Manure Quality Research Articles

Optimization of Manure-Based Substrate Preparation to Reduce Nutrients Losses and Improve Quality for Growth of Agaricus bisporus

With the growing world population, food demand has also increased, resulting in increased agricultural waste and livestock manure production. Wheat straw and cow dung are rich nutrient sources and, if not utilized properly, may lead to environmental pollution. Keeping in view the cultivation of Agaricus bisporus on straw/manure-based substrate, the current study aimed to optimize the conventional manure preparation technique to reduce nutrient losses and keep the quality of manure at its best. The treatments were considered as traditional and optimized schemes for mushroom substrate preparation. The results achieved herein indicated that the nutrient losses were low in the optimum scheme. For carbon (C), the loss was 43.55% at the substrate stage in the traditional scheme and reduced to 37.75% in the optimum scheme. In the case of nitrogen (N), the loss was 22.01% in the traditional scheme and was lower (18.49%) in the optimum scheme. The nutrient concentration in Agaricus bisporus was higher with the optimum scheme compared with the traditional scheme. It was 1.74% for C, 7.17% for N, 3.58% for phosphorus (P), and 4.92% for potassium (K). The optimum scheme also improved the Agaricus bisporus yield per unit area (84.55%) and the total yield (28.92%). The net income of the optimum scheme was 102.95% higher compared to the traditional scheme. The economic analysis also revealed that the benefit–cost ratio of the optimum scheme was high (48.86%) compared with the traditional scheme. This study concludes that the use of the optimum scheme can better utilize the wheat straw and cow manure waste for substrate preparation and reducing nutrient losses. In addition, the final mushroom residue can also be used as a leftover substrate for further utilization.

Chemical Composition and Fermentation Characteristics of Different Proportions of Fermented Poultry Manure and Sheep Feces as Unconventional Feed

The aim of this recent study was to investigate the effects of different ratios of poultry manure and sheep feces on the fermentation quality of fermented poultry and sheep manure (FPSM). This study used poultry manure, dry sheep feces, cassava flour, molasses, and the addition of multiple microbes (Saus Burger Pakan, SBP®). Dried and ground sheep feces, as adsorbents, were mixed with fresh poultry manure at different ratios, including 40% sheep feces and 60% poultry manure (T40), 50% sheep feces and 50% poultry manure (T50), and 60% sheep feces and 40% poultry manure (T60). Each treatment was replicated in triplicate, and 30 kg of each silo was fermented for 14 d. After fermentation, the samples from each treatment were analysed to determine their physical characteristics, chemical compositions, fermentation characteristics, and microbial contamination. The data were analysed using analysis of variance (ANOVA) followed by Duncan’s test if any significant difference was detected. The FPSM results showed that T60 presented (P<0.05) higher amounts of dry matter, crude fibre, pH, and lactic acid bacteria colonies. This study recommended the addition of as much as 60% SBP® inoculum and absorbent poultry manure to produce optimum and effective fermentation quality in poultry manure processing.

The maturity, humus content, and microbial metabolic function of sheep manure compost on the Qinghai-Tibet Plateau can be significantly improved by reducing the moisture content.

The Qinghai-Tibet Plateau (QTP) is characterized by an extreme hypoxia, which may lead to lack of sufficient oxygen for compost production, and thus seriously affecting the compost quality. The moisture content (MC) has a direct effect on the oxygen content of composting pile. At present, the research on the optimum moisture content of compost production on the QTP is still lacking. This study aimed to investigate the influences of MC on fermentation quality of sheep manure composting on the QTP and to further analyze the changes of microbial metabolic function and enzyme activity under different MC. Composting experiment with low MC (45%) and conventional MC (60%) was conducted in both summer and autumn. The results showed that the composting efficiency of 45% MC was better than 60% in both seasons, which was mainly manifested as longer high-temperature period (summer:16d vs 14d, autumn: 7d vs 2d), higher germination index (summer:136.1% vs 128.6%, autumn:103.5% vs 81.2%), and more humus synthesis (summer:159.8g/kg vs 151.2g/kg, autumn:136.1k/kg vs 115.5k/kg). The 45% MC can improve microbial metabolism, including increasing the abundance of functional genes involved in carbohydrate metabolism, amino acid metabolism, and nucleotide metabolism and improving the activities of cellulase, β-glucosidase, protease, polyphenol oxidase, and peroxidase. In conclusion, 45% MC can improve the fermentation efficiency and products quality of sheep manure compost on QTP.

