Use Of Fertilizers In Agriculture Research Articles

Moving towards a mechanistic understanding of biostimulant impacts on soil properties and processes: a semi-systematic review

Biostimulants are gaining prominence in scientific research, with the potential to enhance plant productivity through benefits to crop yield/quality and tolerance to environmental stresses. Through possible improvements to nutrient use efficiency, they may also lessen the adverse environmental impacts of conventional inorganic fertilizer use in agriculture. The application of biostimulants is currently uncommon as a farming practice, with uncertain effectiveness in delivering these potential benefits. Current research focuses on biostimulant effects on plant physiological changes. There is little scientific evidence on the impact of biostimulants on soil properties (biological, physical, or chemical) or soil functions. This knowledge gap should be addressed considering the vital role of soil processes in the bioavailability of nutrients, as reflected in crop productivity. This review evaluates laboratory and field experimental work on the effectiveness of common, non-microbial biostimulants, with a focus on their modes of action within the soil matrix. Of 2,097 initial articles returned through the search strings, 10 were within the scope of this review. A common soil biostimulant mechanism emerges from this literature. This relates to the supply of nutrients provided by the biostimulants, which stimulate native soil microbiology in mineralizing organic material in the soil, thus producing more bioavailable nutrients for plant uptake. Additionally, some articles link biostimulant effects to soil physical and chemical changes, which in turn impact soil biology (and vice versa). However, there is inconsistent evidence to provide full support for these explanatory mechanisms. This review highlights the need for further research into the effect of biostimulants on the native soil microbiology and associated soil properties, to provide greater clarity on biostimulants’ modes of action and greater mechanistic insights into how they can be used to improve crop production.

Heavy metals in soil, finger millet and weeds due to nutrient management practices under a 43-year-old long term fertilizer experiment

Chemical fertilizers contain traces of heavy metals and long-term use of fertilizers in agriculture could lead to the accumulation of heavy metals in the soil. Specific amounts of fertilizers and manure have been consistently applied for the past 43 years. Soil and plant samples were collected and quantified for heavy metals. The results revealed that the application of FYM and inorganic fertilizers led to a higher concentration of heavy metals in surface soil and decreased with soil depth. The application of 100% RDF resulted in higher concentrations of metals in samples of finger millet and all the heavy metals were below toxic limits. The PLI of heavy metals was found to have a value <10, indicating that soils are less polluted. Cd and Pb had BCF values of <1 for grain and straw, which indicates a lower concentration of metals in soil than those taken up by plants, while >1 for As and Cr indicates a higher uptake in grain and straw than in soil.

The Enzyme Activity of Dual-Domain β-Propeller Alkaline Phytase as a Potential Factor in Improving Soil Phosphorus Fertility and Triticum aestivum Growth

The widespread use of non-renewable phosphate fertilizers in agriculture poses a significant pollution threat to soil, necessitating the exploration of sustainable alternatives for phosphate fertility. Releasing phytate phosphorus through microbial phytases presents an eco-friendly solution for sustainable phosphate fertility in agriculture. This study directly inoculated dual-domain β-propeller alkaline phytase (phyHT) derived from Bacillus sp. HJB17 into the soil. The study analyzed the impact of inoculated phyHT on the physicochemical properties of the soil, assessed the variations in enzyme activity of phyHT within the soil, and examined the effects of the treated soil on wheat growth. Additionally, the study explored the enhancement of the available phosphorus in the soil through the inoculation of phyHT in both crop residues and organic fertilizer. PhyHT exhibited the highest catalytic activity at 37 °C and pH 8.0. After soil adsorption, phyHT maintained stable enzymatic activity. PhyHT markedly boosted the available phosphorus in the soil while reducing the soil phytate content by about 20%, increasing the phosphorus levels and enhancing soil fertility. PhyHT effectively degraded phytates in an organic fertilizer and crop residues, increasing the available phosphorus. PhyHT supplementation enhanced growth, biomass, and phosphorus content in both the shoot and root weights of Triticum aestivum. This study establishes phyHT as a viable and eco-friendly method to enhance phosphorus fertility in soil. The direct application of microbial phytases can serve as a sustainable source of phosphate fertility in soil.

