Effectiveness of wastewater use in rice cultivation on basis of water-saving technologies

Abstract

This article covers the results of the scientific research, conducted in the conditions of Khorezm region (Uzbekistan) on cultivation of rice on the basis of seedling as a second crop in the fields after winter wheat. As an introduction of resource conservation technologies in agriculture for cultivation of rice biologically treated water with the help of water hyacinth (Eichhornia crassipes) were used in the experiments. Saving irrigation water concerning the purification of waste water from urban public water supply is one of the purposes of the research. According to the research results, while analyzing the physical and chemical content of waste water in the pool with water hyacinth, it was determined that its composition was changed, the water temperature increased from 250C to 290C, the medium changed from acidic to alkaline (6.7-8.2) the color changed from reddish to whitish, the smell disappeared (5.0-0.0), the amount of suspended matters decreased (29.0-0.0 mg/l), the amount of oxygen increased (11.2 mg/l), 5 day biochemical consumption of oxigen (BCO5) decreased (71.4 -10.1 mg/l), the amount of O2 in the oxidation process decreased from 58.2 to 9.2 mg/l and ammonia, nitrites, and nitrates disappeared, besides chlorides decresed up to 40.5-15.3 mg/l, sulfates decreased up to 38.5-12.5 mg/l, phosphates decreased up to 4.2-0.5 mg/l, plant biomass increased from 200 mg/l to 1460 mg/l. At the same time, it was determined that due to the use of wastewater, up to 9250 m3 irrigation water was saved and crop yield was increased to 73 quintals per hectare.