Alternative Phosphorus Sources Research Articles

Sewage sludge compost as an alternative source of phosphorus to rye in acidic sandy soil

Today, the use of chemical fertilisers is significantly determined by their production and purchase costs, which are high. In contrast, phosphorus (P) is present in sewage sludge in a form that is easy for plants to absorb. Good quality sewage sludge compost (SSC) could contain a high quantity of P, together with other macro- and microelements and organic matter. The effect of regular SSC application on soil characteristics as well as plant parameters has been studied since 2003 in Nyíregyháza in a small plot experiment. Focusing on the P in the soil-plant system, our hypothesis was that SSC covers plants’ P demand through enhancing soil P content and its plant availability in the acidic sandy soil. The effect of the SSC was examined at the doses of 0, 9, 18, and 27 t ha-1 on rye as a test crop. Some soil chemical parameters (pH, soil organic matter - SOM, ammonium lactate (AL) extractable P2O5), and the relationship between plant development (green weight, shoot length), physiological parameters (SPAD index), plant shoot P content, and soil available P content were studied. The obtained data indicated that the SOM content, pH, and available P content of the treated plots increased as a result of the long-term applied SSC compared to the control. Measurement of the relative chlorophyll content showed a strong correlation with the available P content of the soil, but surprisingly less correlation with shoot P content was found. The results of plant biomass and soil P content proved that SSC could be used as a low-cost and good source of P for plants.

The Impact of Suspension Fertilizers Based on Waste Phosphorus Salts from Polyol Production on the Yield of Maize Intended for Green Fodder

The need to import phosphorus raw materials for fertilizer purposes in Europe as well as the need to manage increasing amounts of waste contributed to the search for alternative sources of phosphorus. One of these is waste sodium–potassium phosphate from the production of polyols. Additionally, a current problem is providing an adequate amount of food, where fertilizers play the main role. Due to the increase in meat consumption, the attractiveness of growing corn for feed is increasing due to its high yield potential and rich composition. The article presents the impact of suspension fertilizers based on waste from the production of polyols on the yield of corn intended for green fodder. In a 3-year field study, the effects of a waste phosphorus source were compared with a commercial granulated phosphorus fertilizer—fosdar. In addition, the suspension fertilizers were assessed according to their composition by testing fertilizers containing only basic nutrients (NPK) and ones enriched with secondary ingredients (S and Mg) and microelements (Zn, Mn and B). The research confirmed the effectiveness of the tested suspension fertilizers. Although the yield obtained was lower than in the case of fosdar fertilization, it still remained at a high level of over 70 t∙ha−1 of fresh yield.

Evaluating the agronomic efficiency of alternative phosphorus sources applied in Brazilian tropical soils

Understanding the efficacy of alternative phosphorus (P) sources in tropical soils is crucial for sustainable farming, addressing resource constraints, mitigating environmental impact, improving crop productivity, and optimizing soil-specific solutions. While the topic holds great importance, current literature falls short in providing thorough, region-specific studies on the effectiveness of alternative P sources in Brazilian tropical soils for maize cultivation. Our aim was to assess the agronomic efficiency of alternative P sources concerning maize crop (Zea mays L.) attributes, including height, shoot dry weight, stem diameter, and nutrient accumulation, across five Brazilian tropical soils. In greenhouse conditions, we carried out a randomized complete block design, investigating two factors (soil type and P sources), evaluating five tropical soils with varying clay contents and three alternative sources of P, as well as a commercial source and a control group. We evaluated maize crop attributes such as height, dry weight biomass, and nutrient accumulation, P availability and agronomic efficiency. Our results showed that, although triple superphosphate (TSP) exhibited greater values than alternative P sources (precipitated phosphorus 1, precipitated phosphorus 2 and reactive phosphate) for maize crop attributes (e.g., height, stem diameter, shoot dry weight and phosphorus, nitrogen, sulfur, calcium and magnesium accumulation). For instance, PP1 source increased nutrient accumulation for phosphorus (P), nitrogen (N), and sulfur (S) by 37.05% and 75.98% (P), 34.39% and 72.07% (N), and 41.94% and 72.69% (S) in comparison to PP2 and RP, respectively. Additionally, PP1 substantially increased P availability in soils with high clay contents 15 days after planting (DAP), showing increases of 61.90%, 99.04%, and 38.09% greater than PP2, RP, and TSP. For Ca and Mg accumulation, the highest values were found in the COxisol2 soil when PP2 was applied, Ca = 44.31% and 69.48%; and Mg = 46.23 and 75.79%, greater than PP1 and RP, respectively. Finally, the highest values for relative agronomic efficiency were observed in COxisol2 when PP1 was applied. The precipitated phosphate sources (PP1 and PP2) exhibited a similar behavior to that of the commercial source (TSP), suggesting their potential use to reduce reliance on TSP fertilization, especially in soils with low clay contents. This study emphasized strategies for soil P management, aimed at assisting farmers in enhancing maize crop productivity while simultaneously addressing the effectiveness of alternative P sources of reduced costs.

