Clay Soil Research Articles

Numerical Analysis of Terrain Variabilities and Their Impact on the Traction Performance of Agricultural Tire

This study uses numerical analysis to examine how terrain variability affects agricultural tire traction performance, utilizing ANSYS simulations and the Wong and Preston-Thomas tire model. Tractor tire performance was evaluated across ten different clay soils with varying mechanical properties. The ANSYS simulations modeled tire-soil interactions, and the Wong and Preston-Thomas model predicted traction performance based on stress data. Results showed notable variations in thrust, drawbar pull, and motion resistance, with certain soils delivering better traction. The study offers insights for optimizing tire design to improve vehicle productivity on diverse terrains. Keywords: Wong and Preston-Thomas tire model, numerical analysis, traction performance, ANSYS simulation, clay soil parameters, tire-soil interaction.

Fabrication of carboxymethyl tamarind kernel gum-based hydrogel and its applicability in different types of soils for agronomy

An avant-garde agricultural hydrogel - Carboxymethyl tamarind kernel gum-poly sodium acrylate-polyacrylamide hydrogel was designed by free-radical polymerization of biopolymer: carboxy-methyl tamarind kernel gum and monomers: sodium acrylate, acrylamide, using N,N′ methylene bisacrylamide as crosslinker and potassium persulphate as initiator, to explore its application as a soil conditioner. It was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric techniques. Swelling was investigated at different pH and in saline solutions. The fabricated hydrogel absorbed 189 ml/g of distilled water. Minimal 0.1 % hydrogel-amended different soils unveiled an upswing in maximum water holding capacity: Sandy soil (43%), Clay soil (31 %), Silty soil (29 %) & Loamy soil (9 %).; decrease in porosity: Sandy (29 %) > Loamy (15.2 %) > Silty (6 %) > Clay (5.9 %), increase in available water content: Clay soil (17.52 %), Silty (13.45 %), Loamy soil (9.416 %), Sandy soil (10.375 %); increase in bulk density: Clay (1.7 %), Silty (5.3 %), Loamy (10 %) and Sandy (13%) as compared to control sample. These sequels were corroborated by water retention capacity in chickpea plants. The designed hydrogel, as a soil conditioner, was commendable in all types of soils but is worth applying in sandy and loamy soils. This hydrogel richly assists as a soil conditioner and boosts plant performance in a green eco-friendly way.

Differences in soil biological activity and soil organic matter status only in the topsoil of Ferralsols under five land uses (Allada, Benin)

Land use change on the Ferralsols of the Allada Plateau in southern Benin has led to a slight decline in soil organic carbon (SOC) stocks over the last two decades. However, as in many African landscapes, detailed characterisation and quantified data on the SOC stocks and soil biological activity under major land uses are still poorly understood. The aim of this study was to characterise the biological activity and organic matter status of Ferralsols (0–30 cm) under the five major land uses on the Allada Plateau, i.e., forests, tree plantations, young and adult palm groves, and croplands (pineapple, maize). Soil biological activity was assessed using the standardised litter decomposition method (Tea bag index) and soil respiration (during a 28-day soil incubation). Soil organic matter status was characterised by quantifying SOC pools: soil microbial biomass carbon (MB-C), potassium permanganate oxidisable carbon (POX-C), and SOC associated to soil particle-size fractions (e.g. particulate organic matter, POM, and SOC associated to the clay soil fraction). The results indicated that SOC pools and biological activity were lower in tree plantations than in forests. The standardised litter decomposition was also slower in tree plantations than in forest. In croplands and palm groves, SOC pools and soil microbial biomass and respiration were lower than in forests and tree plantations. This high level of biological activity in forests, and at a lesser level in tree plantations, was effective in accumulating carbon in C pools associated to the clay fraction. Agricultural land uses, such as croplands and palm groves decreased all the soil C pools even those associated to the clay fraction, except for POX-C. However, these land-use effects on SOC pools decreased strongly with depth. At 10–30 cm, the differences in SOC pools or soil respiration between the five land uses were no more noticeable. Our results indicated that the amount of organic inputs was an essential factor to sustain high soil biological activity and SOC stabilisation in the clay size fraction, but only in the topsoil. Maintaining forests in the landscape is a priority in order to preserve SOC stocks and soil biological activity, which neither monospecific tree plantations nor cultivation can do at the same level.

