Potential Use In Agriculture Research Articles

Effect of biosolids on the nitrogen and phosphorus contents of soil used for sugarcane cultivation

The application of biosolids improves soil nutrient availability and crop productivity; however, their application needs to be carefully evaluated so as to avoid the risk of contamination. In this study, a 12-month field experiment using a randomized block design with factorial arrangement was conducted to evaluate the effects of biosolids on the nitrogen and phosphorus contents of a sugarcane-cultivated inceptisol. Three types of dewatered biosolids were used: anaerobically digested (B), anaerobically digested and thermally dried (BST), and anaerobically digested and lime-stabilized (BA) biosolids. The results showed that biosolid use increases soil nitrogen content by up to 37% of the total Kjeldahl nitrogen, 42% of NO3−, 13% of NO2−, and 32% of NH4+. Biosolid treatments exceeded the phosphorus requirement for sugarcane cultivation by up to 277% for B, 170% for BST, and 368% for BA. The application of biosolids sufficient to meet crop nitrogen requirements significantly increased soil phosphorus content, suggesting an overdose and low crop response to the available phosphorus. The application of biosolids yielded results similar to those of mineral fertilizers, suggesting their potential use in agriculture.

Klebsiella jilinsis 2N3 promotes maize growth and induces resistance to northern corn leaf blight

The northern corn leaf blight (NCLB) is one of the most damaging diseases of maize and is caused by the hemibiotrophic ascomycete fungal pathogen Setosphaeria turcica. Previously, we reported that Klebsiella jilinsis 2N3 is a bacterium that can degrade sulfonylurea herbicides. Interestingly, we found that 2N3 can also promote maize growth and induce resistance to NCLB. 2N3 can grow in a nitrogen-free environment, dissolve inorganic phosphorus and potassium, and produce indoleacetic acid and a siderophore. To further evaluate its potential use in agriculture, the ability to promote maize growth and inhibit NCLB were determined by pot experiments. 2N3 significantly promoted the growth of maize seedlings and their chlorophyll content. After challenge inoculation for 14 days with S. turcica, the causal agent of NCLB, 2N3-treated maize plants showed a 67.44% decrease in the disease index. 2N3 enhanced the activities of catalase, phenylalanine ammonia lyase, peroxidase, superoxide dismutase, polyphenol oxidase, and chitinase in maize leaves. The mechanism of induction of resistance appeared to be primarily owing to the enhancement of the transcript levels of the marker genes of systemic acquired resistance (ZmPR1, ZmPR5, ZmOPR2, and ZmPAL) and the activation of the salicylic acid signaling pathway.

Insights into the Role of Tick Salivary Protease Inhibitors during Ectoparasite-Host Crosstalk.

Protease inhibitors (PIs) are ubiquitous regulatory proteins present in all kingdoms. They play crucial tasks in controlling biological processes directed by proteases which, if not tightly regulated, can damage the host organism. PIs can be classified according to their targeted proteases or their mechanism of action. The functions of many PIs have now been characterized and are showing clinical relevance for the treatment of human diseases such as arthritis, hepatitis, cancer, AIDS, and cardiovascular diseases, amongst others. Other PIs have potential use in agriculture as insecticides, anti-fungal, and antibacterial agents. PIs from tick salivary glands are special due to their pharmacological properties and their high specificity, selectivity, and affinity to their target proteases at the tick–host interface. In this review, we discuss the structure and function of PIs in general and those PI superfamilies abundant in tick salivary glands to illustrate their possible practical applications. In doing so, we describe tick salivary PIs that are showing promise as drug candidates, highlighting the most promising ones tested in vivo and which are now progressing to preclinical and clinical trials.

