Coastal Sandy Soil Research Articles

Research on Improving the Horizontal Bearing Performance of Wind Power Pile Foundation with Added Wing Structure

The growing recognition of renewable energy’s importance, particularly its role in sustainability, has propelled wind energy to a prominent position. Receiving substantial global policy support due to its unique advantages, wind energy has seen a significant increase in installed turbine capacity. Consequently, expectations for the foundational bearing performance of these turbines have heightened, reflecting the enhanced focus on sustainable energy solutions. In response to these demands, this research introduces an innovative single pile foundation design that aims to elevate bearing capabilities to new heights. This research delves into the horizontal bearing properties of this novel foundation and the stress-strain dynamics of geotechnical materials under loading conditions. To achieve this, we utilize the Gudehus-Bauer subplastic model, specifically tailored for coastal sands within the ABAQUS finite element analysis software. Calibration and verification of the Gudehus-Bauer model’s parameters were meticulously conducted based on laboratory tests focusing on the coastal sands of the Yangtze River basin in China, enabling the development of a precise finite element model for the new single pile foundation in sandy coastal soils. Our findings reveal that this reinforced single pile foundation not only mirrors the horizontal bearing capacity and failure mechanisms of traditional designs but also surpasses them in performance. Numerically, this innovative structure boasts a remarkable 19.34% increase in horizontal ultimate bearing capacity and a minimum of 21.91% reduction in maximum displacement compared to standard single piles. These results underscore the superior horizontal bearing performance of our novel foundation design, which not only enhances structural integrity but also aligns with the principles of sustainable engineering by optimizing material usage, reducing environmental impact, and contributing to the broader goal of promoting renewable energy as a sustainable energy source.

Biopolymer Urea Composite for Enhancing Nitrogen Use Efficiency in Coastal Sandy Soils of Kerala, India

Aim: To formulate biopolymer urea composites in pellet form and to test their efficacy on the release and leaching of nitrogen in northern coastal sandy soils of Kerala. Place and Duration of Study: Department of Agronomy, College of Agriculture, Padannakkad, Kasaragod, Kerala agricultural University, between May 2023 and March 2024. Methodology: Pellets of biopolymer urea composites (BUCs) were formulated by mixing prilled urea with coconut shell charcoal (C1), gypsum (C2), rice husk biochar (C3), and zeolite (C4) as coating materials and potato starch (S1) and tapioca starch (S2) as binding materials. The experiment was laid out in a Factorial Completely Randomised Design. Castor oil was uniformly sprayed on the composites after formulation. These composites were tested against urea for their nitrogen content and pH. Release behavior of nitrogen in soil and distilled water and leaching behavior in the soil were studied using CRD as the experimental design. The treatments were: T1: Urea, T2: BUC 1, T3: BUC 2, T4: BUC 3, T5: BUC 4, T6: BUC 5, T7: BUC 6, T8: BUC 7, T9: BUC 8 and T10: Control (Soil). Results: Total nitrogen content was not significantly varied across different treatments, but the increase in pH was significant for the treatment, C4. Release of nitrogen in distilled water revealed marked differences among the treatments. Urea exhibited significantly elevated nitrogen release on first day compared to other treatments, whereas T9 and T4 initially showed substantially lower values, which gradually increased, reaching significantly higher levels by day 30. The soil incubation study demonstrated that urea exhibited significantly higher values of ammoniacal and nitrate nitrogen release on the 7th day, reaching their maximum on 14th day and then decreased gradually till 30 days. All other treatments showed significantly lower release of ammonia into the soil, followed by a gradual increase, reaching a maximum at 90 days. Leaching of ammoniacal and nitrate nitrogen was maximum for T1 on day 8. Significantly lower nitrate nitrogen leaching values were recorded by T9 towards the end of the experiment. Conclusion: T9 showed initial release of nitrogen at significantly lower rates. Furthermore, it had a significantly higher pH compared to other treatments, rendering its suitability for acidic soil.

