Lysimeter experiments were conducted under greenhouse conditions to investigate canola (Brassica napus L.) plant water use, growth, and yield parameters for three different water table depths of 30, 60, and 90 cm. Additionally, control experiments were conducted, and only irrigation was applied to these lysimeters without water table limitations. The canola plant’s tolerance level to shallow groundwater was determined. Results showed that groundwater contributions to canola plant for the treatments at 30, 60, and 90 cm water table depths were 97%, 71%, and 68%, respectively, while the average grain yields of canola were 4.5, 5.3, and 6.3 gr, respectively. These results demonstrate that a 90 cm water table depth is the optimum depth for canola plants to produce a high yield with the least amount of water utilization.

Food sustainability is continuously restricted by water shortage and poor water quality in water-scarce regions. In this study, a pot experiment was carried out under rain shelter conditions to quantify the impact of the different levels of water salinity on the yield, leaf nutrients, and growth traits of garden cress under different water-deficit levels. Twelve treatments included three water-deficit (WD) levels (I₀, I₁, and I₂ indicating 100, 80, and 60% of field capacity, respectively) in combination with four saline irrigation water levels (IWS) (S₁, S₂, S₃, and S₄, indicating 0.38, 2, 4, and 8 dSm⁻¹, respectively). Also, multiple linear regression analysis was performed to predict garden cress yield using WD, IWS, and soil salinity (EC_e) parameters in different combinations. The results showed that yield, leaf area, stomata, chlorophyll content, leaf Ca²⁺, K⁺, K⁺/Na⁺, and Ca²⁺/Na⁺ markedly decreased under water deficit and water salinity interaction. The highest and lowest EC_e values were observed at the I₂S₄ (8.67 dSm⁻¹) and I₀S₁ (0.88 dSm⁻¹) treatments. The highest yield was found at I₀S₁ (166.1 g pot⁻¹), and it was 49.8% and 62.0% higher than I₁S₄ and I₂S₄ treatments. The developed models have R² larger than 0.92, showing that they could provide a valuable tool for evaluating and estimating the garden cress productivity under different WD and IWS conditions. Finally, we conclude that WD (80% of FC or lower) combined with a higher IWS of 0.38 dSm⁻¹ is not recommended for irrigating garden cress, which will cause considerable yield and commercial quality reduction of garden cress plants.

Geostatistical approaches (ordinary kriging (OK) and indicator kriging (IK)) were used in this study to investigate the spatial and temporal variations in groundwater nitrate concentrations in Çarşamba plain of Turkey. Groundwater samples were taken in April 2012, July 2012, September 2012 and March 2013 from 78 groundwater wells. The experimental semivariograms were often fitted well by a Gauss model for April 2012 and September 2012, whereas a spherical model was fitted to experimental semivariograms for July 2012 and March 2013. Spatial distribution maps revealed that groundwater nitrate concentrations were above the threshold value of 50 mg L⁻¹ specified for drinking water in 4.3% of the study area in April 2012, 40.8% in July 2012, 32.8% in September 2012 and 19.1% in March 2013. Probability maps created with IK showed that 3.1% and 3.2% of the total area had very strong probability (0.8–1.0) of exceeding the threshold nitrate concentration in July 2012 and September 2012, respectively. Current findings revealed that groundwater nitrate concentrations changed seasonally and increased much more in summer. It was concluded that OK and IK may yield significant outcomes for groundwater management, identification of risky sites for potential pollution and identification of the sites with excessive fertilizer uses.