Mineralization of C and N in Whey-Treated Soils and Absorption of N by Plants

Acid whey deriving from milk processing is a nutrient-rich organic residue, with high potential for use in agriculture. However, in order to establish adequate application doses, it is paramount to understand its mineralization dynamics in the soil. The aims of this study were to evaluate C and N mineralization in two soils fertilized with acid whey and compare the efficiency of distinct incubation methods with and without leaching techniques in predicting the potentially mineralizable N of this residue. Samples of two soils (Haplustox and Haplustult) were submitted to five acid whey doses (0, 80, 160, 240, and 320 kg N ha−1), and the mineralization of C and N was determined. A pot experiment was conducted with the same soils and doses, in order to determine growth and N absorption by maize. C mineralization increased in both speed and quantity with the application of acid whey. Similarly, the potentially mineralizable N was increased, displaying mean values of 79.7 and 68.2 mg N kg−1 in the methods with and without leaching, respectively. N mineralization had strong correlation with absorbed N (r = 0.97 and 0.96, in the methods with and without leaching, respectively). The correlation between net mineralized N and absorbed N was higher without leaching (r = 0.98), in comparison to the leaching method (r = 0.89). Acid whey causes net N immobilization at the beginning of incubation, resulting in low N availability during this period, and its mineralization was better evaluated by the method without leaching.

TRATAMENTO HOMEOPÁTICO PARA MITIGAÇÃO DO ESTRESSE HÍDRICO NA GERMINAÇÃO DE AVEIA PRETA (Avena strigosa Sherb)

O uso de insumos quimiosintéticos na agropecuária tem ocasionado riscos à saúde humana, animal e ambiental. Portanto, é necessário repensar o modelo de agricultura praticada na atualidade com o uso intensivo de insumos de alto impacto ambiental. A homeopatia apresenta promissor potencial de uso na agricultura e na pecuária. Este estudo teve como objetivo a seleção do preparado homeopático e posterior avaliação do uso na mitigação do estresse hídrico em sementes de duas cultivares de aveia preta (Avena strigosa Schreb). O preparado homeopático de Calcarea carbonica foi selecionado por repertorização homeopática e utilizado na potência 7CH. As sementes foram submetidas a dois testes de germinação sob quatro diferentes níveis de estresse hídrico, 0 MPa, -0,2 MPa, -0,4MPa e -0,8MPa e de condutividade elétrica, com e sem aplicação de Calcarea carbonica. Os testes foram avaliados quanto à taxa de germinação e aos resultados de condutividade elétrica. Os melhores resultados de mitigação do estresse hídrico foram obtidos para o teste de germinação nos níveis de estresse por pressão osmótica de -0,2 e -0,4 Mpa para a cultivar IAPAR CABOCLA.

Investigation of two native Australian perennial forage legumes for their potential use in agriculture:

In order to investigate the potential for domestication of native pasture legumes, a seed collecting mission was undertaken between Kalbarri and Esperance in the south of Western Australia followed by establishment of a field nursery at Northam, Western Australia. Indigofera australis subsp. hesperia Peter G.Wilson & Rowe was collected from eight sites, Indigofera brevidens Benth. from one site, and Glycyrrhiza acanthocarpa (Lindl.) J.M.Black from six sites. The field nursery was an irrigated, replicated trial designed to produce seed for future field testing and to provide preliminary information on plant agronomic characteristics. Over 12 months, I. australis produced herbage dry matter (DM) of 2.1–4.4 t/ha compared with 3.4 t/ha for a composite line of tedera (Bituminaria bituminosa C.H. Stirton vars. albomarginata and crassiuscula) and 1.0 t/ha DM for G. acanthocarpa. Most lines had digestibility and crude protein (15–25%) values that would support moderate growth of sheep or cattle. The best line of G. acanthocarpa produced >400 kg/ha of seeds, whereas I. australis had poor production most likely due to poor adaptation to the nursery site. The severity of cutting of I. australis plants had no significant effect on visual assessments of herbage growth. Most plants of I. australis died within 3 years, whereas most plants of G. acanthocarpa, I. brevidens and tedera survived for 3 years. Both I. australis and G. acanthocarpa have potential for use in broadacre agriculture as grazing plants, most likely in niches specifically suited to each, and demonstrate that native plants can contribute to pasture production currently dominated by exotic species.

