The experiment aimed to study the effect of the irrigation water quality on the growth of seedlings and its yield of quinoa plant through some traits i.e., plant height, number of leaves per plant, 1000 grains weight, dry weight per plant , stem diameter, inflorescence length and grain yield per plant. Four treatments were used as follow: T1 (low salinity water, EC 1.25 dS m -1 ), T2 (mix water between low salinity water and agricultural drainage water at ratio 1:1, EC 4 dS m -1 ), T3 (agricultural drainage water, EC 8 dS m -1 ) and T4 (high salinity water, EC 16 dS m -1 ). The treatments application was at the beginning of the plant buds so that the amount of irrigation water up to 75% from field capacity. The significant effects of treatments were found on all tested traits. Also, the results clarified that the rate of chlorophyll ranged between 44.18 (treatment T4) and 53.75 SPAD (treatment T3), water potential of the fourth leaf has ranged from -0.83 to -1.745 MPa for T1 and T3 treatments, respectively, number of leaves per plant was ranged between 26.5 and 28.5 when the plants were irrigated with T4 and T1 irrigation water treatments, respectively. The inflorescence lengths were varied between 8 cm at T4 treatment and 12 cm at T2 treatment. The plant height was ranged between 53.5 cm (T4) and 60.75 cm (T3). The low values of seed yield were recorded at T4 (17.05 g/plant) while the higher values were recorded with T2 treatment (34.08 g/plant). 1000-grain weight values were ranged between 2.97 g at T2 treatment, and 3.49 g at treatment T1.

Al-Hassa oasis is considered as the biggest irrigated one in the World, being well known for its extensive date palm cultivation with an estimate of at least three million trees. The aim of this study is to evaluate the impact of soil fertilization practices on the productivity potential of date palm trees grown under the climatic conditions of Al-Hassa oasis, KSA. The opinions of 258 active farmers were randomly surveyed using specifically designed questioners that were also fortified with personal communications. The size of the samples was designated in accordance to Cocoran equation. The total samples were allocated into two major parts (193 for the old oasis and 65 for the new oasis). Results showed that the farm features (utilized agricultural area (UAA), ownership and labors) are different in both parts of the oasis. Fertilization practices (quantity applied per area or per tree) were diverse causing dissimilar productivity potentials (total or per area or tree). The average production of a tree in the old oasis is 81.4 kg, whilst it is 54.6 kg in the new oasis. Date palm production is significantly affected by total number of trees, applied fertilizer quantity, cultivated area and labor power. The impact of these factors is unlike between the two parts of the oasis. It is then concluded from the study that there are sincere needs for improving the soil fertilization practiced for the date palm trees grown in the Al-Hassa oasis, KSA in order to increase their productivity potential and hence improve the farmers' income.

This study assessed the spatial and temporal variations of land cover in the agricultural areas of the Al-Hassa oasis, Kingdom of Saudi Arabia (KSA). Change detection technique was applied in order to classify variations among different surface cover aspects, during three successive stages between 1985 and 2017 (i.e., 1985 to 1999 (14 years), 1999 to 2013 (14 years), and 2013 to 2017 (4 years)), using two scenarios. During the first stage, significant urban sprawl (i.e., 3,200 ha) occurred on bare lands within the old oasis, while only 590 ha of the oasis’s vegetation area was occupied by urban cover. However, the final stage revealed rapid urban development (1,270 ha by 2017) within the oasis’s vegetation region, while no urban sprawl occurred on bare lands (area of 1,900 ha, same as that in 1999–2013). Vegetation cover of around 1,000 ha changed to the bare soil class, in addition to the areas that were occupied by the urban class (1,700 ha in total). The study provides quantitative information on the influence of urban development on the spatial changes in vegetation cover of the oasis, especially during recent decades.

Diversity in date palm (DP) cultivars plays a crucial role in the agroecosystems of several countries, such as the Kingdom of Saudi Arabia (KSA). This study aims to map and analyze the spatial distribution of the most grown DP cultivars (Khlas, Ruziz, and Shishi) in the Al-Ahsa oasis in the KSA and to highlight their spatial correlation with the corresponding cultivated patches within farms. Descriptive and spatial data on 288 farms were analyzed using GIS, data curation, cross-TAB statistics, clustering maps, and spatial autocorrelation techniques. The obtained results revealed that most of the oasis’s DP farms are within a cultivated area of <500 m2. The larger cultivated areas are mostly in the oasis’s northern and central subregions, agreeing with the spatial distribution of trees. In total, 56.9% of the studied farms grew the cultivars together within the least rank (<500 m2) of cultivated area, having the greatest tendency for DP cultivation. Khlas was the most dominant cultivar being the least absent from cultivation with 3.1% compared to Ruziz (31.9%) and Shishi (37.8%). The spatial distribution of DP plantations in the oasis was also consistent with the spatial variation in soils and irrigation water salinity, necessitating the need for special agricultural extension programs. In conclusion, these outcomes indicate that this study is essential for DP sustainability, growers, authorities, and policy makers.

This experiment was conducted to study the effect of irrigation intervals on growth, yield and its components and some of the chemical characteristics of the soil after the harvest of quinoa (Chenopodium quinoa willd) plant. Three treatments were used as follow: T1 (twice irrigation every week, which is the common in the region), T2 (once irrigation every week) and T3 (twice irrigation every two weeks) using in a randomized complete block design with four replicates. The crop coefficient (Kc) value differed according to the stage of growth where the results showed that the T2 treatment gave the highest mean in all the studied traits followed by the T3 treatment in all traits except the number of seed/m 2 . The results also confirmed that the increase in water reduced the agronomic traits such as harvest index, number of seeds and yield of seeds and straw/m 2 . Also it showed that the pH values in soils were not significantly affected by irrigation, while Ec significantly affected. Correlation coefficient was negative with the most traits and low with the number of grain (0.34) under overall studied treatments which confirms that quinoa is a plant that needs limited amounts of irrigation water. On the other hand there was positive strong correlation between the harvest index and grain yield (0.92). The results showed that moisture stress treatments increased the concentration of the ionic, NH 4 -N and NO 3 -N significantly compared to soils which do not have moisture stress (T1, T2). We assume that the development based on Kc during growth-stages helps in irrigation management and provides precise water applications for quinoa plant. These results indicate that the water requirements of quinoa plant are limited and that quinoa plant growth is not affected by the lack of irrigation water on the crop and its qualities.

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The growth, yield, head quality and NPK contents in lettuce plants grown on a sandy soil fertilized with different rates (0, 75 and 150 gm m -2 ) of 18:7:16 NPK compound fertilizer was evaluated in an experiment conducted for two successive seasons (1998/1999 and 1999/2000). As compared with the control, fertilized treatments showed significant differences in fresh weight per plant, percentage dry/fresh weight, leaf area, total yield, head diameter and head circumference for the two seasons. After harvest, the contents of NPK in the lettuce leaves and the soil were increased by the application of the compound fertilizer at a rate of 150 gm/m 2 . However, the increase in P % in both lettuce leaves and soil was not significant for all treatments.

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