Phosphorus recovery from calcium phosphate enriched activated sludge

This study explores the potential of activated sludge from wastewater treatment plants (WWTP) as an alternative source of phosphorus, vital for fertilisers and other products, compared to large-scale phosphorus mining. The research focuses on analysing optimal conditions and the impact of activated sludge characteristics on phosphorus release from calcium phosphate compounds, particularly hydroxyapatite (HAP). Using batch reactor experiments with varying pH and contact time, the results reveal that lower pH values, particularly pH 4, result in higher phosphorus release. The study also finds that calcium, the predominant metal content in activated sludge, plays a vital role in bonding with phosphates and forming new compounds, effectively reducing phosphorus concentration in the solution. Moreover, the VSS/TSS value in the activated sludge has no significant effect on phosphorus release, but interventions occur at high VSS/TSS values. The reaction rate coefficient is calculated at 0.00033/min at pH 4. Overall, this research emphasises the potential of phosphorus recovery from calcium phosphate enriched activated sludge and underscores the importance of optimising pH and considering activated sludge characteristics for efficient phosphorus release.

Methylphosphonate Is Utilized by Commensal Microbiota of Macroalgae in the Oligotrophic Sargasso Sea

AbstractThe essential nutrient phosphorus is biologically scarce in the Sargasso Sea, yet the pelagic macroalgae Sargassum, for which this area of the North Atlantic Ocean is named, thrives. We tested the hypothesis that Sargassum holobionts utilize methylphosphonate (MPn) as an alternative source of phosphorus, finding lysis liberated phosphonate‐derived methane. The observed activity occurred at concentrations as low as 35 nM MPn and was inhibited by antibiotics, implicating bacterial epibionts of the holobiont capable of MPn lysis at realistic environmental concentrations. Dark incubations resulted in diminished methane production, consistent with commensalism between microbe and host. A survey of macroalgal species inhabiting the Sargasso Sea found ubiquitous capacity for MPn lysis; such capacity was absent in species inhabiting phosphorus‐replete waters of the California Current, pointing to phosphorous limitation as a selective pressure. These results suggest that bacterial epibionts of algal communities acquire phosphorus from phosphonates while simultaneously serving as a source of atmospheric methane.

EU-compliant wastewater recycled phosphorus: How much national cereal demand can it meet?

Finding alternative phosphorus sources is imperative to address negative environmental and societal impacts caused by its current inefficient use. However, the direct use of phosphorus in sewage sludge in agriculture is controversial. This paper uses Denmark, Germany, and Spain as case examples to assess relevant legislation and boundary conditions in agricultural production to identify opportunities and barriers for the utilisation of recycled phosphorus from wastewater in agriculture on a regional level. Only five out of 22 phosphorus recycling technologies considered were in full compliance with legislation across all three countries, and these five were then assessed for their potential to supply phosphorus to major crops within countries. We considered the application of technologies across four scenarios: 1) struvite; 2) vivianite as iron supply; 3) vivianite for calcium phosphate precipitation; and 4) ashes for calcium phosphate precipitation. The most suitable scenario identified for Denmark was vivianite for calcium phosphate precipitation, whereas in Spain vivianite as iron supply was identified as most suitable, and ashes for calcium phosphate in Germany. We found that in 2018, the potential phosphorus supply from recycling technologies was on average 0.38, 0.29 and 0.05 kg of phosphorus per capita for Danish, German, and Spanish regions. These quantities could meet 9.1, 21.7, and 10.0 percent of the phosphorus required to produce major cereals in each country (specifically wheat, barley, and rye). Given current legal constraints, wastewater treatment plant connections and agronomic context, the potential contribution of recycled phosphorus is non-negligible in many sub-national regions. Still, to access the full potential of phosphorus circularity clear product specifications and transport and logistics among regions will be necessary.