The utilization of pulverized waste tire rubber in a soil–cement composite for sustainable compressed earth brick production

This study examined the suitability of blending waste tires with cement in indigenous soil for producing compressed earth bricks (CEB) to achieve a sustainable environment. CEB was produced with clay soil and a combination of cement at 5 and 10% levels with varying dosages of pulverized waste tire at 0, 2.5, 5, 7.5, and 10% mixture. Classification tests were conducted to determine engineering properties such as the particle size distribution, Atterberg limit, specific gravity, optimum moisture and unit weight of the soil. The physical properties of the pulverized tire were evaluated. Moreover, density, water absorption, and compressive strength were determined for hardened CEB samples produced from mixtures of soil and various proportions of blended cement and pulverized waste tire materials. The classification results showed that the soil was silty clay of low plasticity. The density of the CEB samples was observed to increase slightly with the addition of blended cement-tire residue. Furthermore, a considerable improvement in the compressive strength development of the CEB was observed; however, compared with those of the control, the peak compressive strength of the CEB samples was greater when the soil was stabilized with 7.5% pulverized waste tire material and 10% cement. A decrease in the water absorption capacity of CEB was observed with an increase in the amount of pulverized waste tire and cement in the soil mixture. The response models corroborate the experimental findings indicating that amount of waste tire rubber residue and cement had significant effects on the CEB performance. This study ensure the beneficial recycling of waste tires blended with cement in soil for making medium-strength CEB to achieve sustainable, resilient masonry construction applications.Graphical

Labile Fraction of Organic Carbon in Soils from Natural and Plantation Forests of Tropical China

Labile organic carbon (LOC) is a key driver of forest ecosystem function and may mitigate global climate change through carbon sequestration. To explore the accumulation of LOC in tropical forest soils, we sampled from both planted and natural forests in Hainan Province, the southernmost province of China. We analyzed the concentrations of total organic carbon (TOC) and LOC and characterized various physicochemical properties such as pH and soil texture to understand their inter-relationships in tropical natural and plantation forests. Although the TOC concentration was higher in plantation forests (88.61 g/kg) than in natural forests (68.73 g/kg), the LOC concentration was higher in natural forests (5.12 mg/g) than in plantation forests (4.07 mg/g). Over a depth range of 0–50 cm from the surface, both forest types showed decreasing TOC and LOC concentrations with increasing soil depth, indicating surface aggregation. The soil is slightly acidic and primarily composed of sand particles. Correlation analysis showed a highly significant negative correlation between LOC concentration and soil pH in both forest types (p < 0.01). Soil LOC was positively correlated with soil clay and silt particles and negatively correlated with sand particles. This study provides valuable insights into soil carbon sequestration in tropical rainforest ecosystems in both plantation and natural tropical forests.

Geotechnical performance of X-section cast-in-place concrete piles under torsion loads in clay soil – numerical study

ABSTRACT Deep foundations are inexorably subjected to torsional load due to eccentric lateral loads. The conventional piles face shortcoming under torsional loads due to its fair face. So, this study employed an innovative X-section cast in place concrete pile to improvement the torsional capacity of piles. PLAXIS 3D V20 Software was used to study the performance of XCC pile under torsional load, and combined torsional, and vertical loads in clay soil. The numerical results reflect that at the ratio of pile length to pile diameter (Lp/Dp) = 15, and the ratio of the open arc spacing to pile diameter (ap/Dp) = 0.14, open arc degrees (θ°) = 90, the torsional capacity can be improved by 3.96, 5.06, and 5.71 times of torsional capacity of conventional pile with the same cross-sectional area at clay cohesions of 70 KN/m2, 40 KN/m2, and 30 KN/m2, respectively. Also, The XCC pile recorded an increase ratio of 35% in the vertical capacity of piles compared to conventional pile with the same cross-sectional area. It can be concluded that XCC piles exhibit significant resistance to torsional forces due to their cross-sectional geometry which enhances soil-pile interaction.