Evaluation of the concentration and human health risk of nitrate and potentially toxic elements (PTEs) in melons from a southern region of Iran: Identification of pollution sources

Decentralized agriculture, improper monitoring of cultivation conditions, and leaching of contaminants into lands led to the contamination of crops with various potentially toxic elements (PTEs). However, it is essential to know more about the profile level and associated risk of these contaminants and their origin, especially in high-water content crops. This study aimed to investigate the concentration of PTEs in melons of one of Iran's southern cities and follow that health risk assessment in the target population for the first time. Results of the present study confirmed that although the mean concentration of some metals was lower than the safety standard (Cr: 4.6 ± 2 mg/kg and Pb: 7.4 ± 4 mg/kg), their nutritional value was unfavorable regarding some micronutrients (Cu: 88.8 ± 27 mg/kg and Zn: 480 ± 275 mg/kg). The highest metal concentration in cantaloupe was iron (1706.47 mg/kg, p-value<0.05), and nitrate concentration in all melon types was 2.59–524.54 mg/kg (p-value<0.05). Principal component analysis (PCA) with K-means clustering and the Positive Matrix Factorization (PMF) model have shown that contaminants in melons originated from human activities. So, excessive use of agricultural fertilizers is a possible source of nitrates in melons, which have 93 % of factor loading values. The health risk assessment also showed that melons' carcinogenic and non-carcinogenic risk using the deterministic method was lower than the permissible limit (HQ < 1, ILCR<E-4). However, the Monte Carlo simulation estimated HQ > 1 in the children group for the 95th percentile. Furthermore, the level of certainty in the carcinogenesis risk for children, women, and men was estimated at 86.48 %, 64.67 %, and 61.30 %, respectively. Also, the consumption rate was determined as the most important parameter in the sensitivity analysis. As a consequence, there is a potential health risk for Iranians after the consumption of melon due to PTEs and nitrate levels that also originated from anthropogenic sources.

Health risk analysis of nitrate in groundwater in Shanxi Province, China: A case study of the Datong Basin.

In order to identify and effectively control the impact of NO3- pollution on human health, on the basis of investigation, sampling, analysis and testing, statistical analysis software (SPSS19), groundwater pollution analysis software, Nemera comprehensive index method, correlation analysis method and human health risk assessment model are applied for analysis and research. The results indicate that the groundwater in the study area is mainly Class II water, with overall good water quality. The main influencing factors for producing Class IV are NO3-, Fe, F- and SO42-. The use of agricultural fertilizers is the main source of NO3- exceeding standards in groundwater in this area. There are significant differences in the health hazards caused by NO3- pollution in groundwater among different populations, and infants and young children are more susceptible to nitrate pollution. The division of pollution areas and high-risk groups plays an important guiding role in preventing health risks. The new achievements will help people improve their awareness of risk prevention, caring for the environment, respecting nature and implementing precise policies, promoting society to step onto the track of scientific and healthy development.

Distribution of nitrate/nitrite and toxic metals in the soil-potato system and its health risk assessment in Iran.

Potato is one of the essential food products whose health quality is greatly influenced by soil contamination and properties. In the current study, we have investigated the physicochemical characteristics of agricultural areas and the accumulation of nitrite/nitrate and metals in potato products in Hamedan, Iran. After determining the physicochemical characteristics of soil samples from four agricultural regions of Hamedan, 48 potato samples were collected from these regions. The heavy metals and nitrate/nitrite content were determined by ICP-OES and calorimetric methods, respectively. A negative correlation was observed between soil pH changes with nitrite/nitrate content and the accumulation of some heavy elements in potatoes. Furthermore, a positive correlation was found between soil phosphorus content and lead accumulation in potato. In present study, the amounts of lead, nitrate, and nitrite in 83.3%, 56%, and 12% of the collected samples were higher than the permissible limit reported by the World Health Organization (WHO), respectively. The EDI range for nitrate and nitrite was determined to be 130-260 and 1.4-2.7µg/kg/day, respectively, which is much lower than the RfD set by the US Environmental Protection Agency (USEPA) for nitrite and nitrate. Among metal pollutants, the toxic risk caused by lead in potato consumers was higher than the threshold limit. In conclusion, our findings showed that the physicochemical characteristics of the soil could effectively increase the availability of metal pollutants and nitrite/nitrate to the potato product and significantly reduce its health quality. Therefore, monitoring these pollutants in the soil-potato system, preventing the entry of industrial wastewater, and managing the use of agricultural fertilizers can effectively improve the health of this product for consumers.

