Recycling sludge on cropland as fertilizer – advantages and risks

Background: Digested sludge is a good source of plant nutrients. However, depending on the feedstock, it might contain heavy metals, metalloids, organic compounds, pathogens, and pharmaceuticals, which can cause adverse effects on crop growth and contaminate the groundwater, soil, and food chain. Scope: The aim of this review is to focus on the potential risks of inorganic and organic contaminants to plant growth, soil, groundwater, and consequently the food chain and environment related to the utilization of digested sludge as a fertilizer on cropland. Conclusions: Inorganic compounds, such as metals and metalloids, in sludge can occasionally cause reductions in soil microbial biomass. In general, the uptake of metals and organic contaminants does not appear to cause a significant hazard to the plants and the concentrations do not surpass the maximum values allowed in soil. Organic compounds, harmful for human health or the environment, are to a large extent decomposed or volatilized from the land treated with sludge, which decreases their leaching into the environment. Many of the organic compounds are lipophilic and can be bound to soil organic matter. In conclusion, the application of sludge on cropland might be a sustainable management practice; however, further investigations are needed to determine the accumulation and persistence of possible hazardous emerging chemicals and pathogens in the environment and formation of harmful intermediate reaction of inorganic and organic compound products.Peer reviewe

Towards sustainable intensification of feedstock production with nutrient cycling

