Urban Waste Compost Research Articles

Coarse microplastic accumulation patterns in agricultural soils during two decades of different urban composts application

Plastic pollution, a global threat to environmental and human health, is now ubiquitous in the environment, including agricultural soils receiving urban compost amendments. Yet, the accumulation pattern of microplastics in soils are still to be disentangled, with regards to their sources and/or their physical properties such as morphotypes. The aim of this study was to identify the accumulation patterns of coarse microplastics resulting from the long-term amendment of soil with urban waste composts. To this end, we used a field experiment receiving three different urban composts derived from municipal solid waste, biowaste, and a mixture of sewage sludge and green waste. We isolated 1417 coarse microplastic particles from a 21-year archive of soil and compost samples, using density fractionation followed by oxidation, and used Py-GC/MS for polymer identification. Different compost types led to different coarse microplastics accumulation levels. The accumulation pattern showed increasing CMP contents in soils over time. After 21 years of experiment, the calculated number of CMP was in accordance with the estimated values for all three compost types but it was not the case for the CMP mass. No difference of evolution pattern was found between films and fragments. We proposed that biotic transport or abiotic weathering and fragmentation could explain such differences in CMP evolution pattern.

A corrigendum for article: Characterization of urban organic solid waste compost from six districts of the Leoncio Prado province, Peru

Ríos-Velasquez, E.A.; Florida-Rofner, N.; Lama-Isminio, D.A. 2023. Caracterización de compost de residuos sólidos orgánicos urbanos de seis distritos de la provincia Leoncio Prado, Perú. Rev. U.D.C.A Act. & Div. Cient. 26(1):e2371. http://doi.org/10.31910/rudca.v26.n1.2023.2371. Cuando se publicó el artículo señalado arriba, el autor de correspondencia Nelino Florida Rofner incluyó a Demetrio Angelo Lama Isminio. Sin embargo, Demetrio Lama solicitó a la Revista U.D.C.A Actualidad & Divulgación Científica su retiro de la publicación por no participar activamente en el desarrollo del trabajo y no ser su campo de experticia. La solicitud fue atendida por la revista y consultada con Nelino Florida Rofner, quien estuvo de acuerdo con el retiro de Demetrio Angelo Lama Ismino de la publicación. El cuerpo editorial de la revista aclara que, con base en la evaluación de los pares y el proceso editorial, se considera que los datos presentados en el artículo no pierden validez con esta acción. Además del retiro de Demetrio Angelo Lama Isminio del documento, se cambió el apartado de contribución de los autores que inicialmente se publicó de la siguiente manera: Contribución autores: Emilio Anthony Ríos-Velásquez y Demetrio Angelo Lama-Isminio realizaron los trabajos de campo, obtención y análisis formal de los datos para la escritura del borrador del manuscrito. Nelino Florida Rofner contribuyó con la asesoría de la investigación, la contextualización, la metodología, revisión y redacción del manuscrito. Todos los autores participaron en la redacción, revisión, edición del manuscrito y aprueban la versión final. Nelino Florida Rofner y el cuerpo editorial de la Revista U.D.C.A Actualidad & Divulgación Científica piden disculpas por este error.

Substitution of mineral N fertilizers with organic wastes in two long‐term field experiments: Dynamics and drivers of crop yields

AbstractOrganic wastes (OW) are rich in nutrients, and their recycling into agriculture can substitute chemical fertilizers. The level of substitution (partial with mineral fertilizer or exclusive with only OW), along with the method, amount, and timing of OW application, as well as the crop type, can impact crop productivity. The temporal dynamics of crop productivity after repeated applications of OW remain uncertain. Thus, two French long‐term field experiments (QualiAgro and PROspective, started in 1998 and 2000, respectively) were used to evaluate the effect of repeated OW applications on crop yield dynamics and investigate the potential driving factors affecting crop yields. Six different OW were applied: urban sewage sludge (SLU), green waste and SLU compost (GWS), biowaste compost (BIO), municipal solid waste compost (MSW), farmyard manure (FYM), and composted FYM (FYMC). The OW were applied every 2 years in QualiAgro (~4 t C ha−1) and PROspective (~1.7 t C ha−1). QualiAgro was studied under high and low mineral N conditions, while PROspective was examined with and without mineral N fertilization. The results indicated that at the QualiAgro site, a combination of OW and high mineral N treatments resulted in higher maize and wheat yields compared to the mineral N control, while the combination of OW and low mineral N reached the same maize and wheat yield as the mineral N control after 3 and 6 applications of OW, respectively. At the PROspective site, partially substituting mineral fertilizer with OW maintained maize yields but decreased wheat yields, while full substitution led to a decrease in both maize and wheat yields compared to the mineral N control. Results from the gradient boosting model (GBM) showed that soil total N rather than mineral N input was the primary driver of the relative maize yield, while mineral N fertilizer input was more critical for wheat during the second year. We conclude that the joined use of OW and mineral fertilizers is superior to using OW or mineral fertilizer alone for maintaining high yields and soil fertility. We further suggest that OW full substitution of mineral fertilizer may need to apply OW more frequently to meet the crop demands, and/or to use OW with higher N availability like digestates.

