Responses of grafted tomato (Solanum lycopersiocon L.) to abiotic stresses in Saudi Arabia

Quantity and quality of irrigation water are considered the most imperative limiting factors for plant production in arid environment. Adoptions of strategies can minimize crop water consumption while nonexistent yield reduction is considered challenge for scholars especially in arid environment. Grafting is regarded as a promising tool to avoid or reduce yield loss caused by abiotic stresses. Tomato (Solanum lycopersium Mill.), commercial cultivar Faridah was grafted on Unifort rootstock and grown under regulated deficit irrigation (RDI) (100%, 80% and 60% ETc), using two types of irrigation water, fresh (EC = 0.86 dS/m) and brackish (EC = 3.52 dS/m). The effects of grafting and RDI on water use efficiency, vegetative growth, yield, fruit quality were investigated. Plant vegetative growth was reduced under water and salinity stresses. Grafting the plant significantly improves the vegetative growth under both conditions. The results showed that crop yield, Ca+2 and K+ were considerably increased in grafted tomato compared to non-grafted plants under water and salinity stresses. Grafted tomato plants accumulated less Na+ and Cl−, especially under high levels of salinity compared to non-grafted plants. Grafting tomato plants showed a slight decrease on the fruit quality traits such as vitamin C, titratable acidity (TA) and total soluble solids (TSS). This study confirmed that grafted tomato plants can mitigate undesirable impact of salt stress on growth and fruit quality. Keywords: Grafted tomato, Deficit irrigation, Salinity, Water use efficienc

Crop water requirements of date palm based on actual applied water and Penman–Monteith calculations in Saudi Arabia

Abstract This study was conducted in eight different regions of Saudi Arabia to estimate monthly and annual crop water requirements (CWR). Fields that have been selected are located in regions of the Medina (Al Ula), Tabuk (Teimaa), Makkah (Al Jumum), Al Jouf (Sakakah), Riyadh (Sodos), Qassim (Riyad Al Khabra), Hail (AL Kaedh), and East Region (Al Ahsa). The determination of CWRs was based on Penman Monteith method, field water balance, actual water applied in each field, and actual water applied by farmers in adjacent fields. The results based on Penman–Monteith method showed that the crop evapotranspiration, ETc (mm/year) of the sites in, Medina, Tabuk, Makkah, Al Jouf, Riyadh, Qassim, Hail, and East Region were 2418.75, 1940.51, 1837.76, 2259.03, 2139.23, 2207.41, 2008.23, and 2144.87 mm/year, respectively. The CWRs (m3/ha) after taking into account the proportion of cultivated area for each tree were: 9495.24, 7340.18, 7298.93, 8913.59, 8614.96, 8568.68, 7996.99, and 8510.72 m3/ha, respectively. The average date palm numbers were 100 trees/ha. The total annual CWRs (m3/tree) in these sites were 95, 73.4, 73, 89, 86, 85.7, 80, and 85 m3, respectively, as the radius of shaded area per tree is 3.5 m with an effective diameter of 90%, and the rate of leaching was 12, 8, 13, 12, 14, 11, 13, and 13%, respectively. The average overall irrigation water requirements was 8342.41 m3/ha/year (1 ha. = 100 trees). The results of water balance method showed that the water consumed for Qassim and Al Jouf was 3604.31 and 3515.25 m3/ha/year, respectively. The actual irrigation water added by a flow meter for all study sites was 11,305.0, 9463.9, 9692.0, 11,252.75, 1007.40, 10,035.0, 10,272.5, and 10,082.8 m3/ha/year, respectively, while these amounts added by the farmers in adjacent fields were 13,717, 12,277, 12,220, 13,340, 12,050, 12,880, 12,620, and 12,610 m3/ha/year, respectively

Effects of Biochar and Synthetic Polymer on the Hydro-Physical Properties of Sandy Soils