Stabilization of biomass in manure effluent using the thermophilic-aerobic process

Aerobic-thermophilic stabilization of biomass is crucial in improving the processing processes of manure. This method makes it possible to achieve effective and stable processing of organic materials contained in manure using aerobic microorganisms and elevated temperatures. The aerobic-thermophilic process includes the action of oxygen and high temperature, which contribute to the active decomposition of organic substances in manure runoff. The increased temperature helps to create optimal conditions for the action of thermophilic bacteria, which accelerates the process of biological decomposition. Studies show that aerobic-thermophilic treatment of manure effluents helps to reduce the concentration of pathogenic microorganisms and ammonia. This contributes to obtaining cleaner and environmentally safe manure suitable for use in agriculture. Advantages of aerobic-thermophilic stabilization: Faster recycling process compared to traditional methods. Reduction of odors and risk of pathogen contamination. High quality and efficiency of produced manure. Aerobic-thermophilic stabilization of biomass in manure processing is a promising direction in improving modern waste treatment technologies. Its implementation contributes to improving the quality and safety of manure and the effective use of these resources in agriculture. Research and development of this method are essential for achieving sustainable and ecologically clean agricultural production. It has been established that liquid manure of enterprises with intensive milk and pork production technologies with hydraulic manure removal systems with a humidity of 92–96 % should be subjected to aerobic fermentation in an auto thermal mode, as a result of which products are obtained that are safe from a sanitary and hygienic point of view. In addition, the loss of nutrients is reduced. which determines the quality of organic fertilizers. Established that liquid manure businesses for technology-intensive milk production and pig manure removal by hydraulic systems with humidity 92–96 % of it are advisable to expose aerobic biofermentatsiyi in autothermal mode, which allows you to get the products in a safe sanitary and hygienic attitude and reduce the loss of nutrients that determine the quality of organic fertilizers.

Growth and Yield of Broccoli Vegetables (Brassica oleracea var. botrytis L.) on Types and Dosages of Manure

Broccoli is a vegetable commodity that has high commercial value and prospects in Indonesia, because of its role in fulfilling food, feed, and industrial needs. In cultivating broccoli plants, they still face production problems due to nutrient availability problems. Farmers generally use chemical fertilizers continuously. Continuous use of chemical fertilizers will increase soil acidity, damage the physical condition of the soil, reduce organic matter, make plants vulnerable to pests and disease, and reduce soil microbial life. Many consumers are interested in organic broccoli. The use of organic fertilizer as an alternative to chemical (inorganic) fertilizer can reduce environmental pollution and create healthy broccoli (Brassica oleracea) vegetable products. One of the organic fertilizers is manure which is a waste product from domestic animals such as chickens, goats, and pigs which are generally found in Tomohon City. Manure can be used to add nutrients, and improve the physical and biological properties of soil. The quality of manure depends on the animal and greatly influences crop yields. The research objectives are: (1) Studying the effect of the interaction between the type and dose of manure on broccoli growth and yield, (2) Obtaining the type and dose of manure that provides the highest growth and yield of broccoli, and (3) Get semi-organic broccoli by using a 25% dose of compound nitrogen, phosphorus, potassium (NPK) fertilizer. To achieve the above objectives, this research used a Factorial Randomized Block Design (FRBD) with 2 treatment factors and 3 replications the first factor was the type of manure (A) which consisted of A1: Chicken manure, A2: Goat manure, A3: Pig manure. The second factor is the dose of manure (B) which consists of B0: 125 kg NPK/hectare, B1: 20 manure/hectare, B2: 30 kg/hectare. The observation variables include plant height, number of leaves, diameter of broccoli per plant, and wet weight of broccoli per plant. Data analysis uses Analysis of Variance (ANOVA). If the results of the analysis show that there is an effect of treatment, then continue with the BNT test at the 5% level. The results showed that the treatment with goat manure at a dose of 20 tons/hectare and without manure at half the recommended dose of nitrogen, phosphorus, and potassium gave the highest number of leaves (18.67 and 19.67 leaves). The best broccoli crop diameter was treated with goat manure at a dose of 20 and 30 tons/hectare. The weight of the best broccoli crop in goat and pig manure at a dose of 20 tons/hectare was 47.67 grams.