Using Biochar to Improve Soil Fertility and Productivity of Drought-Tolerant Sweet Potatoes in Thanh Hoa Coastal Sandy Soil

The coastal area of Thanh Hoa province has a large proportion of sandy soil and is suffering negative impacts from climate change that affect crop productivity. The aim of this study is to investigate the use of biochar to improve the soil fertility and productivity of drought-tolerant sweet potatoes. The effect of biochar contents on the productivity of three sweet potatoes VC 04-24, KL C3, and VC 68-2 in the coastal sandy soil area of Thanh Hoa province was examined. The results indicated that the yield of sweet potatoes was the highest when applying five tons of biochar per hectare, equivalent to using 10 tons of manure. With the same biochar content, the productivity and other factors related to the product quality of these sweet potatoes such as the number of tubers per plant and the average mass of tuber were the highest. In detail, the estimated commercial productivity of VC 04-24, KL C3, and VC 68-2 were 25.46, 24.92, and 21.76 ton/ha, respectively. With the least significant difference at the probability of 0.05% (LSD0.05), the VC 04-24 and KL C3 showed high productivity. The economic efficiency of the sweet potatoes-growing model at Hai An commune, Tinh Gia district, Thanh Hoa province showed that the productivity of the model was 24 tons/ha, higher than the actual productivity of the control model (20.2 ton/ha). The productivity and the economic efficiency of the model were 18.8% and 31.38% higher than those of the control model, respectively. In addition, the test results showed that using 5-6 ton/hectare of biochar can improve the physical and chemical properties of soils.

Integrated uses of organic and inorganic fertilisers to increase sesame productivity on coastal sand fields

Sesame is recognised as a valuable oil plant with potential health benefits due to its disease mitigating properties. It shows exceptional growth rates in light soil types, such as sandy beach soils which are often deemed infertile. To address the issue, it is necessary to apply eco-friendly fertilisers derived from animal manure. Consequently, research has focused on performance evaluation over two growing seasons, namely the dry and rainy seasons, on coastal sandy soils. Employing a split-plot design across three replicates, the study investigated the influence of planting time and cultivar on the growth and yield of sesame. The study aimed to assess the impact of mixed fertiliser application timing on sesame growth and yield, focusing on both quantitative and qualitative parameters across the rainy and dry seasons. Results indicated that applying a mixture comprising chicken manure and inorganic fertiliser at the planting time significantly affected several growth parameters. These included plant height, chlorophyll content, flowering time, number of branches, net assimilation rate, root volume, and total sesame oil content, particularly in the dry season. Specifically, employing a dosage of 24.75 g of inorganic NPK fertiliser, comprising 1.45 g of nitrogen, 0.74 g of phosphorus, and 1.25 g of potassium per plant at planting time during the dry season, demonstrated the most favourable outcomes in terms of growth, yield components, and soil fertility. This approach also yielded a remarkable 54.51% oil content in the cultivar ‘Sbr-1’.

Rejuvenation of Coastal Sandy Soils through Organics

The coastal zone represents the transition from terrestrial to marine influences and vice versa. They are predominated by sandy soil texture, and have low agricultural productivity due to their properties and are vulnerable to erosion. Effective maintenance of soil organic matter is found to be a pre-requisite to ensure soil health and crop productivity. Therefore, organics based rejuvenation methods for coastal sandy soils need to be developed. A pot culture experiment was done at Kochuveli, Industrial area, in the coastal belt of Thiruvananthapuram district, Kerala, with Amaranthus (variety: Arun) as test crop. The experiment was conducted in a completely randomized design (CRD) with 12 treatments and 3 replications. In the study, effect of different organic manures such as FYM, coirpith compost, vermicompost, city compost, biochar and thermochemical organic fertilizer (TOF), with and without lime on plant growth and yield, soil organic carbon and nutrient dynamics in the southern coastal sandy soils were studied. Soil management using organic manures had considerable impact on the growth and yield characteristics of the crop. Also the analyses of post-harvest soil for nutrient parameters showed that the highest value for organic carbon, nitrogen and potassium were recorded in soil treated with lime+TOF, while the highest value for available phosphorous was recorded in treatment lime+vermicompost. The study showed that soil test based lime application and basal application of TOF @ 25 t ha-1, top dressing with fresh cow dung slurry @ 1kg per 10 litres, along with 272.7 kg rock phosphate and 122.5 kg potassium sulphate ha-1 was the best treatment to improve the soil quality, growth and yield of amaranthus in coastal sandy soils in Thiruvananthapuram district.

