Drainage waste runoff of rice irrigation system as an additional reserve of irrigation water

We review the feasibility of the Dnieper water dilution with drainage and waste by 25% ad using it in technology of agricultural crops cultivation. The data of the Dnieper, drainage and mixed water quality are given. The results of the vegetation experiments showed the dependence of the yield of green mass of crops on irrigation water quality. The grain yield of rice varieties of different maturity classes are studied in dependence on fertilizers, ameliorants, the quantity and quality of irrigation water. The aim was to issue the maximum re-use of drainage waters to minimize discharge of wasteful, resource-saving and environ- mental protection, in particular, of the Black and Azov seas. In the laboratory studies, conducted with the purpose of hydrochemical monitoring and the quality assessment of the Dnieper, mixed (Dnieper — 75% + drainage — 25%), drainage of irrigation waters revealed their significant difference. The main problem of drainage waters is low quality. As evidenced by the data obtained under mixed water diluted with Dnieper was less aggressive in comparison with drainage and waste. Mixed and recorded in drainage waters had higher level of calcium compared to the Dnieper irrigated water, and other nutrients due to the leaching of soil dissolved fertilizers with irrigation water. According to the classification of academician A.M. Kostyakov Dnieper water is suitable (good) for irrigation. Mixed, and especially drainage water requires ongoing monitoring with the consideration of the full range of their application. The interaction of irrigation water, mineral fertilizers and ameliorants provide high yields of rice grain. The reduction in yield when irrigation mixed with water for four years was not significant (4.9–5.1%).