Ферментативна активність ґрунтів заплави р. Сіверський Донець під лісовим ценозом

Abstract

Було досліджено активність ферментів в алювіальних ґрунтах заплави р. Сіверський Донець під лісовим ценозом, які належать до класу оксидоредуктаз (каталази та дегідрогенази), що відіграють провідну роль в окислювально-відновлювальних процесах і беруть участь у синтезі гумусних речовин у ґрунті, класу гідролаз (інвертази та уреази), що причетні до збагачення ґрунту рухомими й доступними для рослин і мікроорганізмів поживними речовинами та класу пептидо- та амідогідролаз (протеази), які обумовлюють динаміку азоту й відіграють важливу роль у ґрунтових процесах. Установлено залежність активності ферментів у ґрунтах заплави від типу та шару ґрунту. Отримані дані свідчать про високу ферментативну активність алювіальних ґрунтів під заплавним лісовим ценозом.

Была исследована активность ферментов в аллювиальных почвах поймы р. Северский Донец под лесным ценозом, которые относятся к классу оксидоредуктаз (каталазы и дегидрогеназы), что играют ведущую роль в окислительно-восстановительных процессах и принимают участие в синтезе гумусных веществ в почве, класса гидролаз (инвертазы и уреазы), которые содействуют обогащению почвы подвижными и доступными для растений, микроорганизмов питательными веществами и класса пептидо- и амидогидролаз (протеазы), которые обуславливают динамику азота и играют важную роль в почвенных процессах. Установлена зависимость активности ферментов в почвах поймы от типа почвы и от глубины отбора проб. Полученные данные свидетельствуют о высокой ферментативной активности аллювиальных почв под пойменным лесным ценозом.

Mainly, the enzyme system in soil has a microbial origin. No reaction occurs in the soil without them. Therefore, the qualitative composition of the enzymes and their activity in the soil affects its quality indicators and determines the direction of soil processes. The activity of soil enzymes may be an additional diagnostic indicator of fertility and soil quality, an indicator of the assessment of the level of soil degradation in different types of ecosystems and be used as an informative indicator in monitoring observations. The object of the study is the enzymatic activity of alluvial soils in the floodplain of the Siversky Donets river under the forest. In the central part of the floodplain, alluvial meadow carbonate light-clay soil was studied (Fluvisols Umbric), which is underlain by the buried soil on the marl, and in the near the terrace depression – alluvial meadow-marsh carbonate light-clay soil on floodplain aluvi (Fluvisols Histic). A soil samples for the research were taken from layers 0-10, 10-20 and 20-30 cm. The enzyme activity was determined by methods that are conventional for soil microbiology. There is a tendency to a decrease of enzymatic activity of the depth values. The highest urease activity was detected under the conditions of a near the terrace depression in the soil layer of 0-10 cm and amounted to 45 mg of NH3 per gram in 24 hours. In the soil of the central floodplain in an identical layer, the value of urease activity was also quite high – 40 mg NH3 per gram in 24 hours. As the depth values increased, the indicators of urease activity declined. The highest catalase activity index is fixed in the 0-10 cm layer in the soil of the central floodplain and is equal to 10.6 O2 cm 3 / g per 1 minute. The smallest – in the layer of 20-30 cm of the soil of the near-bottom floodplain – 5.1 O2 cm 3 / g for 1 minute. The catalase activity gradually decreases with increasing depth in both soils. The values of dehydrogenase activity in the soils of the central floodplain were higher in comparison with the soil of the near terrace depression. The minimum value of the enzyme activity of the protease was observed in the soil layer of the central floodplain 20-30 cm and was 0.9 gelatin units. While for a similar layer of the soil of the near-bottom floodplain the intensity increased and was greater by 1.4 gelatinous units. The maximum values of protease activity were identified in 0-10 cm layers of central soils and near the terrace floodplain (respectively, 4.9 and 7.4 gelatinous units). A invertase shows high activity in the near-surface layers of soils of near the terraced depression and the central floodplain. The activity value, respectively, is 25.4 and 20.0 mg glucose per gram in 24 hours. With increasing depth, a invertase activity decreases. The dependence of the activity of enzymes in the soils of the floodplain on the type and soil layer was established. A high activity of enzymes is observed in the near-surface 0-10 cm layer of soil with a sharp decrease in its depth. The catalase and dehydrogenase activity in both soils, that were investigated, is on average similar with a slight decrease in the soil near the terraced depression. Concerning protease, invertase and urease activities, the opposite tendency is traced. The activity of these enzymes in the soil of the central floodplain is 1.2-1.6 times less than in the soil of the near terrace floodplain. The obtained data indicate about high enzymatic activity of alluvial soils under the floodplain forest cenosis