Metabarcoding analysis of the bacterial succession during vermicomposting of municipal solid waste employing the earthworm Eisenia fetida

A culture-independent DNA metabarcoding analysis of the bacterial communities was carried out throughout a complete vermicomposting cycle of municipal solid waste material using the earthworm Eisenia fetida. 16S rRNA amplicons from the initial material (0 days), an intermediate (42 days), and a final stage (84 days) were sequenced in an Illumina NGS platform and compared. A steady increase in community diversity was observed corresponding to a 2.5-fold higher taxa richness and correspondingly risen values of the Shannon and Simpson ecological indexes and the evenness parameter. A total of 49,665 operational taxonomic units (OTUs) were counted. From the qualitative standpoint, a clear successional shift was observed with an initial community dominated by putatively plant-associated groups belonging to the Rhizobiales order within the Alphaproteobacteria class, regressively leaving the scores of relative abundance (RA) to the Firmicutes phylum and in particular to the Bacilli. Vermistabilization of municipal solid waste (MSW) increased (p < 0.001) the TKN and total P content in the final vermicompost, while pH, TOC, and C/N ratio declined (p < 0.001) in the process. Likewise, a progressive decrease was noticed in β-glucosidase, acid phosphatase, and urease activity while protease and dehydrogenase showed a slight increase, followed by a steep fall. A strong positive correlation was observed among the canonical functions of physico-chemical attributes and enzyme activities. The canonical correspondence analysis (CCA) revealed that significant families did not change on the temporal scale; however, their abundance was influenced by the abiotic environmental factors. In comparison to prior studies on vermicomposting that used different earthworm species (Eisenia andrei) and different substrates, results reflect a considerable degree of substrate specificity for the earthworm species used. The results offer clues to optimize the vermistabilization of MSW along with its potential use in agriculture, to foster improved levels of the circular economy.

Shoreline evolution of Valencia lake and land use and land cover changes in Zamora municipality, Aragua state, Venezuela, period 1986-2016

This study was conducted to estimate the land use and land cover (LULC) changes from 1986 to 2016 at Zamora municipality in Venezuela. Landsat 5 TM, Landsat 7 ETM+, and Landsat 8 (OLI/TIRS) images were obtained to evaluate the shoreline dynamics of the Valencia lake and the magnitude of LULC changes. The images were processed and classified through the object-oriented approach in eCognition Developer 8, for collecting ground-truth data was used Google Earth Engine Python API and Excel software for accuracy assessment. ArcGIS 10.4 and QGIS 2.18 were employed for spatial analysis. It was found that scrublands and farmlands experienced important reductions in area, 13029 ha, and 818 ha respectively, whereas forest, built-up, and water bodies classes showed remarkable increments in area, 11792 ha, 1482 ha, and 634 ha correspondingly. The Valencia lake shoreline underwent an upward trend wherein more than 50% of its raising occurred during the last two study years (2003-2016). It was also observed that land use and land cover changes prompted conflicts with other land uses, 337 ha of lands with high potential for crop yields were affected by the lake shoreline increment and built-up areas grow at a rate of 81 ha /yr. for the last two study years (2003-2016) mainly on lands with high potential for agricultural use.

Review of Novel and Emerging Proximal Soil Moisture Sensors for Use in Agriculture.

The measurement of soil moisture in agriculture is currently dominated by a small number of sensors, the use of which is greatly limited by their small sampling volume, high cost, need for close soil–sensor contact, and poor performance in saline, vertic and stony soils. This review was undertaken to explore the plethora of novel and emerging soil moisture sensors, and evaluate their potential use in agriculture. The review found that improvements to existing techniques over the last two decades are limited, and largely restricted to frequency domain reflectometry approaches. However, a broad range of new, novel and emerging means of measuring soil moisture were identified including, actively heated fiber optics (AHFO), high capacity tensiometers, paired acoustic / radio / seismic transceiver approaches, microwave-based approaches, radio frequency identification (RFID), hydrogels and seismoelectric approaches. Excitement over this range of potential new technologies is however tempered by the observation that most of these technologies are at early stages of development, and that few of these techniques have been adequately evaluated in situ agricultural soils.

Efficacy of plant growth-promoting bacteria Streptomyces werraensis F3 for chemical modifications of diseased soil of ginseng

ABSTRACT Rust rot and root rot of ginseng are common soil-borne diseases with an annual incidence of 20–50%. Here, a strain of Streptomyces werraensis, F3, isolated from ginseng rhizosphere was evaluated for its antifungal activity against ginseng root rot and rust rot-causing pathogens and for its growth-promoting properties. To further assess the potential agricultural use of F3, a pot experiment was performed using ginseng. The results showed that the inhibition rates of F3 bacterial suspension against the mycelial growth of rust rot and root rot pathogens in ginseng were 66.7% and 65.5%, respectively. Compared with the negative control, the germination concise vigour index of ginseng seed increased by 7.25 units upon treatment of the ginseng soil with F3, which could secrete indoleacetic acid and effectively promote the germination of ginseng. The pot experiment proved that F3, when applied as a biological control bacterial agent, improved the pH, organic matter, rapidly available nitrogen, available phosphorus, and available potassium, and the microbial community structure of the soil exposed to the disease for varying time periods. S. werraensis F3 has great potential to be commercialised as a biological control agents and a plant growth-promoting agent to effectively manage ginseng rust rot and root rot diseases.

