In the Astrakhan region, for long-term saline fallow reclaimed lands in the rice engineering system, flushing is required when they are involved in an active agricultural turnover. In modern conditions, keeping the land simply under "water vapor" is ineffective, therefore, before growing crops, rice checks are used as fish ponds. The purpose of the study was to establish the effect of the duration of the fish pond on the hydrophysical, agrochemical indicators of the soil, weediness and yielding capacity of crops in the rotation system during reclamation of the fallow. A one-year and two-year stay of a check under a fish pond contributed to an increase in the content of humus by 0,08-0,11%, organic matter by 0,44-0,53%, easily hydrolysable nitrogen by 6,1-9,2 mg/kg, mobile phosphorus by 9,3-16,4 mg/kg, mobile potassium by 5,4-8,2 mg/kg, moisture reserves in the soil by 1,9-2,5 times and reduced the weediness of barley crops with alfalfa overseeding by 6,5-10,9 times. Grain yield of spring barley variety AS Lacomb was 3,8-4,2 t/ha, green mass of alfalfa Nadezhda – 9,0-11,0 t/ha. A two-year-old pond as a predecessor for growing watermelon in the crop rotation created more favorable conditions for obtaining high-quality cucurbitaceous products, the average yield and marketability for varieties was higher in the mid-season group - by 3,3 t/ha and 0,7% and in the middle-late group – by 1,3 t/ha and 0,3% compared to a one- year pond as a predecessor. The content of dry matter and the amount of sugars exceeded the standards for all studied varieties of watermelon in two groups of ripeness. The largest amount of dry matter and the amount of sugars were found after a two-year pond for the watermelon variety Belye rosy and they were 12,15% and 10,08% respectively.
