Search

Safe and effective circulation of nutrient-rich meat and bone meal (MBM) could become a carbon-based alternative to limited chemical fertilizers (CFs). Therefore, MBM biochars (MBMCs) were produced at 500, 800, and 1000 °C to evaluate their effects on plant growth, nutrient uptake, and soil characteristics. The results revealed that MBMC produced at 500 °C (MBMC500) contained the maximum amount of C, N, and phytoavailable P. All additional MBMC doses with recommended CF increased sorghum shoot yield (6.7-16%) and significantly improved P uptake. Additional experiments were conducted with decreasing doses of CF (100-0%) with or without MBMC500 (7 t/ha) to quantify its actual fertilizing value. MBMC500 showed the capability to reduce CF requirement by 20% without compromising the optimum yield (by 100% CF) while increasing pH, CEC, total-N, available-P, Mg, and microbial population of post-harvest soil. Although a δ 15 N analysis confirmed MBMC500 as a source of plant N, a reduction in N uptake by MBMC500 + 80% CF treatment compared to 100% CF might have limited further sorghum growth. Thus, future studies should concentrate on producing MBMC with better N utilization capability and achieving maximum CF reduction without negative environmental impacts., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Kazunori Iwabuchi reports financial support was provided by Japan Livestock By-product Association., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Anaerobic digestates from sewage sludge (SSADs) are a by-product of the wastewater treatment process that still preserves a certain agronomic interest for its richness in plant nutrients and organic matter. Fertilizing properties of two liquid and two dewatered SSADs were tested on tomato plants (Solanum lycopersicum L.). Pot experiments were performed on sandy soil and peat substrate under greenhouse conditions with a SSADs application rate of 170 kg N/ha over a period of three months. Beneficial effects of SSADs were reported on different growth parameters, revealing an increase in biomass and height up to 37.5 and 6-folds over untreated control. No phytotoxic effect occurred on SSAD-exposed plants. Chemical analysis of soils treated with SSADs showed enrichment of macro- and micro-nutrients as well as organic matter. In some cases, the chemical characterization of leaves revealed an enhancement of uptaken macronutrients. This study contributed in general to deepen the knowledge on the short-term growing season fertilizing effects of SSAD. Despite the treatment dosage was calculated only on nitrogen requirements, the study highlighted the importance of the other nutrients and organic matter on plant growth., Competing Interests: Declaration of competing interest None., (Copyright © 2020. Published by Elsevier Ltd.)

Secondary fertilisers are becoming an important alternative to conventional mined fertilisers. For the first time, the struvite "relative" hazenite (KNaMg2(PO4)2·14 H2O) has been artificially synthesised. A pot trial assessed whether hazenite-fertilised ryegrass had comparable potassium (K), magnesium (Mg), or phosphorus (P) uptake and shoot yields with treatments receiving conventional K (muriate of potash), Mg (kieserite) or P (triple superphosphate, TSP) fertilisers. Ryegrass shoot biomass production and K/Mg uptake in replicates receiving hazenite were as good as or superior to those amended with conventional fertilisers. Phosphorus uptake of plants whose P source was TSP was significantly higher than that of the hazenite-amended replicates without significantly higher shoot biomass, indicating luxury P uptake. Hazenite's constituent sodium (Na) makes it a potentially useful soil amendment for forage grasses or natrophilic crops such as sugar beet. Its component Mg would also be desirable in forage grasses to pre-empt ruminant hypomagnesemia or in crops with a relatively high Mg demand, for example, maize. Furthermore, hazenite represents a good alternative to KCl for chlorophobic crops such as potatoes. However, given its unusual ratio of Mg, P, and K, the ideal application of hazenite would probably be in combination with other fertilisers. [ABSTRACT FROM AUTHOR]

Boron (B) fertilizers are essential for global crop production. Sustainable B use demands a higher efficiency of B fertilizers through controlled B release and an enhanced B recycling from secondary sources, e.g. B-impregnated cellulose fiber insulation (CFI) waste. In this study, thermochemical treatments based on combustion and pyrolysis were investigated for processing CFI waste into a slow-release B fertilizer. Hot-water extractions of obtained materials confirmed that slow-release properties were achieved, and material characterization with XRD, FTIR and 11B-NMR showed that these were largely the result of formation of sparingly soluble Ca–B phases. A seedling toxicity test with fodder rape demonstrated the benefit of this slow-release B in comparison with conventional soluble B to circumvent toxicity, suggesting potential for B application via seed coatings. Finally, a fertilization trial with fodder rape and poppy seed showed that most slow-release B compounds were equally effective as soluble B at recommended B doses, while slow-release B can still benefit from reduced B leaching losses. [Display omitted] • Thermochemical processing of B-rich cellulose fiber insulation (CFI) was tested. • Obtained combustion and pyrolysis products had slow-release B characteristics. • Slow-release B was largely the result of formation of sparingly-soluble Ca–B phases. • B toxicity to plants could be avoided using treated CFI instead of soluble B. • In a plant fertilization trial, treated CFI was equally effective as soluble B. [ABSTRACT FROM AUTHOR]