Characteristic of phosphorus rich compounds in the incinerated sewage sludge ashes: a case for sustainable waste management

Growing concern over mineral resources supply forces us to search for alternative sources of Phosphorus. The possibility to recover phosphorus from incinerated sewage sludge ashes appears to be an important aspect in anthropogenic phosphorus cycle and sustainable economy. To make phosphorus recovery efficient it is important to learn the chemical and mineral composition of ash and phosphorus speciation. The phosphorus content in the ash was over 7%, what corresponds to medium rich phosphorus ores. The main phosphorus rich mineral phases were phosphate minerals. The most widespread was tri-calcium phosphate Whitlockite with various Fe, Mg and Ca proportions. In minority Fe–PO4 and Mg–PO4 were detected. Whitlockite commonly overgrown with hematite, influences negatively mineral solubility and thus recovery potential and indicates low bioavailability of phosphorus. Considerable amount of phosphorus was found in the low crystalline matrix where phosphorus content was around 10 wt% however low crystallinity and dispersed phosphorus also does not strengthen the potential to recover this element.

An Evaluation of Phosphogypsum (PG) -Derived Nanohydroxyapatite (HAP) Synthesis Methods and Waste Management as a Phosphorus Source in the Agricultural Industry

As a raw material, phosphorus availability in agriculture has been a critical concern in terms of phosphate rock consumption related to a price-dependent supply-demand chain. Novel approaches have been proposed for alternative phosphorus sources in agricultural applications. Although nano-hydroxyapatite (nHA) is a commonly used bioceramic material, its utilization as an alternative phosphorus fertilizer is an emerging field. Phosphogypsum (PG), a by-product of wet process phosphoric acid production, is a promising raw material for nHA production. With an approximate 300 Mton annual accumulation rate of PG puts pressure on the research for introducing alternative strategies for the resource utilization of legacy PG piles in an environment-friendly and cost-efficient manner. Valorization of PG as the calcium and phosphorus precursor in nHA production would both provide an efficient waste management strategy and low-cost raw material. This study gives a brief review of the various synthesis routes on PG-derived nHA and criticizes nHA utilization as a phosphorus fertilizer.

Synthetic nano-hydroxyapatite as an alternative phosphorus source for wheat grown under field conditions

The aim of this study was to investigate the effects of nano-hydroxyapatite (nHAP) over conventional phosphorus fertilizer in terms of phosphorus nutrition and other nutrients through which it enhances the growth of wheat plants. The experiment was carried out with wheat plants under real field conditions for two consecutive years. Under laboratory conditions, nHAP was synthesized and characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopes (SEM), and elemental dispersive X-rays (EDX). The substance we synthesized according to the characterization tests mentioned here is nano-hydroxyapatite. The application of nHAP was carried out at decreasing rates (80, 60, 40 kg P2O5 ha−1) before sowing, and their effects were compared with 80 kg P2O5 ha−1 diammonium phosphate (DAP) as a reference treatment. Phosphorus and other mineral element concentrations were determined in all plant samples taken at the beginning of the booting stage. In addition, grain samples were taken at harvest. In the nHAP treatment, the plants’ phosphorus, nitrogen and potassium concentrations increased by approximately 25%, 17% and 10%, respectively. This was compared to the DAP treatment. The concentrations of iron and zinc in grain also increased by 46% and 15%, respectively. These increases in grains are particularly noteworthy for biofortification studies. In conclusion, nHAP can be an alternative to conventional fertilizers by reducing phosphorus consumption. However, more studies are required on different plants and long-term field studies regarding the uptake, translocation and interactions of nHAP with other elements.

