渭北黄土区核桃根际土壤酶活性动态变化研究.

In order to probe the dynamic changes of enzyme activity in rhizosphere of 6-year-old Juglans regia in the loess area of northern Wei River, taken 6 -year-old walnut rhizosphere soil in the loess area of northern Wei River as research objects, the samples were collected respectively at different time ( by the end of Aпril, June, August and October of 2009) and different soil depths (0 - 20, 20 - 40, 40 - 60, 60 - 80, 80 - 100 cm ), and the catalase, urease, phosphatase and invertase activities were determined. The results showed that the activities of catalase, urease, phosphatase and sucrase around J. regia rhizosphere soil decreased with the soil deepening, and in the 0-20 cm soil layer, the activities of four enzymes were the highest. With the different sampling time, the dynamic changes of enzymatic activities showed inconsistent variations. The catalase and urease activities first increased, then decreased, and then increased; Phosphatase activity first decreased, then increased and decreased at last; Sucrase activity first decreased, and then increased. It was concluded that the spatial dynamic change of enzymes activity was related to J. regia root exudates, and the root could not reach the deeper soil layer, so the enzyme activities were decreased with the soil deepening; The dynamic changes of enzyme activities with time were different due to the enzymatic synthesis affected by the type and quantity of J. regia root exudates. [ABSTRACT FROM AUTHOR]