Guava is a nutritious fruit that has perishable behavior during storage. We aimed to determine the influences of some edible coatings (namely, cactus pear stem (10%), moringa (10%), and henna leaf (3%) extracts incorporated with gum Arabic (10%)), on the guava fruits’ properties when stored under ambient and refrigeration temperatures for 7, 14, and 21 days. The results revealed that the coating with gum Arabic (10%) only, or combined with the natural plant extracts, exhibited a significant reduction in weight loss, decay, and rot ratio. Meanwhile, there were notable increases in marketability. Moreover, among all tested treatments, the application of gum Arabic (10%) + moringa extract (10%) was the superior treatment for most studied parameters, and exhibited for the highest values for maintaining firmness, total soluble solids, total sugars, and total antioxidant activity. Overall, it was suggested that coating guava with 10% gum Arabic combined with other plant extracts could maintain the postharvest storage quality of the cold-storage guava.

A field experiment was carried out at Al-Bahariya Oasis, Giza, Egypt, during three successive seasons to find out the effect of application of bentonite (BN) as a natural clay deposit at either 6 or 12 kg/palm tree and humic substances (HS) as organic amendment at either 0.75 or 1.0 L/palm tree incorporated with Bacillus polymyxa (BP) as a biofertilizers at 14 and 28 mL/L rates on growth, yield, and fruit weight of 10-year-old Siwi date palm cv. (Phoenix dectylifera L.). Siwi trees were cultivated in sandy texture soil at a distance of 8 × 8 m and were irrigated with 100%, 85%, and 70% of ET crop. Effects of the previous treatments on growth, date palm crop, soil properties, water relations, water-use efficiency (WUE), and economic return were also studied. The obtained results showed that the mean values of leaf length, leaflet length and width, fruit set%, bunch weight, yield/palm, yield/fed, fruit weight, flesh weight, and fruit pulp weight were increased in response to the different individual and combined treatments used in this study with various significance levels compared to the control treatment means in the studied three seasons. However, the superiority was for combining between amending the sandy soil with either low concentrations of BN (6 kg/tree) + HS (0.75 Liter/tree) + BP (14 mL/L) or high concentrations of BN (12 kg/tree) + HS (1.0 L/tree) + BP (28 mL/L) and irrigation with 85% of ETc water level, as such combinations attained the highest values in most of the mentioned values over both the sole and combined treatments in the studied three seasons. Furthermore, the results indicated that the highest monthly ETc values occurred during June and July months, while the lowest values occurred during December and January months. Additionally, water productivity (WP) increased considerably by reduction of water quantity (70% ETc) associated with soil conditioner treatment (BN.12 kg +HS 1 L + BP. 28 mL/L), and values were 2.17, 2.25, and 2.27 kg fruit/m³ of water irrigation during the growing seasons, respectively. The highest net return was attributed to irrigation with 85% of ETc water level along with the application of soil conditioners at high rates. Accordingly, it is advisable to apply the soil conditioners of bentonite (at 6 or 12 kg/tree) and humic substances (at either 0.75 or 1.0 L/tree) with B. polymyxa (at either 14 or 28 mL/L) plus irrigation with either 85% or 70% of ETc water level to obtain the best growth, highest yield, (WP), and gross return from var. Siwi date palm grown under an oasis agro-system.

Arid sandy soils are characterized by poor water retention, low nutrient availability, and limited productivity, posing major constraints to sustainable date palm cultivation under increasing water scarcity. A three-year field experiment was conducted to evaluate the combined effects of bentonite (BN), humic substances (HS), and Bacillus polymyxa (BP) under three irrigation regimes (70, 85, and 100% of crop evapotranspiration (ETc)) on soil hydro-physical properties, nutrient uptake, and fruit quality of ‘Siwi’ date palm (Phoenix dactylifera L.). Twelve treatment combinations (3 irrigation regimes × 4 soil amendment treatments) were evaluated over three consecutive growing seasons. The integrated application of BN, HS, and BP significantly improved soil hydro-physical properties by increasing field capacity and plant-available water while reducing bulk density. These improvements were associated with enhanced leaf N, P, and K concentrations and greater accumulation of total soluble solids, total and reducing sugars, phenolic compounds, flavonoids, and β-carotene compared with the untreated control. The combined application of BN (12 kg palm⁻¹) + HS (1 L palm⁻¹) + BP (28 mL palm⁻¹) produced the most favorable overall responses. Moderate deficit irrigation (85% ETc) provided the best balance between fruit quality and water conservation, maintaining superior fruit biochemical quality while reducing irrigation water use by approximately 15% compared with full irrigation. Multivariate analyses further supported these findings by revealing strong positive associations among soil water availability, nutrient status, sugars, and antioxidant-related compounds, while climatic variables were closely associated with seasonal variation in fruit biochemical characteristics. Overall, the integrated application of bentonite, humic substances, and B. polymyxa under 85% ETc irrigation represents an effective management strategy for improving soil performance, enhancing fruit nutritional quality, and increasing water-use irrigation efficiency in sandy soils under arid conditions.