Heavy Metals in Common Fishes Consumed in Dhaka, a Megacity of Asia: A Probabilistic Carcinogenic and Non-Carcinogenic Health Hazard.

Heavy metal contamination of fish is a serious public health concern worldwide, including in Bangladesh. In this study, six commonly consumed fish species namely Hilsha (Tenualosa ilisha), Kachki (Corica soborna), Punti (Puntitus ticto), Taki (Channa punctatus), Meni (Nandus nandus), and Tengra (Mystus tengara) were analyzed for arsenic (As), cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu), chromium (Cr), manganese (Mn), and nickel (Ni), by inductively coupled plasma mass spectrometry. The fish samples were collected from wholesale markets in Dhaka city, the main business hub of Bangladesh where the fishes converged from countrywide and are redistributed to the whole city. The metal concentration varied among the studied fish species. Hilsha, the national fish of Bangladesh, contained the highest As among the other fishes of this study, whereas Zn, Cd, Cu, Mn, and Ni were the highest in Kachki, and Pb and Cr were the highest in Tengra. The probable source of metal accumulation in the fish species may be the river or marine water that can be contaminated by industrial waste, pesticide, and/or fertilizer use in agriculture and/or commercial fish feeds. All analyzed fish species showed serious heavy metal pollution, having high average pollution load index (APLI) values (> 1). The estimated daily intake (EDI) values for the metals were lower than the maximum tolerable daily intake (MTDI). The hazard index (HI) for all the fish species was above 1 for adults, showing non-carcinogenic health risks. The targetcarcinogenic risk (TCR) values were below the acceptable limit (10-4) for most of the metals, indicating safe for consumption with respect to the risk of cancer.

Potential of organic wastes typical of the Brazilian Amazon for fertilizer use in agriculture

Characterization of different organic wastes is essential to reveal alternative nutrient sources useful for agriculture. The objective of this work was to characterize a variety of organic wastes generated in the Brazilian Amazon in order to identify nutrient sources for potential use as organic fertilizers. Samples of nine different organic wastes from agricultural, livestock and forestry activities were collected in the state of Pará, Amazon region, Brazil. These samples were characterized using reference methods for analyses of organic fertilizers. Palm oil mill boiler ash was highly concentrated in P, K, Ca, and Mg and also highly alkaline, being considered a promising material for use as fertilizer and lime in acid soils. Palm oil mill decanter cake was the best N source; it also contained relevant amounts of K, S, and Zn. Cattle manure was more concentrated in N and oil palm empty fruit bunch in K. Residual eucalyptus charcoal was high in Ca but also in Na and Al. Oil palm fruit fiber, oil palm fruit shell, wood sawdust of the pile top, and wood sawdust of the pile slope were consistently poor in nutrients. All wastes presented low concentrations of As, Ba, Cd, Cr, Hg, Pb, and Se. This study identified organic wastes differing in prevalent nutrients for potential use as organic fertilizers. Such a difference could be explored in further studies by combining two or more wastes with complementary prevalent nutrients in order to better meet the nutritional requirements of different crops in the Brazilian Amazon.