Seaweed supplementation to organic dairy cows may reduce climate impact of manure in pasture soils during a laboratory incubation

AbstractIntroductionEnteric methane (CH4) emissions are one of the largest components of the anthropogenic CH4 budget, and with accelerating climatic changes, there are calls to reduce anthropogenic greenhouse gas emissions. Certain seaweeds fed as supplements can reduce enteric CH4 emissions from ruminant animals by as much as 80%; however, these studies have yet to analyze downstream impacts that may arise from the deposit of affected manures on pastures or agricultural fields.Materials and MethodsHere we conducted a 28‐day soil and manure incubation utilizing manures collected from dairy cows in a seaweed feeding trial to analyze the impacts of manure on greenhouse gas fluxes and nutrient cycling. Cows were fed different diets with a control group (no seaweed supplementation), and a 3% and 6% by dry‐weight seaweed (Chondrus crispus) supplementation. Three soil moisture treatments were also tested, with a field moist capacity [67% gravimetric water content (GWC)], a drier group (50% GWC), and a saturated treatment (84% GWC).ResultsWe found that manure from seaweed‐fed cows reduced emissions of carbon dioxide and had similar emissions of methane and nitrous oxide to the control. Higher moisture levels increased CH4 emissions and nitrous oxide emissions with CH4 emissions trending higher in seaweed supplements trending higher in. Inorganic nitrogen turnover varied more based on moisture levels than seaweed supplements, as did the magnitude of methane and nitrous oxide emissions. Total carbon and nitrogen mostly decreased except in the 3% seaweed supplementation, which increased carbon and nitrogen with a drop in C:N in the 50% GWC group.ConclusionSeaweed supplements may partially reduce climate impacts of manures from cows fed seaweed supplements or at least not cause harm or impact manure quality. Given feeds may reduce enteric CH4 emissions, they may be a part of a successful strategy to reduce climate impacts of cattle.

Effects of turning frequency on fermentation efficiency and microbial community metabolic function of sheep manure composting on the Qinghai–Tibet Plateau

This study explored the effects of turning frequency on fermentation efficiency and microbial metabolic function of sheep manure composting on the Qinghai–Tibet Plateau (QTP). Five treatments with different turning frequencies were set up in this study: turning every 1 day (T1), 2 days (T2), 4 days (T3), 6 days (T4), and 8 days (T5). Results showed that the high temperature period for T1 and T5 lasted only 4 days, while that for T2–T4 lasted more than 8 days. The germination index of T1 and T5 was lower than 80%, while that of T2–T4 was 100.6%, 97.8%, and 88.6%, respectively. This study further predicted the microbial metabolic function of T2–T4 using the bioinformatics tool PICRUSt2 (Phylogenetic Investigation of Communities by Reconstruction of Unobserved States) and determining the activities of various functional enzymes. The results showed that carbohydrate metabolism, protein metabolism, and nucleotide metabolism were the main metabolic pathways of microorganisms, and that T2 increased the abundance of functional genes of these metabolic pathways. The activities of protease, cellulase, and peroxidase in T2 and T3 were higher than those in T4, and the effect of T2 was more significant. In conclusion, turning once every 2 days can improve the quality of sheep manure compost on the QTP.Graphical

Analysis of Manure Separation Technology Efficiency into Fractions Followed by Liquid Fraction Rectification

