耕作方式和秸秆还田对棕壤土壤养分和酶活性的影响

Effects of tillage and straw management on nutrient contents and enzyme activities of brown soil

在沈阳农业大学试验基地开展田间控制试验,研究翻耕秸秆移除（CK）、翻耕秸秆还田（PTS）、免耕秸秆移除（NT）、免耕秸秆还田（NTS）、旋耕秸秆移除（RT）、旋耕秸秆还田（RTS）6种耕作和秸秆还田方式对棕壤养分含量和酶活性的影响。结果表明,（1）对比CK,RTS和PTS增加了表层（0~15 cm）土壤有机碳（SOC）和全氮（TN）含量、β-1,4-葡萄糖苷酶（βG）、β-1,4-N-乙酰葡糖氨糖苷酶（NAG）和酸性磷酸酶（AP）活性,但NTS和RTS比CK降低了下层（15~25 cm）SOC含量,PTS对比其他处理显著增加了下层NAG活性,RTS和PTS对比CK显著增加了两土层硝态氮（NO3^--N）含量。（2）3种耕作方式配合秸秆还田的处理与无秸秆还田处理相比,增加了表层土壤SOC、TN含量以及βG、NAG、AP活性,降低了下层SOC含量,但增加了NAG和AP活性。旋耕和翻耕配合秸秆还田的处理与无秸秆还田处理相比,增加了两土层NO3^--N含量,而免耕趋势相反。（3）主成分分析表明,RTS和PTS处理增加了表层土壤有机碳、氮含量,改善了土壤速效养分含量,提高了土壤酶活性,是适合棕壤的耕作结合秸秆还田的方式。

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 experimen- tal 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） con- tents, and β-1,4-glucosidase （βG）, /3-1,4-N-acetyl-glucosaminidase （NAG） and acid phos- phatase （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, theopposite 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 were effective managements to improve soil quality tillage with straw incorporation （ RTS or PTS） in brown soil.