heterotrophic respiration. Therefore, the application of organic compost from cattle excreta was more efficient to improve organic carbon in dryland Mollisol.

Growth of cocoa seedlings (Theobroma cacao L.) in application of cow manure compost and density of Bacillus subtilis bacteria

Cocoa rejuvenation is important to maintain high productivity. The rejuvenation mainly uses seedlings; thus providing high-quality seedlings is important. This research aimed to determine the effect of various doses of cow manure compost and the density of Bacillus subtilis bacteria on the growth of cocoa seedlings. The research was implemented at the Teaching Farm, Faculty of Agriculture, Hasanuddin University, Makassar City, from 2021 to 2022. The experiment was arranged in a split-plot design with three replications. The main plot was the dose of cow manure (without compost, 1.25 kg per polybag, and 2.5 kg per polybag). The subplot was the density of Bacillus subtilis (without bacteria, 104 CFU.mL-1, 108 CFU.mL-1, and 1012 CFU.mL-1). The results showed an interaction between the dose of cow manure 2.5 kg per polybag and the bacterial density 1012 CFU.mL-1 on chlorophyll a (347.91 mol.m-2), chlorophyll b (158.33 mol.m-2), total chlorophyll (444.57 mol.m-2), and leaf area of cocoa seedlings (813.96 cm2). A compost dose of 2.5 kg per polybag showed the best results for plant height (8.98 cm). Keywords: bacteria density; bivariate correlation; chlorophyll content; manure dose; organic fertilizer

Evaluation of different breeding waste compost applications on lettuce cultivation: growth, quality, mineral elements, and heavy metals accumulation

In China, increasing breeding waste has caused environmental problems. This study explored the possibility of using breeding waste compost (BWC) instead of chemical fertilizer in vegetable cultivation. The experiment included no fertilizer (CK), 100% chemical fertilizer (CF), 10, 20, and 30% substitution of cow dung compost (CDC), goose dung compost (GDC), and duck dung compost (DDC) with chemical fertilizer (C01, C02, C03, G01, G02, G03, D01, D02, D03). The results showed that BWC, particularly GDC, promoted lettuce growth and development. Compared to CK, the leaf fresh and dry weight of G03 were the highest, increasing significantly by 6.60 and 7.29 times, and the root fresh and dry weight of G02 were the highest, increasing significantly by 12.72 and 6.00 times. Different BWC improved soluble sugar, soluble protein, and Vitamin C to varying degrees, and the nitrate contents of some BWC treatments were lower than that of CK and CF. Conversely, CF had the highest nitrate accumulation and limited effects on certain growth and quality parameters. The mineral elements in lettuce were also affected by the type and dosage of fertilizers. The total nitrogen of CF, total phosphorus of G03, total potassium of G02, Ca and Mg of D01, Fe of CF, and Zn of G02 were at the peak. The rapid increase of biomass in GDC treatments led to reductions in Ca and Fe. Applying fertilizers would affect heavy metals in lettuce to unequal degrees, but all were within the food safety scope. The principal component analysis revealed the comprehensive effect of GDC treatments was recommended.

Increased Growth of RED Jabon (Anthocephalus macrophyllus) Seedlings using Various Doses of Compost Fertiliser on Used Gold Mine Planting Media

Mining operations disrupt the equilibrium of terrestrial ecosystems, leading to a decline in soil fertility and overall environmental quality. The adverse effects of such activities can severely impact forest ecosystems, resulting in disturbances to physical, chemical, and biological conditions. Consequently, initiatives aimed at restoring soil health to its pre-mining state are essential, often involving revegetation efforts. The cultivation of red jabon trees in nutrient-deficient and less fertile soils necessitates the incorporation of organic matter to enhance soil quality, typically achieved through the application of compost. This study aimed to evaluate the effects and optimal ratios of compost mixed with ex-gold mining soil on the growth of red jabon seedlings. The experimental design included four treatment groups and five replications, yielding a total of 20 experimental units. The treatments for compost application were as follows: D1 = control (no compost), D2 = 10% compost + 90% ex-gold mining soil, D3 = 30% compost + 70% ex-gold mining soil, and D4 = 50% compost + 50% ex-gold mining soil. The parameters observed included survival rate, height growth, diameter growth, dry weight of the plants, and root-to-crown ratio. The findings indicated that the application of compost significantly influenced the growth of red jabon seedlings. Notably, treatment D4 (50% compost + 50% ex-gold mining soil) yielded the most favorable results, achieving a survival rate of 100%, a height increase of 16.56 cm, a diameter increase of 2.21 mm, a dry weight of 40.73 g, and a root-to-crown ratio of 4.84.