Exploring the Effects of Enriched Urban Compost and Wastes on Growth and Yield Parameters in Maize (Zea mays L.)

Maize (Zea mays L.) is a crucial global crop, vital for food security and diverse applications. Maize cultivation heavily depends on fertilizers, particularly nitrogen-based ones and their widespread use poses risks like nutrient runoff, causing pollution and economic challenges.
 Balancing growth optimization with environmental/economic considerations requires optimizing fertilizer application and sustainable practices. This study aims to reduce reliance on chemical fertilizers by replacing them with microbial-enriched urban compost and wastes in various combinations with inorganic fertilizers to enhance maize yields.
 A treatment incorporating 75% NPK + 7.5 t ha-1 of microbial-enriched urban solid waste compost demonstrated the highest plant height, leaf count, cob length, kernel yield, and stover yield. The combined use of enriched compost and chemical fertilizers resulted in increased nutrient availability, improved soil properties, and a favorable microbial environment, contributing to enhanced overall yield.

Cultivation of Melilotus officinalis as a source of bioactive compounds in association with soil recovery practices.

Melilotus officinalis is a Leguminosae with relevant applications in medicine and soil recovery. This study reports the application of Melilotus officinalis plants in soil recovery and as a source of bioactive compounds. Plants were cultivated in semiarid soil under four different fertilizer treatments, urban waste compost at 10 t/ha and 20 t/ha, inorganic fertilizer and a control (no fertilizer). Agronomic properties of soil (pH, EC, soil respiration, C content, macro- and microelements) were analyzed before and after treatment. Also, germination, biomass, element contents, and physiological response were evaluated. Metabolite composition of plants was analyzed through Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Results showed a significant enhancement of the soil microbial activity in planted soils amended with compost, though there were no other clear effects on the soil physicochemical and chemical characteristics during the short experimental period. An improvement in M. officinalis germination and growth was observed in soils with compost amendment. Metabolite composition of plants was analyzed through Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Principal Component and Agglomerative Hierarchical Clustering models suggest that there is a clear separation of the metabolome of four groups of plants grown under different soil treatments. The five most important discriminative metabolites (annotated) were oleamide, palmitic acid, stearic acid, 3-hydroxy-cis-5-octenoylcarnitine, and 6-hydroxynon-7- enoylcarnitine. This study provides information on how the metabolome of Melilotus might be altered by fertilizer application in poor soil regions. These metabolome changes might have repercussions for the application of this plant in medicine and pharmacology. The results support the profitability of Melilotus officinalis cultivation for bioactive compounds production in association with soil recovery practices.

Effect of Segregated and Unsegregated Urban Solid Waste Drum Composts on Growth, Yield and Nutrient Uptake by Finger Millet (Eleusine coracana L.)

A greenhouse experiment was conducted in Department of Soil Science and Agricultural Chemistry, University of Agricultural Sciences, Gandhi Krishi Vignana Kendra, Bangalore to study the effects of segregated and unsegregated urban solid waste drum compost on plant height, number of leaves, ear head weight, ear head length, 1000 grain weight, grain yield and straw yield in finger millet (Eleusine coracana L.) during kharif-2015. The results revealed that plant height, number of leaves, ear head weight, ear head length, 1000 grain weight, grain yield and straw yield and uptake content were significantly improved by the application of 100% NPK+ segregated urban solid waste compost (10 t ha-1) followed by 100% NPK+ unsegregated urban solid waste compost (10 t ha-1) as compared to the treatment which include only in inorganics.

