Soil Physical Properties Research Articles

Physico-mechanical properties of soil during the treatment period

Results of research work on physical and mechanical properties of soil during is main cultivation are presented in this article. It is established that physical and mechanical properties of soil act as defining factors in design development of working elements and justification of operating modes of soil-cultivating machines. They mainly depend on the type and texture of soil.

Harnessing SMAP satellite soil moisture product to optimize soil properties to improve water resource management for agriculture

Estimation of accurate soil physical and hydraulic properties are of prime importance for the management of water resources in agriculture-dominant regions. This study introduces a simplified framework for estimating soil physical and hydraulic properties crucial for managing agricultural water resources. The developed framework optimizes soil properties for the Regional Hydrological Extremes Assessment System (RHEAS) to enhance the performance of its core hydrological model, Variable Infiltration Capacity (VIC). These soil properties were optimized using six years (2015–2021) of satellite soil moisture observations from NASA’s Soil Moisture Active Passive (SMAP) mission with a modified Shuffled Complex Evolution (SCE-UA) optimization algorithm. A total of three most sensitive soil properties that control model soil moisture simulations, such as Ksat (Saturated hydraulic conductivity), expt (exponent parameter in Campbell’s equation for hydraulic conductivity), and bd (Bulk density) were optimized for the Lower Mekong River (LMR) basin. To better assess the impact of optimized soil properties, streamflow simulation as well as agricultural drought severity assessment, were estimated using the RHEAS framework’s VIC Routing module and Soil Moisture Deficit Index (SMDI) module, respectively. The streamflow simulation involved four approaches: an initial open-loop setup, one optimized with SMAP soil moisture data (SMAP), another optimized with actual streamflow data (Runoff), and a final one combining the previous two datasets (SMAP_Runoff). Switching from the initial setup to the SMAP-optimized model increased the Nash-Sutcliffe Efficiency (NSE) by 56.4 % and upgrading from the streamflow-optimized to the combined data model raised the NSE by 21.9 %. This showcases the benefits of optimizing soil properties for more accurate simulations. Furthermore, the optimized model accurately represented the severity and extent of historical agricultural droughts, aligning with regional drought reports of LMR basin. This framework offers a valuable tool for hydrological modeling and drought management, particularly in data-scarce and agriculture-intensive regions, informing agricultural water resource management, irrigation decision-making, and food security initiatives within the LMR basin and beyond.

Mechanisms of phosphorus activation in charosphere and non-charosphere: The priming effect of biochar

Biochar is widely used in soil to increase the soil phosphorus content, but a special ecological zone called the “charosphere” zone is formed where biochar comes into contact with soil. The physical and chemical properties of charosphere soil are different from those of the original soil and the biochar itself, leading to uncertainty regarding the effect of charosphere soil on the phosphorus cycle. Hence, we designed a barrier device to separate biochar from soil and analyzed the impact of biochar diffusion on soil nutrient content and microbial activity. Then, the variation characteristics of the community structure of phoD-harboring bacteria and fungi in the carbonosphere (group B) and non-carbonosphere (group C) were explored. Finally, the key factors and potential driving mechanisms of soil phosphorus activation were explored. The results show that biochar improved soil microbial activity and stimulated the soil nutrient recycling, resulting in a 67.28 % greater percentage of the labile P fraction in group B than in group C. The alpha diversity and nutrient transfer efficiency of the phoD-harboring bacterial community in group B were greater than those in group C, while the phoD-harboring bacterial co-occurrence network of group C was more complex. Moreover, the synergy between the co-occurrence networks of the soil fungal community was stronger than that of the bacterial community. Biochar stimulates microbial activation of phosphorus by increasing the DOC content and pH in the charosphere, and the phoD-harboring bacterial community dominates soil phosphorus activation. These findings offer a new perspective on how biochar regulates soil phosphorus cycling, providing crucial information to guide the application of biochar in agroecosystems.