USAGE OF HOMEOPATHIC TREATMENTS FOR PLANT PATHOGEN CONTROL, AN OVERVIEW OF THE HISTORY AND TRENDS: A COMPREHENSIVE REVIEW

The extensive use of synthetic chemical fertilizers in agriculture is causing environmental problem. In this situation it is desirable to find out suitable agents, which would increase plant growth without compromising with the quality of food and of soil. This paper represents the history and trends of homeopathic drugs utilized in the control of plant pathogens in plant pathology. This method started with the pioneering work of kolisko in 1923 on wheat germination and Junker in 1928 on growth of microorganisms. Literature search on the Homeopathic drugs in the control of plant pathogens, which have shown the anti-fungal, anti-viral, anti-bacterial properties have been reviewed in this present paper. From the literature during the present study the different homeopathic drugs were found were used in agriculture. The contents of the article cover all the scientific reports published in Agricultural sectorfrom 1966 to till dates. A total 120 papers have been reported from homeopathic treatments used in Agriculture. Amongst these Arsenicum album, Natrum muriaticum, Cina, Thujawere found as the most used compounds. The science of homeopathy has great potentials and could give a new direction that requires attention of the researchers in alternative agriculture. This review discusses the experimental evidence relating to the use of homeopathic drugs in plant pathology, with view to assess the potential of homeopathy in agriculture.

Pengaruh Pemberian Biourin Sapi dan Lama Inkubasi Terhadap Ketersediaan Hara Nitrogen dan Fosfor pada Tanah Podsolik

Podzolic soil is characterized by acidic condition, low base saturation, and low CEC and nutrient contents. The use of chemical fertilizers in agriculture may damages soil and environment and may eventually affect the health of humans. The objective of this study was to quantify the effect of cow urine on changes in pH, available N (NH4+ and NO3-), and available P of Podsolic soil. This study employed the completely randomized design two factors, in which first factor was the amounts of applied cow biourine: control (without biourine, 5.2, 10.4 and 15.6 mL of biourine), while the second factor was the incubation period: 2 and 4 weeks. Following the completion of each incubation period, soil pH, contents of ammonium, nitrate, and available phosphrous were determined for each treatment. Results of this study showed that the application of cow biourine with an incubation time of two and four weeks significantly influenced the ammonium and nitrate contents in soil. The higher amount of biourine applied, the higher ammonium and nitrate contents in the soil. The research results also showed that the application of cow biourine had an influence on available P content, but had no effect on changes in soil pH.

Can Azospirillum brasilense compensate part of the phosphate fertilizer in soybean crop by promoting plant growth?

Bioinoculants are widely used in Brazil, based on their efficiency and low cost, in addition to increase in grain yield and lower use of fertilizers in agriculture. In this context, we investigated the use of Azospirillum brasilense to compensate part of phosphate fertilization in soybean crop by promoting plant growth. The field trials were carried out in 2020/21 crop season in four locations in Brazil. The treatments consisted of control (no P application and no microbial inoculation); complete fertilization (100% of the recommended P for the crop and no microbial inoculation); standard commercial inoculant + 75% of the recommended P for the crop; Azosphera® (inoculant based on A. brasilense, strains Ab-V5 and Ab-V6) + 75% of the recommended P for the crop. The effects were assessed on grain yield, thousand grain weight, nodulation, root and shoot dry weight, N and P content in grains and leaves. The results obtained show that inoculation of soybean crop with Azosphera® inoculant, combined with 75% of the recommended phosphate fertilization, in general, provided higher nodulation and plant dry weight and increased grain yield compared to control, and these parameters also did not differ from treatment with complete phosphate fertilization. Thus, the results show that the use of Azosphera® inoculant promoted soybean plant growth and it was possible to compensate the 25% reduction in phosphate fertilization, without impairing the development and yield of soybean crop.

AMMONIUM, NITRATE AND NITRITE CONCENTRATIONS IN DRINKING WATER OF THE SOUTH BAČKA DISTRICT OF VOJVODINA

Safe drinking water is one of the basic conditions for life on our planet, necessary for all vital processes in the biosphere. Pollution of water sources, largely from wide-scale agricultural fertilizer use, has resulted in nitrate and nitrite contamination of drinking water. Aim: To determine the concentrations of ammonium, nitrate, and nitrite in drinking water as potential hazards in the settlements of the South Bačka administrative district of Autonomous Province of Vojvodina (northern part of Serbia). A cross-sectional study was conducted during 2019. We analysed 8434 drinking water samples (7319 purified chlorinated, 386 untreated but chlorinated, and 729 untreated). For assessing the concentration of ammonium, nitrate, and nitrite in drinking water, samples were analyzed by a certified laboratory at the Institute of Public Health of Vojvodina using spectrophotometric method. After analyzing samples of purified chlorinated, untreated chlorinated, and untreated water, the exceedance of the prescribed values of ammonium were found in 0.45%, 64.77% and 68.45%, and for nitrites in 0.04%, 5.96% and 0.82% of the samples, respectively. The concentration of nitrate in drinking water concerning the degree of water purification (purified chlorinated and untreated water) exceeded the prescribed value in 0.01% and 5% of the samples, respectively. Determined exceedances of the prescribed limit values for nitrite concentrations recorded in purified chlorinated, untreated chlorinated, and untreated drinking water as well as for nitrate mainly in untreated drinking water, could be considered as potential hazards for human health, especially for the sensitive population group.

