A large diameter triaxial specimen of 61.9 mm was made by mixing coconut shell fibers with red clay soil. The shear strength of coconut shell fiber-reinforced soil was investigated using a dynamic triaxial shear test with confining pressure in a range of 50-250 kPa, a fiber content of 0.1%-0.5%, and a loading frequency of 0.5-2.5 Hz. The Hardin-Drnevich model based on the coconut shell fiber-reinforced soil was developed by analyzing and processing the experimental data using a linear fitting method, determining the model parameters a and b, and combining the influencing factors of the coconut shell fiber-reinforced soil to improve the Hardin-Drnevich model. The results show a clear distinction between the effects of loading frequency and fiber content on the strength of the specimens, which are around 1 Hz and 0.3%, respectively. Hardin-Drnevich model based on coconut shell fiber-reinforced soil can better predict the dynamic stress-strain relationship of coconut shell fiber-reinforced soil and reflect the dynamic stress-strain curve characteristics of the dynamic stress-strain curve coconut shell fiber-reinforced soil.

To address the issues of high porosity and low strength in calcium sand of artificial islands, this study focuses on improving the calcium sand's mechanical properties. The effects of WER curing methods and coconut fiber modification on the UCS and microscopic mechanisms of calcium sand are investigated. The results indicate that both fiber incorporation and the increase in WER ratio can enhance the unconfined compressive strength of calcareous sand, with the addition of a certain amount of coconut coir fiber showing a more significant strength increase. The optimal recommended dosage of WER is 15%, which results in an UCS of 1218 kPa, an increase of nearly 4.27 times compared to 9% WER dosage. Coconut coir fiber has good tensile strength that can improve the compressive strength of calcareous sand after curing. The UCS of calcareous sand cured with a fiber content of 0.3% to 0.5% is increased by 1247 kPa to 1792 kPa compared to cured soil with no fiber. The strong binding nature of WER addresses the issue of large porosity in calcareous sand. Together with the penetrating coconut coir fibers, it forms a three-dimensional reticular framework structure, thereby enhancing the compressive performance of the calcareous sand-cured soil mass.

Targeting the engineering properties of poor strength and susceptibility to damage in roadbeds and slopes within clay regions, xanthan gum is employed as a soil enhancer, concurrently addressing the issue of the low utilization rate of plant coir fiber. The unconfined compressive strength test (UCS) is used to analyze the influence of different maintenance methods, maintenance duration, xanthan gum dosage, and coconut fiber dosage on the mechanical properties of the enhanced soil. Furthermore, based on scanning electron microscope (SEM) tests, the underlying mechanisms governing the mechanical properties of fiber-reinforced xanthan gum-improved soil are uncovered. The results indicated that the compressive strength of amended soil is significantly enhanced by the incorporation of xanthan gum and coir fiber. After 28 days of conditioning, the compressive strength of the amended soil under dry conditions (conditioned in air) was significantly higher (3 MPa) than that under moist conditions (conditioned in plastic wrap) (0.57 MPa). Xanthan gum influenced both the compressive strength of the specimens and the degree of strength enhancement, whereas coir fibers not only augmented the strength of the specimens but also converted them from brittle to ductile, thereby imparting residual strength post-destruction. Microscopic analysis indicates that the incorporation of xanthan gum and coconut shell fiber significantly diminishes the number of pores and cracks within the soil matrix, while enhancing the internal inter-particle cementation. This synergistic effect contributes to soil improvement, providing theoretical and technical guidance for roadbed enhancement and slope repair.

This study examines the effectiveness of the bi-stabilization of clay soils using cane molasses and coconut fiber, focusing on improving the geotechnical and mechanical properties of clay. The performance of the two stabilizers, both individually and in combination for bistabilization, was assessed. The geotechnical properties were determined through sieve analysis, Proctor tests, and Atterberg limit methods, while the mechanical properties were measured using a hydraulic press. The results showed that cane molasses reduced plasticity, enhanced soil cohesion, and increased dry density with molasses content. The Atterberg limits (liquid limit, plastic limit, and consistency index) were maximized at a 4% molasses content, with respective increases of 9.28%, 44.80%, and 37.9% compared to clay without molasses (CB). Coconut fiber improved the flexural strength by 361.9% for CF1, whereas molasses improved the compressive strength by 12.24% compared to plain clay. Bi-stabilization allowed for a maximum improvement in flexural strength of 509.52% compared to CB, 49.42% compared to molasses-stabilized clay bricks (CSM), and 31.96% compared to clay composites with coconut fiber (CF). The compressive strength improved by 22.54% compared with CB, 9.21% compared with CSM8, and 14.94% compared with CF 1/2. In summary, bi-stabilization with sugarcane molasses and coconut fiber provided enhanced performance compared with their individual use.