Influence of Simulated Erosion on Soil Properties and Maize Yield in the Southern Guinea Savanah Zone of Nigeria I

Long term studies were initiated to study topsoil loss and its effects on soil properties and crop yield. This study was conducted during the 2016 through 2019 cropping seasons to assess the influence of artificial topsoil loss on soil properties and grain yield of maize. Three geo- referenced sites within the Federal University of Agriculture Makurdi, Nigeria namely: Site 1, Site_2 and Site_3 were used for the experiment. Erosion levels were established in June 2016 only by the incremental removal of topsoil at various depths. The study of crop productivity using simulated erosion was conducted using Randomized Complete Block Design (RCBD) with desurfaced soil depths of 0cm (control), 5cm, 10cm, 15cm and 20cm as treatments. One profile pit was also dug in each of the three sites for soil characterization and soil type establishment. Data collected on soil physical and chemical properties as well as crop growth parameters and grain yield were subjected to Analysis of Variance (ANOVA) using R Statistical Software. Results of the study showed that the soils of the three sites were classified as Kandic Paleustepts for Site_1, Typic Plinthustalfs for Site_2 and Typic Hapluderts for Site_3. We report the effects of topsoil loss on soil characteristics in this paper for two years only.

Exploring the interplay between soil thermal and hydrological changes and their impact on carbon fluxes in permafrost ecosystems

Accelerated warming of the Arctic can affect the global climate system by thawing permafrost and exposing organic carbon in soils to decompose and release greenhouse gases into the atmosphere. We used a process-based biosphere model (DVM-DOS-TEM) designed to simulate biophysical and biogeochemical interactions between the soil, vegetation, and atmosphere. We varied soil and environmental parameters to assess the impact on cryohydrological and biogeochemical outputs in the model. We analyzed the responses of ecosystem carbon balances to permafrost thaw by running site-level simulations at two long-term tundra ecological monitoring sites in Alaska: Eight Mile Lake (EML) and Imnavait Creek Watershed (IMN), which are characterized by similar tussock tundra vegetation but differing soil drainage conditions and climate. Model outputs showed agreement with field observations at both sites for soil physical properties and ecosystem CO2 fluxes. Model simulations of Net Ecosystem Exchange (NEE) showed an overestimation during the frozen season (higher CO2 emissions) at EML with a mean NEE of 26.98 ± 4.83 gC/m2/month compared to observational mean of 22.01 ± 5.67 gC/m2/month, and during the fall months at IMN, with a modeled mean of 19.21 ± 7.49 gC/m2/month compared to observation mean of 11.9 ± 4.45 gC/m2/month. Our results underscore the importance of representing the impact of soil drainage conditions on the thawing of permafrost soils, particularly poorly drained soils, which will drive the magnitude of carbon released at sites across the high-latitude tundra. These findings can help improve predictions of net carbon releases from thawing permafrost, ultimately contributing to a better understanding of the impact of Arctic warming on the global climate system.

Estimating the impact of the thermo-physical properties of the multilayer soil on earth-air heat exchanger system performance

This study developed a new method for experimentally measuring and estimating multilayer soil thermo-physical properties. It also tested how multi-layered soil influences an earth-air heat exchanger (EAHE) system in Gödöllő, Hungary. Thus, this research has introduced these combination characteristics that increase EAHE system performance by properly estimating soil multi-layer properties and thermal gradients and their thermal performance effects. New laboratory and theoretical methods can evaluate multilayer soil thermal and physical properties depending on moisture content and density. The first layer had the lowest soil moisture content (6.10 %), the fifth layer had the highest (12.8 %), and the mixed layer had the middle value (9.12 %). The densities of these soil types ranged from 930.49 to 1184.03 kg/m3. When installing the EAHE system, the second layer is better for cooling purposes. Third-layer soil pipe air is 3.74 % hotter than second-layer air. Mixed soil heats and cools moderately. It is 1.74 % hotter and 2 % colder than the second and third layers of soil, respectively.