Introduction. There is not enough data on the used intensive technologies of processing pig manure into organic fertilizer to accurately calculate the content of nutrients in the final products and, accordingly, their doses of application. Aim of the Article. To determine the efficiency of pig manure processing technology, which includes liquid fraction rectification, by the quantitative and qualitative characteristics of manure and final products, and to trace the redistributing total nitrogen between the final products on the example of a pilot pig breeding complex production. Materials and Methods. For the study, there was chosen a typical pig-breeding complex, where the pig manure processing included slurry acidification, flocculation, separation into fractions in a decanter centrifuge, rectification of liquid fraction, passive composting of solid fraction, and long-term storing of liquid fraction. The technology allows producing three types of end products: solid organic fertilizer, concentrated liquid (ammonia water), and fertilizer solution. Quantity and quality of pig manure and the end products were calculated by the known methods. Experimental studies were performed to compare the results. Samples were analyzed in the analytical laboratory of Institute for Engineering and Environmental Problems in Agricultural Production in 2022. Three replications were carried out for each sample. The experimental data were statistically analysed in MS Excel. Results. Quantitative and qualitative characteristics of pig manure, its solid and liquid fractions, and end products were calculated. The difference between the calculated and actual values does not exceed 10.2% that indicates the reliability of calculations. Discussion and Conclusion. The introduction of a new technology at the pig-breeding complex has reduced atmospheric emissions by 10% due to the nitrogen conservation, has reduced operating costs for transporting organic fertilizer by 47% due to the concentration of nutrients in a smaller volume and has improved soil fertility through fertilizer irrigation.

Strategies Steering Intensification Pathways of Farmers in Central Malawi

AbstractSmallholder farmers face many challenges to improve their livelihoods and food security. Intensification of agricultural production can help to achieve these goals. Yet farmers are highly heterogenous in their strategies towards intensification, potentially following unsustainable intensification pathways. Using Q Methodology, we ascertain different strategies regarding farm improvement and intensification of smallholder farmers in the Dedza and Ntcheu Extension Planning Areas in Central Malawi. These strategies were associated to coherent sequential choices as expressed in “managerial intensification pathways” (MIPs). Three main strategies emerged: Seed Saving Peasants, Aspirant Modern Farmers and Entrepreneurial Business(wo)men. These were subsequently linked to four MIPs. Seed Saving Peasants focus strongly on local seed systems and post-harvest protection of grains, but also allocate more labour to improving crop residue use and manure quality, thus pointing to a labour-oriented MIP. Aspirant Modern Farmers willingly adopt hybrid seeds and inorganic fertilizers but require more extension support; these farmers follow a technology-oriented MIP. Entrepreneurial Business(wo)men are early adopters of new technologies and benefit from improved access to market information and suppliers of new technologies and follow a sustainable technology-based or techno-ecological intensification pathway. This study shows that strongly contrasting perspectives on intensification exist among smallholders and it is expected that their preferred intensification choices will have diverging impacts on the sustainability of their farms. A diversity of extension, advice and incentive instruments will be needed to support farmer decision making towards sustainably intensified farms.

Quality of Cow Manure Compost Using Effective Microorganism (EM4) and Black Soldier Fly (BSF) Fly Larvae (Maggot)

This study aims to determine differences in the quality of cow manure compost using Effective Microorganisms (EM4) and the quality of cow manure compost using Black Soldier Fly (BSF) Larvae (Maggot). The experimental design used in this study was a completely randomized design consisting of 4 treatments and 5 replications. Treatment Po = Cow dung, P1 = Cow dung + EM4, P2 = Cow dung + maggot, P3 = Cow dung + EM4 + maggot. Parameters observed were temperature, color, smell, texture and C-organic compost which showed a very significant difference (p <0.01) to the mean value of fermented cow dung, the lowest total N was found at p1 with a value of 0.69% while the highest value is found in p2 with a value of 1.13%, the lowest C/N ratio is found in p2 with a value of 36.97% while the highest value is found in po with a value of 63.54%, the lowest P2O5 is found in p1 1.42% while the the highest was at 2.45%. The lowest K20 is at p2 with a value of 1.41% while the highest value is at p3 with a value of 2.346%., and the lowest PH is at p2 with a value of 8.214% while the highest value is p1 8.72%. Keywords: Microorganism, black soldier fly, fly larvae, quality Compost

Bioconversion of fruit waste and sewage sludge mixtures by black soldier fly (Diptera: Stratiomyidae) larvae

