Changes In Chemical Attributes Research Articles

Modification of sand fertility parameters during cleaning and purification process

The use of sand as a substrate in nutritional studies is frequent, but there is no formal protocol for cleaning and purifying this substrate for various agronomic studies, including those related to plant nutrition. The study aimed to evaluate the changes in chemical attributes resulting from the cleaning and purification of common construction sand. The experimental study, of a quantitative nature, was carried out under greenhouse and laboratory conditions. An experiment was carried out whose treatments were levels of hydrochloric acid (HCl) concentration, immersion times in the acid solution, and purification in an autoclave. It was found that sterilization in an autoclave significantly decreased the pH of the sand and increased the phosphorus content. From a day of rest with HCl, the decrease in the pH of the sand was significant. On the other hand, the phosphorus content increased linearly with the immersion time in HCl. The use of HCl completely eliminated the levels of potassium, calcium, magnesium, and copper, and significantly decreased the contents of iron and manganese (above 70%) and zinc (above 80%). To exhaust or significantly decrease the levels of nutrients present in the sand, one should use 3% HCl, without rest, for phosphorus and one day of incubation for potassium, calcium, magnesium, and copper, iron, manganese, and zinc.

Chemical attributes, bacterial community, and antibiotic resistance genes are affected by intensive use of soil in agro-ecosystems of the Atlantic Forest, Southeastern Brazil.

Soil is one of the largest reservoirs of microbial diversity in nature. Although soil management is vital for agricultural purposes, intensive practices can have a significant impact on fertility, microbial community, and resistome. Thus, the aim of this study was to evaluate the effects of an intensive soil management system on the chemical attributes, composition and structure of prevalent bacterial communities, and presence and abundance of antimicrobial resistance genes (ARGs). The chemical characterization, bacterial diversity and relative abundance of ARGs were evaluated in soils from areas of intensive vegetable cultivation and forests. Results indicate that levels of nutrients and heavy metals were higher in soil samples from cultivated areas. Similarly, greater enrichment and diversity of bacterial genera was detected in agricultural areas. Of the 18 target ARGs evaluated, seven were detected in studied soils. The oprD gene exhibited the highest abundance among the studied genes and was the only one that showed a significantly different prevalence between areas. The oprD gene was identified only from soil of the cultivated areas. The blaSFO, erm(36), oprD and van genes, in addition to the pH, showed greater correlation with in soil of cultivated areas, which in turn exhibited higher contents of nutrients. Thus, in addition to changes in chemical attributes and in the microbial community of the soil, intensive agricultural cultivation systems cause a modification of its resistome, reinforcing the importance of the study of antimicrobial resistance in a One Health approach.

Effects of boron sources and rates on grain yield, yield components, nutritional status, and changes in the soil chemical attributes of soybean

Boron (B) deficiency has been demonstrated as a frequent problem in soybean crops, as soybean exhibits a large sensitivity to this nutrient, regardless of its uptake efficiency in the soil. The objective of this study was to evaluate the effects of B sources and rates on the yield, yield components, nutritional status, and changes in the chemical attributes of soil cultivated with soybean. The experimental design was completely randomized in a 2 × 5 factorial design with four replicates. The treatments consisted of two sources (H3BO3 and ulexite) and five B rates (0, 2, 4, 8, and 16 mg kg−1). The grain yield (GY), yield components, nutritional status, and soil chemical attributes were evaluated. B sources–rates interactions (S × R) were significant for most variables evaluated. The B (H3BO3) application resulted in higher B levels in the leaves and the soil cultivated with soybean than those obtained with ulexite. GY was highest with a B application of 4 mg kg−1, exhibiting a toxic effect in H3BO3 at 8 and 16 mg kg−1. The application of B increased N, S, Fe, and B concentrations while decreasing P and K in the leaves. The shoot dry weight yield, number of pods, grains per pot, and 100-grains weight were also influenced by the B rates. The highest GY ranged from 0.3- to 0.8 mg kg−1 in the soil and 50- to 100 mg kg−1 in the soybean diagnostic leaf.

Effects of wastewater disinfectants on the soil: Implications for soil microbial and chemical attributes

In most cases, chlorination is used for effluent disinfection. However, this process can lead to the formation of byproducts hazardous to the environment and public health. Therefore, new disinfectants, such as calcium hypochlorite (CH) and peracetic acid (PAA), were investigated as alternatives. This study aimed at determining doses of the disinfectants PAA and CH to be applied to the soil and analyzing the possible changes in the major chemical and microbiological attributes of the soil, thus encouraging the practice of reusing wastewater in agriculture. Initially, toxicity bioassays were conducted with lettuce (Lactuca sativa L.) seeds in order to determine which concentrations affected germination and also which would be analyzed. From these trials, three concentrations of each disinfectant were chosen to be subjected to basal respiration, microbial biomass carbon and metabolic quotient analyses. Doses of 3, 5 and 10 mg L−1 were used for PAA, and concentrations of 25, 32 and 64 mg L−1 for CH. Thus, it was observed that the greater concentration of each disinfectant provided a significant increase in the metabolic potential of microorganisms. However, it was observed that PAA increased ecotoxicity besides promoting changes in the chemical attributes of the soil, compared to CH. On the other hand, concentrations of 3 mg L−1 and 25 mg L−1 of PAA and CH, respectively, did not cause large impacts and could be an alternative in effluent disinfection with the aim of recycling it in agriculture.