What is the Molecular Basis of Nonhost Resistance?

This article is part of the Top 10 Unanswered Questions in MPMI invited review series.Nonhost resistance is typically considered the ability of a plant species to repel all attempts of a pathogen species to colonize it and reproduce on it. Based on this common definition, nonhost resistance is presumed to be very durable and, thus, of great interest for its potential use in agriculture. Despite considerable research efforts, the molecular basis of this type of plant immunity remains nebulous. We here stress the fact that "nonhost resistance" is a phenomenological rather than a mechanistic concept that comprises more facets than typically considered. We further argue that nonhost resistance essentially relies on the very same genes and pathways as other types of plant immunity, of which some may act as bottlenecks for particular pathogens on a given plant species or under certain conditions. Thus, in our view, the frequently used term "nonhost genes" is misleading and should be avoided. Depending on the plant-pathogen combination, nonhost resistance may involve the recognition of pathogen effectors by host immune sensor proteins, which might give rise to host shifts or host range expansions due to evolutionary-conditioned gains and losses in respective armories. Thus, the extent of nonhost resistance also defines pathogen host ranges. In some instances, immune-related genes can be transferred across plant species to boost defense, resulting in augmented disease resistance. We discuss future routes for deepening our understanding of nonhost resistance and argue that the confusing term "nonhost resistance" should be used more cautiously in the light of a holistic view of plant immunity.

Laser-Induced Biochar Formation through 355 nm Pulsed Laser Irradiation of Wood, and Application to Eco-Friendly pH Sensors.

Due to the limited availability of agricultural land, pH sensing is becoming more and more important these days to produce efficient agricultural products. Therefore, to fabricate eco-friendly and disposable sensors, the black carbon, which is called biochar, is formed by irradiation of a UV pulsed laser having a wavelength of 355 nm onto wood and applying the resulting material as a pH sensor. The surfaces of three types of wood (beech, cork oak, and ash) were converted to the graphitic structure after UV laser irradiation; their morphologies were investigated. In addition, since the content of lignin, an organic polymer, is different for each wood, optimal laser irradiation conditions (laser fluence) needed to form these woods into pH sensors were considered. Depending on the degree of oil-like material generated after laser irradiation, a disposable pH sensor that can be used from one to three times is fabricated; due to the environmental characteristics of wood and biochar, the sensor shows high availability in that it can be easily discarded after use on agricultural land. After that, it can be used as filter in soil. Our wood-based pH sensor sensitively measures sequential changes from pH 4 to pH 10 and shows a very linear change of △R/R, indicating its potential for use in agriculture.

Treatment and Re-Use of Raw Blackwater by Chlorella vulgaris-Based System

In this study, we examined a Chlorella vulgaris-based system as a potential solution to change liquid waste, such as blackwater, into valuable products for agriculture while protecting waters from pollution without technical demanding pre-treatment. To evaluate the possibility of nutrient removal and biomass production from raw blackwater, four blackwater dilutions were tested at lab-scale: 50%, 30%, 20%, and 10%. The results showed that even the less diluted raw blackwater was a suitable growth medium for microalgae C. vulgaris. As expected, the optimum conditions were observed in 10% blackwater with the highest growth rate (0.265 d−1) and a nutrient removal efficiency of 99.6% for ammonium and 33.7% for phosphate. However, the highest biomass productivity (5.581 mg chlorophyll-a L−1 d−1) and total biomass (332.82 mg dry weight L−1) were achieved in 50% blackwater together with the highest chemical oxygen demand removal (81%) as a result of the highest nutrient content and thus prolonged growth phase. The results suggested that the dilution factor of 0.5 followed by microalgae cultivation with a hydraulic retention time of 14 days could offer the highest biomass production for the potential use in agriculture and, in parallel, a way to treat raw blackwater from source-separation sanitation systems.