Bioconversion of fruit waste (FW) and sewage sludge (SS) sludge mixtures into valuable products was investigated using black soldier fly (Hermetia illucens) larvae (BSFL) under a lab-scale trial. For that, five different setups of FW and SS mixtures (100FW; 100SS; 70SS+30FW; 50SS+50FW; 70FW+30SS) were prepared and changes in larval biomass, feed loss, and residual waste physicochemical properties were estimated until the emergence of fly in all waste mixtures. BSFL caused a significant decrease in total organic carbon (11.71–34.79%) and carbon-to-nitrogen ratio (C/N ratio) while the increase in total nitrogen (8.35–123.30%), total phosphorus (17.02–143.36%), and total potassium (19.40–48.87%) contents in the feedstock. The germination index and C/N ratio of frass were below the standards decided for manure quality in a few setups suggesting the non-stability of frass for agronomic applications due to the short duration (20 d) of composting. Larval biomass yield, feed conversion ratio and nutrient mineralization were found to be higher in 50SS+50FW and 70FW+30SS feedstock combinations suggesting their suitability as ideal feedstock for optimal BSFL cultivation. The impact of toxic substances in sewage on BSFL survival, growth and waste stabilization processes, and frass metal enrichment could be investigated in future studies.

Improving the Quality of Rabbit Manure in Livestock Farming Groups in The Bedugul Tourist Area, Tabanan-Bali

To support the growth and development of plants in the Bedugul tourist area, in addition to using inorganic fertilizers, most farmers still use organic fertilizer derived from chicken manure which is easily obtained in large quantities from outside the Candikuning Village area. Until now, the source of organic fertilizer that can actually be used from solid and liquid rabbit manure in Candikuning Village is still not carried out further processing to improve the quality of rabbit manure as a nutrient source fertilizer for plants. This opportunity can actually be used by livestock farmer groups in Candikuning Village as an opportunity to supply organic fertilizer from solid and liquid rabbit manure. The group's problem is that solid and liquid rabbit manure has not been processed optimally, there is no house where the drying and fermentation process has not been carried out, and packaging and labeling have not been carried out. Therefore, partner groups need to be facilitated from the aspects of processing technology and improving the quality of rabbit waste, packaging and labeling, product quality testing in the laboratory, and partner group business management. This PKM program is carried out in livestock farming groups in Candikuning Village, Baturiti District, Tabanan Regency-Bali Province. The method used to achieve the goal is through socialization, counseling, mentoring, training, and the application of technology with direct practice in the field. In this activity, the output target that has been achieved is that the partner group is independently able to utilize solid and liquid rabbit manure waste into "SOF" (Solid Organic Fertilizer) and "LOF" (Liquid Organic Fertilizer) with good quality has been packaged and labeled so that it can compete in the market and increase the income of the partner group.

Co-composting of cattle manure with biochar and elemental sulphur and its effects on manure quality, plant biomass and microbiological characteristics of post-harvest soil.

Improvement of manure by co-composting with other materials is beneficial to the quality of the amended soil. Therefore, the manure was supplied with either biochar, elemental sulphur or both prior to fermentation in 50 L barrels for a period of eight weeks. The manure products were subsequently analyzed and used as fertilizers in a short-term pot experiment with barley fodder (Hordeum vulgare L.). The experiment was carried out under controlled conditions in a growth chamber for 12 weeks. The sulphur-enriched manure showed the lowest manure pH and highest ammonium content. The co-fermentation of biochar and sulphur led to the highest sulphur content and an abundance of ammonium-oxidizing bacteria in manure. The biochar+sulphur-enriched manure led to the highest dry aboveground plant biomass in the amended soil, whose value was 98% higher compared to the unamended control, 38% higher compared to the variant with biochar-enriched manure and 23% higher compared to the manure-amended variant. Amendment of the sulphur-enriched manure types led to the highest enzyme activities and soil respirations (basal, substrate-induced). This innovative approach to improve the quality of organic fertilizers utilizes treated agricultural waste (biochar) and a biotechnological residual product (elementary sulphur from biogas desulphurization) and hence contributes to the circular economy.