Sludge contains valuable nutrient sources such as N (3.1%), P (2.6%) and micronutrients as well as organic matter. Nevertheless, depending on the feedstock materials, sludge contains heavy metals and metalloids that can be partly taken up by plants. The continuing need for disposal of sludge is a challenge due to the increasing world population. Experiments were conducted at glasshouse and field at Viikki Experimental Farm, University of Helsinki, Finland, during 2008-2012, in order to study the suitability of sewage sludge and digested sludge as nutrient sources for bioenergy crops. Leaf N content, leaf area index, leaf area formation, net photosynthesis, water relations and biomass accumulation were determined. In addition, the effects of sludge on feedstock quality in terms of macronutrient and trace element content in crop biomass, C:N mass ratio and ash content as well as higher heating value and gross energy yield were studied. Further attention was paid to the role of mycorrhizal colonization in the improvement of N and P availability to the host plants. In the first glasshouse experiment, sewage sludge was applied in a high dose (1 kg sludge per 5 kg soil), a low dose (50% of high), or a low dose premixed with an equal mass of peat. In the subsequent glasshouse and field experiments, treatments for each crop species were standardized on the basis of total N, where 100% represented 120 kg ha-1 of N for maize, 90 kg ha-1 for oilseed rape, and 60 kg ha-1 for fibre hemp and ryegrass. The second glasshouse experiment comprised five treatments (soil + synthetic fertilizer, soil + sewage sludge, soil + digested sludge, sand + synthetic fertilizer, sand + sewage sludge), while the field experiments comprised six treatments (100% synthetic fertilizer, 50% + 50% synthetic fertilizer in a split application, 50% synthetic fertilizer + 50% sewage sludge, 100% sewage sludge, 150% sewage sludge and 100% digested sludge). Each experiment was arranged in a randomized complete block design with 3-6 replicates. Sewage sludge-peat mixtures significantly increased leaf area, and improved net photosynthesis of maize and hemp. Sewage sludge resulted in higher biomass accumulation in maize and hemp at 90 and 150 DAS than in the other treatments in the field study, while biomass accumulation of oilseed rape was equally high following applications of both sewage sludge and synthetic fertilizer throughout most of sampling dates. Sewage sludge application resulted in more numerous fungal spores in soil and increased root colonization in comparison to synthetic fertilizer. The highest root colonization rate was in maize, followed by hemp. Sewage sludge and synthetic fertilizer applications resulted in higher N uptake in maize, hemp and oilseed rape than in the other treatments. However, sewage sludge resulted in the highest P uptake in maize and hemp, while high sewage sludge and digested sludge resulted in the highest P uptake in oilseed rape. Also, sewage sludge resulted in the highest accumulation of many heavy metals and metalloids in plant biomass. Sewage sludge application provided the optimum feedstock quality in maize, hemp and oilseed rape, in terms of reducing the content of alkali metals, Cl and ash, while sewage sludge and synthetic fertilizer applications gave the optimum C:N ratio for methane production in maize and hemp. Thus, recycling nutrients from sludge provides an opportunity to minimize the use of synthetic fertilizer with its high consumption of fossil fuel, and improves sustainability in agriculture. Sewage sludge improved plant growth, mycorrhizal colonization of roots and plant uptake of N and P, and feedstock quality. However, the potential losses of P can be a serious environmental issue in long-term sludge use, and the high content of Cu in sludge makes it the heavy metal of greatest concern.Yhdyskunta jätteiden ja vedenpuhdistuslietteiden biokaasuprosessissa jäljelle jäävä hajoamaton aines, mädäte, sisältää arvokkaita ravinteita kuten typpeä (3,1 %), fosforia (2,6 %) ja hivenaineita, sekä orgaanista ainesta. Näiden ravinteiden kierrätystä tulisi lisätä, jotta voitaisiin vastata kasvavaan kasviperäisten raaka-aineiden tarpeeseen maailmanlaajuisesti. Mädätteet saattavat kuitenkin sisältää epäpuhtauksina esimerkiksi raskasmetalleja ja metalloideja, jotka voivat kulkeutua kasveihin. Tutkimus toteutettiin Helsingin yliopistossa ja Viikin opetus- ja tutkimustilalla vuosina 2008 2012, kasvihuone- ja peltokokeina. Työssä tutkittiin mädätteiden soveltuvuutta bioenergiakasvien (maissi, hamppu ja lupiini) lannoitukseen. Viljelykokeissa selvitettiin mädätteiden vaikutusta kasvien lehtialan ja biomassan muodostumiseen, yhteyttämistehokkuuteen ja vesitalouteen. Lisäksi kasveista määritettiin raaka-aineen laadun kannalta oleellisten alkuaineiden, tuhkan ja energian pitoisuudet sekä lämpöarvo. Erityistä huomiota kiinnitettiin myös sienijuuren esiintymiseen kasvien juuristossa ja sen vaikutusta kasvien typen ja fosforin ottoon. Ensimmäisessä astiakokeessa mädätettä sekoitettiin peltomaahan (liete:maa 1:5; 0,5:5; sekoitettuna turpeeseen 0,5:5). Myöhemmissä astiakokeissa ja kenttäkokeissa mädätettä lisättiin maahan sen sisältämän typen määrän mukaisesti, vastaamaan kasvien typentarvetta: N 100% vastasi 120 kg ha- 1 N maissilla , 90 kg ha- 1 rapsilla ja 60 kg ha - 1 hampulla ja raiheinällä. Kokeissa verrattiin mädätteitä ja väkilannoitteita (väkilannoitetypen määrä vastasi mädätteiden sisältämän typen määrää) sekä näiden yhdistelmiä. Mädätteen ja turpeen seos lisäsi maissin ja hampun lehtialaa ja yhteyttämistehokkuutta huomattavasti, minkä seurauksena myös kasvien biomassa lisääntyi. Sen sijaan rapsin kohdalla vastaavia eroja ei ilmennyt eri mädäte- ja väkilannoitekäsittelyjen välillä. Mädätteet lisäsivät merkitsevästi sieni-itiöiden määrää maassa ja juurten mykorritsa kolonisaatiota väkilannoitekäsittelyihin verrattuna. Mädätteet lisäsivät myös kaikkien kasvien typenottoa sekä maissin ja hampun fosforinottoa verrattuna väkilannoitteisiin. Toisaalta kasvien biomassassa oli eniten raskasmetalleja ja metalloideja mädätekäsittelyjen seurauksena. Mädätteillä lannoitettujen kasvien massan laatu oli kuitenkin bioenergiakäytön kannalta optimaalinen, sillä sen alkalimetalli- ja tuhkapitoisuus oli väkilannoitteella lannoitettujen kasvien massaa parempi, kun taas mädätteellä ja väkilannoitteella ei havaittu eroja metaanintuotannon kannalta oleellisessa kasvien hiilen ja typen pitoisuuden suhteessa. Tutkimuksesta saatujen tulosten perusteella mädätteet soveltuvat bioenergiakasvien lannoitteiksi. Tämä edesauttaa pyrkimystä kasvintuotannon kestävyyden parantamiseen paitsi ravinteiden kierrätyksen osalta myös fossiilisten polttoaineiden käytön tarpeen vähentämisen kautta. On kuitenkin muistettava, että mädäteet saattavat sisältää raskasmetalleja ja metalloideja, jotka voivat kerääntyä kasveihin tai maahan pitkän aikavälin kuluessa, minkä lisäksi mädätteissä voi olla esimerkiksi taudinauttajia tai lääkejäämiä, joita tässä työssä ei tutkittu

