Innovative superabsorbent hydrogels were synthesized from watermelon rind (WR), an abundant agricultural waste. The process involved free radical polymerization of acrylic acid (AA) and acrylamide (AAm) with WR particles activated by ammonium persulfate (APS), resulting in (AA-co-AAm)/WR hydrogels with high equilibrium swelling capacities of 749 ± 32 g/g. Notably, after eight cycles, the WR hydrogel maintained 94.88 % of its initial swelling capacity, significantly outperforming the (AA-co-AAm) hydrogel without WR (13.80 % retention). This durability, combined with excellent water retention across various soil textures and high adsorption capacity for methylene blue (MB), underscores the WR hydrogel as a superior soil moisture conservation agent. This study marks a significant advance in recycling organic waste and enhancing water management in agricultural soils, demonstrating the potential for sustainable hydrogel development.

Enhancing soil stability through the incorporation of straw and biochar is well documented. Nevertheless, the combined impact of straw, biochar, and nitrogen supplementation on soil aggregates and organic carbon still needs to be explored, with limited attention given to various sieving methods in the existing literature. Therefore, the current experiment used four sieving methods—routine wet sieving (RoutW), fast-wetting sieving (FastW), slow-wetting sieving (SlowW), and wetting–stirring sieving (WetS)—to investigate the effects of adding straw (0 or 4.5 t ha⁻¹), biochar (from maize straw, 0 or 15 t ha⁻¹), and N (0 or 100 kg ha⁻¹) on soil aggregate stability and soil organic C in silt–loam soil of rainfed farmland in northwest China. The field experiment was started in 2014; soil samples were collected in 2021. The results revealed that straw returned, biochar, and N addition significantly increased soil mean weight diameter (MWD) and soil organic C (SOC). Compared to CN0 (zero-amendment) plots, straw returned with nitrogen addition (SN100) significantly increased the MWD of aggregates by 130.3% (RoutW), 121.66% (FastW), 73.94% (SlowW), and 91.78% (WetS) in the 0–30 cm soil layer. The addition of biochar and nitrogen (BN100) treatment showed the most significant effects on the relative slaking index (RSI), relative mechanical breakdown index (RMI), and SOC; compared with CN0 treatment, BN100 plots can reduce RSI and RMI by 42.90% and 54.66% and increase SOC by 53.27% for all soil layers. Therefore, adding organic materials with N can enhance the stability of soil aggregates and SOC of silt–loam soils in northwest China. Integrating biochar as an organic soil amendment in the agricultural practices of northwest China presents a multifaceted solution that addresses soil health, crop productivity, and environmental sustainability. The current study provides valuable insights that support adopting this innovative approach, paving the way for future sustainable agricultural practices that can benefit both the region and the global community.

Drought stress critically hinders agricultural productivity, especially in arid and semi-arid zones. The results of this study show that the application of watermelon rind-based hydrogels (WR hydrogels), synthesized from a watermelon rind, acrylic acid (AA), and acrylamide (AAm), significantly enhanced soil water retention by 77.46% at a 0.3% concentration, increasing the plant height by 28.98% and biomass by 35.28% under controlled greenhouse conditions (25 °C/20 °C day/night temperature cycle, with a 12 h photoperiod at 400–500 μmol·m⁻²·s⁻¹ of illuminance and 30–40% relative humidity). The accumulation of proline and soluble sugars decreased, indicating reduced osmotic stress in barley subjected to mild and severe drought conditions (6–15% FC and 17–26% FC). The chlorophyll content rose by 16.36%, boosting photosynthetic activity. A correlation and principal component analysis further highlighted the positive effects of hydrogel addition on plant growth and drought resistance. These findings underscore the potential of WR hydrogels as an effective soil amendment for promoting sustainable agriculture in water-limited conditions.

In the context of increasing water scarcity and environmental pollution, this study investigates the synthesis and application of p(AA-Oco-AAm)-g-Citrus Sinensis Peel hydrogel (CSP hydrogel) to enhance soil water retention and remove organic dyes from wastewater. Hydrogels were prepared using a combination of acrylamide and acrylic acid, with the incorporation of citrus peel as a natural resource. The water absorption capacity of the hydrogels was evaluated, achieving a maximum retention rate of 477 g/g, significantly improving the water-holding ability of various soil types. Additionally, the hydrogels demonstrated a strong affinity for methylene blue, with an equilibrium adsorption capacity reaching 2299.45 mg/g, indicating their effectiveness in wastewater treatment. Kinetic and isothermal adsorption models were applied to analyze the adsorption dynamics, revealing a superior fit to the Langmuir model. The hydrogels maintained structural integrity and reusability over multiple cycles, underscoring their potential for sustainable agricultural practices and environmental remediation. This research highlights the dual benefits of utilizing agricultural waste for the development of eco-friendly materials while addressing critical challenges in water management and pollution control.

