The thesis summarizes the theoretical generalization and scientific justification of the drip irrigation regimes of tomato seedlings for combine harvesting in the conditions of the Steppe of Ukraine.
The experimental part of the studies was carried out during 2009-2011, 2015 and 2016-2018 on the lands of SE "OH "Brylivske" IWPLR NAAS. The adaptation of the «Penman-Monteith» method according to the determination of tomato ETc was carried out in 2017 under the production conditions of the PSP Agrofirm Rodnichok (Mykolaiv region) and Organic Systems LLC (Kherson region). The formation of the water regime of the soil, the processes of evapotranspiration, and the productivity of plantations were investigated depending on 6 various levels of moisture availability in the soil.
The main scientific and applied result of the work is the substantiation of the optimum regime of drip irrigation of tomato, which is based on the formation of a relatively high and, at the same time, narrow level of pre-irrigation soil moisture.
According to the results of studies of the water regime of the soil, the regularities of the formation of drip irrigation regimes and the processes of plant evapotranspiration are established, and the statistical model «Evapotranspiration –Yield» is built. The plant growth and development features were studied and established on the basis of the relative growth rate criteria – RGR, net assimilation – NAR, and the productivity of the leaf apparatus – LAR depending on drip irrigation regimes, and productivity and quality indicators of seedling tomato fruits. It is established that the implementation of irrigation regimes with SMBI (soil moisture before irrigation) 80; 80-85-70 and 90 % of FMC provided the maximum in the experiment 149,2-152,0 t/ha with LSD0,5 4,53-5,72 t/ha. According to additional criteria (irrigation rate, ETc, CE, WUE and Cei), the optimal irrigation regime is 80-85-70 % FMC, which is differentiated by the phases of plant development.
Various methods for diagnosing the timing of vegetative irrigation were tested and their adaptation to drip irrigation conditions of the Steppes of Ukraine was carried out: by the concentration of the cellular juice of the leaves and the calculated «Penman-Monteith» method. The features of the formation of moist loamy soil wetting zones during drip irrigation were studied; their geometric parameters were established depending on the duration of irrigation.
The calculations substantiate the economic and bioenergy efficiency of introducing drip irrigation technologies for tomato seedlings in the conditions of the Steppe of Ukraine.
Key words: evapotranspiration, drip irrigation, irrigation rate, soil moisture before irrigation, irrigation regime, tomato seedlings, productivity