Synthesization and characterizations of coal fly ash-coffee grounds-based composite as super-absorbent for application in soil

To recycle and utilize two types of harmful solid waste, coffee grounds (CG) and coal fly ash (CFA), a novel and low-cost superabsorbent composite (MCG-PAA/CFA) was synthesized by aqueous solution polymerization with modified coffee grounds (MCG), acrylic acid (AA) and CFA as raw materials, and it was applied to soil to improve its drought resistance. Various reaction conditions were comprehensively investigated and analyzed to assess their influence on the water absorbency of the superabsorbent composite (SAC). After optimization, the MCG-PAA/CFA exhibited water absorbency capacities of 1260(±10.6) g/g and 82(±1.4) g/g in deionized water and physiological saline, respectively. After adding 3 wt% MCG, the water absorption of SAC was improved from 415 to 746 g/g. After further introduction of 2 wt% CFA, the water absorption of SAC increased from 746 to 1260 g/g. Fourier Transform Infrared (FTIR) analysis confirmed that the grafting reaction was successful and that CFA participated in the reaction, while scanning electron microscope (SEM) and thermogravimetric analysis (TGA) results revealed that the grafting reaction and the introduction of CFA improved the surface morphology and thermal stability of the SAC. Kinetic analysis was conducted to investigate how the grafting reaction and the introduction of CFA affected the swelling and water retention kinetics of the superabsorbent composite. In the soil experiment, adding only 0.1 wt% MCG-PAA/CFA can improve the water holding capacity of sandy soil, loam soil and clay soil by 6.65%, 4.42%, and 3.76% respectively This SAC composite has great potential in soil drought resistance.

Influence of irrigation regimes, variety and cow dung rates on selected chemical properties of a sandy clay loam soil in Sokoto, Nigeria

Influence of irrigation regimes, variety and cow dung rates on selected chemical properties of a sandy clay loam soil in Sokoto, Nigeria

Factors influencing shorebird use of post‐harvest flooded rice fields in California's Sacramento Valley

AbstractBecause of the importance of the Central Valley of California, USA, to shorebirds along the Pacific Flyway, conservation investments have been made in the area's agricultural fields and managed wetlands. Increasingly, landowner incentive programs are being used to deliver shorebird habitat, presenting opportunities to answer remaining questions about which implementation strategies and field management practices are most effective at attracting birds. To provide management guidance for these investments, we collected and analyzed 5 years of data (2014–2018) on shorebird abundance in flooded rice fields enrolled in a dynamic habitat incentive program. The program incentivized flooding in fallow and post‐harvest rice fields in seasons when habitat is relatively sparse, specifically the early fall and late spring. Across nearly 9,000 field observations over 5 years, we explored the relationship between abundance and density (birds/ha) of shorebirds and vegetation cover, soil clay, landscape‐level flooding, and local flood timing, duration, and depth. We observed more shorebirds in fields that were approximately 50% flooded, had water depths of 5–10 cm, and had minimal rice straw or stubble cover, with strong or very strong evidence for each of these relationships. We found that the timing of habitat provisioning was important, with moderate evidence that earlier fall flooding and strong evidence that the duration of fall flooding was associated with higher shorebird density. We observed lower shorebird densities in locations with ample flooded rice habitat in surrounding areas, potentially because shorebirds spread out across the landscape. We found very strong evidence that flooding consistency, either at a site that was continually flooded over many months or a site that had been flooded in previous years, was associated with higher shorebird density. Soil clay content was associated with decreased observed shorebird density, potentially through its influence on the ability of shorebirds to forage for invertebrate prey. These results suggest best practices for shorebird habitat creation in agricultural landscapes, providing important information for conservation and population recovery.

Performance and behaviour of prebored and precast pile with floating pile tip based on A full-scale field static axial load test