Transfer of antibiotic resistance genes from soil to rice in paddy field

The global spread and distribution of antibiotic resistance genes (ARGs) has received much attention whereas knowledge about the transmission of ARGs from one matrix to another is still insufficient. In this study, the paddy fields fertilized with chemical fertilizer, swine compost, and no fertilizer were investigated to assess the transfer of ARGs from soil to rice. Soil and plant samples were collected at day 0, 7, 30 and 79 representing various stages of paddy growth. High throughput qPCR was applied to quantify ARGs using a set of 144 primers. Gene copy number of ARGs measured in soil initially decreased and then increased in soil with no fertilizer and chemical fertilizer, indicating that crop planting and flooding conditions did influence the ARGs profiles in soil. Application of swine compost significantly enhanced the relative abundance and gene copy number of ARGs in paddy soil. Rice seedlings contained substantial amount of ARGs and their relative abundance continually decreased after transplant. Compared with initial stage, detection frequencies of ARGs increased in soil without swine compost at harvest time (day 79), indicating the transmission of ARGs from irrigation water to soil. Detection frequencies of ARGs increased in soil and rice root with swine compost at harvest time, indicating the transfer of ARGs from swine compost to soil and rice root. There was no significant difference in abundance and diversity of ARGs in rice grains with these three different fertilizations. The source of the ARGs in rice grain still needs further exploration.

Evaluating the Response of Watermelon (Citrullus lanatus (L.) to Organic and Inorganic Fertilization in Makurdi, Southern Guinea Savannah, Nigeria

Watermelon consumption in Nigeria is on the increase due to increasing awareness of its nutritional value while its production is on the decrease due to inefficiency of resource management (inputs like fertilizers). This study aims to optimize watermelon (Citrullus lanatus L.) production through the use of organic and inorganic fertilizers. The field experiment was conducted at the Teaching and Research Farm of Joseph Sarwuan Tarka University, Makurdi in the 2019 cropping season under rain-fed conditions. The site falls within the Latitude 7°4'1N and Longitude 8°3'7E at an elevation of about 97m above sea level in the Southern Guinea Savanna Agro-ecological Zone of Nigeria. The experiment treatments, namely and they were T1 (Control 0kg/ha), T2 (150 kg/ha Compost), T3 (200 kg/ha Compost), T4 (250 kg/ha Compost) and T5 (300 kg/ha NPK 20:10:10) laid out in Randomized Complete Block Design with three replications. The study revealed that in comparison with control treatments, 300 kg/ha NPK 20:10:10 produced (31.04t/ha) fruit yield, the application of 250 kg/ha compost enhanced growth and yield parameters of watermelon with fruit yield of (17.65t/ha). The research findings suggest that using compost manure at the rate of 250 kg/ha for watermelon production is viable since it is economical and environmentally friendly alternative to NPK fertilizer due to it cheap and easy to prepare methods, its beneficial effects on soil, groundwater and the environment. It is further recommended that, in Makurdi, smallholder farmers, should adopt the application of compost at the rate of 250 kg/ha for optimum yield

Effects of multi-component passivator on heavy metal passivation, compost quality and plant growth

Direct land application of conventional compost may cause ecological risks due to the presence of heavy metals. To effectively reduce heavy metal bioavailability in compost, a multi-component passivator comprising Candida utilis, sodium humate, zeolite and attapulgite was developed, which showed passivation rates of 59.28%, 86.93% and 38.95% for zinc (Zn), copper (Cu), and ferrum (Fe), respectively, in compost. The addition of customized multi-component passivator in compost not only reduced the mobility of heavy metals, but also improved the quality of the compost and further increased the abundance of lignocellulose-degrading beneficial microorganisms in compost. Subsequent fertilization results showed that the compost product fermented with customized multi-component passivator greatly improved the growth of Chinese cabbage, with significant increases in height, weight, root length, and total chlorophyll contents of 97.63%, 210.13%, 20.42%, and 40.38%, respectively. It can be concluded that the custom-made multi-component passivator is expected to be a good additive for heavy metal passivation, high-quality compost, and plant growth.