A dataset of global ocean alkaline phosphatase activity

Utilisation of dissolved organic phosphorus (DOP) by marine microbes as an alternative phosphorus (P) source when phosphate is scarce can help sustain non-Redfieldian carbon:nitrogen:phosphorus ratios and efficient ocean carbon export. However, global spatial patterns and rates of microbial DOP utilisation are poorly investigated. Alkaline phosphatase (AP) is an important enzyme group that facilitates the remineralisation of DOP to phosphate and thus its activity is a good proxy for DOP-utilisation, particularly in P-stressed regions. We present a Global Alkaline Phosphatase Activity Dataset (GAPAD) with 4083 measurements collected from 79 published manuscripts and one database. Measurements are organised into four groups based on substrate and further subdivided into seven size fractions based on filtration pore size. The dataset is globally distributed and covers major oceanic regions, with most measurements collected in the upper 20 m of low-latitude oceanic regions during summer since 1997. This dataset can help support future studies assessing global ocean P supply from DOP utilisation and provide a useful data reference for both field investigations and modelling activities.

Soil phosphorus availability and fractionation in response to different phosphorus sources in alkaline and acid soils: a short-term incubation study

Using agricultural wastes as an alternative phosphorus (P) source has great prospects to improve soil P status. A 70-day incubation experiment was carried out to investigate the effects of superphosphate (SSP), poultry manure (PM), cattle manure (CM), maize straw (MS), and cattle bone meal (CB) with the same total P input on soil P availability and fractions in typical acidic (red soil) and alkaline (fluvo-aquic soil) soils. The results showed that in both fluvo-aquic and red soils, CM out-performed other P sources in improving soil P availability. Changes in soil Olsen-P (ΔOlsen-P) were greater in fluvo-aquic soils with SSP, PM and CM additions than in red soils. Among the different P sources used, only CM has increased the labile soil P fractions to levels similar to that with SSP. Compared with SSP, more monoester P and inositol hexakisphosphate were detected in soils amended with PM and CM. A structural equation model (SEM) analysis suggested that soil pH had a direct positive effect on the labile P fractions in the acidic red soil amended with different P sources. In summary, CM is a superior P source for increasing plant available soil P, with considerable practical implications for P recycling.

Contrasting Roles of DOP as a Source of Phosphorus and Energy for Marine Diazotrophs

The oceanic dissolved organic phosphorus (DOP) pool is mainly composed of P-esters and, to a lesser extent, equally abundant phosphonate and P-anhydride molecules. In phosphate-limited ocean regions, diazotrophs are thought to rely on DOP compounds as an alternative source of phosphorus (P). While both P-esters and phosphonates effectively promote dinitrogen (N2) fixation, the role of P-anhydrides for diazotrophs is unknown. Here we explore the effect of P-anhydrides on N2 fixation at two stations with contrasting biogeochemical conditions: one located in the Tonga trench volcanic arc region (“volcano,” with low phosphate and high iron concentrations), and the other in the South Pacific Gyre (“gyre,” with moderate phosphate and low iron). We incubated surface seawater with AMP (P-ester), ATP (P-ester and P-anhydride), or 3polyP (P-anhydride) and determined cell-specific N2 fixation rates, nifH gene abundance, and transcription in Crocosphaera and Trichodesmium. Trichodesmium did not respond to any DOP compounds added, suggesting that they were not P-limited at the volcano station and were outcompeted by the low iron conditions at the gyre station. Conversely, Crocosphaera were numerous at both stations and their specific N2 fixation rates were stimulated by AMP at the volcano station and slightly by 3polyP at both stations. Heterotrophic bacteria responded to ATP and 3polyP additions similarly at both stations, despite the contrasting phosphate and iron availability. The use of 3polyP by Crocosphaera and heterotrophic bacteria at both low and moderate phosphate concentrations suggests that this compound, in addition to being a source of P, can be used to acquire energy for which both groups compete. P-anhydrides may thus leverage energy restrictions to diazotrophs in the future stratified and nutrient-impoverished ocean.

PSVII-4 Potential Value of Turkey Litter Ash and Dried Swine Lagoon Sludge as a Phosphorus Source for Growing Pigs