Synthetic polymers, such as polyacrylamide (PAM), and biochar are generally used as soil amendments to improve soil properties. This paper explores a laboratory column experiment conducted to investigate the effects of biochar (pyrolysis at 400⁻450 °C) and polymers, with different application rates, on the hydro-physical properties of sandy soil. The experiment evaluated four rates each of biochar (0.0% (C), 2% (B1), 4% (B2), 6% (B3) and 8% (B4)) and polymers (0.0% (C), 0.2% (P1), 0.4% (P2), 0.6% (P3), and 0.8%(P4)), as well as a mixture of them. The infiltration rate decreased significantly when a mixture of biochar and polymers was adopted. B1 showed a decrease of 32.73% while a mixture of 8% (B4) and (0.8%) P4 exhibited a decrease of 57.31%. The polymers increased the infiltration rate at low concentrations (P1 and P2) and reduced it at high concentrations (P3 and P4). The cumulative evaporation decreased significantly for most treatments. B1 recorded the highest decrease in cumulative evaporation with a percentage decrease of 31.9%. The highest decrease in hydraulic conductivity (Ks) was for B1. However, the mixture of B4 and P4 resulted in the highest increase in soil moisture content at field capacity compared to the control and other treatments. P4 and the mixture of B2 and P2 showed significant (p < 0.05) increases in the percentage of stable aggregate (SA) in fraction size (0.25⁻0.125 mm). Although the mixture of B4 and P4 had the highest increase in soil moisture content, this study recommends using the B1 treatment on sandy soil in arid environments due to its strong hydro-physical properties and affordability

Calibration of Soil Moisture Sensors (ECH₂O-5TE) in Hot and Saline Soils with New Empirical Equation

The use of soil moisture sensors is a practice applied to improve irrigation water management. ECH2O-5TE sensors are increasingly being used to estimate the volumetric water content (VWC). In view of the importance of the efficient use of these devices, six main factors affecting the accuracy of sensor measurements were studied: soil moisture levels, soil salinity, temperature, organic matter, soil texture, and bulk density. The study showed that the electrical conductivity of the soil and the temperature independently affect the measurements, while the influence of other factors interferes with that of salinity. This study found that the sensor measurements of the VWC were closest to the actual VWC at the soil ECe and temperatures of 2.42 dS m−1 and 25 °C, with root-mean-square errors (RMSE) of 0.003 and 0.004 m3 m−3. Otherwise, the measured VWC values of these sensor readouts significantly overestimated the actual VWC, with an increasing soil ECe and/or producing temperatures higher than the stated values, and vice versa. Given the importance of these sensors for obtaining accurate measurements for water management, a simplified empirical equation was derived using the data collected from a wide range of measurements to correct the influences of electrical conductivity and temperature on the measurement accuracy of the sensors, while considering the influence of the soil’s texture. Thus, the following equation was proposed: ϴva = θvsaECe2+bECe+c+dT2+eT+f−1. The results concerning the measurement of different VWC levels via these sensors and the proposed L&O correction equation were compared with the corresponding actual VWC values determined by gravimetric methods. It was found that this empirical equation reduced the differences in the RMSE between the sensor readings for the VWC and the actual VWC from 0.072 and 0.252 to 0.030 and 0.030 m3 m−3 for 1 and 5 dS m−1, respectively, with respect to the EC’s influence at 25 °C and reduced the RMSE from 0.053 and 0.098 to 0.007 and 0.011 at 3 and 50 °C, respectively, regarding the effect of the temperature at EC 2.42 dS m−1 at different levels of the actual VWC values

Impact of deficit irrigation and addition of biochar and polymer on soil salinity and tomato productivity