Environmental agate mining impacts and potential use of agate residue in rangeland

The impacts of agate exploitation on soils and the adjacent landscapes are poorly understood. In addition, agate processing produces residues whose potential use in agriculture must be evaluated, in order to develop cleaner production practices. The aims of this study were: i) to estimate the effects of agate mining on the soil and the adjacent landscapes; ii) to evaluate the chemical and mineralogical composition of agate; and iii) to test the use of agate powder in native grassland soils. Remote sensing techniques were used to map the soil uses around mine sites to evaluate their interference with the adjacent landscapes. Agate powder, an industrial residue, was chemically and mineralogically characterized, and its effects on soil were tested. We used 0; 1000; 2000; 4000 and 8000 kg ha−1 of agate powder applied to natural grassland in a randomized block design experiment with four replications. The application was repeated in the 47th week after the initial application. The findings showed that the mines had a weak effect on the surrounding landscapes (i.e., native forest, native pasture and annual crops). However, locally, the soil organic matter contents of mine areas decreased, while the potential acidity and toxic aluminum levels increased. Low doses of agate used in rangeland soils had a healthy effect on soil pH, potential acidity and toxic aluminum, while high doses decreased the available K in soil and in the dry matter of the rangeland plants. Little effects were observed on the Si content in the soil or in the plants. Finally, our study highlights that agate exploitation has local impacts on the soil and adjacent landscapes and that agate residue may be used in rangelands at low doses with beneficial results for some soil attributes. These results consists in cleaner production practices for beneficing industry, farmers and environmental since preserving rangeland areas.

Kamafugite From the Alto Paranaíba Province as a Multi-nutrient Fertilizer

The study evaluated the potential agricultural use of kamafugite as a multi-nutrient fertilizer in the cultivation of Urochloa brizantha. Two experiments were carried out under greenhouse conditions, one using a Ferralsol and the other an Arenosol. The experimental design was a randomized block with four replicates, in a factorial scheme 4 &amp;times; 2 + 2, comprising four doses of kamafugite (1667, 3334, 6668, and 13336 mg dm-3), two product forms (filler and powder), and two additional treatments, TSF + KCl and a control treatment without K2O and P2O5 application. The sources were incubated for 60 days on two soil types and, after the incubation period, Urochloa brizantha plants were grown and two consecutive cuts were performed. The kamafugite was efficient in increasing plant dry mass and the levels of P, K, Ca, and Mg accumulated in plants, mainly in the 2nd Urochloa brizantha crop. The granulometry filler was more efficient in the sandy soil and the form powder in the clayey soil. Kamafugite can be used as an alternative source of nutrients for the Urochloa brizantha crop, being a low-cost and a potential source to improve tropical soil fertility over time.

Life Cycle Assessment of Chemical vs Enzymatic-Assisted Extraction of Proteins from Black Soldier Fly Prepupae for the Preparation of Biomaterials for Potential Agricultural Use

The cradle-to-grave life cycle assessment (LCA) was applied to the preparation of biomaterials derived from proteins, extracted from black soldier fly (BSF) prepupae, after the larvae were reared o...

EFEITO DO LODO DE CURTUME ADICIONADO EM SUBSTRATO COMERCIAL PARA PRODUÇÃO DE MUDAS DE PIMENTA MALAGUETA

O aproveitamento de resíduos agroindustriais é pouco recorrente, embora seja viável economicamente e benéfico ao meio ambiente. Por sua vez, tais materiais apresentam elevadas porções de matéria orgânica e nutrientes, indicando alto potencial em utilização agrícola. Portanto, objetivou-se avaliar o desenvolvimento e qualidade de mudas de pimenta malagueta, cultivadas em seis diferentes substratos, contendo proporções de 0 a 90% de lodo de curtume em substrato comercial Bioplant®, além do substrato testemunha, o Provaso®. Aos 21 dias após a semeadura foi contabilizada a emergência das plântulas e, aos 42 dias, as características de desenvolvimento e qualidade de mudas. Para a maioria das variáveis analisadas, o lodo de curtume, nos substratos, promoveu um bom desenvolvimento das plântulas de pimenteira, apresentando desempenho semelhante ao Provaso®. Todavia, o aumento das porções de lodo, aplicadas acima de um nível ótimo, tem efeito negativo, sendo observado declínio nos parâmetros de crescimento e qualidade das plântulas. Além disso, observou-se que o Bioplant® necessita de suplementação mineral para atender as necessidades iniciais das plântulas, sendo essa basicamente sustentada pelo lodo de curtume adicionado a mistura do substrato. Por fim, o aproveitamento deste resíduo, como complemento ao substrato comercial Bioplant®, para produção de mudas de pimenta, mostrou-se viável agronomicamente, promovendo uma boa qualidade e satisfatório desenvolvimento das mudas.