Anaerobic digestate is a by-product from the biogas production which can be applied as replacement for mineral fertilizers. But digestate has both phytostimulating and phytotoxic effects on plants. Fertilizers toxicity and phytotoxicity should be measured to preserve the environment. The phytotoxicity of digestate from anaerobic digestion of swine manure was evaluated using several official protocols. Germination toxicity was tested on Pisum sativum L. and Lepidium sativum L., roots elongation on Hordeum vulgare L. and shoots elongation on Lactuca sativa L. To determine digestate growth toxicity, pot experiments were performed on two Solanum lycopersicum L. cvs. Digestate dilutions ranging from 5 to 30 % were tested in the different assays. Standard protocols were applied to non-standard species: Cichorium endivia L. (shoots elongation) and two Capsicum annuum L. cvs (pot trials). Digestate concentrations stimulating germination and early life stages were between 2 and 3 %. Pot trials suggested that during more advanced growth stages, digestate can be applied at 20-30 %. The main finding was that to minimize digestate phytotoxicity, direct contact with germinating seeds or young plants should be avoided. During plants late growth, digestate administration might be increased carefully to minimize salinity and ammonia excess. Soil samples from the pot trials were analysed at the starting, mid- and final experimental stages. Conclusion was that digestate utilization may have also a soil liming effect, increasing electric conductivity, pH and contrasting soil acidification. [ABSTRACT FROM AUTHOR]

The 'phosphorus problem' has recently received strong interest with two distinct strands of importance. The first is that too much phosphorus (P) is entering into waste water, creating a significant economic and ecological problem. Secondly, while agricultural demand for phosphate fertilizer is increasing to maintain crop yields, rock phosphate reserves are rapidly declining. Unravelling the mechanisms by which plants sense, respond to, and acquire phosphate can address both problems, allowing the development of crop plants that are more efficient at acquiring and using limited amounts of phosphate while at the same time improving the potential of plants and other photosynthetic organisms for nutrient recapture and recycling from waste water. In this review, we attempt to synthesize these important but often disparate parts of the debate in a holistic fashion, since solutions to such a complex problem require integrated and multidisciplinary approaches that address both P supply and demand. Rapid progress has been made recently in our understanding of local and systemic signalling mechanisms for phosphate, and of expression and regulation of membrane proteins that take phosphate up from the environment and transport it within the plant. We discuss the current state of understanding of such mechanisms involved in sensing and responding to phosphate stress. We also discuss approaches to improve the P-use efficiency of crop plants and future direction for sustainable use of P, including use of photosynthetic organisms for recapture of P from waste waters. [ABSTRACT FROM AUTHOR]

In a context of climate change and circular economy, it is fundamental to produce animal manure-based fertilizers attractive to farmers who are reluctant to use heterogeneous materials, poorly characterized and with unbalanced nutrient contents, namely N:P ratios different from plant requirements. Hence, the aim of the present study was to assess the potential of different treated and non-treated animal manures to produce tailor-made manure-based fertilizers with known N:P ratios. Seven manures were considered: cattle, caprine and poultry solid manures, two contrasting cattle slurries and two contrasting swine slurries. Slurries were further treated by solid-liquid separation, acidification, and acidification followed by solid-liquid separation. Raw and treated manures were fully characterized to assess the effect of manure type and treatment on their nutrient contents and N:P ratios, to incorporate them in manure-based fertilizers with selected N:P ratio. The present results were essential to support the manure-based fertilizer production and identify which materials could be considered: it appears clearly that the pig slurry with all stages of production and the correspondent liquid fraction cannot be used due to their low nutrients content. It was shown that the solid fractions rich in P and with a N T :N–NH 4 + ratio close to 1 are an excellent material to prepare manure-based fertilizers. Acidification, combined with solid-liquid separation, produced a liquid fraction rich in both N and P and with a N T :P T ratio close to 1, with the additional benefit of a slow N-release material. Some of the manures or sub-products obtained after treatment provided the usual N:P ratio required by farmers and could be used directly as substitutes of mineral fertilizers. Nevertheless, the blending of some of these materials has a stronger potential to the production of specific manure-based fertilizer. • Animal species and manure management influence manure composition and N:P ratio. • Slurry treatment is a good tool to modify N:P ratio of manure. • Combination of raw and/or treated manures allow producing manure based fertilizers. • Manure based fertilizers can have N:P ratio similar to mineral fertilizers.. [ABSTRACT FROM AUTHOR]