SEWAGE SLUDGE AS NUTRIENT SOURCE FOR BIOENERGY CROPS

Sewage sludge is rich in organic matter, and plant nutrients such as nitrogen, phosphorus andpotassium. Nevertheless, using sludge as fertilizer for crops to produce food or feed is limited due to thepresence of trace contaminants such as heavy metals. Therefore, the aim of this study was to investigatethe use of sewage sludge as a nutrient source for bioenergy crops such as fibre hemp, oilseed rape andwhite lupin. Specific attention is paid to the biomass accumulation and the quality of the plant material aswell as the ability of the crops to take up the heavy metals from soils in order to ensure that the amount ofpollutant does not cumulate.Fibre hemp (Cannabis sativa L.) cv. Uso, oilseed rape (Brassica napus L.) cv. Wildcat and whitelupin (Lupinus albus L.) cv. Amiga were sown in 5-L pots in a greenhouse. Three potting mixes wereused: a standard peat-based potting compost with 50% sludge, sludge with peat (50%:50% by weight), or100% sludge, and a constant mass of 666 g potting mix per pot. Dry weight of plants and leaf area weremeasured four times during the growth of fibre hemp and oilseed rape and at maturity of white lupin. Netphotosynthesis and leaf temperature of plants were measured three times. Ash content and elementalanalysis was made from samples collected at harvest.Sewage sludge application significantly affected most parameters measured. In fibre hemp,maximum dry weight, leaf area and photosynthesis values were obtained from the sludge – peat treatment.In oilseed rape, the maximum values of dry weight of plant, leaf area, photosynthesis, number of siliquesper plant and number of seeds per plant were obtained from the 100% sludge treatment. However, thehighest number of branches per plant, weight of siliques per plant, seed weight per plant and whole plantweight were obtained from the sludge – peat treatment. In white lupin, the sludge – peat treatment resultedin highest net photosynthesis, number of pods per plant, number of seeds per plant and whole weight plantat harvest. Highest sludge application resulted in highest heavy metal concentration in plant material offibre hemp and white lupin. However, high heavy metal concentration in oilseed rape were obtained whensludge was mixed with peat.It is concluded that sewage sludge is suitable for use as a nutrient source for bioenergy cropsstudied. In future experiments we will estimate the optimum level of sewage sludge for each one of thesecrops and determine its potential for use in field conditions

The Green Synthesis of Silver Nanoparticles from Avena fatua Extract: Antifungal Activity against Fusarium oxysporum f.sp. lycopersici

Using plant extracts as eco-friendly reducing and stabilizing agents for the synthesis of nanoparticles has gained significant attention in recent years. The current study explores the green synthesis of silver nanoparticles (AgNPs) using the Avena fatua extract and evaluates their antifungal activity against Fusarium oxysporum f.sp. lycopersici (Fol), a fungal plant pathogen. A green and sustainable approach was adopted to synthesize silver nanoparticles before these nanoparticles were employed for anti-fungal activity. The primary indication that AgNPs had formed was performed using UV-vis spectroscopy, where a strong peak at 425 nm indicated the effective formation of these nanoparticles. The indication of important functional groups acting as reducing and stabilizing agents was conducted using the FTIR study. Additionally, morphological studies were executed via SEM and AFM, which assisted with more effectively analyzing AgNPs. Crystalline behavior and size were estimated using powder XRD, and it was found that AgNPs were highly crystalline, and their size ranged from 5 to 25 nm. Synthesized AgNPs exhibited significant antifungal activity against Fol at a concentration of 40 ppm. Furthermore, the inhibitory index confirmed a positive correlation between increasing AgNPs concentration and exposure duration. This study suggests that the combined phytochemical mycotoxic effect of the plant extract and the smaller size of synthesized AgNPs were responsible for the highest penetrating power to inhibit Fol growth. Moreover, this study highlights the potential of using plant extracts as reducing and capping agents for the green synthesis of AgNPs with antifungal properties. The study concludes that A. fatua extract can synthesize antifungal AgNPs as a sustainable approach with robust antifungal efficacy against Fol, underscoring their promising potential for integration into plant protection strategies

Will novel coronavirus (Covid-19) pandemic impact agriculture, food security and animal sectors?