Studies on Variations in Physico-chemical, Biochemical and Biological Characteristics at Different Maturity Stages of Segregated and Unsegregated Urban Solid Waste of Drum Compost

Improper disposal of solid waste is one of the main causes of environmental pollution. Converting solid waste into compost and using it as an organic fertilizer in agriculture are an effective waste management method. Quality of such fertilizer may affect both human and environmental health. Therefore, in this study, compost from segregated and unsegregated urban solid waste compost was analyzed for its physical-chemical, biochemical, biological characteristics and the results were compared with the standards. In this descriptive-analytical study, compost samples were collected throughout a 3-month period at intervals of 20 days (2 methods, S1-Segregated, S2-Unsegregated urban compost) for physio-chemical analysis. In the present study, physical parameters such as moisture content, temperature and bulk density were 23.65%, 31 (°C) and 1.01 (g/cm-3). Chemical parameters such as pH, EC, C/N ratio, organic carbon, Total Nitrogen, Phosphorus, Potassium, Ca, Mg, S, Fe, Mn, Cu, Zn, Ni, Pd and Cr content were 7.75, 1.12 (dS m-1), 17.78, 29.16, 1.64, 0.45, 1.11, 1.47, 0.74, 0.76%, 3529.11, 350.67, 41.11 and 118.07(mg kg-1), respectively. The heavy metal concentration viz., nickel, lead, chromium content were 12.75, 23.87 and 12.53 (mg kg-1), respectively. Heavy metals concentration was detected at all the decomposition stages of composting and were to found to be within the permissible limits of Ohai-EAP standards. From the results, it can be concluded that, segregated urban waste composting could produce acceptable quality of compost, which can be used as fertilizer or soil amendment.

Effect of size and additives on the decomposition process and nutrient content of urban organic waste compost

To participate in overcoming the problem of 500 tons of organic waste per day in Makassar City, in 2017-2019 Environment and Forestry Research and Development Institute of Macassar conducted research activities to develop community-based organic waste management models for pollution control and urban farming development. One of the activities is making compost from urban litter using a shredding machine to speed up the decomposition process, and mixing household waste rich in N, P, K and micro nutrients to increase the nutrient content of the compost. Observations showed that the litter mincing process significantly accelerated the decomposition process. Furthermore, the addition of nutrient-rich material from household waste into compost material has increased the nutrient content of compost which is higher than the SNI standard, thereby increasing the competitive value of compost against factory-made chemical fertilizers. These two activities have an impact on increasing public interest in managing urban organic waste to reduce pollution while developing urban farming.

Effect of Biochar on Yield, Yield Components, and Macronutrients of Rice (Oryza sativa L.)

Biochar has recently caught researchers’ attention due to its potential of improving soil fertility and immobilizing pollutants and its emergence as a proper method of increasing crop yields. An experiment was conducted on the effect of chemical, ecological, and organic (biochar and compost) nutritional systems on yield and yield components of rice as a split-plot field experiment based on a randomized complete block design with three replications in two sites in Lahijan in 2018-2019. The experimental factors included nutrition at three levels (ecological, chemical, and control) as the main plot and the organic matter at four levels (urban waste compost, biochar, Azolla, and control) as the sub-plot. The combined application of chemical and organic fertilizers produced the highest grain yield, reflecting the positive effect of their combination on grain yield and yield components of rice cv. ‘Hashemi’. The results showed that the highest grain yield of 3699 kg ha-1 was related to the treatment of chemical fertilizer and biochar and the lowest (2209 kg ha-1 , i.e., a 40% decline) to the control (no chemical or biological fertilizer application). The highest number of fertile tillers and panicles per plant was obtained from the application of chemical fertilizer and biochar, the highest number of filled grains per panicle (116 grains) was observed in the application of chemical fertilizer and biochar at the university farm, and the lowest (84 grains) from the control (unfertilized treatment) at the Kateshal farm. The nutrient uptake was significantly higher in the chemical and biochar treatment than in the other treatments. Organic systems had varying impacts on rice yield and reduced the application of chemical fertilizers. Biochar contributed to increasing the growth, yield, and nutrient uptake of rice plants.

