Adding Vertisol and emulsified lubricating oil as soil conditioners and its effect on moisture retention in sandy soil and the dry weight yield of natural plants

Abstract

A field experiment was conducted at the Al-Burjasiya Research Station, Al-Zubair District, during the 2023-2024 winter season, on a sandy loam soil, to demonstrate the effect of Vertisol and emulsified lubricating oil as soil conditioners, on soil moisture retention and desert plant growth. The experiment included the use of soil conditioners, two soil conditioners. The first; Vertisol, at levels of 10% (C1), 20% (C2), and 30% (C3), as a suspension at a ratio of 1 part soil to 6 parts water, added directly to the surface of the experimental units, calculated per 1 cm³ of sandy soil. The second conditioner is used lubricating oil mixed with water. It was emulsified by adding a synthetic emulsifying agent (an anionic surfactant). It was added at levels of 0.1% (O1), 0.3% (O2), and 0.5% (O3). The conditioners were added based on the weight (W/W) of the soil, to a depth of 15 cm, in addition to the control treatment (C0%). The moisture and rainfall treatment factor included four treatments: Re-irrigation after 50% of the available water has been lost to the soil's field capacity (R1), irrigation treatment equivalent to the highest rainfall (R2), attenuation treatment equivalent to the average rainfall (R3). R2 and R3 were derived from rainfall data, for a 41-year time series of previous years. These were added as standard irrigation treatments equivalent to rainfall, distilled water (R.O.) was used as a substitute for rainwater, and a direct rainfall treatment of the study year (R4), irrigation and re-irrigation were carried out in treatments (R2 and R3), based on the highest frequency of rainfall in any given month. The results showed that the conditioners were superior in increasing soil moisture content, significant differences were observed among the application levels. Vertisols C3 soil treatment and the emulsified lubricating oil O3 treatment recorded the highest PW values (17.483 and 15.236%), this was significantly higher than the control treatment (10.376%). Regarding moisture content, treatment (R1) recorded the highest PW value, significantly higher than the other treatments, reaching 14.455%, the lowest value was recorded in treatment (R3), which reached 13.711%. The results also showed a significant advantage of soil conditioners in the dry weight of desert plants compared to the control treatment. The emulsified lubricating oil conditioner outperformed the Vertisol soil conditioner in recording the highest dry weight values. O3 lubricating oil treatment recorded the highest values ​​(16.845 tons ha^-1). There was a significant difference between the levels of added conditioners, the lowest dry weight was recorded in the control treatment (2.580 tons ha^-1). The results also showed that the moisture treatment R1 resulted in the highest plant dry weight (13.122 tons ha^-1), the lowest values ​​were recorded using the moisture treatment R3 (6.524 tons ha^-1).