Electrical resistivity imaging of crude oil contaminant in coastal soils – A laboratory sandbox study

Characterizing the subsurface distribution of crude oil after a spill in a coastal environment is challenging due to variations in the soil and fluid properties. In situ sampling is limited in capturing the lateral and vertical migration of the crude oil within the vadose and saturated zones. This study presents a laboratory sandbox framework used to assess the effectiveness of electrical resistivity imaging for investigating the spatiotemporal distribution of crude oil in coastal sandy soils. A sandbox with dimensions L = 240 cm, W = 60 cm, and H = 60 cm was constructed using a 10 mm plexiglass and filled to a 40 cm height with 2 mm medium to fine-grained sand. At each stage of the experiment, 20 kg of sand was mixed with 1 l of water to create moist sand, after which the mixture was flushed over 12 h to remove suspended fine particles. Both saturated and unsaturated conditions were simulated by setting the water table at 10 cm and draining a fully saturated system overnight. Two liters of crude oil were spilled and monitored for 30 h. A surface array of 98 electrodes, with a unit electrode spacing of 2 cm, was installed along two transects 12 cm apart. Resistivity measurements were collected using a dipole-dipole array before, during, and after the simulated crude oil spill. The time-lapse electrical resistivity results revealed an initial gravity-induced vertical migration under both saturated and unsaturated conditions; over time, lateral migration of crude oil became apparent. In the saturated zone, there was a noticeable reduction in the percentage difference in resistivity from 700 % to 400 % after 24 h, depicting a spatial and temporal redistribution of the crude oil attributed to variation in pore geometry. This highlights the sensitivity of electrical resistivity measurements to subtle but measurable anisotropy in the distribution of soil pores. Overall, electrical resistivity proved successful in imaging the non-ideal behavior of crude oil pollutants and the associated spatial changes in the pore-size distribution of subsurface sediments.

Drought-Stressed Apple Tree Grafted onto Different Rootstocks in a Coastal Sandy Soil: Link between Fast Chlorophyll a Fluorescence and Production Yield

Domesticated apple is a drought-sensitive species that spread from continental to Mediterranean temperate regions, where it can particularly experience prolonged water stress. One strategy to improve drought resistance in apple is engrafting on selected rootstocks. This study explores the potential of fast chlorophyll a fluorescence for the comparison of rootstock sensitivity to drought, looking for significant correlations with fruit productivity. The experiment was conducted in a field located in the coastal Po River Plain, Northern Italy, characterized by a loamy sandy soil, particularly prone to drought (86% sand). Mature plants of apple cv. Superchief® Sandidge engrafted on three different rootstocks (CIVP21pbr, MM106, M26) were monitored throughout the summer of 2021 and compared between irrigated and non-irrigated parcels, and at the end of the season, fruit production was evaluated. Despite soil water tension only reaching −13 kPa, the non-irrigated plants experienced a small but consistent loss of Photosystem II (PSII) activity and a lesser capacity of light energy conservation in the photosynthetic electron transport chain. The fruit weight correlated with PSII photochemical indexes recorded during early drought, particularly FV/FM and PIABS; a correlation emerged between fruit number per plant and median values of electron transport parameters, including PITOT. Although all rootstocks underwent a 40% loss of productivity, the fluorescence parameters revealed a graded susceptibility to drought, M26 > CIVP21pbr > MM106, which matched well with the plant vigour. The least drought-sensitive MM106 produced less numerous but heavier fruits than the other two rootstocks.

Experimental Study on Enhancing the Mechanical Properties of Sandy Soil by Combining Microbial Mineralization Technology with Silty Soil.

Currently, coastal sandy soils face issues such as insufficient foundation strength, which has become one of the crucial factors constraining urban development. Geotechnical engineering, as a traditional discipline, breaks down disciplinary barriers, promotes interdisciplinary integration, and realizes the green ecological and low-carbon development of geotechnical engineering, which is highly important. Based on the "dual carbon" concept advocating a green and environmentally friendly lifestyle, Bacillus spores were utilized to induce calcium carbonate precipitation technology (MICP) to solidify coastal sandy soils, leveraging the rough-surface and low-permeability characteristics of silty soil. The mechanical-strength variations in the samples were explored through experiments, such as calcium carbonate generation rate tests, non-consolidated undrained triaxial shear tests, and scanning electron microscopy (SEM) experiments, to investigate the MICP solidification mechanism. The results indicate that by incorporating silty soil into sandy soil for MICP solidification, the calcium carbonate generation rates of the samples were significantly increased. With the increase in the silty-soil content, the enhancement range was 0.58-3.62%, with the maximum calcium carbonate generation rate occurring at a 5% content level. As the silty-soil content gradually increased from 1% to 5%, the peak deviator stress increased by 4.2-43.2%, enhancing the sample shear strength. Furthermore, the relationship between the internal-friction angle, cohesion, and shear strength further validates the enhancement of the shear strength. Silty soil plays roles in adsorption and physical filling during the MICP solidification process, reducing the inter-particle pores in sandy soil, increasing the compactness, providing adsorption sites, and enhancing the calcium carbonate generation rate, thereby improving the shear strength. The research findings can provide guidance for reinforcing poor coastal sandy-soil foundations in various regions.

