International Journal of Recycling of Organic Waste in Agriculture
Volume:8 Issue: 2, Spring 2019

Studying the effect of citrus pulp silage in the growth performance, amino acid retention of sharpsnout sea bream juveniles. Citrus pulp is an energy and protein source that has been used to replace wheat meal in Diplodus puntazzo fingerlings; 96 fish of 21.5 ± 0.67 g were nourished with two experimental diets for 105 days. The control diet (CON) contained 421.6 g/kg of protein and 22.6 MJ/kg of energy. The citrus pulp diet (CPD) included 442.7 g/kg of protein and 22.02 MJ/kg of energy. At the end of this trial, the CPD did not affect the growth parameters, but the feed efficiency values exhibited statistically significant differences, with those fish fed the CPD having higher values, possibly due to the presence of limonene in the diet. The CPD also resulted in a reduction in amino acid (AA) content due to the protein being bound to fibre; this consequence did not affect the final fish AA profile. For AA retention, only arginine displayed significant differences, although the rest of the AAs also showed effects of AA reduction from the CPD. Citrus pulp silage can be used in D. puntazzo feeding, without adverse in the growth performance and the amino acid profile, although it did cause a reduction in feed efficiency.

The purpose of this work was to evaluate the impacts of the amendment of industrial landfill sludge (ILS) in two different soils with cultivation of sunflower and sorghum plants.

The plants grew in two types of soils (Typic Paleudult—TP, and Grossarenic Hapludult—GH) with different doses of ILS (0, 2, 5, 10, and 20 Mg ha−1). The evaluation of the pH, electrical conductivity, available concentrations of P, K, Ca, Mg, and Na, and the hydrolysis of FDA in the soils were tested. The height and dry mass of both plants were measured, as well as the stem diameter of the sunflower. The total concentration of Cu, Cd, Cr, and Pb was evaluated in the plants and soils, in addition to the translocation factor of those in the plants.

The amendment of ILS in the soils was efficient to increase the pH and macronutrients, as to increase the biomass production. The largest production occurred with 10 Mg ha−1, and the highest dose (20 Mg ha−1) had negative effects in all treatments. Both plants had low accumulation of Cu, Cd, and Pb in their tissues. Cr increased in the roots of sunflower plants (especially in the TP soil) without translocation to the shoots.

The amendment of ILS in soils is an alternative to disposal with benefits to plants and soil quality. TP soil presented better results, being more secure to receive the sludge due to its higher content of clay when compared to the GH soil.

Organomineral fertilizers formulated from different organic sources have been studied for the fertilization of several crops. Filter cake is currently one of the most used sources of organic matter; however, sewage sludge also presents characteristics of agronomic interest, being one of the major environmental problems in Brazil. In this sense, the efficiency of pelletized organomineral fertilizers produced with both sources were evaluated for the development of soybean under different fertilization levels. The experiment was carried out in greenhouse conditions. The soil was characterized as Red Eutrophic Oxisol. The experimental design was randomized block design in a 2 × 4 + 2 factorial scheme, corresponding to two sources of organic matter (sugarcane filter cake and treated sewage sludge), in four doses (50, 75, 100 and 125% of recommendation for soybean cultivation), as well as a mineral fertilization and no-fertilization treatments. The plant development was evaluated (stem diameter, plant height and chlorophylls a and b) at 30, 60 and 90 days after sowing. Organomineral fertilizers formulated from sanitized sewage sludge or sugarcane filter cake promote a higher soybean plant height in relation to mineral fertilizer, especially after the middle of the crop cycle. The level of fertilization referring to 75% of the recommended dose for soybean, when made with sanitized sewage sludge or filter cake, resulted in large stem diameter in relation to mineral fertilization. Organomineral fertilizers based on sanitized sewage sludge or filter cake promote increases in soybean characteristics up to 90 days.

This study assessed the constituent element in rock phosphate (RP) that is responsible for enhancing quick decomposition of cow dung–waste paper mixtures during vermicomposting. Feedstock weighing 5 kg was achieved by mixing 2.16 kg shredded waste paper together with 2.84 kg cow dung sprinkled with water and then enriched with (1% P) as RP from triple superphosphate (TSP), phosphoric acid (PHA) and Ca in the form of CaCl2 at the level supplied by RP. After mixing, they were loaded into vermireactors and inoculated with matured earthworms at a stocking density of 12.5 g worms/kg feed for the entire 56 days. The decomposition of the mixtures was then monitored by measuring maturity parameters, a germination test for phyto-toxicity and morphological properties was assessed using scanning electron microscopy (SEM). Results revealed that rapid decomposition of waste was recorded where TSP was applied than RP whereas Ca-source had the least effect. A C:N ratio of 12 was achieved within 28 days where TSP was added, while RP, PHA and CaCl2 needed 42, 56 and more than 56 days, respectively. It was evidently revealed from the results that P was basically the cause of the improved decomposition of the waste mixtures. To achieve quicker and well-humified enriched vermicompost with a C:N ratio of 10 within 20 days of vermicomposting, add water-soluble P sources.

