关键词: 景观格局, 破碎化, 西安市, 生态系统服务价值

Abstract: To investigate the effects of different tillage and straw management on soil nutrient contents and enzyme activities, a field experiment was conducted in brown soil at the experimental station of Shenyang Agricultural University. Six treatments were established, i.e. moldboard plow tillage with straw removal (CK), moldboard plow tillage with straw incorporation (PTS), notill with straw removal (NT), notill with straw incorporation (NTS), rotary tillage with straw removal (RT), and rotary tillage with straw incorporation (RTS). Soil carbon, nitrogen, and phosphorus contents and related hydrolase activities were analyzed in 0-15 cm and 15-25 cm layers. The results showed that (1) soil organic carbon (SOC) and total nitrogen (TN) contents, and β-1,4glucosidase (βG), β-1,4-N-acetylglucosaminidase (NAG) and acid phosphatase (AP) activities were higher under RTS and PTS than under CK in 0-15 cm. However, SOC content was significantly lower under NTS and RTS than under CK in 15-25 cm. The NAG activity was significantly higher under PTS than under the other treatments in 15-25 cm. The soil nitrate nitrogen (NO₃^--N) contents were higher under RTS and PTS than under CK in two soil layers. (2) Higher SOC and TN contents, βG, NAG and AP activities in 0-15 cm and lower SOC contents, higher NAG and AP activities in 15-25 cm were observed under straw return treatments than under straw removal treatments among the three tillage treatments. The NO₃^--N contents were higher under RTS and PTS than under RT and CK in two soil layers, however, the opposite trend was observed under NTS and NT. (3) Principal component analysis showed that RTS and PTS improved SOC, TN and NO₃^--N contents and the activities of the three enzymes. The results suggested that rotary or moldboard plow tillage with straw incorporation (RTS or PTS) were effective managements to improve soil quality in brown soil.

Key words: ecosystem service value, landscape pattern, Xi’an City., fragmentation