Effects of Different Proportions of Ammonium Sulfate Replacing Urea on Soil Nutrients and Rhizosphere Microbial Communities

In order to investigate the effects of ammonium sulfate, an industrial by-product, on soil nutrients and microbial community when applied in different proportions instead of using urea as nitrogen fertilizer, a pot corn experiment was conducted. A completely randomized block experimental design was used, with a total of five treatments:CK (no fertilization), U10S0 (100 % urea), U8S2 (80 % urea + 20 % ammonium sulfate), U6S4(60 % urea + 40 % ammonium sulfate), and U0S10 (100 % ammonium sulfate). The basic physical and chemical properties of soil and the dry weight of maize plants were determined by conventional methods, and microbial sequencing was performed using the Illumina NovaSeq platform. The experiment results showed that:① In each growth stage of maize, the pH of soil treated with fertilization (7.85-8.15) was decreased compared with that of CK (8.1-8.21), and the pH showed a decreasing trend with the increase in ammonium sulfate content. ② The soil available nitrogen content increased gradually with the increase in the ammonium sulfate ratio at each growth stage of maize. Compared with that in the CK and U10S0 treatments, the ratio in the U0S10 treatment increased 30.56 % to 63.68 % and 13.22 % to 38.43 %, respectively. The variation trend of organic carbon content was opposite to that of available nitrogen (U8S2 > U6S4 > U0S10), and the addition of ammonium sulfate was still higher than that of U10S0 at other growth stages except for the seedling stage. ③ The protease activity of all fertilization treatments was higher than that of the control, and the protease activity was gradually enhanced with the continuous growth of corn and the increase in the ammonium sulfate ratio. The protease activity of the U0S10 treatment was higher than that of the U10S0 treatment at each growth stage of corn, which increased by 10.54 %-100 %. Soil sucrase activity ranged from 0.04 to 0.24 mg·(g·24 h)-1, and those in the U0S10 treatments were significantly higher than those in the U10S0 and CK treatments at all growth stages, increasing by 20.32 % to 99.16 % and 24.31 % to 79.33 %, respectively. ④ The species abundance of bacteria and fungi in maize rhizosphere under all fertilization treatments were lower than those under the CK treatment, followed by those under the U10S0 treatment. The species diversity trend of the bacterial community in the three treatments with ammonium sulfate replacing urea were U8S2 > U0S10 > U6S4, and that of fungi were U6S4 > U8S2 > U0S10. ⑤ The maize dry weight of the U10S0 treatment and U0S10 treatment was the highest, which was 39.47 % and 36.16 % higher than that of the CK treatment, respectively, but the difference was not significant. The Pearson model showed that the species abundance and diversity of soil rhizosphere fungi and bacteria were affected by relevant environmental variables, among which pH value and soil available nitrogen content were the most important factors affecting microbial diversity. In conclusion, when corn planting in calcareous brown soil, replacing urea with a certain proportion of ammonium sulfate can improve soil nutrients more than urea alone, which affects the growth and rhizosphere microbial community of corn to a certain extent and has a greater yield.

Effects of Different Forms of Nitrogen Addition on Soil Physical and Chemical Properties and Microbial Community Structure of Perennial Alpine Cultivated Grassland

