施用椰壳生物炭对砖红壤氮素淋失和油麦菜吸收利用的影响

Impacts of Biochar Addition on Nitrogen Leaching and Use Efficiency of Leaf-used Lettuce

为明确施用生物炭对油麦菜生长、氮素利用和淋溶的影响,通过盆栽试验,测定了不同处理条件下砖红壤-油麦菜系统土壤淋溶液不同形态氮淋失量、油麦菜农艺形态指标以及植株吸氮量。结果表明:有机氮淋溶量占砖红壤总氮淋溶量的73.8%~77.5%。常规化肥处理铵态氮、硝态氮、有机氮和总氮淋溶量最高,分别为3.9,48.3,163.2,215.4 mg/盆。椰壳生物炭(1%,2%,5%,m/m)与腐植酸肥配施处理铵态氮、硝态氮、可溶性有机氮和总氮淋失量分别比常规化肥处理降低40.6%~52.4%,28.8%~54.9%,22.7%~55.5%,24.4%~55.4%。添加椰壳生物炭油麦菜生物量、氮素利用率分别比单施腐植酸肥提高9.46%~26.44%,9.86%~13.61%;但是过量施用会影响生物量的积累,抑制根系的生长。椰壳生物炭施用量为3.2%(m/m)时油麦菜生物量最大。

It is very important for non-point pollution control to using appropriate agronomic approaches to re-duce nitrogen leaching loss from soil.This experiment was conducted to clarify the impacts of biochar addition on leaf-used lettuce growth,nitrogen utilization and leaching.With pot experiment,leaching amounts of different form nitrogen,agronomic characteristics and nitrogen uptake of leaf-used lettuce were determined under no fertilizer, chemical fertilizer,humic acid fertilizer and application.The results showed that the dissolved organic nitrogen (DON) accounted for 73.8% -77.5% of total N leaching.Among all treatments,the highest amout of N was leached for the conventional treatment,and its ammonium nitrogen(AN),nitrate nitrogen(NN),DON and total ni-trogen (TN) leaching were 3.9,48.3,163.2,215.4 mg/pot,respectively.Compared with chemical fertilizer treat-ment,AN,NN,DON and TN leaching with coconut shell biochar (1%,2%,5%;m/m) were reduced by 40.6% -52.4%,28.8% -54.9%,22.7% -55.5% and 24.4% -55.4%.The biomass of leaf-used lettuce and N use ef-ficiency with biochar application increased 9.46% -26.44% and 9.86% -13.61%,respectively.However,its o-ver-application affected the biomass accumulation of leaf-used lettuce and restrained its root growth.The biomass of leaf-used lettuce was up to the maximum with the 3.2% (m/m) biochar admentment.