This study investigates the load transfer mechanism of a Prebored and Precast pile (PP pile), constructed installed in accordance with the rules applicable to the Hyper-Straight pile method (HS pile), in clay soils. While the HS pile method, developed in Japan, typically results in high bearing capacity piles in various soil types, its performance in clay soils remains understudied. Our research focuses on a unique configuration where the pile tip “floats” within a soil–cement mixing (SCM) column near the bottom of the borehole, a condition that significantly influences the system’s performance.We conducted a full-scale axial static load test on a 500 mm diameter and 140 mm thickness straight shaft precast prestressed concrete spun pile. The pile was instrumented with vibrating wire strain gauges (VWSG) and displacement measuring devices (tell-tales), embedded 15 m deep in a 750 mm diameter SCM column (15.75 m long). The pile tip was positioned 75 cm above the bottom of the borehole, creating a floating condition within the SCM material. Both the pile and the surrounding SCM were instrumented to provide comprehensive data on the system’s behavior.The test involved two loading–unloading cycles. The 1st Cycle reached a maximum load of 3627 kN, resulting in a 75.52 mm pile head settlement. The 2nd Cycle achieved a maximum load of 4181 kN, leading to a 118.04 mm pile head settlement. In the 1st Cycle, we observed upward movement of the SCM material around the shaft after the pile skin friction reached its maximum capacity. Stress at the pile tip exceeded the unconfined compressive strength of the SCM material, indicating potential local shear failure.Contrary to expectations based on HS pile performance in other soil types, the ultimate bearing capacity of our pile was determined to be 2000 kN, comprising 545 kN from skin friction and 1455 kN from end bearing. This result aligns more closely with the behavior of conventional bored pile rather than the “hyper” capacity typically associated with HS pile. Consequently, we classify our pile as a “prebored and precast pile,” like systems used in China and Korea.Our study concludes that the strength of the SCM material and the pile tip location significantly influence the pile’s bearing capacity in clay soils. These findings highlight the critical impact of soil type on the performance of piles constructed using the HS method. The observed behavior suggests that current design methods for HS pile may overestimate capacity in clay conditions, emphasizing the importance of soil-specific analysis and testing.This research contributes to the understanding of PP pile behavior in clay soils, providing valuable insights for geotechnical engineers. It underscores the need for refined prediction models and design methods specific to these soil conditions, paving the way for more accurate and reliable foundation designs in regions with predominant clay soils.

Distinct features of topsoil carbon fractions across urban forests in eastern China

AbstractRapid urbanization has increased the areas of urban forests that store considerable soil carbon (C). Different soil C fractions may show distinctive contents and spatial patterns in view of their contrasting sensitivities to various drivers. However, current studies on soil C fractions are mostly limited to natural ecosystems and little is known about the large‐scale patterns and drivers of soil C fractions in urban forests. Based on a field survey of urban forests across a north–south transect in eastern China, we analysed the spatial variations and main drivers of topsoil (surface layer, 0–10 cm; subsurface layer, 10–20 cm) C fractions (i.e., soil organic C, SOC; soil inorganic C, SIC; particulate organic C, POC; mineral‐associated organic C, MAOC). Our results showed that topsoil contents of POC, MAOC and SOC changed non‐linearly with latitude, with lowest values occurring in the cities in the warm temperate region. In contrast, SIC content showed the highest values in the warm temperate region. POC instead of MAOC was found to be a major fraction of SOC in urban forests. The spatial variation in topsoil POC content was mainly explained by mean annual temperature, soil clay and silt content, and park age. The spatial variation in MAOC content was mainly explained by soil clay and silt content, mean annual precipitation, mean annual temperature and park age. In contrast, the spatial variation in SIC content was mainly explained by mean annual precipitation and soil pH. These findings demonstrate distinct features of different soil C fractions in urban forests and provide useful implications for urban soil carbon management.

Initial soil moisture and soil texture control the impact of storm surges in coastal forests

Flooding and salinization triggered by storm surges threaten the survival of coastal forests. The forest root zone (top 40 cm of soil) is the most affected by surge flooding. Determining the effect of a storm surge on edaphic conditions is essential to estimate vegetation response. Pre-storm soil hydrology could mitigate or enhance the salinization effect, ultimately determining the resilience of the forest. Here we assess the influence of pre-storm soil water content and salinity on storm surge effects in coastal vegetated areas. A 1D model (HYDRUS-1D) is used to simulate saltwater infiltration from above through the unsaturated zone. Different water content and concentration scenarios, along with scenarios with variable storm surge salt concentration, storm surge height and storm surge flooding duration are considered. In soils characterized by silt and clay, the maximum salinized soil depth increases as water content increases, affecting the top 40 cm of soil, except for clay loam soil, for which only the top 20 cm are salinized. In sandy soils, the salinization process involves the entire soil column. The contribution of water content to salinization varies from 12 % to 30 % along the top 40 cm in fine soils. In fine soils, the storm-surge height also becomes relevant. A study case is presented to support the numerical results. Field data confirm that soil water content controls the salinization of the root zone in clay and silt soils. Overall, we conclude that the root zones of coastal forests with clay and silt soils and low water content are the most at risk during storm surges. These events have the potential to radically change edaphic conditions and affect ecosystems.

