生物黑炭对日光温室土壤硝态氮动态变化的影响

Effect of biochar on dynamic changes of nitrate in greenhouse soil

采用田间小区试验,研究了生物黑炭对设施土壤硝态氮动态变化的影响,以期利用生物黑炭解决设施土壤硝态氮累积和淋溶问题。结果表明,生物黑炭能显著降低设施土壤表层及剖面硝态氮含量,且使用量越大,效果越明显。以番茄生长后期为例,7.5 t/hm2黑炭(T2),15 t/hm2黑炭(T3),30 t/hm2黑炭(T4)处理与习惯处理(T1)相比,表层土壤硝态氮含量分别降低11.71%、16.08%、24.83%,剖面硝态氮含量也分别降低11.63%、17.51%、25.38%。设施土壤硝态氮含量季节性变化明显,施用生物黑炭能降低设施土壤硝态氮周年变化幅度,使用量越大,效果越明显。生物黑炭也可降低蔬菜硝酸盐含量,且使用量越大,蔬菜硝酸盐含量越低。低量生物黑炭对蔬菜产量影响不大或有提高作用,但随使用量的增大,产量有下降趋势,因此,设施土壤生物黑炭使用量不宜过高。

The problem of nitrate accumulation and leaching in greenhouse soil has been drawn increasing attention. A field plot experiment was conducted to study the effect of biochar on dynamic changes of NO3^- - N in greenhouse soil. The results showed that the biochar improved the soil NO3^- - N content in the early stage, but significantly reduced the accumulation of nitrate in surface and profile soil of greenhouse in the late stage. For example, T2, T3, T4 compared with T1, surface soil NO3- - N contents were reduced by 11.71% , 16. 08% and 24. 83%, the accumulation of NO3- - N in soil profile were re- duced by 11.63%, 17.51% and 25. 38%, respectively, in the late stage of tomato. There was obvious seasonal change of nitrate content in greenhouse soil. The application of biochar reduced greenhouse soil nitrate annual variations. The greater the amount of use, the effect was more obvious. For example, annual variations of T2, 13, T4 compared with T1 were reduced by 12. 35%, 13.72% and 25. 99%, respectively. The application of biochar also reduced the nitrate content of vegetables, and the greater the amount, the more obvious effects. The low amount of biochar had little effect on vegetable yields or improved the yields, but with increasing use dose, the yields tended to decline. Therefore, the application a- mount of biochar should not be too high in greenhouse soil.