This study aimed to investigate the impact of different nitrogen forms on soil physicochemical properties and microbial community structure in perennial alpine cultivated grasslands, in order to provide scientific basis for developing nitrogen addition strategies for perennial alpine cultivated grasslands. In June 2022, a 4-year-old Qinghai grassland mixed with Poa pratensis Qinghai and Festuca sinensis Qinghai was established at the Bakatai Farm in Gonghe County, Hainan Tibetan Autonomous Prefecture, Qinghai Province. The study was conducted without fertilization as a control (CK), and three different forms of nitrogen treatments were set up, namely, U:urea (amide nitrogen), A:ammonium sulfate (ammonium nitrogen), and N:calcium nitrate (nitrate nitrogen); the nitrogen application rate for each treatment was 67.5 kg·(hm2·a)-1, and the composition and diversity of soil nutrients and microbial communities under different treatments were analyzed. The results showed that the input of exogenous ammonium nitrogen significantly increased NH4+-N content, AP content, and EC; amide nitrogen input significantly increased SOC content and TN content; and nitrate nitrogen input significantly increased NO3--N content, AN content, and TC content. Exogenous nitrogen input changed the structure of soil bacterial and fungal communities, as well as the relative abundance of dominant phyla and genera, but it did not significantly affect the alpha diversity of bacterial and fungal communities. Principal coordinate analysis (PCoA) showed that different forms of nitrogen addition had a significant impact on the Beta diversity of bacterial communities, whereas the impact on fungal communities was not significant. Redundancy analysis (RDA) indicated that nitrogen addition mainly changed the composition and structure of microbial communities through soil ammonium nitrogen. Overall, ammonium nitrogen fertilizer should be given priority in the soil remediation process of perennial cultivated grasslands in the Qinghai Tibet Plateau.

Mitigation of salinity stress in ‘Chandler’ walnuts through the application of Ascophyllum nodosum extracts to soil: effects on growth, yield, and its impact on physical and biological soil properties

Mitigation of salinity stress in ‘Chandler’ walnuts through the application of Ascophyllum nodosum extracts to soil: effects on growth, yield, and its impact on physical and biological soil properties

The Influence of Different Land Use Practices on Specific Physical Characteristics of Soil in Gaya, a Region within the Savanna Ecosystem in Nigeria

This study examines the impact of various land use types on specific physical properties of soil at the Kano University of Science and Technology Research Farm in Gaya, Gaya L.G.A., Kano State, Nigeria. The four agricultural land uses investigated are cropland, forest, grazing, and plantation land. Soil samples were randomly collected from two depths (0-15 cm and 15-30 cm), with five samples from each depth per land use type, resulting in 40 samples. Bulk densities were measured using the core method. The results indicated no significant effect (Fpr > 0.05) of land use on bulk density and porosity. However, bulk density values exhibited an increasing trend: cropland (1.602 g/cm3) < forest land (1.667 g/cm3) < plantation land (1.669 g/cm3) < grazing land (1.69 g/cm3). Grazing land had the highest mean bulk density, while cropland had the lowest. At 0-15 cm depth, plantation land had the highest mean bulk density (1.698 g/cm3), and cropland had the lowest (1.547 g/cm3). At a depth of 15-30 cm, forest land had the highest mean bulk density (1.767 g/cm3), while plantation land had the lowest (1.641 g/cm3). Total porosity showed an increasing trend from grazing land (30.8%) to plantation land (33.6%), cropland (34.3%), and forest land (37.7%). Factors such as organic matter content, aggregate size, and soil depth influenced the bulk density and porosity characteristics. Overall, bulk density was higher than standard values, indicating compaction: sandy soils were too compact, loamy soils were very compact, and clay soils were highly compact. Total porosity generally fell within the moderate range, and particle density was within the normal acceptable range of 2.65 g/cm3.

Free iron oxides modulate the surface properties of Benggang soil on Southern China: insights into erosive mechanisms

