Washing soil salt on saline lands
To obtain high yields of agricultural crops on saline soils, excessive water-salt solutions must be removed without disturbing the spread of the plant's root system. This can be achieved by washing the salt from the soil. According to scientific data, cotton yields decrease by 15-20% on slightly saline soils, by 30-50% on moderately saline soils, and by 70-80% on highly saline soils compared to non-saline soils. Therefore, improving the meliorative condition of the lands is an important factor.
After timely and quality execution of shudgorlashing (shallow drainage), general and current land leveling works, depending on the salinity of the soil, saline soils in the Republic require the following: on weakly saline soils, 1500-2000 m³/ha of water is used for washing salt one time; on moderately saline soils, 2500-3000 m³/ha twice; and on highly saline soils, 4000-4500 m³/ha three times. When washing salt from the soil, water is supplied separately through each furrow from the upper part of the field to the lower part. It is strictly prohibited to open water from one field to another. On moderately and highly saline lands, after each water input, depending on the soil's mechanical composition, additional water is supplied after 2-3 days for light soils, 5-6 days for medium soils, and 7-8 days for heavy soils to wash out the salt 2-3 times. Attention must be paid to ensuring that the surface of the soil in each field is covered with a certain amount of water during the next watering.
The washing process should start with heavy soils and then proceed to lighter soils. The area of fields for washing salt (sections) should range from 0.25 to 0.50 hectares, taking into account soil permeability, land slope, and mechanical composition, with embankments of 50-60 cm in height, and drainage channels between sections.
The most optimal period for washing salt in our republic is from November 20 to February 10. However, in the Republic of Karakalpakstan and Khorezm region, the salt washing process is carried out 2-3 times depending on the level of salinity, and it is recommended to complete the process in the first decade of March. Salt washing should be done when the drainage and collector systems are functioning well. The evenness of the land plays a crucial role in washing salt. Salt can only be washed effectively on flat land; otherwise, harmful salts, which dissolve in water, will rise to the higher parts of the landscape and accumulate, leading to poor germination of crops.