Optimizing Phosphorus Fertilizer Use on the Loess Plateau: Impact on Soil Properties and Crop Production Efficiency

Various phosphorus (P) fertilizers are commonly utilized in agricultural production on the Loess Plateau. However, there exists a widespread issue of improper matching between P fertilizers, crop types, and soil types. This study proposes a scientifically based approach to managing phosphate fertilizer through a matching experiment. A field experiment was conducted to investigate the effects of different P fertilizers on soil P profiles in a wheat–corn rotation between October 2017 and September 2021. The experiment adopted a randomized block design. P fertilizer was applied as a basal fertilizer at rates of 115 kg P2O5 ha−1 during the wheat season and 90 kg P2O5 ha−1 during the maize season. Nitrogen (N) fertilizer application rates were 120 kg N ha−1 for wheat and 180 kg N ha−1 for maize. N fertilizer was divided into two applications, with 60% applied at pre-planting and 40% at the jointing stage of wheat or the V12 stage of maize. P fertilizer variants utilized in the study included ammonium dihydrogen, ammonium phosphate, calcium-magnesia phosphate fertilizer, calcium superphosphate, and ammonium polyphosphate. The transformation process of phosphate was examined, revealing that the commonly considered dominant diammonium phosphate fertilizer was not the optimal choice in this production system. Ammonium polyphosphate, calcium superphosphate, and ammonium dihydrogen were deemed more suitable for application in Loess soil. Furthermore, an analysis was conducted on the relationship between P fractions, soil properties, and soil Olsen-P. This research emphasizes the significance of strategic phosphate fertilizer use in agriculture to ensure efficient production and to help address the global P scarcity.

Human health risk assessment and carcinogenicity due to exposure to potentially toxic elements on soil pollution in Southwest Iran

Background/objectives: Potentially toxic elements (PTEs) are one of the dangerous pollutants in the environment that can cause morbidity and mortality in humans. This study was designed to evaluate the concentration of PTEs, assessment its human health risk assessment and carcinogenicity in the north of Ahvaz, the southwest of Iran. MethodsThe soil samples were collected from the agricultural fields and riversides for investigating the health effects of the selected PTEs on the soil of the Weiss and Arab Assad regions in Ahvaz. ResultsAccording to the result of this study, the highest level of Fe was observed in the soil samples of the Weiss and Arab Assad regions, 9013.70 and 9208.93 mg/kg, while Cd showed the lowest concentration in the soils of Weiss and Arab Assad fields, 1.58 and 1.56 mg/kg, respectively. Potentially toxic elements hazard quotient (HQ), non-carcinogenic risk (HI), and risk index (RI)) in the soil of agricultural fields in the Arab Assad and Weiss regions showed that Cd, Pb, Ni, Cu, Cr, Zn, Fe, Mn, and Co posed a significant risk to human health. Thus, it is recommended to observe health issues due to the non-carcinogenic risk index of metals. ConclusionGenerally, the excessive use of agricultural fertilizers (phosphate and nitrate), industrial, and human activities can increase the contamination of the resources and products, which has irreversible effects on human health, especially in carcinogenic risk.