Benggang, an erosional phenomenon located in southern China, exhibits distinctive characteristics that can have profound ecological and agricultural consequences as well as pose risks to human life. Previous investigations have primarily focused on elucidating the relationships between the physical and chemical attributes of soils collected from Benggang. However, the precise role of free iron oxides in the surface properties of Benggang soil and its contribution to the formation of Benggang remains largely unexplored. In this study, we aim to investigate the role of free iron oxides in Benggang soil by removing them and subsequently introducing goethite to evaluate their impact on the soil’s surface properties. Our results reveal a decrease in the surface charge density of soil colloidal particles with increasing soil depth. Specifically, the uppermost red soil layer exhibits the highest value, followed by the sandy soil and the lowermost clastic layer. Upon removing free iron oxide, we documented reductions of 44.28% (red soil), 20.62% (sandy soil), and 8.70% (clastic layer) in the surface charge density of colloidal particles. The red soil layer presented an over 18-fold increase compared to the initial linear shrinkage, followed by the sandy soil and clastic layer. Notably, the addition of goethite to the iron oxide-free soil layers resulted in the recovery of approximately 81.93%, 121.13%, and 104.35% of the initial surface charge density, respectively. Moreover, significant changes in volume shrinkage were observed, with approximately 97.54% (red soil), 94.75% (sandy soil), and 89.72% (clastic layer) of the initial values being influenced. These findings underscore the substantial influence of free iron oxide on the physicochemical properties of Benggang soil and contribute to a comprehensive understanding of the erosive mechanisms underlying Benggang formation.

Study on the enhancement of citric acid chemical leaching of contaminated soil by modified nano zero-valent iron.

This study aimed to evaluate the effect of modified nanoscale zero-valent iron (SAS-nZVI) on chemical leaching of lead and cadmium composite contaminated soil by citric acid (CA). The synthesized SAS-nZVI was used as a leaching aid to improve the removal rate of soil heavy metals (HMs) by CA chemical leaching. The effects of various factors such as SAS-nZVI dosage, elution temperature and elution time were studied. At the same time, the effect of chemical leaching on the basic physical and chemical properties of soil and the morphology of HMs was evaluated. The results show that when the SAS-nZVI dosage is 2.0g/L, the leaching temperature is 25°C, and the leaching time is 720min, the maximum removal rates of Pb and Cd in the soil are 77.64% and 97.15% respectively. The experimental results were evaluated using elution and desorption kinetic models (Elovich model, double constant model, diffusion model). The elution and desorption process of Pb and Cd in soil by SAS-nZVI-CA fitted well with the double-constant model, indicating that the desorption kinetic process of Pb and Cd is a heterogeneous diffusion process, and the elution process is controlled by diffusion factors. After leaching with SAS-nZVI-CA, the physical and chemical properties of the soil changed little, the mobility and toxicity of HMs in the soil were reduced, and the HMs content in the leaching waste liquid was reduced. It can be concluded that SAS-nZVI enhances the efficiency of CA in extracting Pb and Cd from soil, minimizes soil damage resulting from chemical leaching technology, and alleviates the challenges associated with treating leaching waste liquid.

Relation of several pedological characteristics to engineering qualities in expansive clays of Northern Venezuela

The Caribbean Coastal Region of Venezuela with a semi-arid climate presents adequate conditions for the development of soils with expansive clays, which are the main pathology registered by the roads and surrounding infrastructures in the region. Correlation studies in temperate soils have shown that there is a close association between Atterberg limits (AL) with the clay content, less information exists in the literature between the association of AL and other soil physical properties of soil (e.g. in situ water-content and soil particle density). The main objectives of this research were to: evaluate the presence of expansive clays in northern Venezuela through the limits and indices of Atterberg, and to relate the AL to soil physical properties determined during both soil surveys and geotechnical evaluation of risks. The plasticity index (PI) and the shrinkage limit (SL) of the clays are high, whereas the plasticity chart of the samples indicates two well-defined groups, a major one, in the area of low plasticity, the other group in the area of high plasticity. The information shown a close association between the original moisture content of the samples with the AL, highlighting, the strong association of LL and PI with moisture content in situ. However, the soil particle density and the bulk density were negatively related to moisture content. The information presented here for tropical samples confirms the information in the literature for temperate zones, where it is concluded that the liquid, plastic and plasticity index limits were highly significantly related to the clay content.

