Проведена оценка перспективных биологических препаратов, в сравнении с химическими, для защиты сои от болезней в условиях Западной Сибири. Выявлено, что наиболее эффективными в подавлении болезней, а также в увеличении урожайности сои оказались бактофит и иммуноцитофит.
Soybean is the crop of great significance in agriculture. Some components, obtained after processing the soybean are being used in many industrial sectors, such as food, mixed fodder, textile and other. In addition, the ability of soybean to assimilate the atmospheric nitrogen plays an important role in saving of soil fertility.
Although the history of the growing of soybean in Russia is known long ago, this is relatively new crop for West Siberia. Development the technology of growing soybean makes this culture available for this region. Under the conditions of West Siberia the soybean crops are permanently damaged by diseases, causing the yield losses and reducing the seed mass. The most important diseases for West Siberia are bacterioses, fusarium root rot and complex root rots. These diseases often spread by 80-100%.
Increasing environmental pollution requires several researches for seeking the ecological-safe and pesticide-free methods to carry out. The conception of reducing the use of chemical pesticides becomes a part of legislative acts in many countries of European Union. The needed level of chemical pesticides replacement depends on several factors, including soil and weather conditions in this region.
Taking into account the necessity of ecological alternative we carried out several trials of biological preparations, belonging to various groups, such as immunomodulators, bacteria-based and BAS-based formulations on the crops of soybean cultivar SibNIIK-315. The experiments were conducted during 2005-2007 in the field plots of Siberian Institute of Fodder Crops. According to most widespread diseases, the preparation based on antibiotics (phytolavin 300 and strekar), bacteria (bactophyt) and multipurpose stimulator immunocitophyt (based on arachidon acid) were selected.
Chosen biological formulations were applied by seed treatment with moisturizing and by spraying the plants. Condition of seeds, roots, overground organs as well as influence of preparations on yield structure elements was registered. The chemical fungicide vincit was used as chemical standard.
Before the treatment preliminary analysis of seed was done. It showed that seeds were damaged by bacterial and fungal pathogens at high level. Therefore, we could conduct the trials of preparations at high infection level. Seed infection was exceeded by 4-6 times comparing to economic threshold. We managed to identify the Pseudomonas bacteria and several species of Fusarium fungi among the isolated pathogens.
Starting from the flowering phase we carried out estimation of the disease spreading and its severity. Overground organs of soybean were significantly damaged by bacterial blights. High humidity and temperature level promote the rapid disease spreading. Deterrent effect was provided only by immunocitophyt, some infection reducing on the seeds of a new yield, obtained from test plots were also registered. Treatment by other preparations doesn’t provide significant influence on the spreading and severity of diseases.
Weather conditions, mainly the abundant precipitation, provide the fast growth of soybean. Root part of the plans often crackled and were damaged by root rot. In bactophyt variant spreading and severity of diseases tends to decrease, although differences were not statistically reliable. The smaller damage in the flowering phase was explored in strekar variant; we observed decreasing both spreading and severity of the disease. Other variants don't provide significant decreasing of these parameters.
Growth-stimulating effect of bactophyt and immunocitophyt was observed. First shoots have been observed 2-3 days earlier in the variants with these preparations in comparison to raw seeds. Seed treatment with preparations, selected for the trial, provided the better shoots, although seed lesion did not changed essentially.
The positive influence of treatments on a growth of the soybean was also established. For example, average height of plants in the start of flowering was 6-7 cm higher, than in control. The antibiotic formulations and vincit didn't influence plant's height. Moreover, reliable effects of increasing the tuberous bacteria activity and root nodes forming were shown with bactophyt and immunocitophyt application.
Soybean capacity in the West Siberia is usually estimated about 1,63-2,88 t/ha. However, during the 2005-2007 years the higher yield of soybean was obtained (about 3 t/ha). Nevertheless, with the comparison of control we observed increasing of the saved yield in the experimental plots. For all 3 years the elements of the main yield structure tend to improve on the plots with bactophyt and immunocitophyt. Values of these parameters exceed the values, obtained with antibiotic preparations and chemical standard vincit.
Thus, the application of biological preparations is more reasonable because they have both the fungicide, growth-stimulating and immunizing effects. Using the bactophyt and immunocitophyt for seeds and plant treatment cause more rapid germination of soybean, stimulate the growth of tuberous bacteria, restrain the severity of phytopatogen organisms. This causes to decreasing the spread and severity of main diseases, provides stable soybean yield rise at the level of 0,5-0,6 t/ha. All of this provides increasing ecological stability of soybean agrocenose in the Siberian region.