Abstract The objective of this study was to evaluate turkey litter ash (TLA) and dried swine lagoon sludge (SLS) as alternative recycled sources of phosphorus. Analyzed concentrations (as-is basis) of Ca, P, and Na were 8.31, 3.98, and 0.70, respectively for TLA and 5.81, 4.31, and 0.12 for SLS. Fifty-six individually housed pigs (BW of 34.92±0.29 kg) were blocked by initial BW and randomly allocated within block to 1 of 7 treatments. Treatments consisted of a negative control diet (NC; 0.50% Ca and 0.12% available P (40% of requirement), NC plus 0.075% P from either monosodium phosphate (MSP), TLA, or SLS, and NC plus 0.150% P from either MSP, TLA, or SLS. Diets were balanced using MSP, calcium carbonate, salt and fine sand to maintain all other dietary ingredients at equal levels. A constant Ca:P ratio of 1.40 was maintained. Pigs were limit-fed individually at 3x197 kcal ME/kg BW0.60 based on the BW for each block. Final body weight tended (P = 0.085) to increase linearly with increasing P from MSP, but not from TLA (P = 0.271) or SLS (P = 0.367). Overall ADG linearly increased (P = 0.022) with increasing P from MSP (761, 814, and 839 g/d), tended to increase (P = 0.072) with P from TLA (761, 786, and 810 g/d), and was not impacted (P = 0.164) by P from SLS (761, 797, and 814 g/d). Kidney weight relative to BW linearly decreased (P = 0.041) with increasing MSP, but liver, heart, and spleen weights were not affected (P > 0.07). Serum P linearly increased (P = 0.007) with increasing MSP (8.76, 9.08, and 10.00 mg/dL), but not with TLA (P = 0.250; 8.76, 8.52, and 9.28 mg/dL) or SLS (P = 0.143; 8.76, 9.18, and 9.41 mg/dL). Serum Ca concentrations linearly decreased (P < 0.033) with increasing MSP, TLA, and SLS. Data suggest that the value of TLA and SLS as a P source is limited compared with MSP.

Utilização de resíduo de sangue como fonte alternativa de fósforo no cultivo de girassol (Helianthus annuus L.)

ABSTRACT The aim of this work was to increase the aerial part, biometry, and yield of achenes from sunflower plants on the effect of increasing doses of blood residue, as an alternative source of phosphorus (P), in a clayey-textured red Oxisol. The experimental design used was randomized blocks, with six treatments and four replications. The treatments consisted of five doses of blood residue (0, 6, 12, 24 and 48m3 ha-1) and a control treatment that received phosphate chemical fertilization, 80kg ha-1 of P2O5. The increasing doses of blood residue and chemical fertilization do not show disproportionality for P concentration in soil, leaf, plant height (PH), stem diameter (SD), chapter diameter (CD) and achene production. The analysis of the principal component (PC) revealed that the first PC presents the greatest accumulated variation (74%). Based on the first PC, the dose of 12m-3 ha-1 has greater influence for PH, SC, and CD. Due to the greater influence on the biometric characteristics of sunflower plants, the blood residue (12m-3 ha-1 = 98.4kg P ha-1), can be used as an alternative source of phosphorus for the cultivation of sunflower in clayey oxisols.

Effect of Various Rates of P from Alternative and Traditional Sources on Butterhead Lettuce (Lactuca sativa L.) Grown on Peat Substrate

Previous research indicated the potential use of struvite (STR) as an alternative source of phosphorus (P) in crop production. A greenhouse experiment was conducted to evaluate the effect of STR and triple superphosphate (TSP) on the growth and chemical composition of butterhead lettuce grown on peat substrate over a three-month period (May–July). Both alternative (STR) and conventional (TSP) fertilizers were applied at three rates: (1) recommended rate based on the elemental content of substrate and crop nutritional need; (2) reduced rate (50% lower than recommended); and (3) increased rate (50% higher than recommended). Unfertilized (control) plants were also grown in the pot experiment. As expected, fertilizer application tended to increase the content of heavy metals in the substrate. Thus, an increase in Zn, Pb, and Cu content in peat substrate was found following STR amendments. However, compared with unfertilized plants, the applied rates of the STR and TSP fertilizers did not increase the content of Cd and Cu in the plant leaf, while Hg content was below the detection limit. In addition, Zn content in the plant leaf significantly decreased following STR and TSP applications. In comparison to unfertilized plants, both alternative and conventional fertilizers increased the content of P and nitrate nitrogen (N-NO3−) in the plant leaf while their effect on Mg content was negligible. The increased rate of STR was the best fertilizer treatment because it produced the largest number of leaves, which were also characterized by the highest P content. Our findings showed that STR was an effective source of P in butterhead lettuce cultivation without adverse effects on heavy metal accumulation.