Thermal desorption remediation effects on soil biogeochemical properties and plant performance: Global Meta-analysis

Soil contamination remains a global problem, and numerous studies have been published for investigating soil remediation. Thermal desorption remediation (TDR) can significantly reduce the contaminants in the soil within a short time and consequently has been used worldwide. However, the soil properties respond to TDR differently and are dependent on the experimental set-up. The causative mechanisms of these differences are yet to be fully elucidated. A statistical meta-analysis was thus undertaken to evaluate the TDR treatment effects on soil properties and plant performance. This review pointed out that soil clay was reduced by 54.2%, while soil sand content was enhanced by 15.2% after TDR. This might be due to the release of cementing agents from clay minerals that resulted in the formation of soil aggregates. Soil electrical conductivity enhanced by 69.5% after TDR, which might be due to the heating-induced loss of structural hydroxyl groups and the consequent liberation of ions. The treatment of TDR leads to the reduction of plant germination rate, length, and biomass by 19.4%, 44.8%, and 20.2%, respectively, compared to that of control soil. This might be due to the residue of contaminants and the loss of soil fertility during the thermal process that inhibited plant germination and growth. Soil pH and sulfate content increased with heating temperature increased, while soil enzyme activities decreased with thermal temperature increased. Overall, the results suggested that TDR treatment has inhibited plant growth as well as ecological restoration.

Monitoring of Architectural Monuments

The article presents the main provisions that it is advisable to follow when organizing and conducting monitoring during the operation of cultural heritage sites. It is noted that the existing regulatory documents do not take into account the specifics of monitoring during operation, but are mainly aimed at protecting the monument from neighboring construction.Criteria are proposed to control the technical condition of historical buildings. Among them is the rate of development of long-term precipitation, which is considered as an indicator of the intensity of natural and man-made impacts on the building.Among them is the rate of development of long-term precipitation, which is considered as an indicator of the intensity of natural and man-made impacts on the building. It is noted that for stone structures, critical masonry stretching deformations serve as an effective criterion for the preservation of historical buildings, since in calculating the interaction of structures and foundations they are the primary criterion for calculating the second group of limiting states. In relation to it, the criterion of absolute precipitation and relative difference of precipitation is secondary. It is shown that over time, for buildings built on weak water-saturated clay soils, an increase in the unevenness of precipitation occurs. Special attention is paid to taking into account the accumulated uneven precipitation of buildings of historical development. The article presents the most characteristic types of deformations of buildings, among which in St. Petersburg the bend is most common, which is due to the regularity of building and rebuilding sections of urban neighborhoods.Monitoring is also considered as a reliable means of diagnosing the technical condition of the monument. The monitoring function is considered as a means of controlling the limitations of the monument’s operability, which continues to be operated in conditions of limited operational technical condition.

Improving the performance of evidential belief function model using five machine learning models in earth fissure susceptibility mapping

The frequency and occurrence of earth fissures threaten human settlements, infrastructure, and agricultural lands in many parts of the globe. This natural hazard has particularly posed great challenge in the North, Central, and Eastern parts of the Najaf Abad Basin of Iran. This paper presents a comparative analysis of machine learning algorithms for earth fissure susceptibility assessment, and involves the creation of an earth fissure database by selecting and validating 200 fissure locations. To improve the accuracy of the fissure locations, various geographic data sources, such as Google Earth images, field surveys, and GPS measurements, were employed. The locations were divided into training and validation sets based on sixteen conditioning factors for finding the earth fissure susceptible zones using EBF (Evidential belief function), EBF – Multilayer Perceptron (MLP), EBF – Function Tree (FT), EBF – Alternating decision tree (ADtree), EBF – Adaptive Boosting (AdaBoost), EBF – Random SubSpace (RSS), EBF – Naive Bayes Tree (NBTree) models. The results show that earth fissures occur in greater concentrations where groundwater levels are lowest, and their prevalence is closely associated to both agricultural activities and the presence of clay, clayey sand, and silty clay soils. Susceptibility analysis results revealed that 15–21 % agricultural dependent population falls under the very high susceptibility risk zone in and around the major cities of the Najaf Abad region. The receiver operating characteristic (ROC) curve analysis showed that the EBF-RSS algorithm has higher accuracy (>99 %) compared to other algorithms (>85 %) in training and validation phases for earth fissure susceptibility prediction. Our findings emphasise the need to prioritise these susceptible areas for sustainable land and water management strategies and implement effective measures to mitigate the impact of earth fissures. Our study also advances our knowledge on geospatial analysis and earth fissures-related hazard assessment by applying five machine learning algorithms that shows spatial similarity in susceptibility categories with splendid accuracy performance.