Alterações de atributos químicos em solos sob diferentes anos de cultivo de Vitis vinífera L.

Entre os problemas relacionados à super fertilização nas vinhas, está o uso indiscriminado de N, P e K e de pesticidas à base Cu e Zn, que podem resultar na degradação dos atributos químicos do solo e no desequilíbrio nutricional das plantas. Este estudo teve como objetivo avaliar alterações nos atributos químicos de solos com diferentes anos de cultivo de Vitis vinifera L. cv. Pinot Noir. Foram analisados solos com diferentes períodos de cultivo (4, 9 e 16 anos) e em diferentes profundidades (0-10, 10-20, 20-30, 30-40, 40-50 e 50-60 cm). Foram avaliados os seguintes atributos químicos do solo: pH H2O, H + Al, MO, fósforo e potássio disponíveis, cálcio, magnésio e alumínio trocáveis, manganês, cobre, zinco e boro, além da Capacidade de troca de cátions (CTC), saturação por bases e saturação por alumínio. O delineamento experimental foi o de blocos casualizados em parcelas subdivididas, considerando três períodos de cultivo (4, 9 e 16 anos) e seis profundidades (0-10, 10-20, 20-30, 30-40, 40-50 e 50-60). cm), com três repetições. Os atributos químicos do solo foram submetidos à análise de variância e as médias foram comparadas pelo teste de Tukey (p <0,05). Houve variação significativa nos teores de macro e micronutrientes em relação às áreas e profundidades. Áreas com 9 e 16 anos apresentaram maiores teores de macronutrientes e micronutrientes, principalmente nos primeiros 10 cm de profundidade, devido aos usos sucessivos durante os anos de manejo da vinha após o plantio das vinhas.

Changes in chemical attributes during ripening of traditional fermented sausage, “Pirot ironed”

“Pirot ironed” is a traditional Serbian dry-fermented sausage manufactured in the south-east of Serbia. The changes in the chemical attributes of Pirot ironed sausage were followed during ripening. Samples were taken on the processing days 0, 7, 14, 21 and 28. Pirot ironed sausage was produced from the most valuable cuts of beef and chevon, without addition of starter cultures or fat tissues. Sausages were manufactured in a traditional drying/ripening chamber, where they were pressed every two days to acquire the typical flat form and to speed up the drying. The final water activity was 0.839. The lowest pH value recorded was 5.30 on the processing day 28. During ripening, the water content decreased significantly from 74.72% to 40.32%, while the protein and the fat amounts increased significantly from 19.12% to 45.79% and from 1.22% to 6.21%, respectively. Up to now, the properties of Pirot ironed sausage have not been recognized or published in scientific literature in spite of the long tradition and popularity of this meat product in Serbia.

Short-term effects of liming on chemical attributes of tropical sandy soil and soybean (Glycine max L.) yield

Lime application is the most appropriate technique to raise soil pH, decrease Al3+ toxicity and increase Ca2+ and Mg2+ contents in acidic tropical and subtropical moist soils. The objective of this research is to evaluate changes in chemical attributes and soybean yield in sandy soil after lime incorporation. The soil was classified as a typical Quartzipsamments cultivated with (Brachiaria decumbens Stapf) pasture, and its degradation state was classified as strong. The experimental design was a randomized block with six replicates and four lime doses (0, 2, 4 and 8 Mg ha-1). The soil in the area was prepared with one plowing and two harrowings, followed by lime application and two more harrowings to incorporate the lime up to 0.2 m depth. The dependent variables analyzed were soybean yield; numbers of pods filled, pods not filled, and total pods and soil pH in water, CaCl2 and KCl. All parameters were measured at depth of 0.0-0.1, 0.1-0.2 and 0.2-0.3 m. The increase of soil pH by the different lime rates were observed just in 0.0-0.1 and 0.1-0.2 m layers. After 6 months no changes in soil pH were observed in subsoil (0.2-0.3 m). With lower H+ and Al3+ activity and higher basic cation availability, soybean yield was also changed. The maximum soybean yield of 2,929 kg ha-1 was observed with 4.6 Mg ha-1 lime application, although pod number per plant remained constant, independent of limestone dose.