Livestock manure availability and syngas production: A case of Sudan

Sudan is facing an energy crisis caused by a large deficit in electric power supply and transportation fuels such as gasoline and diesel. Only about 32% of the population have access to electricity. Fuels subsidies have been removed causing a huge prices-hike. Therefore, Sudan is in urgent need to promote its abundant biomass resources to mitigate the energy crisis. In recent years, syngas from biomass gasification has emerged as a potential energy source for power generation and manufacturing synthetic gasoline and diesel via Fischer–Tropsch (FT) synthesis. The paper reports (1) the availability of Sudan’s livestock manure for syngas production and (2) the optimization of syngas production for the applications of power generation and FT synthesis. The study covers eight (8) livestock manure of Sudan origin, viz. Cattle Dairy, Cattle Non-Diary, Sheep, Goat, Broiler, Layer, Horse, and Camel. Sudan has a large livestock population but poor manure management. Despite poor management, the available manure (10%) amounts to 17 Mt/year with an energy value of 300 EJ/year (7.14 Mtoe/year). The process optimization is accomplished using the optimization section of the Model Analysis Tools of the Aspen Plus simulator. The cold gas efficiency and H2/CO≥2.0 molar ratio are taken as the optimization objective function and constraint, respectively. The operating conditions under which the objective function and the constraint are satisfied are steam to biomass ratio (0<SB<5), equivalent ratio (0≤ER<1.0), and gasification temperature (500 °C≤Tg≤ 1300 °C). The optimum set of operating conditions are ER = 0, SB = 0.46-1.0, Tg = 750 °C -1000 °C. The syngas quality of all livestock manure except Camel are: H2 mole fraction = 0.47-0.56, LHV = 10.0-15 MJ/kg, and H2/CO ≥ 2.0. The syngas produced amounts to 22.42 Mt/year with an energy value of 270 EJ/year (6.44 Mtoe/year). This energy could level the deficit in electric power and transportation fuel demands.

Hydrothermal carbonization improves the quality of biochar derived from livestock manure by removing inorganic matter

The application of hydrothermal carbonization to improve biomass-derived energy sources is crucial because of insufficient supplies of fossil fuels and concerns associated with the impact of fossil fuels on the environment. Hydrothermal carbonization technology has been developed to circumvent the energy-intensive drying step required for the thermal conversion of high-moisture organic feedstocks into fuel. In this study, the quality of livestock manure was upgraded, and its energy density was increased through hydrothermal carbonization at various temperatures. The evolution of waste biomass under hydrothermal carbonization was chemically analyzed. The increased carbon content of the resulting biochar upgraded its fuel properties, leading to energy savings in the treatment process. After hydrothermal carbonization, the H/C and O/C ratios were lower owing to chemical conversion. The optimal temperature for hydrothermal carbonization was approximately 220 °C. The inorganic content resulted in a lowered degree of agglomeration and reduced the likelihood of fouling during combustion. The thermogravimatric analysis also provided the changing combustion characteristics due to the increased fixed carbon content. Fourier transform infrared spectra revealed that hydrothermal carbonization reaction reduced the numbers of C–O and C–H functional groups and increased the number of aromatic C–H functional groups. The equilibrium moisture content decreased rapidly when hydrothermal carbonization was conducted at temperatures higher than 200 °C, and the initial moisture content was reduced by 75% after hydrothermal carbonization at 300 °C.

Effects of Green Manure Combined with Phosphate Fertilizer on Movement of Soil Organic Carbon Fractions in Tropical Sown Pasture

The application of green manure is a common way to increase the soil’s level of total organic carbon (TOC) and its fractions. However, the amount of green manure to apply and how the combined application of phosphate fertilizer affects the movement of TOC, and of its fractions, is still unclear. We conducted a column experiment with two treatments of phosphate fertilizer (with and without) and green manure (0, low amount level, high amount level). The longitudinal movement distance and accumulation amount of each organic carbon fraction were investigated after 14 days and 28 days. The results indicated that green manure, phosphate fertilizer, and incubation time affected the movement of the soil organic carbon fractions by affecting the initial quality of the green manure (TOC, cellulose, and lignin content), as well as the changes in quality. Green manure significantly increased the accumulation amount of the organic carbon fractions in the soil, and the high-level input of green manure increased the movement distance and accumulation amount of the organic carbon fractions; phosphorus fertilizer did not have a significant effect on the movement distance of the organic carbon fractions, but it did significantly affect accumulation amount. The 28-day incubation period increased the movement distance and the accumulation amount of the organic carbon fractions, with the exception of the particulate organic carbon (POC), compared to the 14-day incubation period. Taken together, these findings suggest that the high-level of input of green manure combined with the application of P fertilizer is beneficial for increasing the movement of the organic carbon fractions to the depth of the soil, and promotes their accumulation, which is an important agronomic management strategy for improving soil acidity in tropical regions.