Organic Matter Characterization and Phytotoxic Potential Assessment of a Solid Anaerobic Digestate Following Chemical Stabilization by an Iron-Based Fenton Reaction.

Digestates, a byproduct of the anaerobic bioconversion of organic wastes for the production of biogas, are highly variable in chemical and biological properties, thus limiting their potential use in agriculture as soil amendment. Using a lab-scale glass reactor, we aimed to assess the feasibility to chemically stabilize the solid fraction of an anaerobic digestate by applying a Fenton reaction under constant pH (3.0), temperature (70 °C), reaction time (8 h), and various combinations of H2O2 and Fe2+. In Fenton-treated samples, the phytotoxic potential (determined on a test plant), total phenols, and the bad smell odor index markedly declined, whereas total C and N remained unaltered. Thermogravimetric (TG) analysis and Fourier transform infrared (FT-IR) spectroscopy revealed contrasting changes in extracted humic and fulvic fractions being increased or depleted, respectively, in aromatic substances. Process feasibility and optimum conditions for an effective biomass stabilization were achieved with a H2O2/Fe2+ ratio between 0.02 and 0.03.

VenoMS-A Website for the Low Molecular Mass Compounds in Spider Venoms.

Spider venoms are highly complex mixtures. Numerous spider venom metabolites are uniquely found in spider venoms and are of interest concerning their potential use in pharmacology, agriculture, and cosmetics. A nontargeted ultra-high performance high-resolution electrospray tandem mass spectrometry (UHPLC-HR-ESI-MS/MS) approach offers a resource-saving way for the analysis of crude spider venom. However, the identification of known as well as the structure elucidation of unknown low molecular mass spider venom compounds based on their MS/MS spectra is challenging because (1) acylpolyamine toxins are exclusively found in spider and wasp venom, (2) reference MS/MS spectra are missing in established mass spectrometry databases, and (3) trivial names for the various toxin metabolites are used in an inconsistent way in literature. Therefore, we introduce the freely accessible MS website for low molecular mass spider venom metabolites, venoMS, containing structural information, MS/MS spectra, and links to related literature. Currently the database contains the structures of 409 acylpolyamine toxins, 36 free linear polyamines, and 81 additional spider venom metabolites. Implemented into this website is a fragment ion calculator (FRIOC) that allows us to predict fragment ions of linear polyamine derivatives. With three metabolites from the venom of the spider Agelenopsis aperta, it was demonstrated how the new website can support the structural elucidation of acylpolyamines using their MS/MS spectra.

Estimation of Canopy Area of Fruit Trees Using Light Unmanned Aerial Vehicle (UAV) and Image Processing Methods

Some vegetative properties measured in fruit trees are important indicators in examining of plant growth calculation, estimation of leaf area index in evapotranspiration, fertilizer requirement etc. These measurements reflect the effects of the cultivation treatments in many areas of commercial growing and scientific studies. One of the most important measurements is the status of the canopy development. Canopy width, area and volume can be measured with some calculations. However, more technological equipment may be needed to reduce work and labor, and to make the results more precise and clearer. Recently, unmanned aerial vehicles, which have become widespread, have a wide potential for use in agriculture. By using image processing methods, it is possible to make more objective and high accuracy evaluations much faster. In this study, the images of the apple trees (Malus domestica Borkh) cultivar Golden grafted onto MM106 rootstock, were taken by light unmanned aerial vehicle to calculate the canopy area and then these images were analyzed using image processing methods for calculating canopy areas. Both circular and elliptical calculation methods were used. The area calculations with image processing methods were compared with the areas obtained manually. Comparisons were made by regression analysis. For the most successful method R value was 0.9662 for elliptic area and 0.9346 for circular area which was calculated by image processing. The results demonstrated that the image processing can be an alternative method to determine the canopy area according to accuracy ratios.