Tanzanian Bat Guano as an Alternative Source of Phosphorus for Organic Rice Production

Many tropical and subtropical soils are low in phosphorus. This is partly because of excessive weathering, high phosphorous (P) fixation rates, and low P levels in soil parent materials. Continuous removal of P from soils by crops, coupled with limited application of P fertilizers, is also among the contributing factors for low P in soils. Phosphorus is among the most limiting macronutrient in rice (Oryza sativa L.) production. This study was conducted to evaluate the suitability of bat guano collected from Kisarawe (BGK-A and BGK-B) and Sukumawera caves (BGS) in Tanzania. The screen-house experiment at the Sokoine University of Agriculture was designed as a 4 × 6 factorial experiment conducted as a randomized complete block design (RCBD). Guano and triple superphosphate (TSP) were used as standard fertilizer at six P application rates. The yield of rice in response to applied TSP was comparable to applied guano but in the order TSP > BGK-A > BGS > BGK-B. All parameters increased with an increase in applied amounts of P from guano and TSP. Besides this study revealed the significant (P = .05) interaction between P sources and P rates on plant height (PH), micronutrient concentration and dry matter (DM). The study showed the correlation between grain yield (GY) and other crop components of dry matter (DM), the number of panicles (NP), Panicle height (PAH), plant height (PH) and number of tillers (NT). A significant and positive correlation was found for the GY-DM (r = 0.58, P = .05), GY-PAH (r = 0.65, P < .001), and GY-NT (r = 0.420, P = 0.1). But strong positive correlation was found between GY-PH (r = 0.76, P < .001) and GY-NP (r = 0.84, P < .001). It was concluded that studied guanos can be used as an alternative source of P, especially for smallholder farmers.

Enhanced bioavailability of phosphorus in sewage sludge through pyrolysis aided by calcined clam shell powder

Phosphorus is an indispensable element, while the existing phosphate rock resources are not enough to maintain the long-term demand of modern agricultural development. To ensure the sustainability of economic and social, it is necessary and urgent to seek the alternative phosphorus source of phosphate rock. In this study, calcined clam shell powder (CSP) was firstly used as a modifier and mixed with sewage sludge (SS) for co-pyrolysis to obtain sludge-derived pyrochars containing a large amount of bioavailable phosphorus. The effect of different temperatures (500, 600, 700, 800 °C) and dosages (0%, 10%, 20%, 30%) on the change in the form of phosphorus during the pyrolysis process were investigated. With the increase of temperature and the addition of CSP, the orthophosphate (Ortho-P) increased from 63.69% in the original SS to nearly 100%. Furthermore, the main phase of inorganic phosphorus (IP) changed, mainly in the form of apatite phosphorus (hydroxyapatite increased from 8.88% to 35.97%), and the concentration of easy-to-lose phosphorus reduced to 0.11 mg/g. After co-pyrolysis of SS with CSP, the passivation situation of heavy metals (HMs), such as Zn, Mn, Cr, Cu, Cd and Pb was significantly improved, thus reducing the potential environmental risk. The planting experiment proved that the sludge-derived pyrochars obtained by adding 20% CSP at 800 °C promoted the germination of seeds and the growth of seedlings. Consequently, the product of SS co-pyrolysis with CSP could be used as an excellently bioavailable and environmentally friendly phosphate fertilizer for agricultural production.

The Nutritional quality of the white worm (Agathymus remingtoni Stallings & Turner Lepidoptera: Hesperiidae) of maguey lechuguilla (Agave lechuguilla Torrey)

Objective: to evaluate the nutritional quality of white worm larvae (Agathymus remingtoni) of the maguey lechuguilla plant (Agave lechuguilla).Design/Methodology/Approach: samples of A. remingtoni larvae were collected from the stems and leaves of wild maguey lechuguilla that grows in the hills of the community of San Francisco, Municipality of Epazoyucan, in the state of Hidalgo, Mexico. Proximate analysis was performed and the calcium and phosphorus contents were determined inlarvae samples.Results: larvae of A. remingtoni had a protein content of 33.69% on a dry basis, and 12.05% on a wet basis. Other results obtained were as follows: ethereal extract 15.97%, dry matter 35.76%, moisture 64.24%, ash 0.82%, crude fiber 0.85%, free nitrogen extract 6.07, calcium 0.40%, and phosphorus 0.56%.Limitations/Implications: During: in the literature review carried out, no reports were found on the nutritional quality of the white worm (Agathymus remingtoni) of maguey lechuguilla (Agave lechuguilla).Findings/Conclusions: Agathymus remingtoni larvae have excellent nutritional content, which makes them an alternative source of protein, fat, calcium, and phosphorus for human consumption and livestock feed.