The whole world is in a great danger due to the novel coronavirus (COVID-19) pandemic. In December 2019, the outbreak of COVID-19 took place in Wuhan, China and then rapidly spread all over the world. The current study provides potential expectations for the adverse impact of (COVID-19). The global infection affected globe on agricultural level such as agriculture, food supplies and animal production sectors. Till today, 29th April 2020, there is no vaccine available for treating novel coronavirus, consequently, the outbreak resulted in closing borders and reducing production following social distancing measures. This short communication illustrates the possible implications and expected outcomes of the outbreak of coronavirus (COVID-19) on agricultural, food security, integrated pest management (IPM), animal productivity; and it predicts, as well, the possible adverse impacts on the economy worldwide. Brazil has one of the most important tropical agriculture in the world, being a leader in soybean production in the world. This chain impacts others such as meat and eggs. The impact of COVID-19 will be positive, encouraging the country to consolidate its leadership in the world market, stimulating exports, the machinery, inputs and fertilizers market, as well as generating employment and income in the country

Bio- and synthetic fertilizers for reducing root rot and wilt and improving growth and flowering characteristics of rose

Root rot and wilt diseases are among the most pressing obstacles to the production of rose flowers in Egypt. Isolation results showed that these diseases are mainly caused by seven soil-borne fungi. However, Fusarium roseum, Verticillium dahlia, and Rhizoctonia solani were the most pathogenic fungi against Rosa gallica and R. chinensis compared to other isolated fungi. The present study aimed to investigate the potential of some bio- and synthetic fertilizers, including seaweed extract, Rhizobacterin, NPK, and potassium silicate, as well as the chemical fungicide vitavax 200, to control root rot and wilt and improve growth and flowering traits of both R. gallica and R. chinensis. Under in vitro conditions, the highest linear growth inhibition of pathogenic fungi was achieved by seaweed extract followed by potassium silicate, at 400 ppm each. In addition, vitavax 200 at 400 ppm completely inhibited the linear growth of these fungi. The results also showed that all treatments applied in vivo significantly reduced the incidence of diseases on rose plants in both seasons, leading to an improvement in all growth and flowering parameters and an increase in the content of photosynthetic pigments, total carbohydrates, nitrogen, phosphorus, and potassium. In this regard, seaweed extract (4 and 2 g/L) and potassium silicate (4 g/L) were the most efficient, while Rhizobacterin (2 g/L) and NPK (2 g/plant) were the least effective. However, vitavax 200 was the most effective of all the treatments used. In conclusion, the results proved the possibility of increasing the tolerance of R. gallica and R. chinensis against root rot and wilt, while improving growth and flowering characteristics by using some bio- and synthetic fertilizers

Using biocontrol agents and sodium nitrophenolate to control powdery mildew and improve the growth and productivity of marigold (Calendula officinalis L.)

In vitro and in vivo studies were conducted to investigate the potential of four biocontrol agents (BCAs), namely Bacillus megaterium, Pseudomonas fluorescens, Trichoderma viride, and T. harzianum, individually and in combination with sodium nitrophenolate (SN) to control marigold powdery mildew. The results showed that all treatments led to a significant inhibition in the conidial germination of Golovinomyces cichoracearum in vitro. Maximum inhibition was recorded by T. harzianum (1×109 CFU mL-1) + SN (1.5%), followed by T. viride + SN, and B. megaterium + SN at the same concentrations as follows: 83.6, 79.1, and 70.6%, respectively. While the lowest inhibition (20.4%) was recorded by P. fluorescens (1×105 CFU mL-1). In the greenhouse, all treatments applied significantly reduced the disease severity and the area under the disease progress curve (AUDPC). The combination treatments had a better disease control response than individual treatments. Similar results were achieved in the field, where disease severity reduced to 9.2 and 10.3% in plants treated with T. harzianum + SN in the first and second seasons, respectively, compared to 40.2 and 44.1% in control in both seasons. Likewise, AUDPC reduced to 274 and 315 in plants treated with T. harzianum + SN in the first and second seasons, respectively, compared to 1207 and 1340 in control in both seasons. The treatments improved growth and productivity characteristics, as well as photosynthetic pigments, total phenolic compounds (TPC), and polyphenol oxidase (PPO) activity, while significantly reducing free proline (FP). In conclusion, BCAs applied individually or in combination with SN can be used effectively to suppress powdery mildew of marigold