An experiment was designed to introduce a substitute for peat, which is used in the production of bedding for the cultivation of ornamental plants and is imported and expensive. For this reason, the usability of peanut shells and Azolla, whose accumulation in the environment causes environmental problems, is a major research question. In this work, Dieffenbachia amoena was grown in a growing medium that had substituted peanut shells and Azolla mixes composts (0, 15, 30, 45, 60, and 100 v/v %) for peat. The controls received only peat: perlite (2:1 v/v) without composts. It was found that, as the substitution of compost increased, nutrients also increased in the growing medium. Nonetheless, the nutrients led to minor changes in the leaves. As compost increased, the bulk density of the growing media decreased (0.17, 0.16, 0.15, and 0.15 g cm−3). The range of substrate physical properties, such as container capacity, air-filled porosity, and total porosity, was within the recommended range. The 15–100% substitution of compost increased the electrical conductivity and pH of the growing media. The 30% compost treatment led to significant differences in the final height (32.06 cm), trunk diameter (11.66 mm), stem and leaf fresh weight (57.52 g), and stem and leaf dry weight (5.10 g) in comparison with the controls. Considering the high price of peat in comparison with compost, replacing peat with 30% compost is economically preferable. Compost was thus found to be a good alternative to peat as an ornamental plants growing medium.

This study reports on water management in the fields found in arid areas by the improvement of the soil’s water retention capacity. This was done using hydrogels from animal wastes to mitigate the effects of climate change that lead to rapid evaporation of water hence increased desertification rates. The modification of the cow dung to hydrogels involves the oxidation of urea or uric acid from chicken dung to form compounds that can undergo a condensation reaction with cellulose in the cow dung. This formed a product with high water retention capacity. The materials were characterized using Fourier transform infra-red spectroscopy and thermo-gravimetric analysis which confirmed the derivatization of some functional groups. The thermo-stability was improved, as the degradation temperatures for urea, glycerol, and chicken dung derivatives were 245, 220, and 228 °C, respectively, while the unmodified form was 198 °C. The UV–Vis analysis showed no evidence of starch in the modified material which was also confirmed by Lugol’s test. It was found out that modification had influence on the swelling ability giving it superabsorbent properties with swelling capacities (300 g g−1) within 5 min of moisture exposure plus a high water retention capacity of 90%. The application of the modified materials in the growing of some selected plants showed that the moisture content could be sustained for a period of 6 weeks before the plants wilted. This confirms that the modified form of manure has potential application for hydration of plants in arid areas.

A field trial was conducted on a silty-loam soil under potato culture in NW Spain, to assess the effect of municipal solid waste (MSW) compost in a heavily fertilized acid soil. Three doses of compost (0, 30 and 60 Mg compost ha−1 soil) or inorganic fertilization (~ 140 N: 120 P2O5: 240 K2O kg ha−1 soil) were assayed. The effects of compost on soil physical, chemical (nutrient status and potentially toxic trace elements) and biochemical properties were evaluated after 1 and 5 months. Compost addition at the highest dose decreased bulk density and increased soil porosity and soil stability against water erosion. Soil pH, total organic C and N, cation exchange capacity and available P, Ca, Mg and K were also higher in compost-amended soils, whereas no effect on NH4+-N and NO3−-N was observed. Compost significantly increased soil microbial biomass and dehydrogenase activity. Due to the high nutrient status in the control soil, potato yield was not increased by compost or inorganic fertilization. A negative consequence of compost addition was the increased extractability of trace metals such as Zn, Cu, Pb and Ni, although their total concentrations in soil or in potato tubers did not increase with respect to the control. Overall, results show that positive effects of MSW compost can be expected even in rich soils that do not need fertilization for maintaining their productive function in the short-term. These positive effects prove the benefits of recycling urban wastes in agricultural soils as a sustainable way of waste management.

