Agrobiological methods of fertility rehabilitation of degraded irrigated lands of the south-east of Kazakhstan

The results of the research open up fundamentally new directions in the use of water resources, in the study of the fertility of saline and secondarily saline lands, in the development of agrobiological and agro-reclamation methods for their improvement, in the development of effective methods for the environmental sustainability of irrigated agriculture. The developed system will significantly reduce costs and allow the widespread introduction of drip irrigation technology over large areas and in many farms in the region. The developed system of irrigated agriculture can be the basis for the adaptation of agriculture in the Ili-Balkhash basin to global climate change with the introduction of a drip irrigation system for rice, diversification of crop production with the introduction of new salt- and drought-resistant crops, and the development of effective methods of amelioration of secondary saline lands. The results of the conducted studies show that in the experimental area under the studied crops, before drip irrigation, there was a slight salinity. Thus, the dense residue under crops varies in the arable 0-20 cm layer within 0.15-0.39 %, and in the subarable 20-40 cm layer in the range of 0.13-0.58 %. After drip irrigation, the content of dense residue under the studied crops slightly increased to 0.34-1.48 % in the arable layer to 0.12 -0.88 %, that is, to the level of low and medium salinity. The results of studies on the study of various methods of irrigating rice on takyr-like soils indicate an increase in rice yields with drip irriga tion. In 2021, with drip irrigation with mulching film, the rice grain yield was 38.5 c/ha. The introduction of 100 kg of ammophos during the row sowing of rice increases the grain yield by 42.2 c/ha. With drip irrigation without a film, the greatest efficiency of nitrogen fertilizers is manifested. With double fertilization with irrigation water of 30 kg/ha in the phase of tillering and panicle ejection, the yield of rice increases by 45.7 c/ha. 651-478 c/ha of green mass of Sudanese grass and 325-287 c/ha of sorghum were obtained, with drip irrigation the soybean grain yield was 51.5 c/ha, which indicates the high ameliorative properties of these crops for cultivation on saline and secondarily saline soils of Akdalinsky irrigation array for fodder purposes. The best reclamation crops for cultivation in saline takyr-like soils of the Akdala irrigation array are soybean, Sudanese grass and sorghum.