Nomenclature notes on vegetation of the Salicetea purpureae Moor 1958 class in Ukraine

A brief history of the syntaxonomic studies of floodplain vegetation of the Salicetea purpureae class in Ukraine is presented and the tasks of further research are established. Our study has shown that the vegetation of the class includes more than 30 associations, which belong to 6 alliances and 2 orders. According to the ecological peculiarities, they are divided into willow shrubs on the gravel banks of streams in the montane and subalpine belts of the temperate and boreal zones of Europe and the Caucasus (Salicion eleagno-daphnoidis), willow and poplar forests of lowland and foothill rivers formed on alluvium in the nemoral zone of Europe and at high altitudes in the Mediterranean region (Salicion albae), willow shrubs on the sandy-loamy soils of the river banks of lowlands and foothills of the nemoral zone of Europe (Salicion triandrae), willow shrubs on riverine dunes in central Ukraine (Artemisio dniproicae-Salicion acutifoliae), shrubs on temporarily flooded clay soils in central Ukraine (Rubo caesi-Amorphion fruticosae). The problems of using the phytosociological nomenclature during the analysis of the Salicetea purpureae vegetation on the territory of Ukraine are highlighted. It was found that half of the syntaxa listed in Ukrainian geobotanical literature are synonyms, published invalidly, or need typification. Every syntaxon is accompanied by explanations of its non-validity with citations of the relevant articles published in the 4th edition of the International Code of Phytosociological Nomenclature. In addition to the incorrectly cited associations, two of the six alliances (Artemisio dniproicae-Salicion acutifoliae, Rubo caesii-Amorphion fruticosae) also require correction because their description was based on the invalid nomenclatural types formed by the selection of species which are invalid according to The Euro+Med PlantBase. In this paper, we aimed to analyze the studies on the vegetation of the Salicetea purpureae class on the territory of Ukraine using the Braun–Blanquet approach, determine the issues that require more detailed research in the future, and make some notes on nomenclature discordances. Such review makes it possible to determine all mismatches in phytosociological nomenclature.

A Comparative Study of Real-World vs. Small-Scale Mat Foundations on Expansive Clay Soils for Low-Cost Housing

A Comparative Study of Real-World vs. Small-Scale Mat Foundations on Expansive Clay Soils for Low-Cost Housing

Effect of soil type on tipping point hydrological requirements for Axonopus compressus grass under extreme drought stress

Critical soil suctions (threshold, tipping point, and permanent wilting) corresponding to initial drought response, near-death stage, and complete mortality, respectively; is essential for formulating irrigation schemes of vegetation grown in compacted soil under drought conditions. The effect of soil types on these critical soil suctions are unexplored and is crucial in understanding the soil-specific plant water functions. This study aims to establish the drought response of Axonopus compressus (grass), based on stomatal conductance (gs) and chlorophyll fluorescence parameters (CI) grown in different soil types. A. compressus were grown in six soil types (2 coarse-grained and 4 fine-grained soils) for 8 weeks, followed by continued drought condition. The gs and CI were monitored along with soil suction and moisture content. Both leaf and root growth were observed to be higher in coarse-grained soils than fine-grained soils, even though the water retention of the coarse-grained soils were comparatively less. Drought stress initiation in plants was captured by ψthreshold from the CI (especially in fine-grained soils) before the gs response. The three critical soil suctions estimated from the correlation between CI and ψ were found to be increasing with higher soil clay fraction. Corresponding plant available water contents (based on v/v volumetric water content) with each of three critical soil suctions were found to be dependent on the relative growth of canopy to root growth that occurred in different soil medias. Especially, plant available water in ‘tipping suction’ was dependent on the soil clay fraction (i.e., higher fraction could restrict root water uptake) and is presented with a simple empirical correlation for A. compressus.