IMPROVEMENT OF TECHNOLOGY OF OBTAINING HIGH QUALITY OF ORGANIC FERTILIZERS WITH THE USE OF ASSOCIATED LAYER WATER AND PROBIOTICS

At the current level of development of agricultural production there are facts of environmental degradation due to the use of agrochemicals. The introduction of scientifically sound ecological technology of agriculture, which is based on the system of ecological safety of the environment and human health, can prevent possible negative effects. To ensure the sustainable development of modern agricultural production and the use of chemicals in limited quantities, there is a problem of their partial replacement by alternative low-cost measures based on natural processes of self-renewal. The aim of our studies was to determinate the effectiveness of obtaining high-quality organic fertilizers using associated water (SPV) and probiotic preparations that accord the requirements of environmentally friendly resource-saving technologies for growing crops. Ecological and trophic groups of soil microorganisms were determined by seeding certain dilutions of soil suspensions. The results of experiments show positive changes in quality and phytosanitary state of organic manure during three months of combined use of SPV (150 l t) and probiotics (100 l/t). The results of bacteriological research show that the level of pathogenic microorganisms decreased by 98-100% after 3 months of composting with native and 10% probiotic solution. Salmonella and Escherichia coli pathogens have not been identified. The cleaning efficiency was lower at 1% and 0.1% probiotic solution. According to mycological research the total number of fungi was 206.9 thousand/g, by 27% more than the control sample. The content of pathogenic fungi decreased by 88% compared to control. It was found that SPV and probiotics changes the chemical composition of manure. Although SPV does not contain large amount of essential mineral nutrients, but SPV are a valuable natural source of microelements that have a positive effect on the crops growth. In particular, the content of potassium in manure increased by 20.8%, phosphorus - by 41.8%, total nitrogen - by 45.8%, organic matter - by 10%. Thus, the integrated use of SPV and probiotics can destroy ruderal vegetation, reduce the germination of weed seeds, improve the quality of manure by enriching it with microelements, disinfect manure from pathogenic microorganisms and fungi. All these advantages make it possible to obtain high-quality organic fertilizer that allows you to optimize the soil nutrient regime. Research results show that the use of SPV and probiotics contribute to increase biological activity in the top soil layer, which determines the specific conditions of transformation of organic matter and productivity of agrobiocenosis. The proportion of microorganisms in the microbial cenosis with SPV 1200 l/ha and probiotics 100 l/ha is 19.2 ± 0.90 million (number of cells in 1 gram of completely dry soil), which is much higher than control (5.9 ± 0.21 million). Using SPV 1200 l/ha and probiotics 100 l/ha stimulates the growth and development of microscopic fungi and cellulose-destroying microorganisms involved in the decomposition of crop residues. There is an increase in the number of oligonitrophilic microorganisms that complete the mineralization of organic residues.

Simulation of variable-rate manure application under different application scenarios

Although the variable-rate manure application (VRMA) offers a promising solution to overcome the shortcomings of the conventional uniform-rate (UR) application, effectively incorporating this technique into precision agriculture solutions presents a substantial challenge. This study entailed developing a quantitative analysis tool to calculate manure consumption, evaluate environmental risks, and compare different treatment schemes under different implementation scenarios. Firstly, a simulator was designed and developed in the LabVIEW development environment with MATLAB. Next, this tool was used to compare traditional UR application with VRMA, by which manure application rate was varied according to soil phosphorus (P) maps measured with an on-line visible and near infrared soil sensor, or according to data-fusion (DF)-based management zone (MZ) maps, developed by fusion of on-line measured soil properties and crop normalized difference vegetation index (NDVI). In the DF case, simulations included Robin Hood (RH) and Kings approaches, which meant to apply the largest manure application rate at the poorest fertility zones, or in the richest fertility zones, respectively. The implementation scenarios included both map-based (MB) without accounting for on-line manure sensing and map-sensor-based (MSB) with on-line manure sensing in three commercial fields in Flanders, Belgium. The results revealed that the P-based-VRMA scheme consumed 1–13% less nitrogen (N) and P2O5 in the case of ignoring legislative limits, compared to the UR and this was true for the RH-VRMA scheme in all three fields and for the Kings-VRMA scheme in two out of three fields. This was because the P-based maps have larger rich fertility areas (e.g., large P concentration) than the MZ maps that both the RH and Kings approaches used. Furthermore, imposing the “MAP6” legislation limits caused all VRMA schemes to consume less fertilizer than would be the case without restrictions, reducing environmental risks due to decreasing the amount of applied N and P2O5. According to the simulation results, the MSB scenario saved 6–9% manure compared to the MB scenario in the P-based-VRMA scheme when the mean value of real-time sensed P2O5 in the applied manure was greater than the nominal values measured in the laboratory. Opposite results were observed in the UR, RH-, and Kings-VRMA schemes. The MSB was more expensive than the MB by 5–7%, when the mean N content of manure used for MSB was lower than that for MB. We concluded that the manure consumed in VRMA depends on treatment schemes, measured manure quality, imposing legislative limits, and the proportion of rich, medium, and poor fertility areas in a field. It is essential to impose the legislative limits to prevent over-applications of N and P2O5, while further agronomy study should evaluate the impact of these limits on crop responses.