W. Chan-Cupul, J. M. Palma-Garcia, E. Ruiz-S & aacute;nchez, and E. Cruz-Crespo. 2025. Assessment of the effects of inoculation with entomopathogenic fungi on the vegetative growth and yield of Capsicum chinense under water stress conditions. Int. J. Agric. and gastronomic value. The cultivation of C. chinense is increasingly challenged by global warming and droughts, which impact both plant health and market stability. Climate change affects agriculture by altering temperature and precipitation patterns, leading to soil moisture loss, drought, phenological damage, and increased pest and disease incidence. The use of bioinoculants, including entomopathogenic fungi (EFs), may be a strategy to mitigate drought in C. chinense production. The aim of this study was to assess the impact of Beauveria brongniartii and Purpureocillium lilacinum inoculation on the vegetative growth and yield of C. chinense var. Chichen Itza under two water stress conditions. Experiments were conducted in a gothic greenhouse, and C. chinense seedlings were transplanted into growth bags [coconut fiber (70%) and dust (30%)] with controlled irrigation at 75% and 100% levels. The EFs were applied weekly for the first month (50 mL at 1x107 conidia mL-1). Agronomic parameters, including plant height, stem diameter, chlorophyll index, leaf area, fruit quality, and yield, were measured. The results indicated that both B. brongniartii and P. lilacinum significantly increased plant height and stem diameter in the early stages of growth under water stress conditions. B. brongniartii notably increased plant growth and maintained fruit yield even under reduced irrigation. However, no significant differences were observed in the chlorophyll index or overall fruit yield among the treatments. The results of this study suggest that B. brongniartii and P. lilacinum can improve C. chinense resilience to water stress, suggesting potential applications in sustainable agriculture amidst climate change.

The coconut rhinoceros beetle (CRB; Oryctes rhinoceros) is one of the most destructive insect pests of coconut and oil palms in tropical Asia and the Pacific islands. Members of a new variant, known as CRB-G (clade I), have recently spread into the Pacific islands, causing significant damage. Biopesticides containing Metarhizium spp. are the strongest candidates for inundative biological control against the emerging CRB threat. Selection of the most virulent and robust isolate may determine the impact of this control option on the pest. In this work, CRB specimens with natural fungal infection were collected in Papua New Guinea (PNG) and Solomon Islands (SI). Putative entomopathogenic fungi were isolated and identified. These new isolates and some previously obtained from other Pacific countries were molecularly identified, characterized, and tested for virulence against CRB larval populations in PNG and SI in laboratory bioassays. Of the new isolates collected, four obtained from SI were identified as Metarhizium majus (conidia length similar to 11-15 mu m), and four from PNG were identified as Metarhizium pingshaense (conidia length similar to 4-6 mu m). The most virulent isolate was M. majus AgR-F717, which caused 100 % mortality in 20-23 days against a CRB variant from the CRB-S grouping (clade II) in laboratory bioassays carried out in PNG. Isolates of M. pingshaense did not show pathogenicity against CRB larvae. M. majus AgR-F717 was also the most virulent in laboratory bioassays using the mixed SI population (from both CRB-S and CRB-G groupings) and was selected for further evaluation using artificial breeding sites. Under field conditions, this isolate demonstrated its ability to infect CRB, dispersal up to 100 m from treated artificial breeding sites, and persistence in soil for at least four months. The new isolate AgR-F717 of M. majus has demonstrated potential as an augmentative biological control agent for CRB in PNG and SI.

The authors used the crushed coconut shell to make granular columns which were obtained from the market area of Kuantan, Pahang. The coconut was crushed into a similar size of coarse aggregate for the replacement of non-renewable resources like sand and gravel. From its general properties, a coconut shell is hard and can withstand a certain value of exerted value regardless of compression or tension. Besides, the coconut shell is an agricultural product and is found abundantly after human consumption. For this research, the stone-column method was used. The installation of a single coconut shell column was implemented through the Vibro-replacement technique on the soft clay soil. Before accessing the shear strength parameters, the evaluation of the physical and mechanical properties of coconut shells and kaolin was executed via the appropriate geotechnical laboratory approaches. The shear strength parameters were analysed with the control and reinforced specimens through the Unconfined Compression Test (UCT). For the shear strength value, the average value from 4 specimens was utilized as the final value. A total of 16 samples were constructed for all the specimens, reinforced design comprised of 13 mm column diameter, and column heights of 60 mm and 80 mm were categorized as partially penetrated columns while 100 mm was a fully penetrated column. The highest shear strength improvement was recorded when the column height was 100 mm, resulting in 28.51 %, whereas the least was recorded when 60 mm of height was constructed, only 17.28 %. Conclusively, the positive results of shear strength improvements were yielded by the utilization of coconut shells and proved that it was practical and economical.