Soil salinization restricts the sustainable development of global agriculture, expanding at an annual rate of approximately 1 million hectares. In China, the total area of saline–alkali land reaches 170 million hectares, of which the arable land area exceeds 50 million hectares. The arid northwest region witnesses worsening soil salinization due to arid climate and improper irrigation practices, which seriously affects the yield of crops such as spinach (Spinacia oleracea L.). As a leafy vegetable with high nutritional value and economic significance, spinach exhibits growth inhibition, leaf yellowing, and disrupted physiological metabolism under saline–alkali stress. Therefore, this study investigates the alleviating effects and mechanisms of Attapulgite Clay-g-(AA-co-AAm) Hydrogel (ACH) on spinach under salt stress (NaCl) and alkaline stress (NaHCO₃). The results show that ACH has a loose, porous structure. As the addition of Attapulgite Clay increases, the surface roughness and porosity improve while retaining organic functional groups (amide groups, carboxyl groups) and inorganic Si-O bonds, providing a structural foundation for stress mitigation. In terms of yield enhancement, ACH effectively alleviates salt–alkali stress: under severe salt stress (SS2), 0.2% ACH increased leaf area by 91% and leaf weight by 95.69%; under mild alkaline stress (AS1), 0.2% ACH increased leaf area by 46.3% and leaf weight by 46.21%; and under severe mixed salt–alkali stress (MS2), 0.4% ACH increased root weight by 49.83%. Physiologically, ACH reduced proline content (51.25% reduction under severe mixed stress) and malondialdehyde (MDA) content (68.98% reduction under severe alkaline stress) while increasing soluble sugar content (63.54% increase under mixed stress) and antioxidant enzyme activity (SOD, POD, CAT). In terms of ion regulation, ACH reduced Na⁺ accumulation in roots and leaves (61.12% reduction in roots and 36.4% reduction in leaves under severe salt stress) and maintained potassium–sodium balance. To conclude, ACH mitigates the adverse effects of salt–alkali stress by coordinately modulating spinach’s growth, physiological metabolic processes, and ion balance. This synergistic regulatory effect ultimately contributes to sustaining high yields of spinach.

This study investigates the effects of low nitrogen (N) and phosphorus (P) stress on the growth and yield of nine barley (Hordeum vulgare L.) genotypes (1267-2, 1749-1, 1149-3, 2017Y-2, 2017Y-16, 2017Y-17, 2017Y-18, 2017Y-19, and XBZ17-1-61), all of which are spring two-rowed hulled barley types from the Economic Crops and Beer Material Institute, Gansu Academy of Agricultural Sciences. Data were collected over two consecutive growing seasons (2021–2022) at Huangyang Town (altitude 1766 m, irrigated desert soil with 1.71% organic matter, 1.00 g·kg⁻¹ total N, 0.87 g·kg⁻¹ total P in 0–20 cm plough layer) to elucidate the correlation between stress tolerance traits and yield performance. Field experiments were conducted under two treatment conditions: no fertilization (NP0) and normal fertilization (180 kg·hm⁻² N and P, NP180). Growth indicators (plant height, spike length, spikelets per unit area, etc.) and quality indicators (proportion of plump/shrunken grains, 1000-grain weight, protein, starch content) were measured, and data were analyzed using correlation analysis, principal component analysis, and structural equation modeling. The results revealed that low N and P stress significantly impacted quality indicators, such as the proportion of plump and shrunken grains, while having a minimal effect on growth indicators like plant height and spike length. Notably, the number of spikelets per unit area emerged as a critical factor positively influencing yield. Among the tested genotypes, 1749-1, 1267-2, 1149-3, 2017Y-16, 2017Y-18, 2017Y-19, and XBZ17-1-61 exhibited superior yield performance under low N and P stress conditions, indicating their potential for breeding programs focused on stress resilience. Included among these, the 1749-1 line showed the best overall performance and consistent results across both years.