秸秆还田方式和氮肥类型对黄淮海平原夏玉米土壤呼吸的影响

Effects of straw incorporation and N fertilization on soil respiration during maize (Zea mays L.) growth in Huanghuaihai Plain

  • 摘要: 为了研究黄淮海平原不同秸秆还田方式和施氮类型对夏玉米农田生态系统土壤呼吸的影响, 于2010年6-10月, 采用LI-COR-6400-09土壤气室连接红外线气体分析仪(IRGA)对玉米农田行间掩埋秸秆区的土壤呼吸作用进行了连续测定。结果表明, 常规施肥下, 玉米生育期内秸秆行间掩埋处理(ISFR)的平均土壤呼吸速率显著高于秸秆移除(NSFR)和秸秆覆盖(SFR)处理(P<0.05)。秸秆行间掩埋配合施用化学氮肥处理中, 配施50.4 kg(N)·hm-2处理(ISF3)的平均土壤呼吸速率为(178.85±46.60) mg(C)·m-2·h-1, 显著高于配施33.6 kg(N)·hm-2处理(ISF2)的(124.11±23.18) mg(C)·m-2·h-1(P<0.05)。秸秆行间掩埋配合施用鸡粪处理中, 鸡粪施用量为33.6 kg(N)·hm-2(ISOM2)处理的平均土壤呼吸速率为(208.08±31.54) mg(C)·m-2·h-1, 施用16.8 kg(N)·hm-2(ISOM1)和50.4 kg(N)·hm-2(ISOM3)处理的为(135.07±21.97) mg(C)·m 2·h 1、(171.43±43.31) mg(C)·m-2·h-1, 相比ISOM2处理, ISOM1和ISOM3处理的平均土壤呼吸速率降低了35.09%和17.61%。ISOM2处理玉米季CO2排放累积量为499.39 g(C)·m-2, 显著高于ISF2处理的297.86 g(C)·m-2。秸秆行间掩埋配合施用化学氮肥对土壤呼吸速率的影响小于配合施用鸡粪的影响, 配合施用16%总氮的鸡粪, 即33.6 kg(N)·hm-2时C/N比最适宜土壤微生物的代谢活动。

     

    Abstract: A field experiment was conducted in the Fengqiu State Key Agro-ecological Experimental Station in China's Henan Province to measure soil respiration in maize farmland ecosystems from June to October, 2010. Soil respiration was measured in the nine-treatment experiment using LI-COR-6400-09 Soil Respiration Chamber completed with Infrared Gas Analyzer (IRGA). The results indicated that soil respiration rates at 20 cm depth under treatments of burying straws in-between maize lines (ISFR) was significantly higher (P< 0.05) than those under the treatments of removing (NSFR) and mulching (SFR) straw with conventional fertilization. Average soil respiration rates of ISFR, NSFR and SFR were (209.22±75.63) mg(C)·m-2·h-1, (169.51±45.50) mg(C)·m-2·h-1 and (161.14±26.32) mg(C)·m-2·h-1, respectively. Average soil respiration rate under buried straw plus chemical N fertilizations of 16.8 kg(N)·hm-2 (ISF1), 33.6 kg(N)·hm-2 (ISF2) and 50.4 kg(N)·hm-2 (ISF3) were (148.67±35.07) mg(C)·m-2·h-1, (124.11±23.18) mg(C)·m-2·h-1 and (178.85±46.60) mg(C)·m-2·h-1, respectively. The difference between ISF3 and ISF2 treatments was significant at P< 0.05. Under treatments of buried straw with chicken manure applications of 16.8 kg(N)·hm-2 (ISOM1), 33.6 kg(N)·hm -2 (ISOM2) and 50.4 kg(N)·hm-2 (ISOM3), average soil respiration rates were (135.07±21.97) mg(C)·m-2·h-1, (208.08±31.54) mg(C)·m-2·h-1 and (171.43±43.31) mg(C)·m-2·h-1, respectively. Compared with ISOM2, ISOM1 and ISOM3 significantly decreased soil respiration rates by 35.09% and 17.61%. The cumulative CO2 emissions under ISOM1, ISOM2 and ISOM3 during maize growth were 324.16 g(C)·m-2, 499.39 g(C)·m-2 and 411.43 g(C)·m-2, with significant differences in both cumulative CO2 emissions and average soil respiration rates among the treatments at P < 0.05. Cumulative CO2 emission under ISOM2 treatment during maize season was significantly higher than that under ISF2 treatment. It was therefore concluded that the effect of burying straws in-between maize lines combined with chicken manure on soil respiration rate was significantly greater than that with chemical N fertilizer. At chicken manure application rate of 33.6 kg(N)·hm -2, the conditions of C/N ratio were optimum for soil microbial metabolism and population.

     

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