Assessment of Integrated Poultry Manure and Synthetic Fertilizer Effects on Maize (Zea mays) Growth and Soil Properties: A Study from Bayero University, Kano

The study investigated the effects of organic and inorganic nutrients on crop productivity and soil health, with a focus on maize growth and soil properties. It was conducted at Bayero University, Kano and comprised six treatments laid out in a Completely Randomized Design (CRD) with three replications. The treatments included poultry manure, synthetic fertilizers, and their combination. The research aimed to assess the impact of these treatments on maize growth and their residual effects on soil physical and chemical properties. Various plant growth parameters and soil properties were evaluated, and the data obtained were analyzed using Analysis of Variance (ANOVA) and Student-Newman-Keuls test (SNK). The results indicated that all treatments significantly influenced morphological parameters, including plant height, number of leaves, stem girth, and leaf area, compared to the control. Maize growth was notably higher with the application of integrated poultry and inorganic fertilizer or solely inorganic fertilizers. Additionally, soil organic carbon, total nitrogen, phosphorus, and potassium contents increased when poultry manure was applied alone or in combination with inorganic fertilizer. The application of poultry manure significantly raised soil pH, organic carbon content, total nitrogen, available phosphorus, exchangeable potassium, calcium, magnesium, and effective cation exchange capacity (ECEC) of the soil. Furthermore, the exchangeable acidity of the soil was reduced by the application of poultry manure alone. Soil texture was improved, soil bulk density decreased, and porosity increased due to the application of poultry manure. The study concluded that the combined application of poultry manure and inorganic fertilizer enhanced the growth of maize and could serve as a good soil management practice for tropical soils. It also suggested that integrating inorganic fertilizers with organic manures at optimum rates could improve crop productivity on a sustainable basis. The findings of this study may contribute to the development of sustainable nutrient management programs aimed at enhancing crop productivity with high efficiency and minimal nutrient loss in the future.

Dynamics Thresholding for Assessment of Land Fires Susceptibility, Brantas Hulu

Abstract Forest fires are often an environmental problem that has the potential to cause environmental damage. It is predicted that as temperatures increase due to climate change, the risk of land and forest fires will become greater. This research aims to (1) model the vulnerability of land and forests to fire and (2) examine inherent land factors such as the type and physical properties of soil and land-use typology against fire. This research is quantitative, combining remote sensing data and field observations. Machine learning algorithms and dynamic thresholding will be tools for data analysis. Model verification will be carried out using national fire disaster data as well as field observations. The Brantas Hulu watershed has a high probability distribution of vulnerability. The training data Area Under the Curve (AUC) value is 0.923, and the test data The training data Area Under the Curve (AUC) value is 0.923 value is 0.912. The variables used provide different contribution values. Land Cover 2019 has the highest contribution to the model, namely 26.5%, and the lowest contribution to the model, namely Evapotranspiration 2023, Normalized Burn Ratio (NBR) 2023, and Normalized Difference Vegetation Index (NDVI) 2023, namely 0.1%. Forest and land fires can occur due to triggers from human activities. It is necessary to explain to the public not to burn grass and debris. Avoid burning when the weather is windy. Strong winds are the main factor in forest fires becoming more widespread.

Winter cover crop performance in the Southern Piedmont region of South Carolina

AbstractCover crops (CCs) offer in‐field and environmental benefits when integrated into cropping systems. Low CC adoption in the Southern Piedmont region of South Carolina is partially due to the lack of information on CC performance and benefits within the region. To address this, eight winter CCs and a fallow/pigweed (Amaranthus spp.) treatment were investigated for their influence on soil temperature, volumetric water content (VWC), percent cover, biomass, and the occurrence of soil water repellency (SWR). A randomized complete block design experiment was conducted in the fall and winter of 2021–2022 (EXP A) and repeated in 2022–2023 (EXP B). Experiments were treated separately as methods were revised for EXP B. CCs minimally influenced soil VWC over both experiments with no consistent trend. CC did not influence soil temperatures during EXP A. In EXP B, the fallow/pigweed had the highest soil temperatures on two (out of 10) measuring events (p < 0.05). No SWR was found in either experiment. Establishment and fresh and dry CC biomass were most likely influenced by air temperatures and daylight hours driving germination during days with minimal rainfall. In both experiments, annual rye (Lolium multiflorum) produced cover quickly and yielded high biomass. Crimson clover (Trifolium incarnatum) took longer to establish but also yielded one of the highest biomasses. This study demonstrated that winter CCs had little influence on soil physical properties and that while cereal rye (Secale cereale) is a common CC utilized for erosion control, the greater biomass and surface roots of annual rye make it a superior CC for use in Southern Piedmont agroecosystems.

