摘要
通过大田试验,设置5种不同的施肥比例(基肥∶分蘖肥∶拔节肥∶穗肥-2∶2∶3∶3(R1)、3∶2∶2∶3(R2)、4∶2∶2∶2(R3)、4∶3∶1∶2(R4)与0∶0∶0∶0(CK)),研究氮肥运筹对稻田NH3挥发和氮肥利用率的影响。结果表明,(1)相对于不施肥,施肥显著提高了稻田NH3挥发量。氮肥施用后,NH3挥发损失量占施氮量的6.2%—8.5%,其中,以分蘖期NH3挥发损失量最大,齐穗期次之,苗期和拔节期最小。施肥处理间,处理R1稻田累积NH3挥发量最小,显著低于其它施肥处理,比处理R2、R3和R4分别低9.1%(P<0.05)、10.9%(P<0.05)和17.7%(P<0.05)。(2)相关分析表明,田面水NH+4、pH值和土壤NH+4和pH值均与稻田土壤NH3挥发通量呈显著或者极显著相关;(3)处理R1水稻氮肥利用率相对于处理R2、R3和R4增加了28.4%(P<0.05)、55.4%(P<0.05)和74.9%(P<0.05)。研究表明,氮肥后移能有效降低免耕稻田NH3挥发,提高水稻的氮肥利用率。
NH3 volatilization is an important process of N loss from fertilizer nitrogen （N） applied to no-tillage rice fields. It has been demonstrated that no-tillage promotes NH3 volatilization. However, few studies have been conducted to investigate the effects of N management on NH3 volatilization from no-tillage on a clay loam soil （Anthrosol, World Reference Base for Soil volatilization and N use efficiency from no-tillage rice fields in paddy fields. Therefore, a field experiment was conducted Resources） to study the effects of N management on NH3 the city of Wuxue in central China during the 2012 rice- growing season. In this study, five experimental treatments were arranged in a completely randomized design with three replications. Five treatments were applied including five application rates of N fertilizer in the seedling, mid-tillering, flowering and heading stages of rice： 2：2：3：3 （ R1 ）, 3：2：2：3 （R2）, 4：2：2：2 （ R3）, 4：3：1：2 （R4） and 0：0：0：0 （CK）. The NH3 volatilization fluxes were determined 20 times using a venting method during the 2012 rice growing season. NH~ concentrations and pH of the soils and field surface water were also measured. The obtained results showed that application of N fertilizer significantly enhanced both NH4 concentrations of the soils and field surface water and the soil pH. Compared with the other fertilized treatments （R2, R3 and R4）, R1 significantly decreased NH4 concentrations of the soils and fieldsurface water. In the fertilized treatments, during the rice growing season, each application of N fertilizer led to NH3 volatilization fluxes peaking after 1--3 days, and then dropping rapidly to those in the unfertilized treatment levels within 1-2 weeks. The NH3 volatilization fluxes in the CK treatment were relatively low, and remained nearly unchanged. The NH3 volatilization fluxes ranged from 2.0 to 21.94 mg＇m%d-1 for the CK treatment and from 2.21 to 209.6 mg-m-2-d-1 for the fertilized treatments. Mean NH3 volatilization fluxes in the RI, R2, R3 and R4 treatments were （13.8＋2.0）, （15.3＋ 0.2）, （15.8±0.1） and （14.2±0.1） mg·m^-2·d^-1, respectively, which were 1.57, 1.81, 1.88 and 1.69 times, respectively, that in the CK treatment. The cumulative amounts of NH3 volatilization were （8.52±0.20） （ CK）, （ 19.59± 2.30） （RI）, （21.85±0.68） （R2）, （21.98±0.45） （R3） and （23.79±1.15） kg N/hm2（Rd）. For fertilized treatments, the highest cumulative NH3 volatilization was observed at the mid-tillering stage （accounting for 11.9%--14. 7% of the total ）, followed by the heading stage, with the minimum being found at the seeding and booting stages. Compared with no N fertilizer, application of N fertilizer significantly increased NH3 volatilization by 56.5%--64.2% from the no-tillage paddy fields. In fertilized treatments, N losses through NH3 volatilization accounted for 6.2%--8.5% of the applied N. Among the four fertilized treatments, the cumulative NH3 volatilization was significantly reduced by 9.1%--17.7% under R1 than under the other fertilized treatments. Linear correlation analysis indicated that NH~ concentrations and pH in the soils and field surface water were significantly related to the NH3 volatilization fluxes. Application of N fertilizer significantly affected N uptake of rice, where, compared with the CK treatments, fertilized treatments significantly increased N uptake of rice by 46.5%--89.3%. Compared with the other fertilized treatments, R1 significantly enhanced N use efficiency by 28.4%-- 74. 9%. Therefore, our results suggest that N application at the late growth stage of rice can decrease NH3 volatilization, thus improving N use efficiency of rice under no-tillage rice fields.
出处
《生态学报》
CAS
CSCD
北大核心
2013年第18期5556-5564,共9页
Acta Ecologica Sinica
基金
国家科技支撑计划:粮食丰产科技工程(2011BAD16B02)
国家自然科学基金(31100319)
中央高校基本科研业务费专项资金(2013PY106)
关键词
氮肥运筹
NH
NH
氮肥利用效率
nitrogen management
NH3
NH4
nitrogen use efficiency
