Optimization of options for differential application of nitrogen fertilizers in the precision farming system

Saabunud / Received 26.01.2020 ; Aktsepteeritud / Accepted 12.05.2020 ; Avaldatud veebis / Published online 12.05.2020 ; Vastutav autor / Corresponding author: Edvin Nugis e-mail: [email protected] paper aims to present the use of various treatments for the differential application of nitrogen in the precision farming system. To assess the state of the vegetation cover, both ground-based observations and associated remote sensing methods were used. Assessment of the state of plants (Menkovsky of AFI, 2009–2011) was carried out according to the phases of their growth and development using an N-tester in the field, as well as analysis of plant samples in a specialized laboratory. Remote sensing was carried out at the time of the analysis of plant samples using unmanned aerial vehicles equipped with cameras that allow shooting in different areas of the spectrum. The test sites with predetermined doses of nitrogen fertilizers for decrypt the obtained images were used. It is shown that for differential application of nitrogen fertilizers in spring wheat crops it is advisable to use the optical characteristics of the state of plants performed using calibration test sites. We have found that the maximum yield in the differentiated nitrogen applications treatment (TK-4) was 4510 kg per hectare (kg ha–1 ). At the same time, the minimum in the TK1 treatment was 3780 kg ha–1 . On average, over the years of research differentiated fertilizer application increased the collection of protein per hectare by 15–17%. In the TK-4 treatment for three years, a grain was obtained that corresponded to the first quality class (exceed 14%) in terms of protein content. Our novel research has shown that for characterizing the state of plants an assessment is given which was performed using calibration test sites

Maintaining soil fertility by optimizing the use of nitrogen fertilizers in precision farming system

The article presents data of research on conservation and improvement of soil fertility using precision farming technologies. The study was carried out under conditions of humid climate (North-West of Russia, Leningrad region). Technologies for differentiated application of nitrogen fertilizers were tested in the fields of the Agrophysical Research Institute. In comparison with high-intensity agricultural technologies, differentiated fertilizer application was used, which was carried out with the help of a solid mineral fertilizer spreader with an on-board computer and GPS Amazon ZA-M 1500. Precision farming technologies had slightly more complex modifications. They were characterized by the introduction of increasingly informative methods of differentiated use of nitrogen fertilizers, which reduced fertilizer doses. New instruments, equipment and technologies were used, including the use of an N-sensor optical instrument, aerial photographic maps and calibration test sites with predefined nitrogen doses

Increase in plant productivity and soil fertility based on monitoring studies in the system of test polygons

The work presents the formation of a system for assessing soil fertility and plant development using test monitoring polygons. Monitoring polygons became the basis for the introduction of modern technologies to increase plant productivity and soil fertility. The monitoring sites were located in the main agro-climatic regions of the Leningrad Region on soil types typical for the respective region. Analysis of the dynamics of the main parameters of soil fertility in test plots shows a tendency towards a decrease in the content of mobile forms of potassium and acidification of soils, as well as other signs of degradation. A decrease in soil fertility is associated with a decrease in the proportion of applied fertilizers and a decrease in soil liming. This process develops on all types of soils, with the exception of those areas that are located in suburban farms. The data for the test sites are consistent with the overall results of the agrochemical surveys. For industrial practice, test sites and information collected on them can serve as “information keys” for decoding space and aerial photographs in order to assess the state of agroecosystems, monitor changes in soil fertility and plant development. On the example of the cultivation of spring wheat, the way of precision assessment of the management of the productivity of cultivated crops and the increase of soil fertility is shown. The mechanism for the implementation of the plant productivity management system was carried out with the introduction of elements of precision farming

Centralspindlin links the mitotic spindle to the plasma membrane during cytokinesis

At the end of cell division, cytokinesis splits the cytoplasm of nascent daughter cells and partitions segregated sister genomes. To coordinate cell division with chromosome segregation, the mitotic spindle controls cytokinetic events at the cell envelope. The spindle midzone stimulates the actomyosin-driven contraction of the cleavage furrow, which proceeds until the formation of a microtubule-rich intercellular bridge with the midbody at its centre. The midbody directs the final membrane abscission reaction and has been proposed to attach the cleavage furrow to the intercellular bridge. How the mitotic spindle is connected to the plasma membrane during cytokinesis is not understood. Here we identify a plasma membrane tethering activity in the centralspindlin protein complex, a conserved component of the spindle midzone and midbody. We demonstrate that the C1 domain of the centralspindlin subunit MgcRacGAP associates with the plasma membrane by interacting with polyanionic phosphoinositide lipids. Using X-ray crystallography we determine the structure of this atypical C1 domain. Mutations in the hydrophobic cap and in basic residues of the C1 domain of MgcRacGAP prevent association of the protein with the plasma membrane, and abrogate cytokinesis in human and chicken cells. Artificial membrane tethering of centralspindlin restores cell division in the absence of the C1 domain of MgcRacGAP. Although C1 domain function is dispensable for the formation of the midzone and midbody, it promotes contractility and is required for the attachment of the plasma membrane to the midbody, a long-postulated function of this organelle. Our analysis suggests that centralspindlin links the mitotic spindle to the plasma membrane to secure the final cut during cytokinesis in animal cells