Use of biochar and NPK fertilizer in soybean cultivation in Alfisol to improve soil physical properties and plant growth

Abstract The decrease in soil properties due to using artificial fertilizers requires finding a solution, one of which is using biochar. This research aims to assess the effect of the application of rice husk biochar and NPK compound fertilizer on the physical properties of Alfisols and soybean growth. The study was conducted from March to June 2023 on Alfisol of Kwangsan Village, Jumapolo, using a Randomized Complete Block Design (RCBD) with 10 treatments and 3 replications. The study showed that combining rice husk biochar and NPK compound fertilizer improved soil physical properties: soil C-Organic levels, field capacity, soil porosity, and soil water retention levels, and reduced soil bulk weight. The treatments also increased soybean growth: plant height, number of leaves and branches. Application of 25% NPK compound fertilizer (75kg ha-1) and 100% rice husk biochar (10 tons ha-1) is suggested to progress soil physical properties and soybean plant development in Alfisols.

Application of modified drastic model for oil spills pollution affecting water quality system in part of Niger delta region of Nigeria

Extensive environmental pollution has affected the water resource, agricultural lands, economy and health of the inhabitants of Ahoada communities of the Niger Delta region, Nigeria. The main sources of pollution are oil spills emanating from pipeline interdiction and production-related spillages. Oil spills in the Niger Delta adversely affects the physical, chemical and biological properties of soil, which subsequently results in food shortages due to the reduction of nutrient contents of soils. Therefore, it is crucial to understand the patterns and the types of contaminants for appropriate remediation of the polluted areas. This study applied a novel DRASTIC model approach, incorporating a data-driven method Weight of Evidence (WoE) to examine subsurface aquifer vulnerability to oil spills contamination and present same as in the maps. Geographic Information System (GIS) in combination with DRASTIC and a modified DRASTIC model called DRAPSTIC were used in assessing the extent and vulnerability of the aquifers of the area to contamination. The maps of the DRAPSTIC show similarity in terms of the distribution and classification of the vulnerability index. Very high and high vulnerability classes covered larger areas in Ahoada east under DRAPSTIC compared to DRASTIC. However, under the same DRAPSTIC, larger areas were covered by low vulnerability class in Ahoada West.

Influence of traditional and alternative additives on the physical and mechanical properties of clayey soil

Influence of traditional and alternative additives on the physical and mechanical properties of clayey soil

Relationship between chlorophyll and yield of two rice varieties in different farming systems

Abstract Rice is the staple food of Indonesian society which continues to increase in demand due to population growth. Currently, there are 3 agricultural systems in rice cultivation, namely organic, semi-organic, and conventional. The three systems provide changes in soil physical, chemical, and biological properties, but there is not much information related to chlorophyll levels in plants. This study aims to assess chlorophyll levels and their relationship with the yield of two rice varieties in various farming systems, especially the IR64 and Mentik Wangi varieties. This research is a field survey study followed by laboratory analysis. Determination of sampling locations by purposive sampling on organic, semi-organic, and conventional rice fields with two varieties of rice. Observation parameters include chlorophyll content, harvest dry grain weight, and milled dry grain weight. The results showed that the levels of chlorophyll A in IR64 and Chlorophyll B in IR 64 and Mentik Wangi varieties with organic farming systems were higher than in semi-organic and conventional farming systems. There was a positive correlation between chlorophyll levels and the yield of two rice varieties in different farming systems.