Effect of Permeation Grouting Using Cement Kiln Dust (CKD) On Some Mechanical Properties of Sandy Soil

Permeation grouting is a suitable technique to enhance the geotechnical characteristics of granular soils, several researches have proved that permeation grouting using conventional grouting materials has improved the behavior of the treated soils, but the use of conventional materials causes additional costs. Cement Kiln Dust (CKD) is a significant by-product produced in considerable quantities during the production of Ordinary Portland Cement. This study was conducted to assess the effect of permeation grouting using (CKD) grouts on enhancing some mechanical properties of coastal sandy soil in Syria. To achieve the objective of this study; a laboratory grouting model was manufactured. The studied sand has been grouted with suspensions consisting of different percentages of (CKD) (2, 4, 6, 8, 10, and 12%) as a proportion of the dry weight of the treated sand, and various mixing ratios (Water: CKD) (2:1, 4:1, 6:1, 8:1, and 10:1). Then an inclusive laboratory study was carried out before and after grouting for (7 & 28) days of treatment. The results of this study proved the effectiveness of (CKD) grouts; the grouted sand has obtained a high unconfined compressive strength. Also, the values of both shear strength and cohesion increase, and the values of permeability coefficient decrease as (CKD) content and curing period increase.

Management of collar rot in groundnut in coastal Sandy soils of Andhra Pradesh

Management of collar rot in groundnut in coastal Sandy soils of Andhra Pradesh

Efficacy of Organic Matter Briquette Combined with Nitrogen Fertilizer towards Maize (Zea mays L.) Growth on Coastal Sandy Soil

Application of organic briquettes has promising potency to optimize the efficacy of nitrogen fertilization for maize cultivation (Zea mays L.) under sub-optimal condition. This present study was aimed to select the type of organic briquette to be combined with N fertilizer as well as determine the ratio of the mixture to promote higher growth performance of maize on coastal sandy soil. This study was designated using completely randomized design (CRD) with 2 factors, namely doses of organic briquettes and doses of N fertilizer. As the control for the treatment, the non-briquette forms were also applied. Five replicates were prepared for each treatment. The results showed that organic briquettes application improved the efficacy of N fertilization. Specifically, briquette made from chicken manure significantly enhanced the maize growth on coastal sandy soil with the dose of 10 tons per hectare. This result was marked by the highest yield, namely corn cobs per plant (159.82 g).

Long-term conversion of upland to paddy increased SOC content and N availability in a sand dune of Japan

Land use change driven by anthropogenic activities has greatly affected terrestrial C and N cycling; however, it remains unclear how dynamics of soil organic carbon (SOC) and nitrogen (N) availability respond to long-term land use change in sand dunes. Here, we investigated the changes in SOC, total nitrogen (TN), and their aerobic and anaerobic decomposition or mineralization in a vinyl film paddy, compared with dry land use and management changes (LUMCs) (original upland, greenhouse, and agricultural forest (tree area)) in Shonai sand dunes, northeast Japan. The vinyl film paddy had been singly cultivated for 54 years. Soil samples were collected from five soil depths (0–10, 10–20, 20–30, 30–40, 40–50 cm) to compare the effects of depth and LUMC among the four treatments. The C decomposition (Dec-C) was assessed as the aerobic CO2 production and anaerobic methane and CO2 productions. Meanwhile, N mineralization (Min-N) was determined as aerobic NH4+ and NO3– production and anaerobic NH4+ production. The results showed that the vinyl film paddy increased SOC and TN contents, Dec-C and Min-N than upland and greenhouses at 0–30 cm depth but lower levels than the tree area at all depths. The arithmetic mean for all depths showed the aerobic Dec-C in the paddy (216.0 mg kg−1) was higher than the corresponding anaerobic Dec-C (192.8 mg kg−1). Conversely, the aerobic Min-N (35.9 mg kg−1) was lower than the anaerobic Min-N (75.7 mg kg−1). There were significantly positive correlations among SOC, TN, aerobic and anaerobic Dec-C and Min-N, whereas the paddy had steeper slope than other three LUMCs. Conclusively, our results indicated that long-term conversion of upland to vinyl film paddy increased SOC and TN accumulation and N availability (Min-N) in Shonai sand dunes, which can be applied as an effective agricultural practice to improve fertility of coastal sandy soils.