English

The current study was conducted in growth chamber with the aims to examine the effect of different soil types and temperature regimes on quantitative and qualitative traits of saffron and to assess the agro-climatic suitability of selected sites of Poonch Division of Azad Jammu & Kashmir for field scale saffron cultivation. Soil from 07 sites was collected and processed for pot filling. A total of 63 plastic pots (21 for each temperature level i.e., 19, 26 and 32 oC), were filled with soils of each site and incubated separately in growth chambers. The pots were arranged under completely randomized design (CRD) replicated thrice. Results indicated that maximum number of flowers (1.35 per plant), flower fresh weight (29.03 mg per plant), stigma length (1.21 cm), stigma fresh weight (8.97 mg per plant) and stigma yield (8.60 mg per pot) was recorded for Khaigala site (loam textured soil) at 26 oC followed by Trarkhel (sandy loam textured soil) and Abbaspur (loam textured soil) sites. On an average, maximum 58.30 days were taken to initiate flowering in soil of Alisojal site (clay loam textured soil) with flowering period of 17.06 days. The maximum number of daughter corms (2.92 per plant), corm diameter (9.61 mm), corm weight (15.76 g per plant), corm yield (47.28 g per pot), picrocrocin (11.32%) and safranal (0.22%) content was again recorded for Khaigala site (at 26 oC). However, maximum crocin content (14.33%) was noted for Alisojal site (1831 m altitude). The Cluster and PC analyses revealed that Khaigala, Trarkhel and Abbaspur sites produced saffron of better quality and agro-climatically suitable for establishment of saffron. Further, the saffron grown on loam and sandy loam textured soils showed better performance compared to that of clay textured soils.

Irrigation and oil palm empty fruit bunch mulch enhance eggplant growth, radiation interception and dry matter yield

Organic mulching is a well-known management practice that conserves soil water and nutrients as well as increases crop yield. Nonetheless, research on combined organic mulching using oil palm empty fruit bunch (EFB) and irrigation is limited. Field-based experiments were conducted over three seasons to test the sole and combined effects of EFB as organic mulch and irrigation on the growth, total dry matter yield (TDMY), accumulated intercepted photosynthetically active radiation (AIPAR), and radiation use efficiency (RUE) of African eggplant (Solanum aethiopicum L.) in a low fertile tropical sandy clay loam soil. Air-dried EFB was used as an organic mulch by spreading it on the soil surface at rates of 0 (EFB0), 20 (EFB20), and 40 t ha−1 (EFB40), and either fully-irrigated (I100), deficit-irrigated (I40), or non-irrigated (I0). The I100 plots were irrigated to field capacity (FC) every 3–4 days based on PR2 Profile Probe measurements and the resultant irrigation volume supplied to the plants via drip irrigation tubes. The I40 plots received 40 % of the water given to the I100 plots, and the I0 plots were solely rain-fed. At the end of the third season, the 40 t ha−1 EFB-mulch increased soil pH, electrical conductivity (EC), soil organic carbon, potassium, cation exchange capacity, and the soil’s specific surface area. In the first season, all the measured eggplant growth and yield parameters were neither responsive to irrigation only, EFB-mulch only, or both. In the second and third seasons, the EFB20 and EFB40 treatments significantly (p < 0.05) increased leaf chlorophyll content index (LCCI), photosystem II (Fv/Fm ratio), absolute performance index (PIabs), TDMY, AIPAR, and RUE compared to the non-mulched control treatment. Soil pH was high in the EFB-mulched plots and correlated positively with TDMY and AIPAR. The I100 significantly improved LCCI, Fv/Fm, PIabs, and TDMY during the second season. In the third season, a highly significant interaction between irrigation and mulching was detected on TDMY, AIPAR, RUE, LCCI, Fv/Fm ratio, and pH (H2O). This indicated a positive effect on soil nutrient availability especially phosphorus as TDMY and AIPAR correlated with soil pH. The I100 and I40 significantly increased AIPAR by 48.1 % and 37.2 %, and RUE by 26.7 % and 11.0 %, respectively, compared to I0 during the third season. The total dry matter yield of the African eggplant was enhanced by EFB-mulch, with the effect increasing over up to three growing seasons, especially when combined with irrigation during dry periods.