Soil salinity and sodicity are significant issues worldwide. In particular, they represent the most dominant types of degraded lands, especially in arid and semi-arid regions with minimal rainfall. Furthermore, in these areas, human activities mainly contribute to increasing the degree of soil salinity, especially in dry areas. This study developed a model for mapping soil salinity and sodicity using remote sensing and geographic information systems (GIS). It also provided salinity management techniques (leaching and gypsum requirements) to ameliorate soil and improve crop productivity. The model results showed a high correlation between the soil electrical conductivity (ECe) and remote-sensing spectral indices SIA, SI3, VSSI, and SI9 (R2 = 0.90, 0.89, 0.87, and 0.83), respectively. In contrast, it showed a low correlation between ECe and SI5 (R2 = 0.21). The salt-affected soils in the study area cover about 56% of cultivated land, of which the spatial distribution of different soil salinity levels ranged from low soil salinity of 44% of the salinized cultivated land, moderate soil salinity of 27% of salinized cultivated land, high soil salinity of 29% of the salinized cultivated land, and extreme soil salinity of 1% of the salinized cultivated land. The leaching water requirement (LR) depths ranged from 0.1 to 0.30 m ha−1, while the gypsum requirement (GR) ranged from 0.1 to 9 ton ha−1.

Soil salinity and climate change have a negative impact on global food production and security, especially in arid regions with limited water resources. Despite the importance of planting methods, irrigation, and soil amendments in improving crop yield, their combined impact on saline soil properties and cereal crop yield is unknown. Therefore, the current study investigated the combined effect of soil amendments (i.e., compost, C and zeolite, Z) and planting methods such as raised bed (M1) and conventional (M2), and different fractions of leaching requirements from irrigation water, such as 5% (L1) and 10% (L2), on the soil physio-chemical properties and wheat and maize productivity in an arid region. The combined application of C + Z, L2, and M1 decreased soil salinity (EC) and sodicity (ESP) after wheat production by 37.4 and 28.0%, respectively, and significantly decreased by these factors by 41.0 and 43.0% after a maize growing season. Accordingly, wheat and maize yield increased by 16.0% and 35.0%, respectively under such a combination of treatments, when compared to crops grown on unamended soil, irrigated with lower leaching fraction and planted using conventional methods. This demonstrates the significance of using a combination of organic and inorganic amendments, appropriate leaching requirements and the raised bed planting method as an environmentally friendly approach to reclaiming saline soils and improving cereal crop production, which is required for global food security.

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The limitation of water resources and the remarkable increase in population should be forced research workers to find ways for saving water without significant reduction in yield. The objective of this paper is to study the interaction effect of deficit irrigation and raised bed on wheat yield, water productivity and water saving in north Nile delta, Egypt. Two field experiments were conducted at Sakha Agricultural Research Station, Kafr El-Sheikh governorate during the two successive seasons of 2012/2013 and 2013/2014. A split plot design with four replications was used. Irrigation treatments occupied the main plots, while planting methods arranged in subplots. Three planting methods were flat (traditional method, F1), bed 70cm wide (F2) and raised bed 140cm wide (F3). Four deficit irrigation treatments were irrigated every 21 days (farmer treatment, I1); the second one after 60% (I2) , the third one after 70% (I3) and the fourth one after 80% (I4) depletion of available soil moisture (ASMD). Results showed that mean of amount of irrigation water applied for DI1, DI2, DI3 and DI4 were 4759.2, 4497.6, 3808.8, and 3360.0 m 3 /ha., respectively, and means of water table contribution to ETc were 559.2 and 765.6 m 3 /ha. for I3 and I4 , respectively. Means of irrigation water applied were 4524, 4034.4 and 3763.2 m 3 /ha. for F1, F2 and F3, respectively. F3 and F2 saved 17% and 11% of irrigation water compared with F1, respectively. F3 significantly increased grain and straw yields by 16 and 18% compared to F1. The interaction between DI2 and F3 and between DI1 and F1 resulted in higher grain and straw yields. Means values of water productivity were 5.7, 6.1 and 6.1 L.E /m 3 correspond to 1.2 , 1.18 and 1.5 kg grain/m 3 water applied for F1, F2 and F3 respectively .

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