The aim of this study is to investigate impact of soil amendments (4% biochar, 0.4% polymer, and a combination of them) on soil moisture and salinity distribution, tomato yield, and water use efficiency (WUE). An open field experiments were conducted during two successive growing seasons in 2017 and 2018. The experiment consisted of three level of irrigation treatments 100%, 80% and 60% of ETc; and two different water qualities: fresh 0.9 dSm-1, and saline EC 3.6 dSm-1. Results revealed that at 100 % of ETc, soil water distribution (SWD) increased by 12.94 %, 37.87%, and 42.21% at depths (0-15cm), (15-130cm), and (30-45cm), with the addition of biochar, respectively compared with control at same depths control under freshwater, but the addition of polymer was increased by 6.35 %, 16.56 %, and 16.37 %, respectively. While combination treatments increase by 15.70%, 24.80%, and 41.26 %, at the depths afore- mentioned. Salt concentration was increased by 59.10 % with biochar, while decreasing by 7.19 % and 57.63 % with polymer and mixture treatments, respectively. The results also showed that biochar and mixture treatments improved yield compared to the polymer and control, while saline water decreased the yield compared to freshwater. With deficit irrigation, WUE was increased by 28.54%, 40.98%, and 68.93% at 100%, 80%, and 60% of ETc, respectively, indicating it could be used as an irrigation management strategy under arid and semiarid field conditions.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Grafting improves cucumber water stress tolerance in Saudi Arabia

Water scarcity is a major limiting factor for crop productivity in arid and semi-arid areas. Grafting elite commercial cultivars onto selected vigorous rootstocks is considered as a useful strategy to alleviate the impact of environmental stresses. This study aims to investigate the feasibility of using grafting to improve fruit yield and quality of cucumber under water stress conditions. Alosama F1 cucumber cultivar (Cucumis sativus L.) was grafted onto Affyne (Cucumis sativus L.) and Shintoza A90 (Cucurbitamaxima × C. moschata) rootstocks. Non-grafted plants were used as control. All genotypes were grown under three surface drip irrigation regimes: 50%, 75% and 100% of the crop evapotranspiration (ETc), which represent high-water stress, moderate-water stress and non-water stress conditions, respectively. Yield and fruit quality traits were analyzed and assessed. In comparison to the non-grafted plants, the best grafting treatment under water stress was Alosama F1 grafted onto Shintoza A90 rootstock. It had an overall improved yield and fruit quality under water stress owing to an increase in the total fruit yield by 27%, from 4.815 kg plant−1 in non-grafted treatment to 6.149 kg plant−1 in grafted treatment under moderate -water stress, total soluble solid contents (13%), titratable acidity (39%) and vitamin C (33%). The soil water contents were low in soil surface and increase gradually with soil depth, while salt distribution showed an adverse trend. The positive effects of grafting on plant growth, productivity, and water use efficiency support this strategy as an useful tool for improving water stress tolerance in greenhouse grown cucumber in Saudi Arabia

Effect of Water Quality and Date Palm Biochar on Evaporation and Specific Hydrological Characteristics of Sandy Soil

Experiments were conducted in a soil laboratory using transparent columns (5 and 40 cm in diameter and length, respectively) to evaluate the effects of water quality (i.e., fresh or saline water) with the addition of biochar on soil moisture characteristics. Soil and biochar were gently combined and added into the top 10 cm of each column at a rate of 2%, 4%, 6%, and 8% (w/w). The results show a decrease in cumulative evaporation by 29.27%, 16.47%, 14.17%, and 14.61% with freshwater, and by 21.24%, 12.22%, 21.08%, and 12.67% with saline water for B1, B2, B3, and B4, respectively, compared with unamended soil (B1, B2, B3 and B4 represent the treatments with the biochar rate of 2, 4, 6, and 8%, respectively). Cumulative infiltration was reduced by 34.38%, 43.37%, 58.89%, and 57.07% with freshwater, and by 30.18%, 44.38%, 54.44%, and 49.11% with saline water for B1, B2, B3, and B4, respectively. The infiltration rate was reduced by 32.73%, 42.17%, 57.82%, and 56.85% with freshwater, and 42.09%, 54.61%, 62.68%, and 58.41% with saline water for T1, T2, T3, and T4, respectively, compared with the control. The saturated hydraulic conductivity of B1 decreased significantly by 92.8% and 67.72% with fresh and saline water, respectively. Biochar, as a soil conditioner, could be used in arid conditions with fresh and saline water to enhance the hydrological properties of sandy soils

Impacts of Biochar on Hydro-Physical Properties of Sandy Soil under Different Irrigation Regimes for Enhanced Tomato Growth