Impacts of reduced synthetic fertiliser use under current and future climates: Exploration using integrated agroecosystem modelling in the upper River Taw observatory, UK

The intensification of farming and increased nitrogen fertiliser use, to satisfy the growing population demand, contributed to the extant climate change crisis. Use of synthetic fertilisers in agriculture is a significant source of anthropogenic Greenhouse Gas (GHG) emissions, especially potent nitrous oxide (N2O). To achieve the ambitious policy target for net zero by 2050 in the UK, it is crucial to understand the impacts of potential reductions in fertiliser use on multiple ecosystem services, including crop production, GHG emissions and soil organic carbon (SOC) storge. A novel integrated modelling approach using three established agroecosystem models (SPACSYS, CSM and RothC) was implemented to evaluate the associated impacts of fertiliser reduction (10%, 30% and 50%) under current and projected climate scenarios (RCP2.6, RCP4.5 and RCP8.5) in a study catchment in Southwest England. 48 unique combinations of soil types, climate conditions and fertiliser inputs were evaluated for five major arable crops plus improved grassland. With a 30% reduction in fertiliser inputs, the estimated yield loss under current climate ranged between 11% and 30% for arable crops compared with a 20–24% and 6–22% reduction in N2O and methane emissions, respectively. Biomass was reduced by 10–25% aboveground and by <12% for the root system. Relative to the baseline scenario, soil type dependent reductions in SOC sequestration rates are predicted under future climate with reductions in fertiliser inputs. Losses in SOC were more than doubled under the RCP4.5 scenario. The emissions from energy use, including embedded emissions from fertiliser manufacture, was a significant source (14–48%) for all arable crops and the associated GWP20.

Chemical risk assessment of conventionally and organically grown tomatoes in Côte d'Ivoire

Background: The use of fertilizers in agriculture can be a source of contamination of fruits and vegetables. Aims: This study was to assess the level of contamination of tomatoes by heavy metals (Pb, Cd, Hg, and As), in order to assess the risks of exposure of consumers of tomatoes in Côte d'Ivoire. Material and Methods: More specifically, the assessment focused on the contamination by heavy metals used intensively by producers for the fertilization of vegetable crops. Four heavy metals (mercury, lead, cadmium and arsenic) were tested in tomato samples from both types of agriculture. Results: The average level of mercury in organic tomatoes (0.08290 ± 0.03 mg/kg) and in conventional tomatoes (0.1564 ± 0.1 mg/kg) exceeded the maximum limit (EC N 1881/2006). However, in organic tomatoes, only mercury level exceeded the required standard, the other heavy metals being present in trace amounts. The content of these other metals in the organic tomatoes exceeded the standard. However, the ratio (hazard quotient) of the weekly heavy metal intake to the provisional tolerable weekly intake for all heavy metals was less than one (1). Conclusion: Consumption of tomatoes from the areas in this study did not pose a health risk to the consumer. Keywords: Organic agriculture, conventional agriculture, heavy metals, dietary exposure.

Juglone, a plant-derived 1,4-naphthoquinone, binds to hydroxylamine oxidoreductase and inhibits the electron transfer to cytochrome c554.

Nitrification, the microbial conversion of ammonia to nitrate via nitrite, plays a pivotal role in the global nitrogen cycle. However, the excessive use of ammonium-based fertilizers in agriculture has disrupted this cycle, leading to groundwater pollution and greenhouse gas emissions. In this study, we have demonstrated the inhibitory effects of plant-derived juglone and related 1,4-naphthoquinones on the nitrification process in Nitrosomonas europaea. Notably, the inhibition mechanism is elucidated in which 1,4-naphthoquinones interact with hydroxylamine oxidoreductase, disrupting the electron transfer to cytochrome c554, a physiological electron acceptor. These findings support the notion that phytochemicals can impede nitrification by interfering with the essential electron transfer process in ammonia oxidation. The findings presented in this article offer valuable insights for the development of strategies aimed at the management of nitrification, reduction of fertilizer utilization, and mitigation of greenhouse gas emissions.