Corn and wheat residue management effects on greenhouse gas emissions in the Mid-Atlantic USA

Greenhouse gas (GHG) emissions from crop residue management have been studied extensively, yet the effects of harvesting more than one crop residue in a rotation have not been reported. Here, we measured the short-term changes in methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) emissions in response to residue removal from continuous corn (Zea mays L.) (CC) and corn-wheat (Triticum aestivum L.)-soybean (Glycine max L. Merr.) (CWS) rotations in the Mid-Atlantic USA. A first experiment retained five corn stover rates (0, 3.33, 6.66, 10, and 20 Mg ha-1) in a continuous corn (CC) in Blacksburg, VA, in 2016 and 2017. Two other experiments, initiated during the wheat and corn phases of the CWS rotation in New Kent, VA, utilized a factorial combination of retained corn (0, 3.33, 6.66, and 10.0 Mg ha-1) and wheat residue (0, 1, 2, and 3 Mg ha-1). Soybean residue was not varied. Different crop retention rates did not affect CO2 fluxes in any of the field studies. In Blacksburg, retaining 5 Mg ha-1 stover or more increased CH4 and N2O emissions by ~25%. Maximum CH4 and N2O fluxes (4.16 and 5.94 mg m-2 day-1) occurred with 200% (20 Mg ha-1) retention. Two cycles of stover management in Blacksburg, and one cycle of corn or wheat residue management in New Kent did not affect GHG fluxes. This study is the first to investigate the effects of crop residue on GHG emissions in a multi-crop system in humid temperate zones. Longer-term studies are warranted to understand crop residue management effects on GHG emissions in these systems

Chitosan and chitosan nanoparticles differentially alleviate salinity stress in Phaseolus vulgaris L. plants

Salinity stress can significantly cause negative impacts on the physiological and biochemical traits of plants and, consequently, a reduction in the yield productivity of crops. Therefore, the current study aimed to investigate the effects of chitosan (Cs) and chitosan nanoparticles (CsNPs) to mitigate salinity stress (i.e., 25, 50, 100, and 200 mM NaCl) and improve pigment fractions, carbohydrates content, ions content, proline, hydrogen peroxide, lipid peroxidation, electrolyte leakage content, and the antioxidant system of Phaseolus vulgaris L. grown in clay–sandy soil. Methacrylic acid was used to synthesize CsNPs, with an average size of 40 ± 2 nm. Salinity stress negatively affected yield traits, pigment fractions, and carbohydrate content. However, in plants grown under salt stress, the application of either Cs or CsNPs significantly improved yield, pigment fractions, carbohydrate content, proline, and the antioxidant system, while these treatments reduced hydrogen peroxide, lipid peroxidation, and electrolyte leakage. The positive effects of CsNPs were shown to be more beneficial than Cs when applied exogenously to plants grown under salt stress. In this context, it could be concluded that CsNPs could be used to mitigate salt stress effects on Phaseolus vulgaris L. plants grown in saline soils

Vacinação com EG95 contra a equinococose cística ovina na província de Río Negro: análise de 12 anos de trabalho