Effect of integration of chemical fertilizers with organic manures on growth, yield and nutrient uptake in hybrid maize (Zea mays L.) ​ ​

Maize (Zea mays L.) becoming very popular cereal crop in India because of high production potential of hybrid varieties and it requires heavy doses of fertilizers. But the excessive and continuous use of chemical fertilizers has damaged the soil health, at the same time, the sole use of organic manure cannot compensate the produce obtained by inorganic application. Hence, it is important to reduce the usage of chemical fertilizers and supplementing the same through organic manures. Therefore, field experiment was conducted in Experimental Farm of Annamalai University during 2020 to evaluate the effect of different levels of inorganic fertilizers with different sources of organic manures on the growth, yield and nutrient uptake in hybrid maize. The experiment was laid out in randomized block design with nine treatments viz., 100% recommended dose of fertilizer (RDF), 100% RDF + Seaweed granules @ 20 kg/ha, 100% RDF + Pressmud granules @ 125 kg/ha, 100% RDF + Poultry manure @ 2.5 t/ha, 100% RDF + Urban waste compost @ 10 t/ha, 75% RDF + Seaweed granules @ 20 kg/ha, 75% RDF + Pressmud granules @ 125 kg/ha, 75% RDF + Poultry manure @ 2.5 t/ha, 75% RDF + Urban waste compost @ 10 t/ha and replicated thrice. The results revealed that plant height, leaf area index, dry matter production, grain and stover yield and benefit : cost ratio were favourably influenced by the application of 100% RDF+Poultry manure @ 2.5 t/ha. In nutrient status, uptake of nitrogen and phosphorus was found to be significantly higher with application of 100% RDF+Poultry manure @ 2.5 t/ha, whereas potassium uptake was higher under application of 100% RDF+Pressmud granules @ 125 kg/ha. Thus, for achieving higher productivity, integrated application of 100% RDF with poultry manure @ 2.5 t/ha may be preferred to the hybrid maize cultivating farmers.

Effects of Poultry Manure, Urban Waste Compost and NPK-20-10-10 on the Growth, Yield and Shelf-Life of Two Varieties of Cucumber (Cucumis sativus L.) in the Western Highlands of Cameroon

Organic and inorganic farm inputs in the form of fertilizers is a management practice to improve soil fertility for the growth and development of cultivated crops. A field experiment was conducted to evaluate the growth, yield and shelf-life response of cucumber (Classico F1 and Poinsett-76) to fertilizer applications. The experimental design was a randomized complete block in split plots with three repetitions of the treatments; Control (To: No fertilizer application), poultry manure (T1:20t ha-1), urban waste compost (T2:20t ha-1), NPK-20-10-10 (T3:0.7t ha-1), poultry manure (10t ha-1)+NPK-20-10-10 (0.35t ha-1) (T4), poultry manure (10t ha-1)+urban waste compost (10t ha-1) (T5), urban waste compost (10t ha-1)+NPK-20-10-10 (0.35t ha-1) (T6). Collected data on growth and yield variables from emergence till harvest were analyzed for variation in R version 4.0.1. Results showed that variety and fertilizer had a significant effect (P < 0.05) on all growth variables with Classico F1 variety recording the highest mean values for all growth and yield variables. T1 recorded the highest in all growth variables (vine length, No. of leaves and stem diameter), except for the leaf area in T5 of Classico F1 (404.20 cm2) with the lowest in T0 of Poinsett-76 (87.87cm2). Variety, fertilizer treatments and interactions showed significant effects (P < 0.05) on yield variables. Classico F1 was superior to Poinsett-76, yielding 31.91tha-1 in T1 while Poinsett-76 produced 20.36tha-1 in the same treatment. The lowest yield was recorded in the control treatments (4.45 tha-1 for Poinsett-76 and 7.55 tha-1 for Classico F1). Shelf-life evaluation showed the highest weight loss (20%) in fruits obtained in NPK-20-10-10 treatments within 21 days of storage. These results revealed that the integration of poultry manure or urban waste compost and chemical fertilizer (NPK-20-10-10) improves the growth and yield of cucumber as well as the shelf-life of harvested fruits in the western highlands of Cameroon.

