生物炭包覆尿素在黑土中施用特性和环境效应

Application Characteristics and Environmental Effects of Biochar Coated Urea in Black Soil

为了实现氮肥减施增效的目的,以玉米秸秆生物炭作为包覆材料,使用不同浓度的松香黏结剂,对尿素颗粒进行包覆处理,分别制备了4种玉米秸秆生物炭包覆尿素:3.4%生物炭包覆量(CU1)、6.8%生物炭包覆量(CU2)、7.8%生物炭包覆量(CU3)、8.6%生物炭包覆量(CU4)。采用土柱淋溶法和培养试验,分别探究了其在黑土中的氮素累积释放率和在黑土中的施用特性,以及对温室气体排放的影响。结果表明:与尿素(U)相比,4种生物炭包覆尿素随着生物炭包覆量的增大,玉米秸秆生物炭包覆尿素的氮素累积释放率降低1.9%~15.7%(P<0.05);生物炭包覆尿素增加了黑土中的铵态氮含量,并显著降低硝态氮含量,且硝化抑制率随生物炭包覆量的增大而增高,处理CU4比CU1增高2.52%(P<0.05);4种生物炭包覆尿素在黑土中施用后的氮素利用率相较于尿素(U)提高1.4%~6.1%(P<0.05),小白菜增产1.1~1.3倍。生物炭包覆尿素还显著降低种植过程中产生的N2O(18.7%~46.3%)、CO2(48.5%~58.9%)和CH4(8.8%~24.6%)3种温室气体的累积排放量(P<0.05),综合增温潜势(GWP)降低41.9%~55.9%(P<0.05)。综上,生物炭包覆尿素可以提高小白菜产量和氮素利用率,还可以减少土壤温室气体排放,其中以CU4效果最佳。

In order to achieve the goal of reducing nitrogen fertilizer application and increasing efficiency,urea particles were coated with corn stalk biochar and rosin binder of different concentrations.Four kinds of corn stalk biochar coated urea 3.4%biochar coating amount(CU1),6.8%biochar coating amount(CU2),7.8%biochar coating amount(CU3)and 8.6%biochar coating amount(CU4)were prepared,respectively.Soil column leaching method and cultivation experiment were used to investigate the nitrogen accumulation and release rate in black soil,the application characteristics in black soil,and the impact on greenhouse gas emissions.The results showed that compared with urea(U),four kinds of biochar coated urea increased with the increase of biochar coating amount,the cumulative nitrogen release rate of corn straw biochar coated urea was significantly decreased by 1.9%to 15.7%(P<0.05);Biochar coated urea increased the content of ammonium nitrogen in black soil and significantly reduced the content of nitrate nitrogen;the nitrification inhibition rate increased with the increase of biochar coating amount,and the treatment with CU4 significantly increased by 2.52%(P<0.05)compared to CU1;Compared with urea(U),the nitrogen use efficiency of four kinds of biochar coated urea in black soil was significantly increased by 1.4%to 6.1%(P<0.05),and the yield of Chinese cabbage increased by about 1.1-1.3 times;Biochar coated urea also significantly reduced the cumulative emissions of N2O(18.7%-46.3%),CO2(48.5%-58.9%),and CH4(8.8%-24.6%)produced during the planting process(P<0.05),and the comprehensive warming potential(GWP)was significantly reduced by 41.9%-55.9%(P<0.05).In summary,biochar coated urea can improve the yield of Chinese cabbage and nitrogen utilization efficiency,and also reduce soil greenhouse gas emissions,with CU4 being the best.