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III(i) Water and Crops
Published in Richard J. Chorley, Introduction to Geographical Hydrology, 2019
Such arid soils, which present special water-quality problems, can be divided into: Saline soils: with excess soluble salts, producing plasmolysis and impairing productivity.Saline/alkali soils: with excess soluble salts plus an injurious excess of sodium.Alkali soils: with an excess of sodium and pH of 8.5–10.
Alkali Soils
Published in Ranbir Chhabra, Soil Salinity and Water Quality, 2017
Alkali soils have pH greater than 8.2. Recent studies have shown that there is an intimate relationship between ESP and pH of the saturation paste. As the pH increases, ESP also increases (Fig. 3.10). Since the pH of the saturation paste can be easily determined in the laboratory, this property can be used as an approximate measure of ESP (Table 3.3), which is otherwise a cumbersome determination. The pH of a 1:2 of soil water suspension (pH2) is normally one unit lower than the pH of the saturation paste (pHs) (Fig. 3.11). Though pHs and ESP are well correlated over a large range of ESP, reliable interpretation of the data requires that the pH measurements are thoroughly standardized for any major group of soil.
Pig farm biogas slurry can effectively reduce the pH of saline-alkali soils
Published in Environmental Technology, 2023
Yongli Zhu, Gen Yuan, Zihui Zhao, Yifan Tang, Pingping Li, Jiangang Han
Application of biogas slurry to cropland is regarded as an effective way to recycle nutrients within livestock and crop production, while maintaining healthy soil pH is crucial for sustainable application. This study showed that application of biogas slurry, which is alkaline, can significantly reduce the pH of saline-alkali soils. We found that the oxidation of ammonium is the main reason for the reduction of soil pH following biogas slurry application. Our results also showed that the rich and diverse organic functional groups in biogas slurry, particularly carboxyl, hydroxy, amide and alkyl C, substantially improved the status of soil ions and soil aggregate stability, which may be another reason for the reduction of soil pH. Overall, this study demonstrates that application of biogas slurry on saline-alkali soils can be both efficient, in terms of plant nutrient supply, and sustainable, in reducing soil pH. Therefore, we recommend the substitution of chemical fertilizer with biogas slurry on saline-alkali soils, which can be beneficial for both livestock and cropping industries.
Groundwater quality and associated health risks in a semi-arid region of south India: Implication to sustainable groundwater management
Published in Human and Ecological Risk Assessment: An International Journal, 2019
Magnesium hazard ratio (MHR): Generally, calcium and magnesium do not behave equally in the soil systems, but they establish equilibrium between one another in water (Paliwal 1972). Magnesium damages soil structure when the water has more salinity and sodium content resulting in formation of alkaline soil. Therefore, this alkaline soil adversely affects the crop yields (Adimalla and Venkatayogi 2018). Moreover, Thapa et al. (2017) observed that excessive concentrations of Mg2+ in irrigation water can be toxic to plants due to reduced availability of K+ in soils. Thus, MHR was evaluated to assess groundwater quality for irrigation uses. In the study, the calculated MHR values ranged from 3.8 to 68.3 meq/L. About 55% of the samples were suitable for irrigation while the remaining samples were considered harmful and unsuitable for irrigation because of the determined MHR value larger than 50% (Table 6).
Heavy metal contamination and ecological-health risk evaluation in peri-urban wastewater-irrigated soils of Beni-Mellal city (Morocco)
Published in International Journal of Environmental Health Research, 2020
Ahmed Barakat, Widad Ennaji, Samira Krimissa, Mustapha Bouzaid
The acidity or alkalinity in soils controls the heavy metal mobility. Generally, the mobility of metals in alkaline soils decreases. The measured pH showed values varying between 7.2 and 7.8, with an average of 7.7, suggesting thus that the studied soil samples are alkaline. This alkalinity of the studied soil could be related to the local geology that is carbonated. The alkaline soil nature favorites the heavy metal retention and reduces their mobility in the soils (Tian et al. 2017).