Selecting alternative sterile and non-sterile substrates for mycorrhizal inoculant production

Alternative substrates were evaluated for mycorrhizal inoculants production considering the beneficial effects of arbuscular mycorrhizal fungi (AMF) for plants and environment. The first step of the experiment aimed at evaluating the potential of substrates produced from sugarcane bagasse (SB), coconut fibre (CF) and urban waste compost (UWC) to produce AMF inoculants, by using Brachiaria decumbens as multiplier plant. The experiment has followed a randomized block design, at 7x3 factorial arrangement (seven substrates: SB, CF, SB+CF 1:1, SB+UWC 3:1, CF+UWC 3:1, SB+CF+UWC 3:3:2, Soil+Sand 3:1, vs. three substrate preparations: inoculated/sterilized, inoculated/non-sterilized, non-inoculated/sterilized). Inoculums produced in the first experimental stage were tested at the second stage, based on the inoculated/sterilized preparation. Seed germination, dry shoot biomass, mycorrhizal root rate and total spore production were assessed in both tests. There was significant decrease in seed emergence in organic substrates in relation to Soil+Sand, although the plants growth in organic substrates was greater. Artificial inoculation was not superior to spontaneous substrate mycorrhization or affected inoculum production. Mycorrhizal colonization of roots was equivalent in most organic substrates and in Soil+Sand. However, spore production stood out in organic substrate mixes, mainly when CF and UWC were used. This finding was confirmed at the second experimental stage.

An 18-year field experiment to assess how various types of organic waste used at European regulatory rates sustain crop yields and C, N, P, and K dynamics in a French calcareous soil

Recycling organic waste (OW) in agriculture can improve soil fertility and substitute chemical fertilizers depending on the OW and their treatment. The effects of OW have often been studied in simplified cropping systems to strengthen the observed effects. The objective of this study was thus to evaluate the long-term effects of different types of OW used at European regulatory rates on C storage, crop yields and N, P, and K dynamics. OW has been applied every 2 years at 170 kg N ha-1 since 2001 in the long-term field experiment PROspective in northeastern France on a silty loam calcosol. The 5 types of OW included urban sewage sludge (SLU), green waste and SLU compost (GWS), municipal biowaste compost (BIO), farmyard manure (FYM), and composted FYM (FYMC). The control treatment (CON) did not receive any OW. All treatments were studied after applying (N + ) or not applying (N-) mineral N fertilization at an annual optimal rate. Biowaste digestate was also applied after 2014 in N- treatments. OW application increased crop yield compared with the unfertilized control. Mineral N fertilizer partially substituted by OW allowed crop yield to be sustained compared with mineral fertilizer only, saving 18–54% mineral N fertilizer, 56–80% mineral P fertilizer and 14–76% mineral K fertilizer. No effects on crop grain N, P and K concentrations were found. The efficiency of OW to maintain SOC, total N, Olsen-P and exchangeable K contents in soils greatly varied with the type of OW. Except for SLU, the SOC stocks significantly increased from + 2.9 to + 7.0 t SOC ha-1 for FYMC_N- and BIO_N-, respectively. SLU and digestate had the greatest N fertilizer replacement value (58% and 69%, respectively). N-leaching risk did not increase with OW application in the long term. For a positive ∆P of 100 kg ha-1, Olsen-P increased by 2 mg P kg-1 in the GWS_N- and SLU_N- treatments, whereas Olsen-P decreased in other treatments. A surplus of + 100 kg ha-1∆K raised the exchangeable K stock by 20 and 21 kg K ha-1 in the FYM_N- and FYMC_N- treatments, respectively, whereas exchangeable K decreased in the BIO and GWS treatments. Our results highlight the ability of all tested types of OW to sustain crop yields in the long term when used at EU regulatory rates, while their effects on mineral fertilizer savings, SOC, soil mineral N, Olsen-P, and exchangeable K contents greatly varied according to the considered OW.

EMERGÊNCIA DE SEMENTES E DESENVOLVIMENTO DE MUDAS DE Caesalpinia pulcherrima L. SW. E Cassia grandis L. F. EM SUBSTRATOS ORGÂNICOS