A Framework for Assessing the Bearing Capacity of Sandy Coastal Soils from Remotely Sensed Moisture Contents

A Framework for Assessing the Bearing Capacity of Sandy Coastal Soils from Remotely Sensed Moisture Contents

Improving basil productivity in coastal sandy soil Yogyakarta by balanced Urea-ZA (N-S) fertilizers and application of soil amendment to increase fertilization effectiveness

Basil is a plant that can be cultivated in Psamment (coastal sandy soil). Basil requires nitrogen (N) and sulfur (S), so the N-S balance is needed to obtain optimal results. Psamment contains low colloid, causing nutrients to be barely bound and easily lost. Zeolite and biochar can be a solution. This study aimed to determine the composition and frequency of fertilization, as well as the use of soil amendment for basil growth. This research consisted of two interrelated studies arranged in a Randomized Complete Block Design. The research was conducted in Bugel, Panjatan, Kulon Progo, and the analysis was performed at the Soil Department Laboratory, Faculty of Agriculture, Universitas Gadjah Mada. The first study consisted of two factors, namely Urea-ZA composition (0:0, 60:40, 70:30, 80:20, 90:10, and 100:0) and frequency of fertilization (every 1 and 2 weeks). The application of Urea-ZA (80:20) gave the best fresh-dry weight, N-S content, and N-S uptake of basil, and this result was used as the reference for the second study. The second study consisted of two factors, namely Urea-ZA fertilizer doses (50%, 75%, and 100%), and types and doses of soil amendment (without amendment, zeolite 7.5 t/ha, zeolite 15 t/ha; biochar 7.5 t/ha, and biochar 15 t/ha). It can be concluded that soil amendments application improved the chemical properties of psamment, fresh-dry weight, N-S content, and N-S uptake of basil. Furthermore, biochar and zeolite could increase the effectiveness of fertilization, so the dose of Urea-ZA fertilizer could be reduced until 50%.

Contribution to the knowledge of the oribatid mite genus Discoppia (Acari, Oribatida, Oppiidae)

The supplementary description of the oribatid mite species Discoppia (Cylindroppia) cylindrica (Pérez-Íñigo, 1965) (Oribatida, Oppiidae) is presented, based on materials collected from deep layers of coastal sandy soils in the Republic of Dagestan, eastern Caucasus. The morphology of exobothridial seta, gnathosoma and ovipositor, and the identification of leg setae and solenidia are given for the first time for this species. The revised generic diagnosis, identification key, distribution, and habitats of all known representatives of Discoppia Balogh, 1983 are presented. Some taxonomic nuances within Discoppia are discussed, resulting in the following proposals: Oppia bifidus Bayoumi and Al-Khalifa, 1985 is a junior synonym of D. (C.) cylindrica; Oppia agricola Fujikawa, 1982 is not synonym of D. (C.) cylindrica and transferred to the genus Microppia Balogh, 1983; Oppia tenuis Hammer, 1958 is not representative of Discoppia; Discoppia (Cylindroppia) rostroincisa Subías and Rodríguez, 1986 n. stat. (instead of the existing subspecies status). Together with D. (C.) cylindrica, in the same samples, two rare Oppiidae species were found: Oxyoppia (Oxyoppiella) minuscula Hugo-Coetzee, Lotfollahi, Abbasi-Kalo and Movahedzade, 1917 (known only from the open habitats in Iran) is first recorded in Russia; Graptoppia (Stenoppia) boucheri Ermilov and Frolov, 2021 (known from passalid beetles collected in Ghana and Gabon, West Africa) is first found in the Palaearctic. Both findings in Dagestan are among the northernmost records of their semicosmopolitan subgenera.

