DefinePK

Abstract

Evaluation of the rice meliorative systems operating mode of Kalmykia Republic is presented in the article and shows the criteria of negative processes, such as secondary salinity and salinization of soils, for which the value of hydroecological risk is unacceptable and is within 0.42 and 0.69 respectively. Complex of measures, tools, chemical and biological melioration methods is offered to maintain the melioration situation at an acceptable level, such as reconstruction of the collector drainage system; improving of conditions for removal of waste and drainage waters from the site territory; observance of the washing irrigation regime of soils with the removal of salts with drainage water; regular capital and current planning of map’s checking with bringing the level of the surface to a constant level with variation ± 3...5 cm from zero plane; improving the structure of rice crop rotation; carrying out activities for chemical melioration saline and saltmarsh soils. The results of rice agro-landscapes design research years are presented with the inclusion of improving meliorative crops to the crop rotation, which are capable to increase bio-energy productivity of agro-ecosystem and to provide a positive humus balance, an increasing in rice soil’s fertility, an agricultural landscapes productivity in case of minimum energy costs. Ecological efficiency of resource-saving technologies of dry upland crops cultivation is proved, due to the formation of high harvests without watering with the use of after-rice residual moisture reserves (280…300 mm). Melioration impact ecological efficiency of crops-ameliorants in rice rotation is improvement of water-physical properties (total porosity and aeration porosity increase by 5…7% and 9…12% respectively); reduction of the composition density by 7.52…10.3%; the increase in the number of the most agronomically valuable soil aggregates (0.25…10 mm) by 9.95…16.04%; the increase in the structure coefficient from 0.9 to 1.7…1.9; reduction of the groundwater level and territory flooding risk by 35%. The plowing of plant residues (from 4.0 to 14.8 t/ hectare) allows to increase the humus content by 15…18%, improve the phytosanitary condition of rice fields (by 42…75%), increase the rice grain yield by 0.39…1.13 t/hectare.