The performance of biochar application in water conservation, salt distribution, water infiltration, and tomato growth was evaluated under regulated deficit irrigation (RDI) (40%, 60% and 80% of ETc) and partial root drying (PRD) systems by using different quality irrigation water. Date palm derived biochar was applied to sandy soil at 4% (w/w) in pots, and tomato was grown as the test crop under greenhouse conditions. The results indicated that soil moisture was decreased by 27.38% to 24.95% without biochar application at different levels of irrigation, whereas it increased by 8.11% and 5.48% with biochar application, compared with control treatment of 100% of ETc. Soil moisture was decreased by 12.78%, 15.82% and 12.78% for the 1st stage, 2nd stage and 3rd growth stage, respectively, while it increased by 37.93% at the 4th growth stage compared with full irrigation. Soil salinity ranged between 0.5 and 1.4 dS·m−1 with biochar application, while 0.7–2.1 dS·m−1. Cumulative infiltration at one minute varied between 1.89 and 2.79 cm and 1.74 and 2.79 cm for biochar and non-biochar treatments, respectively. Infiltration rate varied from 0.98 to 2.63 cm min−1 and 1.48 to 1.68 cm·min−1 for fresh and saline water, respectively. Overall, the results revealed that biochar application substantially improved the characteristics of sandy soil, subsequently resulting in water conservation

Impacts of Biochar on Hydro-Physical Properties of Sandy Soil under Different Irrigation Regimes for Enhanced Tomato Growth

The performance of biochar application in water conservation, salt distribution, water infiltration, and tomato growth was evaluated under regulated deficit irrigation (RDI) (40%, 60% and 80% of ETc) and partial root drying (PRD) systems by using different quality irrigation water. Date palm derived biochar was applied to sandy soil at 4% (w/w) in pots, and tomato was grown as the test crop under greenhouse conditions. The results indicated that soil moisture was decreased by 27.38% to 24.95% without biochar application at different levels of irrigation, whereas it increased by 8.11% and 5.48% with biochar application, compared with control treatment of 100% of ETc. Soil moisture was decreased by 12.78%, 15.82% and 12.78% for the 1st stage, 2nd stage and 3rd growth stage, respectively, while it increased by 37.93% at the 4th growth stage compared with full irrigation. Soil salinity ranged between 0.5 and 1.4 dS·m−1 with biochar application, while 0.7–2.1 dS·m−1. Cumulative infiltration at one minute varied between 1.89 and 2.79 cm and 1.74 and 2.79 cm for biochar and non-biochar treatments, respectively. Infiltration rate varied from 0.98 to 2.63 cm min−1 and 1.48 to 1.68 cm·min−1 for fresh and saline water, respectively. Overall, the results revealed that biochar application substantially improved the characteristics of sandy soil, subsequently resulting in water conservation

Long-term detection and hydrochemistry of groundwater resources in Egypt: Case study of Siwa Oasis

Water, it is said, will be the oil of the twenty-first century. Successful water management will be the key to future economic growth and social wealth in both developed and developing countries. Due to the continuous agricultural expansion, urban development, and increased demands on limited water supplies, Egypt is compelled to look for unconventional water resources. One of the most important sources is groundwater in the western desert of Egypt. More water abstraction is currently taking place raising the dangers of overexploitation and deterioration of water quality in Siwa Oasis located in Egypt western desert. The main objectives of this study are to monitor the quality of the Siwa Oasis groundwater over ten years. The present paper presents the results of this investigation and the future outlook for the situation of the limited water resources of the oasis. The data showed spatial differences between water qualities obtained from different locations within the Oasis. It was also observed that there are temporal changes and that water quality is deteriorating in alarming rate over time. Most studied water samples were considered unsuitable for irrigation due to salinity hazards. The reason that may contribute to speeding up groundwater quality deterioration is the unsafe ground water mining on the deep sandstone aquifers which causes the decreases of the fresh water vertical movement from the deep sandstone aquifer to the surface limestone aquifer