Assessment of Soil Quality Index in the Southern Coastal Sandy Soils of Kerala, India

Context: The Indian state of Kerala has a long coastline of 589.50 km all along its western border, which has a great potential in biomass production. The agro-ecological unit 1 (AEU 1) in Kerala represents the southern coastal plains, with typical sandy soils. The major constraints of these coastal sandy soil with regard to agriculture are: low organic matter and clay content, as well as their poor water holding capacity, resulting in limited ability to hold nutrients.
 Aims: A study was carried out to evaluate the physico-chemical parameters and quality of the soils of coastal sandy soils in AEU 1.
 Methods: Fifty geo-referenced composite soil samples were taken from different locations of AEU-1 in Thiruvananthapuram district, and were characterised for physical, chemical and biological attributes. Principal component analysis (PCA) was carried out for the analysed soil properties which resulted in 6 principal components (PCs) and a minimum data set (MDS) was obtained using the selected indicators i.e., texture (clay %), water holding capacity, bulk density, soil pH, organic carbon, available nutrients such as potassium, sulphur, zinc, manganese and boron. The soil indicators were changed to unit-less scores after the development of MDS, and were assigned with appropriate weights based on existing soil conditions and soil nutrient content.
 Key Results: Value of SQI recorted the highest in Kadakkavoor and the lowest in Anchuthengu. Further, the locations were classified into three groups namely poor, medium, and good, based on the relative soil quality index (RSQI). Less than 50% of RSQI is considered poor, from 50% to 70% is medium, while more than 70% is considered good. From the study, majority of the land area (60% of samples) in AEU 1 of Thiruvananthapuram district were observed to have a medium level of relative soil quality index.

Utilizing Compost Soil Conditioner in Beach Sand Soil as a Palm Oil (Elaeis guineensis Jacq) in Pre-nursery Media

The objective of this study was to assess the effect of the type and dose of compost on the growth of oil palm seedlings in pre nursery with coastal sandy soil. The other objective is to know the effect of the type of compost on the growth of oil palm seedlings in pre nursery with coastal sandy soil. Lastly, the study examines the right dose of compost that provides the best growth of oil palm seedlings in pre nursery with coastal sandy soil. The experimental design was set in a factorial completely randomized design (CRD) consisting of two factors from April to June 2020 at the Tridharma Research Station Faculty of Agriculture, INSTIPER. The first factor is the type of compost which consists of 2 levels, Lamtoro compost, and vermicompost. The second factor is the dose of compost consisting of 4 levels: control (without compost), 50 gr compost/polybag, 75 gr compost/polybag, and 100 gr compost/polybag. The research data were analyzed using analysis of variance (α =0,05), and if there was a significant effect, it was continued with the Duncan multiple range test ( α = 0,05). Parameters observed included seedling height, total leaf, leaf width, stem diameter, shoot dry weight, root dry weight, root length, and total roots. The results showed that no combination of types and doses of compost significantly affected the growth of oil palm seedlings in pre-nursery. Using vermicompost can significantly increase oil palm seedlings' leaf area and root dry weight. Using compost at a dose of 50 g/polybag increased seedling height, stem diameter, and root dry weight in pre-nursery of oil palm seedlings.

Effect of Macro and Micronutrients on Nutrient Uptake of Groundnut (Arachis hypogaea L.) in Coastal Sandy Soils

Aim: This experiment was conducted to evaluate the effect of macro and micronutrients on nutrient uptake of groundnut in coastal sandy soils.
 Materials and Methods: A field experiment was conducted at Agricultural College Farm, Bapatla during rabi, 2021-22 to assess the response of macro and micronutrients on nutrient uptake of groundnut in coastal sandy soil.
 Results: The results of the experiment clearly indicated that the nutrient uptake of macro, secondary and micronutrients was significantly influenced by the application of macro and micronutrients. The treatment T5 (125% RDF + Soil application of ZnSO4 @ 50 kg ha-1 and Borax @ 10 kg ha-1) recorded significantly higher uptake of N, P, K, S, Fe, Zn, Cu, Mn and B at peg penetration stage. At pod development stage except iron, the highest values of N, P, K, S, Zn, Cu, Mn and B uptake were recorded in the treatment T5 and it was on par with the treatment T7. The treatment T7 which received 125% RDF + Foliar application of ZnSO4 @ 2 g L-1, FeSO4 @ 5 g L-1 and Borax @ 1.5 g L-1 at 45 and 65 DAS registered the highest uptake of N, P, K, S, Zn, Cu, Mn and B but on par with T5 at harvest stage.
 Conclusion: For iron uptake at pod development and harvest stage, the treatment T7 obtained significantly higher values and it was significantly superior over all other treatments.

