No abstract

Цель исследований-проследить динамику засоренности и определить видовой состав сорняков в полевых севооборотах, выявить влияние севооборота, агрофона и времени на засоренность посевов. Исследования проводили в 1998-2017 гг. в условиях Республики Марий Эл на дерново-подзолистой среднесуглинистой почве с высоким содержанием подвижных форм фосфора и обменного калия. Биоморфологический спектр сорных видов свидетельствовал, что на долю малолетних сорняков приходилось 26 видов, многолетних-9. За время исследований в изучаемых агроценозах наблюдали увеличение обилия сорняков: в первую ротацию-60,78 шт./м 2 , во вторую-67,48 шт./м 2 , в третью ротацию-75,95 шт./м 2. Возрастала численность таких малолетних сорняков, как горец птичий, аистник цикутовый, вероника изящная, пастушья сумка обыкновенная, фиалка полевая, дымянка аптечная и звездчатка средняя. Значительно увеличилась численность мари белой и просо куриного, особенно за последние шесть лет исследований. С каждым годом уменьшалась засоренность пикульником обыкновенным, васильком синим, метлицей обыкновенной и щирицей запрокинутой. Наибольшая засоренность малолетними сорняками (71,86 шт./м 2) наблюдалась в зерновом севообороте, наименьшая-в зернотравянопропашном (54,83 шт./м 2). Максимальное количество многолетних сорняков находилось в I плодосменном севообороте-14,08 шт./м 2. Фон без удобрений по малолетним сорнякам показал наименьшую засоренность-59,95 шт./м 2. На фоне внесения N60P60K60 их численность возросла на 8,98 шт./м 2 (НСР 05-5,50).

The task of establishing the cause of certain facts, events, or processes is one of the most common tasks that courts systematically assign to experts. The article presents a methodological approach for justifying the cause during the preparation of a written opinion within the framework of forensic examination. This approach allows to identify the cause of the investigated event among various factors and can be useful in the context of forensic investigation both to justify conclusions about the cause and to verify the completeness and reliability of the conducted investigation as an express analysis.

The construction of modern poultry farms has significantly increased the proportion of bird droppings in the total production of organic fertilizers. Due to the high concentration of poultry farms on the territory of the Mari El Republic, the need has arisen to search for and scientifically sound introduction of new technologies that are not traditional for our zone of fertilizers, techniques and methods of growing crops based on agricultural biologization in order to significantly reduce the chemical load on the soil. One of the methods to improve soil fertility is the use of granular organic fertilizers based on bird droppings. We conducted studies on the use of GOF based on chicken droppings in the cultivation of spring wheat. Studies have shown that the use of granular organic fertilizers contributed to a significant increase in spring wheat yields. The highest value was observed for the option with the introduction of GOF at a dose of 400 kg/ha, and amounted to 2.18 t/ha, which is 34.6% higher than the option without fertilizers. It should be noted that the use of GOF based on bird droppings contributed to the reduction of root rot susceptibility of spring wheat, the smallest spread and development of root rot was in the variant with 400 kg/ha - 44.7% and 24.1%, which is 28.8% and 41.4% less than in the variant without fertilizers.

The purpose of the research is to study the effect of long-term application of fertilizers on the dynamics of humus in the sod-podzolic medium-loam soil of the Republic of Mari El. It was found that in the control grain-grass crop rotation on the natural soil fertility for 24 years, the humus content in the soil gradually decreased. By the end of the second rotation, it decreased by 0.03%, in the third-by another 0.08 % and the fourth-by 0.02 %. The content of humus in the soil of the first fruit-bearing crop rotation decreased even more intensively than in the control. In 2001, the content of humus in the natural soil fertility decreased by 0.05% compared to the initial state. In 2007, at the end of the second rotation, humus in the first crop rotation decreased by 0.09…0.10 % from the initial state. In 2013 - by 0.16…0.17 %. The lowest humus content- 1.55 % for all the time of research was in the soil of the first fruit-bearing crop rotation at the end of the Quad rotation against the background of natural soil fertility. The difference compared to the initial state in this variant was -0.17 %. The highest humus content was in the soil of the second crop rotation, where rotted manure was applied under potatoes-80 t / ha. By the end of the first rotation, the humus content in the soil of the crop rotation increased by 0.03…0.04 %. By the end of the second-by 0.11% relative to the first rotation, the third-by 0.10…0.12 %, the fourth-by 0.20…0.21 %. Against a background without fertilizers, the humus content was always higher than when using N60P60K60. The most stable humus content was in the soil of the third crop rotation. In this rotation of six fields, two fields were under perennial legumes. During three rotations, the content of humus in the soil in this crop rotation was within the range of 1.72…1.74 %. Only after the fourth rotation, the humus content decreased to 1.70…1.73 %.