No abstract

Introduction of 5.0 t/ha of phosphogypsum contributed to the receipt of 1.69 t/ha of oil flax seeds; yield increase was 0.36 tons per hectare or 27%. The content and collection of oil also reliably increased. Winter wheat grain yield in the variant with phosphogypsum was 5.48 tons per hectare; yield increase, in this case, reached 0.74 tons per hectare or 15.6%. Harvest index (HI) of winter wheat in the trial fields with phosphogypsum was 50.0%; the same in the control variant (without phosphogypsum) – 38.0%.

The research is aimed to improve the agrochemical properties of sod-podzolic soil and increase the productivity of crop rotation with potatoes. The decrease in the mineral and organic fertilizers use in Non-Chernozem zone of Russia leads to low yields of potato tubers and worse agrochemical properties of sod-podzolic soils. Agronomical positive and ecologically safe effects of phosphogypsum on physical and chemical properties of sod-podzolic sandy soil and formation of productivity and quality of potato and spring barley was revealed. With the introduction of phosphogypsum, on average for 3 years, the soil received (kg S/ha per year): with a dose of 0.5 t/ha +35.1, with a dose of 1.0 t/ha +57.6, with a dose of 1.5 t/ha +79.8 and against a background of 3.0 t/ha +105.6, which led to an increase in the content of salpho in the soil, respectively, introduced doses of meliorant – by 9.7, 17.5, 26.5 and 32.9 mg S/kg compared to the initial level. A single application of phosphogypsum to sod-podzolic soil provided an increase in the content of labile phosphorus by 72 and 40 mg/kg against the background of doses of 1.5 and 3.0 t/ha. The As-sessment of the possible toxicity of phosphogypsum showed that the ratio of Ca/Sr in the soil is at a safe level and amounted to 97 in the control variant, against the background of doses of phosphogypsum 0.5, 1.0 and 1.5 t/ha – 104-117. In total, for three years of research, the use of meliorant provided an increase in the productivity of potato – barley – potato crop rotation by 30-38 kg of grains units/ha or 19-24% in comparison with the option where only NPK fertilizers were used.

The purpose of the experiment was to study the influence of periodic using of neutralized phosphogypsum on the fertility of meadow chernozem soils of Krasnodar Territory, achieving of the appropriate level of rice agrocenosis productivity, and the quality of rice grain. The timing of the effective use of phosphogypsum as a phosphorus fertilizer was revealed during the experiment. It was proved that the same level of mobile phosphorus content in rice soils can be achieved by using either phosphogypsum or standard phosphorus-containing fertilizers. Given the fact that nitrogen and potassium fertilizers are already used, using of phosphogypsum provides an opportunity of getting a 6,34 tons/hectare yield of rice (the same result was achieved using N120P80K60 fertilizer). 3 years after re-fertilizing the soil with phosphogypsum we can notice that effectiveness of phosphogypsum in optimization of rice mineral nutrition program contributes to cost savings of 4155 RUB/hectare in comparison with traditional fertilizing system.

In the article are presented the investigation results, which shows the effectiveness of urea with urease inhibitor – nBPT in potato growing agroecosystems. The advantages of the new fertilizer are the yield increase, and quality improvement. Urea with nBPT lead to formation bigger tuber size what is one of the most important characteristic for marketable potato. Fertilizer was tested in experimental fields and in real farm conditions.