Minimizing weed competition through waterlogging in rice (Oryza sativa) under various soil types

National rice production continues to be increased to meet the needs of food security in Indonesia. But in reality, every rice cultivation always raises the problem of weed disturbances. One way to control weeds can be through waterlogging. Waterlogging can suppress weed growth and increase rice yields. This study was conducted from August 2019-January 2020 at greenhouse conditions, Faulty of Agriculture, Universitas PGRI Yogyakarta. The study aimed at knowing the waterlogging period to minimize weed competition and increase the rice yield. This study was arranged in a completely randomized design (CRD) factorial with three replications. The first factor was the waterlogging period, which consisted of three levels : without waterlogging, 1-15 days after planting (DAP) and 1-30 DAP. The second factor was soil types, which consisted of four kinds : latosol, coastal sandy, volcanic and regosol soil. The weed observation was carried out at 60 DAP, and the rice was done at 104 DAP. The results showed that waterlogging could minimize weed competition in rice fields. Furthermore, waterlogging period of 1-30 DAP could inhibit the weed dry weight (WDW) and increase the leaf area index (LAI), shoot : root ratio (SRR), grain dry weight (GDW) and harvest index (HI) in different soil types. Waterlogging period of 1-30 DAP gave the highest GDW in latosol (7.5 t/ha), then decreased in volcanic (6.0 t/ha), regosol (5.9 t/ha) and the lowest in coastal sandy (4.8 t/ha). The research findings showed that waterlogging period of 1-30 DAP could minimize the weed competition and increase the rice yield. Thus, it was highly recommended to be practised as cultural weed control in rice cultivation. In future research, weed types that are tolerant to waterlogging treatment need to be combined with weeding treatment.

Sources and formation of iron minerals in eastern Mediterranean coastal sandy soils – A HRTEM and clay mineral study

Pedogenic iron minerals and their magnetic and color properties have been studied mainly as reflectors of environmental conditions, especially in Chinese and European loess/palaeosol sequences. The suggested sources of iron for the formation of pedogenic iron oxide minerals were inherited iron oxide minerals, primary iron-bearing minerals and phyllosilicates. Reddening of soils is caused by the addition of neoformed pedogenic hematite from the source minerals under favorable conditions. The sources and pedogenic processes of reddening in red Mediterranean soils have been sporadically studied, but not in the abundant sandy coastal plain soils. The current study attempts to fill two gaps: 1. exploring reddening of coastal sandy soils in relation to iron sources, accumulation of dust and soil evolution. The sandy soils were compared to modern dust and to mountainous soils developed on carbonates under the same climatic regime; 2. revealing the role of clay transformation in the release and secretion of iron. For this purpose, mineralogical compositions of bulk samples and clay fraction, as well as bulk chemical composition, were determined. High-resolution transmission electronic microscopy (HRTEM), coupled with energy dispersive spectrometry (EDS) and selected area electron diffraction (SAED), was used for visual observation, point chemical analysis, and crystal structure designation of nanoscale soil particles. The study documents hematite and goethite as the dominant iron minerals in dust, beach sand and coastal sandy soils, as well as in mountainous soils in Israel. The hematite content is higher than that of goethite in all types of samples, except in Calcaric Cambisols, where goethite is dominant. Iron-bearing minerals in dust are transformed in the soil environment to form pedogenic hematite, goethite and ferrihydrite; the scarcity of the latter indicates that the transformation processes are rather rapid. Ilmenite is found, apparently for the first time, as an important source for iron. Dust clays start transformation in the sandy soil environment immediately after deposition, during which adsorbed and structural iron is released and used to form pedogenic iron minerals. The pedogenic processes of iron mineral formation are similar in mountainous and coastal plain soils but are more intense in the latter due to the higher permeability of the sandy substrate.