The production of agricultural residues causes environmental pollution, especially in regions with intensive horticultural production. The solution is to maximise the use of residues, applying the 'zero waste' model and using them to develop construction materials. Natural fibres used to reinforce materials have environmental and economic benefits due to their low cost. This research presents an innovative characterisation using an inverted-plate optical microscope, a high-resolution scanning electron microscope (HRSEM) and a 3D X-ray microscope. A physico-mechanical and chemical characterisation of horticultural fibres was also conducted. The fibres analysed were those produced in the highest quantities, including those from tomatoes, peppers, zucchinis, cucumbers and aubergines. The viability of these natural fibres for use as reinforcements in biocomposites was investigated. The analysis centred on studying the microstructure, porosity, chemical composition, tensile strength, water absorption and environmental degradation of the natural fibres. The results showed a porosity ranging from 47.44% to 61.18%, which contributes to the lightness of the materials. Cucumber stems have a higher tensile strength than the other stems, with an average value of 19.83 MPa. The SEM analysis showed a similar chemical composition of the scanned fibres. Finally, the life cycle of the materials made from horticultural residue was analysed, and negative GWP (global warming potential) CO2eq values were obtained for two of the proposed materials, such as stabilised soil reinforced with agricultural fibres and insulation panels made of agricultural fibres.

The feasibility of lightweight construction materials by incorporating a waste that is difficult to recycle, based on waste from intensive agriculture: vegetable fibers and propylene, is presented. This innovative material consists of a mixture of Alhambra Formation soil (Granada, SE of Spain) reinforced with vegetable fibres from tomato, pepper, zucchini, cucumber, aubergine and polypropylene fibres. The fibres were used in the mixture at a ratio of 2.5%, 5.0%, 7.5% and 10.0%. These values were then compared with control test samples that did not contain any residues. The compatibility of the fibres with the soil of the Alhambra Formation was then evaluated in terms of its physical-mechanical properties, specifically in relation to uniaxial compression and longitudinal deformation. Due to the highly hygroscopic nature of plant fibres, their absorption was measured and the techniques of presoaking and non-soaking the fibres before mixing them with the soil of the Alhambra Formation were investigated. The results of the unconfined compression tests show that the increase in fibre volume leads to a significant decrease in compressive strength. The highest compressive strength from a residue ratio >= 7.5 % was achieved with the cucumber residue and the non-pre-soaking technique. This residue ratio reached an average value of 1.82 MPa, which is 4% lower than the reference specimen without additives. Notwithstanding the decline in mechanical strength with elevated residue quantities, the resulting Alhambra Formation soil composite blended with a 7.5 % cucumber ratio may be regarded as a prospective candidate for implementation using the Projected Earth System technique.

Modern construction is largely dependent on steel and concrete, with natural materials such as earth being significantly underutilised. Despite its sustainability and accessibility, earth is not being used to its full potential in developed countries. This study explores innovative building materials using Alhambra Formation soil (Granada, Spain) reinforced with difficult-to-recycle agricultural waste: polypropylene fibres contaminated with organic matter and leachates. Fibres were added at a ratio between 0.20 and 0.80% of the soil mass, leachates at a ratio between 4.25 and 8.50%, and lime was incorporated at 2.00% and 4.00% for specimens with higher residue content. Physico-mechanical properties, including uniaxial compressive strength and longitudinal strain, were analysed together with the microstructure. The results showed that polypropylene fibres, in comparison to the use of leachates, improved compressive strength and ductility, reaching a compressive strength of 1.76 MPa with a fibre content of 0.40%. On the other hand, this value is 7.4% lower than the reference sample without additives. The fibre-reinforced samples showed a higher porosity compared to the samples with leachates or without additives. This approach highlights the potential of agricultural waste for the development of sustainable construction materials, offering enhancements in the strength and ductility of reinforced soils.

Agricultural residues are generated during the production and processing of agricultural crops. Under modern date palm plantation practices, field operations generate huge quantities of residues, which are discarded with little valorization. The date palm agro-industry produces significant amounts of waste. The accumulation of these residues can cause ecological damage to the oasis ecosystems. There is a lack of comprehensive data on long-term research studies that aim to assess the impact of date palm waste management practices. Composting and/or pyrolysis of date palm residues showed benefits for improving soil physical and chemical properties, particularly in sandy soils. This claim holds particular significance for arid and semi-arid regions, which are characterized by low fertility and are susceptible to soil degradation, accentuated by ongoing climate change. This review summarizes the existing literature concerning the valorization of date palm residues with regards to compost and pyrolysis processes, as well as the impact of their application on soil quality. Further research is required to assess the effects of using date palm residues for better soil amendment management. Research should focus on composting and biochar technologies for date palm residues and their application in arid and semi-arid regions to combat soil erosion and degradation. Increasing the beneficial uses of date palm residues could lead to sustainable and economic growth in dry areas.

Converting agricultural residues into environmentally friendly adsorbents to address the problem of low removal efficiency of low-concentration heavy metal ions is an effective strategy for high-value utilization of agricultural residues. Herein, a simple general strategy is proposed for constructing amphoteric agricultural residues-based porous adsorbents by forming anisotropic cross-linked structures at the heterogeneous interface of agricultural residue, coconut shell carbon, and polyethyleneimine. This green preparation strategy can be widely adapted to agricultural residues with hydroxyl structures, such as bagasse fiber, corn cob, and peanut shell, to prepare highperformance adsorbents with high densities of amphoteric adsorption sites (The density of amino and carboxyl groups was 3.44 mmol & sdot;g- 1 and 3.64 mmol & sdot;g- 1) while maintaining a developed microporous structure (BET specific surface area of 760.68 m2 & sdot;g- 1), the reactant conversion rate was higher than 99 %. Interestingly, the synergistic effect of abundant amphoteric functional groups and developed microporous structures enabled the adsorbents to completely remove Cr(VI), Cu(II), Pb(II), and Cd(II) from water within 10 min, which exhibited a promising synchronous removal efficiency for multiple heavy metal ions. It provides a reference for the remediation of heavy metals contaminated groundwater and soil by agricultural residues-based adsorbent.