ABSTRACT The addition of adequate proportions of organic residues to formulate substrates with soil, render positive results on germination and seedling growth by providing benefits to the physical and chemical attributes of the soil. Determining an adequate proportion of such residues is essential to obtain seedlings exhibiting morphophysiological quality. This study aims to evaluate seed emergence and the development of Caesalpinia pulcherrima (L.) Swartz and Cassia grandis L. f. seedlings in organic substrates. The experiment was set in a completely randomized design arranged in 2 x 3 x 5 factorial scheme, consisting of two soil classes (Oxisol and Entisol), three types of organic substrate (COP (organic compost from tree pruning + cattle and goat manure), CLU (urban waste compost), RES (residue from the extraction of sisal fiber) and five percentages of organic residues (0, 20, 40, 60, 80). The percentage of emergence and emergence speed of seeds, plant height, number of leaves, root length and dry mass were determined. The species showed better results for these variables when adding organic residues to the substrate. The addition of 80% COP or CLU to the substrate provided higher mean values for percentage of emergence in seeds of Caesalpinia pulcherrima, and the substrate constituted by only soil provided higher dry mass in seedlings of this species. The combination of 50% COP and 50% soil (Oxisol and Entisol) resulted in higher means for the percentage of seed emergence, velocity of emergence and biomass production in Cassia grandis L. f. seedlings.

Evaluation of Rock Phosphate Enriched Compost on Soil Nutrient Status after Harvest of Finger Millet-Cowpea Cropping Sequence in High Phosphorus Soils of Cauvery Command Area, Karnataka

A field experiment was conducted at Zonal Agricultural Research Station, VC Farm, Mandya during kharif 2017, summer 2018, kharif 2018 and summer 2019 to study the effect of rock phosphate enriched compost on soil nutrient status after harvest of finger millet-cowpea cropping sequence. Prior to initiation of the field experiment, three different composts viz., urban solid waste compost (USWC), vermicompost and farm yard manure (FYM) were enriched with rock phosphate at 5 per cent. Field experiment consisting of eleven treatment combinations comprising recommended N and K, and P through varied levels of enriched composts. The experiment was laid out in RCBD design with three replications and the test crops were finger millet and cowpea. The initial P2O5 of the experimental site was very high (133.58 kg ha-1). The results revealed that application of recommended N and K + 75 per cent P supplied through enriched USWC (T5) had significantly higher organic carbon (0.56 and 0.58%) in pooled data of both finger millet and cowpea, respectively. Available N (241.94 and 224.86 kg ha-1), P2O5 (138.69 and 120.99 kg ha-1) and K2O (153.92 and 135.31 kg ha-1) were recorded significantly higher in T5 of finger millet and cowpea, respectively. Similarly, in pooled mean, exchangeable Ca [4.15 and 4.04 C mol (P+) kg-1] and Mg [2.16 and 2.05 C mol (P+) kg-1] were recorded significantly higher in treatment which received recommended N and K + 75 per cent P supplied through enriched vermicompost (T8) in both finger millet and cowpea, respectively. The decrease of available P2O5 was 20.98 per cent from initial (133.58 kg ha-1) to final crop (summer 2019) (105.55 kg ha-1).

Urban Organic Waste for Urban Farming: Growing Lettuce Using Vermicompost and Thermophilic Compost

A transformation towards sustainable food production requires improved circular nutrient management. Urban organic waste contains relevant nutrients and organic matter, yet only 4% of global urban nitrogen (N) and phosphorus (P) sources are presently recycled. One recycling approach is the composting of urban wastes for urban horticulture. We characterized compost from various urban waste fractions and assessed their fertilizer value in a pot trial with lettuce plants. Seven treatments were investigated: food waste vermicompost with coir and paperboard bedding material, thermophilic compost from green waste and human feces, two references with mineral fertilization and a sand control. The lettuce yield and total uptake of P, potassium (K), calcium (Ca), and magnesium (Mg) were highest in plants grown in coir-based vermicompost. The fecal compost led to the highest shoot P and K content, but the shoot uptake of Ca and Mg were lower than in the other treatments. All composts required additional N for lettuce growth. In conclusion, urban waste-derived vermicompost and fecal compost demonstrate a high delivery rate of plant-available Ca, Mg, P, and K. Research is needed on macronutrient availability and alternative N sources for the substitution of synthetic fertilization. These findings support the production of urban waste composts, furthering efforts in nutrient recycling.

