秸秆还田与施肥方式下淮河流域安徽段灰潮土氮素淋失特征

为揭示农田灰潮土的氮素淋失特征,采用室内试验槽土壤淋溶试验,设无秸秆+不施肥(CK)、无秸秆+常规施肥(SF)、秸秆破碎填埋10 cm+常规施肥(JGF)、秸秆原状覆盖+不施肥(JG0)、秸秆破碎填埋10 cm+不施肥(JG10)、秸秆破碎填埋20 cm+不施肥(JG20)6种处理,综合研究坡度为5°时不同施肥方式及不同秸秆还田方式下总氮(TN)、总溶解性氮(TDN)、硝态氮(NO3^--N)和铵态氮(NH4⁺-N)的淋失特征。结果表明：不同处理下各形态氮素累积淋失量均在前期最大,秸秆配施化肥较单施化肥能够降低NO3^--N及NH4⁺-N淋失比例,减少土壤氮素的淋失。秸秆还田可抑制氮素淋失,且抑制效果表现为JG10 > JG20 > JG0。JG10能有效抑制TN及NH4⁺-N的淋失率,JG20能有效抑制TDN及NO3^--N的淋失率。氮素大部分以溶解态无机氮淋失,秸秆填埋越深,溶解性无机氮淋失量越小。研究结果对减少农田灰潮土氮素淋失量及控制农业非点源污染具有实际意义。

Characteristics of nitrogen leaching in grey fluvo-aquic soils in the Anhui section of Huaihe River Basin based on straw returning and fertilization

To reveal the characteristics of nitrogen leaching in farmland grey fluvo-aquic soil areas, soil leaching test in laboratory test tank was adopted. Six treatments including no straw + no fertilization (CK), no straw + conventional fertilization (SF), broken straw landfill 10 cm + conventional fertilization (JGF), undisturbed straw covering + no fertilization (JG0), broken straw landfill 10 cm+ no fertilization (JG10), broken straw landfill 20 cm+ no fertilization (JG20) were set up. The leaching characteristics of total nitrogen (TN), total dissolved nitrogen (TDN), nitrate nitrogen (NO3^--N) and ammonium nitrogen (NH4⁺-N) under different fertilization methods and different straw returning methods were comprehensively studied at the slope of 5°. The results show that the accumulative amount of nitrogen leaching in different treatments is the largest in the early stage. The leaching ratio of NO3^--N and NH4⁺-N can be reduced by using chemical fertilizer and straw compared with chemical fertilizer alone, and the leaching loss of soil nitrogen can be reduced. Straw returning can inhibit nitrogen leaching, and the inhibition effect is JG10 > JG20 > JG0. JG10 can effectively inhibit the leaching rate of TN and NH4⁺-N, JG20 can effectively inhibit the leaching rate of TDN and NO3^--N. Most of the nitrogen is leached by dissolved inorganic nitrogen, and the deeper the straw is buried, the smaller the leaching loss of dissolved inorganic nitrogen is. The results have practical significance for reducing nitrogen leaching in farmland gray fluvo-aquic soil and controlling agricultural non-point source pollution.