Pollution characteristics of microplastics in greenhouse soil profiles with the long-term application of organic compost

Organic composts are significant sources of microplastic (MP) pollution in soils, and their input is much higher in greenhouse agriculture than open-field agriculture. However, how long-term compost application affects MPs pollution in greenhouse soil profiles remains unclear. This study examined MPs characteristics in chicken manure compost and earthworms, exploring the long-term impacts of compost application on MPs accumulation and vertical migration in 0–100 cm soil depth through a 15-year greenhouse experiment. Microplastics abundance was 3965 items kg−1 in compost, 191–248 items kg−1 in compost-amended soils, and 2.73–4.52 items individual−1 in earthworms from compost-amended soils; the latter two increased significantly with compost application and were significantly higher than unamended soils. Soil MPs accumulation from long-term compost amendment contributed 45.4% of the total. The proportion of MPs <2 mm in compost (49.7%) was less than in compost-amended soils (65.5%) and earthworms (65.4%). Microplastics size and abundance decreased with increasing soil depth. Microplastics polymer types and shapes in composts, compost-amended soils, and earthworms exhibited similarities, mainly including polyethylene and polypropylene fragments and fibers. Compost-derived MPs in soils exhibited complex weathering morphology and adhered to mineral colloids. Therefore, soil MPs originating from compost gradually weathered and degraded into smaller particles and migrated to deeper soil, maybe resulting in more serious ecological issues.

Impacts of Compost Amendment Type and Application Frequency on a Fire-Impacted Grassland Ecosystem

Composting organic matter can lower the global warming potential of food and agricultural waste and provide a nutrient-rich soil amendment. Compost applications generally increase net primary production (NPP) and soil water-holding capacity and may stimulate soil carbon (C) sequestration. Questions remain regarding the effects of compost nitrogen (N) concentrations and application rates on soil C and greenhouse gas dynamics. In this study, we explored the effects of compost with different initial N quality (food waste versus green waste compost) on soil greenhouse gas fluxes, aboveground biomass, and soil C and N pools in a fire-impacted annual grassland ecosystem. Composts were applied annually once, twice, or three times prior to the onset of the winter rainy season. A low-intensity fire event after the first growing season also allowed us to explore how compost-amended grasslands respond to burning events, which are expected to increase with climate change. After four growing seasons, all compost treatments significantly increased soil C pools from 9.5 ± 0.9 to 30.2 ± 0.7 Mg C ha−1 (0–40 cm) and 19.5 ± 0.9 to 40.1 ± 0.7 Mg C ha−1 (0–40 cm) relative to burned and unburned controls, respectively. Gains exceeded the compost-C applied, representing newly fixed C. The higher N food waste compost treatments yielded more cumulative soil C (5.2–10.9 Mg C ha−1) and aboveground biomass (0.19–0.66 Mg C ha−1) than the lower N green waste compost treatments, suggesting greater N inputs further increased soil stocks. The three-time green waste application increased soil C and N stocks relative to a single application of either compost. There was minimal impact on net ecosystem greenhouse gas emissions. Aboveground biomass accumulation was higher in all compost treatments relative to controls, likely due to increased water-holding capacity and N availability. Results show that higher N compost resulted in larger C gains with little offset from greenhouse gas emissions and that compost amendments may help mediate effects of low-intensity fire by increasing fertility and water-holding capacity.

Potential Combination of Phytoremediation Plants and Compost in Remediation of Hg in Ex-Gold Mine Soil Contaminated Mercury (Hg)

Heavy metal mercury pollution in the environment can have negative impacts on both surrounding ecosystems and human health. Sources of mercury pollution often come from mining activities, particularly from many unlicensed gold mines (PETI) that use the mercury amalgamation method to extract gold. Due to the persistent, bioaccumulative, and toxic nature of mercury, contamination in the soil has increased. One effort to reduce mercury toxicity is the application of absorption methods using phytoremediation plants and compost as regulating factors. The aim of this study is to review sources of information related to the use of phytoremediation plants and the application of compost as remediators to clean mercury (Hg)-contaminated soil. To reduce levels of heavy metal contamination, plants employ five phytoremediation mechanisms: phytoextraction, phytostabilization, rhizofiltration, phyto degradation, and phytovolatilization. Therefore, selecting hyperaccumulator plants that have the ability to accumulate mercury (Hg) at levels 100 times higher than ordinary plants is crucial for effective remediation. Additionally, the use of compost as a source of organic material can enhance mercury mobility. The addition of organic materials such as compost can increase C organic content, cation exchange capacity (CEC), pH, and Hg-chelate formation, thereby maximizing mercury absorption by plants. This combination has a positive impact on reducing mercury levels in the soil and is environmentally safe.