机构地区:[1]中国热带农业科学院橡胶研究所,海南儋州571737 [2]中国热带农业科学院土壤肥料研究中心,海南儋州571737
出 处:《生态环境学报》2019年第7期1361-1368,共8页Ecology and Environmental Sciences
基 金:国家自然科学基金项目(31400529);中国热带农业科学院基本科研业务费项目(1630022019007);国家天然橡胶产业技术体系项目(CARS-34-GW-ZP2)
摘 要:氮肥在土壤中的残留是土壤氮库的重要补充,对于维持土壤氮水平和保证作物高产具有重要作用。目前人们对热带季风气候下橡胶林氮肥施用后的残留特征了解还很少。利用微区试验结合15N示踪技术,研究了橡胶林酸性砖红壤中不同施氮水平下(0、100、200和400 kg·hm^-2)氮肥的残留、累积和迁移。结果表明,不同施氮水平下肥料氮当年根层土壤(0-100cm)残留量为23.36-109.36 kg·hm^-2,残留率为23.36%-31.85%,施氮量的升高显著增加了肥料氮的残留量;2年后,不同施氮水平下肥料氮根层土壤残留量仅20.45-41.78 kg·hm^-2,残留率10.45%-20.45%,施氮量的增加显著降低了肥料氮残留率;试验第1年(枯水年),不同施氮水平下土壤硝态氮主要在根层土壤累积(24.61-172.47 kg·hm^-2),而淋洗迁移到深层土壤(100-200 cm)的硝态氮不多(13.89-51.66 kg·hm^-2)。根层土壤硝态氮累积量与施氮量呈极显著正相关关系;试验第2年(丰水年),不同处理的根层土壤硝态氮累积很少(仅5.39-22.95 kg·hm^-2)。3个氮肥处理的硝态氮均不同程度地迁移、淋洗到深层土壤,达53.36-201.42 kg·hm^-2。深层土壤中的硝态氮累积量与施氮量呈极显著正相关关系。综上,橡胶林氮肥施用后的土壤残留率较低,施氮量是影响橡胶林土壤硝态氮累积、迁移的重要因素。Residual nitrogen(N)fertilizer in soil is an important supplement to soil N pool.It plays an important role in maintaining soil N fertility and ensuring high crop yield.At present,little is known about the characteristics of residual N fertilizer in rubber plantation under tropical monsoon climate.The residue,accumulation and translocation of N fertilizer in acidic Red Latosol with different N levels(0, 100,200 and 400 kg·hm^-2)were studied by micro-plot trial under isotopic 15N tracer technique.The results showed that the amounts of residual fertilizer N in root zone soil(0-100 cm)were 23.36-109.36 kg·hm^-2 at different N levels.The residual rate ranged from 23.36% to 31.85%.The increase of N fertilization significantly raised the residual fertilizer N.After 2 years,the amounts of residual fertilizer N in root zone soil were 20.45-41.78 kg·hm^-2 at different N levels.The residual rates were10.45%-20.45%.The increase of N fertilization significantly reduced the N fertilizer residual rate.In the first year of experiment(dry year),the soil nitrate nitrogen(NO3^--N)mainly accumulated in the root zone soil(24.61-172.47 kg·hm^-2)under different N levels.Meanwhile,NO3^--N leaching to deep layer(100-200 cm)was limited(13.89-51.66 kg·hm^-2).There was an extremely significant positive correlation between NO3^--N accumulation in the root zone soil and N application rate.In the second year of experiment(wet year),the soil NO3^--N accumulated in the root zone soil was in low quantity(only 5.39-22.95 kg·hm^-2)under different N levels.And fate of more soil NO3^--N was to translocate or leak to deep soil layers in variety of degrees,ranging from 53.36 to 201.42 kg·hm^-2.The soil NO3^--N accumulation in deep soil layers was significantly positively correlated with the N application rate.In general,N fertilizer residual rate in soil was on low level in rubber plantation.N application rate was an important factor for characteristics of soil NO3^--N accumulation and translocation in rubber plantation.
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