In the almond industry, the major by-product is the shell, the woody outer layer of the almond fruits. The goal of this research was to study the consequence of the incorporation of almond shell to cultivation substrates on green bean plant grown in a growth chamber. Almond shell was mixed with peat (20%:80%) (AS), or used as mulch (AM) on top of the control (C) substrate (33.3%:66.6% vermiculite and peat). Evaluated parameters included green bean pod production and characteristics and their biochemical parameters, namely pigments, total phenolics and antioxidant activity, and soluble sugars and proteins, but also leaf gas exchange parameters. The use of almond shell as a mulch resulted in unexpected higher crop growth rate, relative leaf growth rate, and leaf area index, with similar production and dimension of pods, when compared to the control assay, with comparable amounts of phenolic compounds, antioxidant capacity, and soluble sugars and proteins, even if gas exchange parameters were negatively affected. By other hand, the data from the almond shell:peat mixture indicate important increase of carotenoid content, contrasting to the control substrate. These results indicate that almond shell has some potential as growing medium for green bean cultivation, when mixed with peat or used as a mulch.

This study was carried out to compare the effects of composted kitchen waste (KW) and poultry manure (PM) soil amendments on growth, yield and heavy metal uptake in edible leaf of Corchorus olitorius. Kitchen waste and PM composted for 8 weeks were applied as soil amendment at the rate of 0 (no amendment), 5, 10 and 15 t ha−1. Corchorus seeds were sown 2 weeks after incorporation of amendment. Compost amendments were the main treatments while application rates were in sub-plots. Treatments were replicated three times in a randomized complete block design. Corchorus were harvested 6 weeks after sowing, following which growth and yield parameters were measured. Concentrations of manganese (Mn), iron (Fe), copper (Cu) and zinc (Zn) in leaf tissue and plant uptake were also determined. Result showed that PM increased Corchorus leaf production than KW. Poultry manure significantly (p ≤ 0.01) increased Cu accumulation in leaf. Bioaccumulation of Cu was 0.005 and 0.011 mg kg−1 for KW and PM, respectively. The metals except Zn in leaf tissue showed significant (p ≤ 0.01) correlation with both fresh and dry weights of Corchorus. Despite high concentration of heavy metals in the compost, bioaccumulation in leaf was lower than maximum allowable limit of 0.1 mg kg−1 for Cu and 0.3 mg kg−1 for Mn, Fe and Zn in vegetables by WHO/FAO/FEPA. Soil amended with composted KW and PM promoted Corchorus growth and yield. Accumulations of heavy metals in leaf tissue are within allowable limit for vegetables.

The study presents the physico-chemical, heavy metal and spectral characterization of aerobic compost to assess the suitability of its use for different purposes generated from two different municipal solid waste dumpsites located in the cities of Solan and Mandi in Himachal Pradesh. The spectral characteristics of the compost material were determined using Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD) technique. The heavy metal analysis of compost material was analyzed through atomic absorption spectroscopy (AAS). The study also focused on the determination of the qualitative nature of compost by utilizing an indexing method based on Fertilizer Control Order (FCO) Standards. The utility of the compost was characterized on the values of ‘Fertility Index’ and ‘Clean Index’. The Fertility Index (FI) of compost for Solan and Mandi was observed 3.5 and 3.6, respectively, whereas Clean Index (CI) of compost for both regions was observed 4.0 and 5.0 at the 60th day of sampling, respectively, with the former being classified as category D and the second being classified as category A of high fertilizing potential. The MSW compost of Solan cannot be used as fertilizer due to its low fertilizing potential. The heavy metal concentration for the study regions has been found within the permissible limits of the fertility control order standards. It is concluded from the study that aerobic composting is a suitable option for processing of waste as well as it can reduce the weight of organic waste in the dumpsite.

Mushroom waste medium can be used as a source of enzymes, but few studies on animal feed improvement using it have been found. In this study, the potential as additives for improving feed efficiency was examined. Extracts from waste media containing shochu lees used for growing three mushrooms cultivation: monkey head mushroom (MHM) Hericium erinaceus, oyster mushroom Pleurotus ostreatus, and shiitake mushroom Lentinula edodes were investigated. Several polysaccharide hydrolase activities in the extracts were measured and the following feedstuffs were partially digested by the extracts: Italian ryegrass, rice straw, and sweet potato runner. Digestibility of neutral detergent fiber (NDF) in the three feedstuffs was compared by the analysis of sugar composition of residual NDF after hydrolysis with sulfuric acid and trifluoroacetic acid. Antioxidant activity of the extract from waste media was also determined by DPPH radical method. The polysaccharide hydrolase activity differed depending on the kind of mushroom and waste medium composition. The waste media containing sweet potato shochu lees showed higher enzyme activities than the standard media did. The additives reduced NDF content in the feedstuffs, especially in treating sweet potato runner with MHM extract. MHM remarkably decreased xylose in NDF of rice straw, and glucose and xylose in NDF of sweet potato runner. The results suggested that the additives might be effective in improving the efficiency of the feedstuffs for heat-stressed or weakened livestock.