Abstract:
The article presents the material on the study of sunflower productivity formation in postharvest crops depending on mineral nutrition under irrigation in the Ssouth of Ukraine. In order
to maximize the productivity of sunflower plants in post-harvest crops, it is necessary to develop
rational tillage measures, optimal fertilizer doses and an integrated plant protection system.
The main objective of the study is to determine the effectiveness of different tillage measures
and nutrition background for growing sunflower in post-harvest crops under different precrops
on irrigated lands of the southern Steppe of Ukraine.
Agroclimatic and soil conditions of the irrigated zone of southern Ukraine allow combining
the cultivation of rapeseed for seeds with post-harvest sunflower for oilseeds. Winter rapeseed
showed higher productivity in the experiments. The yield of its seeds was 32.6 c/ha, which is
11.7 c/ha more than that of spring rapeseed. The optimal conditions for the growth, development
and formation of seeds in sunflower plants are formed when it is grown after the winter rapeseed
as a precrop. At a later sowing date after harvesting spring rapeseed, sunflower significantly
reduces the yield. Soil tillage systems that were studied in the experiment during the cultivation
of sunflower as a post-harvest crop, the best technology was the shallow tillage. In these variants,
the seed yield is 12.2–27.3 c/ha, which is 1.2–2.8 c/ha more than in direct sowing. The use of
nitrogen-phosphorus fertilizers before sowing sunflower in a dose of N90P90 provided the highest
seed yield of 15.9–27.3 c/ha. Compared to the unfertilized control variant and the variant with a
dose of fertilizer N45P45, the yield decreased by 45.9 and 48.8% and 19.0–27.0%, respectively.
Further increase of the fertilizer dose to N135P135 in the experimental conditions did not lead to
an increase in the yield of sunflower seeds. In order to increase the index of irrigated arable land
utilization, rise the coefficient of vegetation period utilization and gross production of oilseeds, it
is advisable to use winter rape as a precursor for post-harvest sunflower crops