Biochemical changes associated with electron beam irradiation of rice and links to kernel discoloration during storage

AbstractBackground and objectivesRice kernel discoloration during storage results in significant economic losses to rice growers and processors. This study aimed to elucidate the extent of chemical changes and microbial involvement on discoloration of rice kernels during storage. To segregate and/or diminish the effects of microbes, one lot of hybrid long‐grain rice (XL753) samples was irradiated with nonthermal electron beam (EB) dose of 14 kGy. The irradiated and nonirradiated control samples of rice at a moisture content (MC) of 21% on a wet basis were stored at three temperatures (20, 30, and 40°C) for 8 weeks. Samples were taken every 2 weeks for microbial and chemical analyses.FindingsA negative relationship was noted between discoloration and microbial load. The trend of increasing discoloration and chemical properties such as free sugars, free fatty acid, and free 5‐hydroxymethyl‐2‐furaldehyde (HMF), especially at higher storage temperatures and durations, suggested that biochemical changes were major drivers of the observed rice discoloration. The higher HMF in highly discolored rice (≥20%) explained nonenzymatic browning in the rice matrix during storage.ConclusionsFrom this study, it was drawn that the rice kernel discoloration was not directly related to the microbial load; the discoloration was seen in EBI rice even with 99% reduction in microbial load. However, it was clarified that the rice discoloration especially in EBI rice samples was related to the observed chemical changes, which were also storage temperature dependent.Significance and noveltyMilled rice discoloration during storage of rough rice is insufficiently understood. There is no information correlating changes in chemical attributes and microbial activity to discoloration of contemporary hybrid rice during storage. Therefore, the results of the current study provide important fundamental information and also suggest storage conditions required to arrest discoloration and maintain quality of contemporary milled hybrid rice.

Changes in chemical attributes of soil treated with tannery sludge in Amazonia

Changes in chemical attributes of soil treated with tannery sludge in Amazonia

Effects of different maturity stages and growing locations on changes in chemical, biochemical and aroma volatile composition of 'Wonderful' pomegranate juice.

This study investigated the changes in chemical attributes of pomegranate fruit such as total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio, pH, individual compounds (organic acids and sugars) and volatile composition as affected by fruit maturity status and growing location (Kakamas, Koedoeshoek and Worcester in South Africa). Headspace solid phase microextraction coupled with gas chromatography/mass spectrometry was used for volatile analysis. A significant increase in TSS from 14.7 ± 0.6 to 17.5 ± 0.6 °Brix was observed with advancement in fruit maturity, while TA decreased from 2.1 ± 0.7 to 1.1 ± 0.3 g citric acid per 100 mL across all agro-climatic locations investigated. Fruit TSS/TA ratio and pH increased from 7.8 ± 2.6 to 16.6 ± 2.8 and from 3.3 ± 0.1 to 3.6 ± 0.2 respectively during fruit maturation across all agro-climatic locations. Fructose and glucose concentrations increased continually with fruit maturity from 69.4 ± 4.9 to 91.1 ± 4.9 g kg(-1) and from 57.1 ± 4.7 to 84.3 ± 5.2 g kg(-1) respectively. A total of 13 volatile compounds were detected and identified, belonging to five chemical classes. The most abundant volatile in unripe and mid-ripe fruit was 1-hexanol, while 3-hexen-1-ol was highest at commercial maturity. Knowledge on the impact of fruit maturity and agro-climatic locations (with different altitudes) on biochemical and aroma volatile attributes of pomegranate fruit provides a useful guide for selecting farm location towards improving fruit quality and the maturity stage best for juice processing.

Changes in chemical attributes of a Fluvent cultivated with castor bean and irrigated with wastewater

Agricultural use of wastewater is an alternative to increase water availability, especially in semiarid regions. However, it may cause undesirable chemical changes in the soil. The aim of this study was to evaluate the influence of wastewater irrigation and castor bean (Ricinus communis L.) cultivation on the chemical attributes of a Fluvic Neosol. The experimental design was in a randomized block, in split-plot scheme, where the main plots were represented by the treatments of irrigation water and castor bean cultivation, and the subplots were the soil layers, with three replications. The treatments were T1 - wastewater irrigation + castor bean cultivation ; T2 - mixture of supply water and wastewater (1:1 ratio) + castor bean cultivation; T3 - supply water irrigation + castor bean cultivation ; and T4 - wastewater application, without castor bean cultivation. The depths of soil layers were 0-10, 10-20, 20-30, 30-40, and 40-50 cm. At the end of study, the content of phosphorus, calcium, potassium, and organic matter increased mainly in the upper layers, and sodium increased in the deeper layers in the wastewater treatments, in comparison to the supply water irrigation. In T4, the disposal of wastewater increased the concentration of magnesium. The pH values, iron and zinc concentration did not statistically differ in the treatments.

