尿素处理下圆褐固氮菌对狗牙根生长及土壤特性的影响

Effect of Azotobacter chroococcum on growth characteristics of bermudagrass and soil characteristics under urea treatment

以狗牙根为材料,通过盆栽试验方法,在不同温度(10、20和30℃)下设置4个肥料[不施尿素与不浇灌圆褐固氮菌菌液(对照组,CK)、施加尿素和浇灌圆褐固氮菌菌液(T1)、只施加尿素(T2)和只浇灌圆褐固氮菌菌液(T3)]处理,研究不同温度下圆褐固氮菌菌液和尿素对狗牙根生长特性、叶绿素含量、土壤养分与土壤酶的影响。结果表明:不同温度、不同肥料以及温度与肥料互作显著影响狗牙根生长特性、土壤碱解氮含量和土壤固氮酶活性,而土壤脲酶活性只受温度与肥料互作的影响;在各温度下, 20℃的T1处理对叶长促进效果最为显著,较对照显著提高33.9%;匍匐茎长和地上部分生物量以30℃的T1处理效果最为显著,较对照分别显著提高56.6%和93.75%;30和20℃下,圆褐固氮菌菌液对狗牙根叶绿素含量影响不显著,尿素对狗牙根叶绿素含量影响显著;30和20℃下, T1处理土壤碱解氮含量提高最为显著,较对照分别提高22.1%和30.3%;30℃下,相对于对照,尿素显著降低土壤脲酶活性;各温度条件下尿素均显著降低土壤固氮酶活性,而圆褐固氮菌在20和30℃下显著提高土壤固氮酶活性;20℃下,土壤碱解氮与狗牙根匍匐茎长、根长和叶绿素含量呈正相关性;30℃下,土壤碱解氮与狗牙根叶长呈正相关性。综合而言,温度是影响狗牙根生长的关键因素,在不同温度下浇灌圆褐固氮菌菌液和施加尿素可改善土壤相关生理特性,对狗牙根的生长产生不同影响。

The effect of nitrogen-fixing bacteria on the growth of gramineous plants in different temperatures was investigated. In this experiment, bermudagrass was used as the material, and four treatments were set up for each of the three temperatures(10, 20 and 30 ℃) by pot experiment, including no urea and no Azotobacter chroococcum bacterial liquid(control group, CK), application of urea and A.chroococcum bacterial liquid(T1), only application of urea(T2) and only application of A.chroococcum bacterial liquid(T3) to study the effects on the growth of bermudagrass, chlorophyll, soil nutrients and soil enzymes. The results showed that different temperatures, different treatments and the interaction between temperatures and treatments significantly affected the growth characteristics of bermudagrass, the content of soil available nitrogen and the activity of soil enzyme, while the soil urease activity was only affected by the interaction between temperatures and treatments;In different temperatures, T1 treatment had the most significant effect on the promotion of leaf length and was higher than the control group by 33.9% in 20 ℃;T1 treatment had the most significant effect on the promotion of stolon length and aboveground biomass and was higher than the control group by 56.6% and 93.75% in 30 ℃;In 30 and 20 ℃, the effect of A.croococcum on the chlorophyll content of bermudagrass was not significant, and the effect of urea on the chlorophyll content of bermudagrass was significant;In 30℃ and 20℃, the effect of T1 treatment on the content of soil available nitrogen was significant and increased by 22.1% and 30.3% compared with the control group;In 30℃, compared with the control group, urea significantly reduced soil urease activity by 35.1%;In each temperature, urea significantly reduced soil nitrogenase activity, while A.croococcum significantly increased soil nitrogenase activity in 20 and 30 ℃;In 20℃,soil available nitrogen was significantly correlated with stollen length,root length and chlorophyll content of bermudagrass;in 30℃,soil available nitrogen was significantly correlated with the leaf length of bermudagrass.Therefore,temperature was a major factor affecting the growth of bermudagrass.By watering A.chroococcumbacterial liquid andapplicating urea in different temperatures could improve the physiological characteristics of the soil and had different effects on the growth of bermudagrass.