Koval H. Intensity level of fall ploughing and phytosanitary state of crops of short-rotation crop rotation of the Right-Bank Forest-Steppe of Ukraine

Results of scientific researches of domestic and foreign authors on the study of influence of the measures and depths of basic soil cultivation on weed infestation of spring crops sowings, spreading of diseases and pests, biological peculiarities of the most common pests in experimental crops were analyzed in the paper. It was found in the result of performed researches that the potential weed infestation of a 10-centimeter soil layer increased after replacing of fall ploughing with subsurface loosening. Such indicators were explained by a more even distribution weed seeds at the arable layer by the profile under surface ploughing and its greater accumulation in the upper layer under subsurface loosening. The deepening of cultivation contributed to seeds strewing into the deeper layers of the soil. Replacement of ploughing with subsurface loosening contributed to increasing in the number of weeds in spring crops sowings. Weed infestation also increased while depth decreasing of soil cultivation. Studied variants of surface ploughing provided lower indicators of crops damage of field crop rotation by the most common diseases compared with subsurface cultivation. And increase in the depth of both measures cultivation contributed to improvement of the phytosanitary state of sowings. Crops of short crop rotation responded differently to replacing of surface ploughing of soil cultivation with subsurface method and reducing of their depth, but in most cases their reaction was negative due to a significant deterioration in the phytosanitary state of sowings. Yield of soybeans in 2014 was the only exception, which did not decrease under depth reducing of both measures of basic soil cultivation. The highest economic indicators of crops growing were obtained under ploughing at a depth of 25–27 cm for spring barley, wheat, rape and oil flax and under soybeans – at a depth of 15–17 cm as basic soil cultivation. Minimization of fall ploughing was accompanied by savings in material-and-financial costs; however it caused worsening most of economic indexes under reducing of crop productivity. It is recommended to apply fall ploughing by 15–17 cm for soybean and by 25–27 cm for spring wheat, barley, rape and oil flax with the aim to prevent worsening of the phytosanitary state of sowings and to save constant yielding of spring crops in the southern part of Right-Bank Forest-Steppe grounded on the basis of received experimental data, their analysis and substantiation.