稻田不同施氮量对土壤呼吸的效应分析及施氮量方案寻优

Effect analysis of different nitrogen fertilizer on soil respiration and optimization of nitrogen fertilizer scheme in rice field

为了探寻不同施氮量对稻田土壤呼吸的影响,本试验在间歇灌溉条件下设置4个施氮肥处理分别为0(CK),150kg/hm^2,180kg/hm^2,210kg/hm^2来研究土壤呼吸对施加不同氮肥的响应关系。结果表明:间歇灌溉下土壤呼吸随着施肥量的增加呈现出先增加后减小的排放关系。在水稻生长期内,施氮肥量150kg/hm^2、180kg/hm^2和210kg/hm^2与对照CK相比,土壤呼吸速率平均增加了10.30%、50.76%(P<0.05)和44.39%(P<0.05)。从增加的幅度来看,施氮肥量180kg/hm^2和210kg/hm^2能够显著提高土壤呼吸速率,加快稻田土壤气体交换。稻田土壤呼吸速率的日变化表现为施氮肥量180kg/hm^2好于0,150kg/hm^2,210kg/hm^2,综合来看施氮肥量180kg/hm^2处理在间歇灌溉条件下最有利于稻田土壤气体交换。对施氮肥处理前土壤呼吸速率和5cm地温进行相关分析,两者有较好的显著正相关(P<0.05),决定系数R2为0.7138,说明前期没有施氮肥时温度是影响土壤呼吸速率的主要因素。

In order to explore the effect of different nitrogen application on soil respiration in paddy field, 4 nitrogen fertilizer treatments were set up under the condition of intermittent irrigation, respectively 0,150,180,210 kg/hm^2 to study the response of soil respiration to different nitrogen fertilizers. The results showed that the soil respiration under intermittent irrigation showed a higher emission relationship with the increase of fertilization amount. In the growth of rice, 150, 180 and 210 kg/hm^2 compared with CK, the average increase in the whole growth period was 10.30%、50.76%(P<0.05)and 44.39%(P<0.05). From the increase, the amount of nitrogen fertilizer 180 kg/hm^2 and 210 kg/hm^2 can significantly improve the soil respiration rate and accelerate the exchange of soil gas in paddy fields. The diurnal variation of soil respiration rate in paddy field showed that nitrogen fertilizer 180 kg/hm^2 was better than 0,150,210 kg/hm^2, so,the application of nitrogen fertilizer 180 kg/hm^2 was the most favorable for paddy soil gas exchange under the condition of intermittent irrigation. The correlation between soil respiration rate and 5 cm geothermal temperature was significantly correlated(P<0.05), and the coefficient of R 2 was 0.7138, indicating that the temperature was the main factor affecting the soil respiration rate.