Viola x wittrockiana L. is an ornamental plant in high demand in horticulture. It is becoming more critical for greenhouse growers to focus on sustainable production to enhance plant quality while reducing negative environmental impacts. Therefore, assessing the effect of recycled phosphorous (P) and nitrogen (N) sources on the growth of viola could become very useful for producers in terms of sustainability. This experiment analysed the optimal fertiliser composition to grow viola using recovered fertilisers in a greenhouse trial under controlled conditions. Well-rooted viola plugs were grown in a standard peat-based growing medium. Using recycled sources of P and N as struvite and potassium struvite, ammonium sulphate, and ammonium nitrate, 14 fertiliser blends were prepared, tested, and compared with the slow-release commercial fertiliser Osmocote. Plants treated with ammonium nitrate showed healthy growth and optimal plant N concentrations. In contrast, most blends using the recovered ammonium sulphate resulted in an unacceptable increase of ammonium concentrations in the growing medium. The combination of ammonium sulphate and potassium sulphate caused an increase in the electrical conductivity in the growing medium, negatively affecting plant growth. However, blend 13 containing struvite, ammonium sulphate and potassium struvite expressed the best chemical composition with non-significant differences in the biomass from the positive controls, as it reduced the amount of potassium sulphate needed. Our results indicate that fertiliser blends containing P as struvite, N as ammonium nitrate or reduced amount of ammonium sulphate, and K as potassium struvite can substitute the use of mineral fertiliser blends to grow ornamental plant species as viola. [ABSTRACT FROM AUTHOR]

The globally growing demand to produce more food with fewer inputs, less energy, and lower greenhouse gas (GHG) emissions challenges current agricultural practices. Recycled fertilizers made of various side streams and types of biomass have been developed mainly to improve nutrient recycling in food systems. However, the knowledge of the impacts of different recycled fertilizers on GHG emissions and energy use is lacking. There is also a need for developing environmental assessment methods for quantifying the impacts of recycling processes, particularly in terms of choosing reasonable methods for co-product allocation. The aims of this study were to address the above mentioned research gaps by i) assessing energy use and GHG emissions of various recycled fertilizers, ii) comparing the recycled fertilizers with mineral fertilizers, and iii) comparing the impacts of using different co-product allocation methods for the recycled fertilizers. Attributional Life Cycle Assessment (LCA) was used for estimating energy use and GHG emissions of recycled fertilizers, including ammonium sulfate, biogas digestate, and meat and bone meal, using kg of nitrogen in the fertilizers as a functional unit. In addition, the energy use and GHG emissions of oat production when using the recycled and mineral fertilizers were quantified. The data were obtained from field experiments, LCA databases, published literature, and fertilizer companies. The life-cycle energy consumption and GHG emissions of recycled fertilizers were found to be lower than that of mineral fertilizer, but also differences between recycled fertilizer products were notable. The biggest differences between fertilizers occurred in manufacturing and transportation. However, this conclusion is highly sensitive to several decisions, such as data sources and LCA methods used. Handling the raw materials of recycled fertilizers as by-products instead of residues adds burdens from primary production to fertilizers. Also handling the materials as waste increases the impacts due to burdens from the recycling process. Since the raw materials of fertilizers have only little economic value, applying economic allocation results to significantly lower impacts than mass allocation. Consequential LCA studies would be needed to improve the understanding of the wider impacts of recycled fertilizers, e.g. considering the benefits of avoided waste management processes. • No statistically significant differences in yields between the fertilizers. • Lower energy use and emissions with recycled than mineral fertilizers. • Notable differences in emissions and energy use between recycled fertilizers. • Effect of data sources and allocation methods were considerable. [ABSTRACT FROM AUTHOR]

Sewage sludge is a valuable source of nutrients and organic matter, which are beneficial for plant growth. The use of sewage sludge for agricultural purposes can be limited by the potential content of heavy metals and toxic organic compounds that pose a threat to the environment. The characterisation of sewage sludges from 11 Polish wastewater treatment plants (WWTPs) in terms of their fertilizing properties and heavy metal contents are presented in the study. Based on the chemical composition of sewage sludge from the WWTP in Żywiec, the compositions of organo-mineral fertilizers dedicated for rapeseed crop was developed. Alternative raw materials such as poultry litter ash and biomass ash were considered as components for fertilizer production. The production process of organo-mineral fertilizers included mixing sewage sludge with poultry litter ash/biomass ash and mineral fertilizers and granulation with mineral acids. The final products contained 24–34% of total NPK and fulfilled the requirements regarding heavy metal content according to Polish legislation. Using sewage sludge for fertilizer production is a promising solution for sewage sludge management, allowing the recycling of 82–140 tonnes of phosphorus (as P 2 O 5) and 42–73 tonnes of nitrogen (N) annually in the WWTP in Żywiec. • Sewage sludge from Polish WWTPs were analysed. • Fertilizers with high NPK content based on 48–52% of waste were produced • Final products fulfil the requirements related to heavy metal content. [ABSTRACT FROM AUTHOR]