Phosphorus recovery from septage treatment plant sludge by struvite formation with alkaline hydrolysis as pre-treatment

Insufficiency of phosphorus due to the limited availability of phosphate rocks is predicted within the next decades. Phosphorus recovery from wastewater sludge was found to be one of the possible alternative sources of phosphorus. Moreover, stringent effluent standards, including that of phosphorus levels, have been newly implemented in the Philippines. Due to these factors, phosphorus recovery from wastewater in Philippine settings was deemed as an important topic to be further studied. In this paper, the feasibility of recovering phosphorus from septage sludge in Metro Manila by the precipitation of struvite crystals was studied. Septage sludge is seen as one of the potential sources and was characterized in terms of the concentration of Mg2+, Ca2+, NH4+ and PO4-3 ions. In the lab-scale experiments conducted, alkaline hydrolysis using sodium hydroxide was performed as a sludge pretreatment before the precipitation proper. Alkaline hydrolysis was done to release the remaining PO4-3 ions from the solids present in the sludge, thereby promoting precipitation after hydrolysis without the need for additional phosphate source. Furthermore, alkaline hydrolysis can effectively release phosphorus without inducing the dissolution of interfering ions such as Ca2+ and other heavy metals. Results show that PO4-3 ions increased by 267.37 mg/L and the total amount of phosphate ions increased from 17.05% to 46.88%, showing the effectivity of the hydrolysis. For the precipitation of struvite, three parameters were controlled: pH, residence time, and Mg:P ratio. After precipitation, the phosphorus recovery efficiency for the runs were each evaluated and analyzed in order to determine the effects of the parameters on phosphorus recovery. The precipitate of the run with the highest phosphorus recovery obtained was then evaluated using XRD analysis. It was found that the sample with the highest phosphorus recovery is 53.12%, which was achieved at pH 9, a residence time of 1 hour, and an Mg:P ratio of 1.5:1. Therefore, it can be concluded that precipitation subjected at pH 9 has the highest potential for higher phosphorus recovery. Further, the residence time has a minimal effect on phosphorus recovery and higher phosphorus recovery can be achieved at a higher Mg:P ratio with increasing potential for struvite recovery.

Consumption, digestibility and cattle condition according to forage composition and quality in maize-cattle from conservation-based agroecosystems

The cereal-cattle conservation-based agroecosystems in neotropical savannas are based on the introduction of a forage of better quality than that of the native pasture. This forage acts as a soil protective coverage under non-tillage managements and like green manure to the maize culture. In order to evaluate how the consumption by bovine, digestibility and animal condition changes in these agroecosystems, we study, during a grazing cycle (110 days in the dry season), the following: total aerial biomass (TAB), green leaf biomass (GLB), fiber content of the leaves (lignin, ADF and NDF), botanic composition of the cattle excreta by microhistological analysis, N-NH3 content in the cattle rumen and the presence of urea in blood. The introduced species were Brachiaria dyctioneura grass (Bd) and Centrosema macrocarpum legume (Cm), both perennials, associated to maize for 4 years of non-tillage management and alternative phosphorus sources. During the grazing period, the level of N-NH3 in the rumen was 12.1 mg/L and 16.6 mg/L in the animals of the agroecosystems Bd and Cm, respectively. In the case of urea in blood, the concentration was significantly higher under legume (24.6 mg/dL) compared to the grass (9.7 mg/dL). Daily weight gain favored Bd (0.68 kg/d) > Cm (0.29 kg/d) > NS (−0.006 kg/d). Body condition was significantly higher in introduced pastures compared to NS. At this time, the microhistological studies of the cattle excreta showed a significant variation of the Bd and Cm consumption, selecting as second option Andropogon gayanus and maize (Zea mays) residues in a higher percentage, depending of the dominant cover crop. Thus, the digestibility was related to the appearance frequency of these species (p < 0.01). The GLB of Cm decreased significantly during the grazing. At the same time, the lignin content increased in both cover crops, influencing the consumption, digestibility and daily weight gain (DWG) of the cattle in the agroecosystems, compared to savanna ecosystem.