Cystic echinococcosis (CE) is a zoonosis caused by species of the complex Echinococcus granulosus, sensu lato in their larval stage. It is an endemic disease in the province of Río Negro, where lamb vaccination with EG95 was incorporated in 2009 with very good results: in fact, it contributed to a significant drop in prevalence of infection in diverse hosts. However, impact studies have revealed the need to improve understanding of local epidemiology. The objective was to identify causes which can still generate infection in dogs. In indigenous reserves comprised within the area of lamb vaccination with 3 doses of EG95, prevalence in adult caprines and ovines was determined by necropsy and serology (ELISA). Through serology, infection rates in vaccinated and non-vaccinated ovines were significantly different (p= 0.0004), as well as between non-vaccinated ovines and goats (p= 0.0013); on the other hand, infection rate differences between vaccinated sheep and non-vaccinated goats turned out non-significant (p= 0.254). Through necropsy, such difference between vaccinated and non-vaccinated ovines turned out significant (p= 0.0016); between non-vaccinated ovines and non-vaccinated goats, it proved non-significant (p= 0.23). With reference to epidemiology and control along the period 2018- 2022, vaccination strategy was maintained, and 2 extra deworming tasks were introduced, performed by the vaccination team. Assessment of animal slaughter for consumption in 41 producers showed that 21 of them slaughter a monthly average of 18 goats, and 36 in all slaughter 35 old sheep. Design and implementation of programme resulted cost-effective, since it was possible to maintain them over time, with clear impact on prevalence decrease in diverse hostsEquinococosis quística (EQ) es una enfermedad zoonótica causada por el estadío larval del complejo Echinococcus granulosus sensu lato. En el año 2009 en la Provincia de Rio Negro se agregó la vacunación  de corderos con EG95, la desparasitación de perros con praziquantel lográndose disminuir la prevalencia de la infección en los diferentes hospederos. Sin embargo, los estudios de impacto señalaron la necesidad de mejorar la comprensión de la epidemiologia local. Objetivo: identificar causas que pueden generar aun infección en los perros Materiales y métodos: se determinó la prevalencia de EQ en caprinos y ovinos adultos mediante necropsia y por serología (ELISA). El análisis epidemiológico se completó con una encuesta a los productores sobre hábitos de faena para consumo. Resultados: Mediante serología. las diferencias en la tasa de infección entre ovinos vacunados y no vacunados resulto significativa (p=0.0004); entre ovinos no vacunados y cabras no vacunadas resultosignificativa (p= 0.0013) y entre ovejas vacunadas y cabras no vacunadas resultaron no significativas (p= 0.254). Mediante necropsia las diferencias en la tasa de infección entre ovinos vacunados y no vacunados resulto significativa (p=0.0016); entre ovinos no vacunados y cabras no vacunadas resulto significativa (p= 0.0016 y entre ovejas vacunadas y cabras no vacunadas resultaron no significativas (p= 0.23). El relevamiento de la faena de animales para consumo en 41 productores mostro que 21 faenan en promedio 18 cabras mensuales y entre 36 faenan 35 ovejas viejas mensuales Conclusión: El diseño y la implementación del programa resultaron costo – efectivas, en tanto ha podido sostenerse a través del tiempo demostrando impacto en la disminución de la prevalencia en los distintos hospedadoresA equinococose cística (EQ) é uma zoonose causada pela fase larval do complexo Echinococcus granulosus sensu lato. Em 2009, na Província de Rio Negro, foram adicionadas a vacinação de cordeiros com EG95 e a desparasitação de cães com praziquantel, obtendo-se uma redução na prevalência da infecção nos diferentes hospedeiros. No entanto, os estudos de impacto apontaram para a necessidade de melhorar o entendimento da epidemiologia local. Objetivo: identificar causas que ainda podem gerar infecção em cães. Materiais e métodos: a prevalência de EQ em caprinos e ovinos adultos foi determinada por necropsia e por sorologia (ELISA). A análise epidemiológica foi completada com um levantamento dos produtores sobre os hábitos de abate para consumo. Resultados: Por sorologia. as diferenças na taxa de infecção entre ovinos vacinados e não vacinados foram significativas (p=0,0004); entre ovinos não vacinados e caprinos não vacinados foi significativo (p= 0,0013) e entre ovinos vacinados e caprinos não vacinados não foi significativo (p= 0,254). Pela necropsia, as diferenças na taxa de infecção entre ovinos vacinados e não vacinados foram significativas (p=0,0016); entre ovinos não vacinados e caprinos não vacinados foi significativa (p= 0,0016 e entre ovinos vacinados e caprinos não vacinados não foi significativa (p= 0,23). O levantamento do abates em média 18 cabras mensais e entre 36 abatem 35 ovelhas velhas mensalmente. Conclusão: O desenho e a implementação do programa foram custo- efetivos, pois se manteve ao longo do tempo, mostrando impacto na diminuição da prevalência em diferentes acolhimentosde animais para consumo em 41 produtores mostrou que 21 abate