生物炭对夏玉米农田土壤有效养分垂直分布及作物利用的影响

生物炭具有改良耕层土壤理化性质和保水保肥的功效。针对华北地区农田养分利用效率低的问题,采用田间试验方法,研究了生物炭不同施用量对夏玉米生长关键期0~100 cm土壤有效态氮、磷、钾垂直分布特征及其对作物养分吸收利用的影响。试验设B0F(0 t/hm²生物炭+化肥)、B5F(5 t/hm²生物炭+化肥)、B10F(10 t/hm²生物炭+化肥)和B20F(20 t/hm²生物炭+化肥)4个处理。结果表明:在施用化肥一致的情况下,随着生物炭施用量增加,土壤有效态氮、磷、钾含量总体表现为B5F>B10F>B20F>B0F,且在抽雄期高于成熟期。在垂直分布上,各处理有效态养分含量在0~20 cm最高,随土层加深而逐渐降低,40~60 cm土层出现累积峰。夏玉米成熟期0~100 cm土壤硝态氮、铵态氮、有效磷和速效钾的累积量于B5F处理达到最高,分别为51.9、52.2、121.2和1184.3 kg/hm²。夏玉米抽雄期和成熟期地上部生物量和氮磷累积量均在B5F处理达到最大值,与B0F相比,分别显著提高24.5%、58.2%、42.5%和13.5%、44.3%、40.8%,产量在B5F达到最大值9940.6 kg/hm²。不同水平生物炭与无机肥配施均可提升土壤有效养分供应的能力,但仅在适量(本研究条件下为5 t/hm²)施用生物炭的条件下才能有效促进夏玉米对土壤养分的吸收和高效利用,进而显著提高夏玉米产量。

Effect of biochar on vertical distribution of available nutrients in soil and crop nutrient utilization in summer maize season

Biochar can improve soil physical and chemical properties and improve soil water and fertilizer conservation in plough layer.Therefore,the vertical distribution of available nitrogen,phosphorus and potassium in 0~100 cm soil under different dose of biochar were studied in a summer maize field to increase nutrient use efficiency in North China.The results showed that,in case of consistent application of chemical fertilizer,the content of available nitrogen,phosphorus and potassium in the soil was in order of B5 F>B10 F>B20 F>B0 F.For the vertical distribution,the effective nutrient content was the highest in 0~20 cm layer,and gradually decreased with the deeper layer,and there was a accumulated layer at 40~60 cm.The maximum contents of nitrate nitrogen(51.9 kg/hm²),ammonium nitrogen(52.2 kg/hm²),available phosphorus(121.2 kg/hm²)and available potassium(1184.3 kg/hm²)in 0~100 cm soil profile were achieved under B5 F treatment,the biomass and content of nitrogen and phosphorus during the shoot stage were 24.5%,58.2%and 42.5%,respectively,higher than those of B0 F;while they were 13.5%,44.3%and 40.8%,respectively,higher during maturation period;and the maximum yield was 9940.6 kg/hm²under B5 F.Therefore,5 t/hm²of biochar application effectively promoted nutrient absorption in soil profile and of nutrients use efficiency of summer maize,and significantly increased summer maize yield.