Atributos do solo e produtividade do milho e do feijoeiro irrigado sob sistema integração lavoura-pecuária

O objetivo deste trabalho foi avaliar as alterações nos atributos físicos e químicos do solo, na capacidade de suporte de pastagem e na produtividade do milho e do feijoeiro irrigado, em sistema de integração lavoura-pecuária, em plantio direto. O experimento de campo foi instalado em área irrigada por pivô central, em Santo Antônio de Goiás, GO, em um Latossolo Vermelho argiloso. Os tratamentos, avaliados por três anos consecutivos, foram: pastagem contínua; sucessão anual pastagem/feijão irrigado; sucessão anual milho/pastagem/feijão irrigado e sucessão anual milho/feijão irrigado no inverno. Cada parcela, correspondente a um tratamento, apresentava área de seis hectares. A espécie forrageira utilizada foi a Urochloa ruziziensis, pastejada por fêmeas bovinas mestiças das raças Gir e Holandesa, com massa aproximada de 450 kg. Não houve alteração da densidade e porosidade do solo nos diferentes tratamentos. A alteração nos atributos químicos dependeu do nutriente avaliado. Sucessões com braquiária no sistema de cultivo aumentaram a proporção de agregados do solo maiores que 2 mm. Os valores de capacidade de suporte da pastagem diminuíram à medida que o número de culturas de grãos implantadas na sucessão anual aumentou. A produtividade do feijoeiro foi influenciada pela sucessão anual envolvendo pastagem, diferentemente do observado na produtividade de milho.

Alterações em atributos químicos do solo pela aplicação de calcário na superfície ou incorporado

The application of lime on the soil surface is necessary in some agricultural situations. The objective of this work was to verify changes in chemical attributes of a medium texture soil as a result of lime application with and without amending. The experiment was carried out in a laboratory setting, in PVC columns, in a completely randomized design, with a 2 x 4 factorial design and a control, with four replicates, totaling 36 columns. The treatments were the combination of two lime rates (4 and 2 t ha-1) and four types of lime application (on surface without amending, and amending in layers of 0 to 5; 0 to 10 and 0 to 20 cm depths), in addition to the control, to which lime was not applied. After 326 days of soil incubation with lime, there was a corrective effect from the lime until 5 cm or 10 cm below the depth in which there was the application or amending. The application of lime resulted in increases of soil base saturation until 10 cm of depth, and until 40 cm of depth when the lime was amended in the layers of 0 to 5, 0 to 10 or 0 to 20 cm depth

Influence of changed management of sugarcane on some soil chemical properties in the humid wet tropics of north Queensland

A study was undertaken to quantify changes in chemical attributes and cation exchange characteristics of soils associated with two forms of changed management in sugar production systems 6–9 years after their implementation. The two production systems included a long-term green cane trash blanketed (GCTB)/burn trial and a rotation experiment established to investigate crop management strategies to reduce the effects of yield decline in long-term sugarcane monocultures. The treatments investigated in the latter trial were (a) long-term continuous GCTB, (b) grass ley, and (c) a bare fallow treatment. Under both the GCTB and grass ley systems, pH significantly declined over 6 years with an associated increase in aluminium saturation and decline in base saturation of the cation exchange complex. Although the decline in base saturation under the GCTB treatment would effectively indicate a degree of degradation, this base diminution is easily reversed through conventional management strategies. Organic carbon levels increased by 4 t/ha under the GCTB treatments compared with the burnt over a 9-year period. In contrast, under a grass ley system, organic carbon increased by 9 t/ha over a 6-year period compared with continuous cane, clearly demonstrating the superior nature of grass leys in sequestering carbon in this tropical environment. The increased net proton addition in the GCTB system relative to the burnt system was estimated to be 0.71�kmol H+/ha.year, and the net proton additions for the continuous cane, grass ley, and fallow systems were 1.38, 3.81, and 0.87 kmol H+/ha.year, respectively. The cation exchange characteristics were derived from bulk samples collected from each of the trials. The divergence between the cation exchange curves due to treatment was greatest in the surface 10 cm, but this diminished with depth, indicating that the influence of trash retention or grass leys on soil charge characteristics was confined to the surface layer. The increases in cation exchange capacity (CEC) at pH 5.5 of the GCTB treatment compared with the burnt, and of the grass ley treatment compared with the continuous cane, were estimated to be 0.67 and 0.75 cmolc/kg over the 0–10 cm depth interval. Plots of effective CEC v. CEC clearly indicated that 9–31% of the cations measured where not associated with the exchange complex and would therefore be subject to leaching loss. Organic C oxidisable by 33 mM KMnO4 (C1) or 333 mM KMnO4 (C3) was highly linearly correlated with total organic C across both sites and all treatments. This suggests that the proportions of different functional organic groups were not greatly affected by burning, trash retention, or pasture.