Effect of Urban Waste Compost Leachate on the Soil Physical, Hydraulic, Moisture Characteristics and Corn Yield

Effect of Urban Waste Compost Leachate on the Soil Physical, Hydraulic, Moisture Characteristics and Corn Yield

Tannery sludge and urban waste compost in the production of Solanum melongena L. through regression and multivariate analysis

In vegetable production, seedling propagation is one of the most important steps as it directly influences the final performance of the plants. In order for such condition, the propagation substrate must be in good condition. The objective of this work was to evaluate the effect of different combinations of tannery sludge and urban waste compost as substrates in comparison to the commercial substrate Maxfértil® on the growth and quality of eggplant seedlings. The experiment was conducted in a greenhouse using a randomized block design with eight treatments and six replications. The commercial substrate was Maxfértil®, a crushed pine bark, with limestone, and seven treatments with increasing proportions of tannery sludge/decreasing urban waste compost (0/100; 10/90; 30/70; 50/50; 70/30; 90/10 and 100/0 v/v). Characteristics of emergence, growth, quality and leaf nitrogen (N) content were evaluated. No difference was found in the emergence of eggplant seedlings among the different treatments used; however, the growth characteristics, quality and N content featured significant effects when the seeds were propagated in alternative substrates. Regression adjustments pointed to an optimal range of 41–49% of tannery sludge associated with urban waste compost for the evaluated characteristics. The strong correlation between SPAD and N content shows its potentiality in detecting N deficiencies in seedlings. The use of tannery sludge residues associated with urban waste compost seems to be an appropriate and sustainable practice for recycling with high agronomic potential.

A Novel Technology for Processing Urban Waste Compost as a Fast-Releasing Nitrogen Source to Improve Soil Properties and Broccoli and Lettuce Production

This study evaluated nitrogen (N) mineralization dynamics in three soils after the addition of heat-treated urban waste amendments or urban waste compost (UWC). The effects of UWC and urea on soil properties and broccoli and lettuce production were compared. The first N mineralization experiment was conducted in a factorial arrangement (4 × 3), as a randomized complete block design (RCBD), with three replicates. Four UWC doses: 12.5, 25.0, 37.5, and 50.0 mg dm−3 were applied to three soils: sandy Ustoxic Quartzipsamment (QS), intermediate-texture red Ultisol (US), and clayey red Oxisol (OS), during eight incubation periods (0, 7, 14, 28, 42, 56, 70, and 84 days). In the second experiment, the effects of UWC and urea fertilizer on soil properties were compared. The growth of broccoli and lettuce plants was evaluated (experiments 3 and 4). The treatments (Experiments 2–4) followed a factorial arrangement (4 × 2; RCBD; three replicates), using OS soil. Four N doses (as for experiment 1) were combined with two N sources (UWC and urea). The processed UWC application proportionally increased the N mineralization rate by 72% in QS, 54% in US, and 66% in OS. Furthermore, UWC application enhanced soil properties (pH and nutrient availability), compared with urea fertilizer, and improved N uptake, resulting in higher fresh biomass production in broccoli and lettuce plants (50.0 and 37.5 mg dm−3, respectively). Our findings suggest that heat-treated UWC is an economical, viable, and efficient fertilizer to improve soil properties and short-cycle vegetable crop productivity.

CLOD STRUCTURE AND THE QUALITY OF MORINGA SEEDLINGS (Moringa oleifera LAM.) GROWN IN COMMERCIAL SUBSTRATE AND IN ORGANIC COMPOSTS

ABSTRACT The cultivation of tuberous-root species such as Moringa oleifera Lam. (moringa) requires well-dimensioned containers and the use of appropriate substrates, since seedlings will be removed from the container before their planting. Sugarcane bagasse, urban waste compost (compost), and vermicompost are promising wastes for substrate composition. The present study aims to assess the quality of moringa grown in substrate produced from sugarcane bagasse associated with compost or vermicompost in different-volume tubes. The study followed a randomized blocks design, at 2x7 factorial arrangement, namely: tubes’ volumes (50 and 240 mL) x seven substrates (commercial substrate; sugarcane bagasse associated with urban waste compost at three different ratios (1:3; 1:1 and 3:1) and sugarcane bagasse associated with vermicompost at ratios 1:3; 1:1 and 3:1). In conclusion, the 240 mL container was the most appropriate one for moringa seedlings’ production. Substrates presenting higher organic compost ratios led to greater shoot and tuberous root growth and to greater nitrogen-use accumulation and efficiency, which was equivalent to that of the commercial substrate. Higher sugarcane bagasse rates in substrate composition made it easier to remove the seedlings from the tubes and led to better physical quality of the clod after seedling removal from the tubes.