Assessment of Crop Residues and Corresponding Nutrients Return to Fields via Root, Stubble, and Straw in Southwest China

China stands as one of the world’s largest agricultural powerhouses, boasting abundant crop resources. Nonetheless, there remains a lack of clarity regarding the extensive scale of crop residue return in the fields. Drawing from direct field measurements and comprehensive survey data, this paper pioneers the reporting of residues from the five primary crops, shedding light on the associated nutrient components, including carbon (C), nitrogen (N), and phosphorus (P) replenishment via crop roots, stubble, and straw in the Southwest China region for the year 2012. The results showed that the total amount of the main crop residue resources was 97.4 Mt, which was composed of 17.8 Mt, 12.6 Mt, and 67 Mt for crop root, stubble, and straw, respectively. After crops harvested, there were 7165.8 kilotonne nutrient C, 132.2 kilotonne nutrient N, and 9.8 kilotonne nutrient P of crop residues returned to the fields through crop root, respectively, accounting for 44.6%, 48.2%, and 43.4% of the total nutrient returned, which was the main part of crop nutrients return to fields. The amount of nutrient C, N, and P returned through stubbles were 5017.3 kilotonne, 75.9 kilotonne, and 6.8 kilotonne, respectively, accounting for 31.3%, 27.6%, and 30.6% of the total return of crops. From the composition proportion of residues nutrients return to field, the orders were all expressed as follows: root &gt; stubble &gt; straw. According to the optimum fertilization amount of the main crops in Southwest China, the returned of crop residues nutrient N in maize, rice, rapeseed, and wheat can replace approximately 5.6%, 18.4%, 11.2%, and 14.8% of nitrogen fertilizer, and 2.4%, 8.3%, 3%, and 9.2% of phosphate fertilizer, respectively. This conclusion is beneficial for regulating the practice of returning crop residues to the fields and the use of agricultural fertilizers, aiming to achieve sustainable development in agricultural production.

Mitigation of CO2 Emissions in Agro-Ecosystems by Composting of Tree Leaf Litter with Effective Microorganisms and Green Sunnhemp Plants

ABSTRACT Managing leaf litter by using different composting methods may be an alternative approach to solid waste management in rural areas. The purposes of the study were to prepare compost from an admixture of tree leaf litter using effective microorganisms (EM) and green sunnhemp plants and assess the patterns and cumulative amounts of carbon dioxide (CO2-C) emission and CO2 mitigation potential. The N content of leaf litter from both compost methods was significantly higher. The EM-treated compost had better concentrations of microbial biomass carbon (MBC), potassium, calcium, and magnesium. The low germination and vigor index were observed in compost treated with green sunnhemp plants. The CO2 emission patterns were similar in both leaf litter compost treatments. The composting techniques used in this study can save roughly 310 kg CO2eq in greenhouse gas (GHG) emissions. Composting leaf litter with EM and green sunnhemp plants could be a useful technique for lowering agriculture’s GHG emissions, besides helping to mitigate climate change, reducing the solid waste from rural areas, and minimizing the use of mineral fertilizer in agriculture.

Lead, Cadmium, and Arsenic in Raw Cow's Milk in a Central Andean Area and Risks for the Peruvian Populations.

Milk and its derivatives are basic foods in Peru, especially for children. The Junín region, in the central Andes, is one of the leading dairy basins. However, the safety of milk is affected by mining-metallurgical activities, wastewater dumping, organic residues, and inappropriate use of organophosphate fertilizers in agriculture whose contaminants reach the food chain, putting human health at risk. The purpose of this study was to evaluate the bioaccumulation of lead (Pb), cadmium (Cd), and arsenic (As) in milk produced on a representative farm in central Peru, which uses phosphorous agrochemicals and is adjacent to a small mineral concentrator and a municipal solid waste dump, and to evaluate the potential risk for the Peruvian population of 2-85 years considering three levels of daily intake by age, which constitutes the innovative contribution of the study. These three elements were quantified by flame atomic absorption spectrometry following standardized procedures. The mean contents of Pb (0.062 mg/kg), Cd (0.014 mg/kg), and As (0.030 mg/kg) in milk exceeded the maximum limits allowed by international standards. At all ages, the target quotient hazard followed a descending order of As > Pb > Cd, being > 1 in the case of As. The hazard index was >1 for children under 7, 9, and 11 years of age in the scenarios of low, medium, and high milk intake. The information is valid for formulating policies to prevent adverse health effects and develop standards and awareness programs, monitoring, and control of heavy metals in milk in Peru.