Digestate and Manure Use in Kohlrabi Production: Impact on Plant-Available Nutrients and Heavy Metals in Soil, Yield, and Mineral Composition

Digestate is a residue of the anaerobic decomposition of organic waste for biogas extraction, but it can be reused as a source of nutrients. To examine the effect of digestate in kohlrabi production, field experiments were conducted during three seasons in two calendar years. The fertilization treatments included the application of solid digestate (two rates—DS1 and DS2), liquid digestate (two rates—DL1 and DL2), solid manure (two rates—MS1 and MS2), and mineral fertilizer (NPK) and were compared with a plot without fertilization (Ø). The results showed a significant increase in the yield with the use of solid and liquid digestate, as well as with NPK, in all growing seasons, while the microelement contents (Zn, Mn, and Cu) in the leaves were at optimum level. The applied treatments did not increase the plant-available nutrients (AL-P2O5, AL-K2O, Fe, Cu, and Zn) in the soil (except Mn). The application of DL2, MS1, and MS2 led to a higher Pb content in kohlrabi stems compared to the control, but the Pb content remained below the maximum permitted limit. Our research showed that digestate can be used as a valuable source of nutrients for kohlrabi production, with a low risk of soil and plant contamination by heavy metals. However, the control of soil, digestates, and manure quality is recommended.

Manure Maturation with Biochar: Effects on Plant Biomass, Manure Quality and Soil Microbiological Characteristics

Application of biochar and composts prepared from organic wastes as soil amendments has been recognized as a beneficial strategy to enhance soil fertility and crop production. However, the modification of manures with applied organic amendments such as biochar has not been well explained. Therefore, the preliminary study was designed to evaluate the impact of two doses of biochar (low 0.4 kg + 10 kg of manure and high 4 kg + 10 kg of manure) on the modification of resulting co-composted manure properties, and subsequently to evaluate the effect of matured manure amendment on the soil chemical and biological properties and plant yield in the pot experiment with barley (Hordeum vulgare L.). The following variants were tested: control, manure (M), manure + low biochar dose (M + LB), manure + high biochar dose (M + HB). Results revealed that, the M + HB significantly improved the co-composted manure properties as compared to control and M + LB, respectively. The most pronounced effects of M + HB treatment were observed on pH, NH4-N and humic acid to fulvic acid ratio (used as an index for manure maturity) relative to other treatments. Similarly, significant variations were observed between AOB (ammonium oxidizing bacteria) and nirs genes under M + HB which lowered the AOB and increased the nirs abundance as compared to other treatments. Moreover, when applied to soil, M + HB increased the observed soil chemical parameters with the exception of TN contents as compared to M and M + LB treatments. Similarly, plant biomass was significantly enhanced under the applied M + HB treatment. However, statistically insignificant differences were observed regarding soil enzyme activities and soil respiration values under the applied amendments. Thus, it was concluded that the co-composted manure with high biochar dose can have the potential to enhance the manure properties, soil fertilization value and plant biomass. However, its effects on soil microbiological and enzyme activities were intended be explored under long-term field experiments.