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| DOI：10.13522/j.cnki.ggps.2019184 |
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| Nitrate Movement in Red Soils under Drip Fertigation in Hilly Areas: Experiment and 3D Simulation |
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PEI Qingbao, YU Lei, KONG Qiongju, CHEN Ruonan, WAN Yiguo
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1.Jiangxi Water Conservancy Research Institute, Nanchang 330099, China; 2.Nanchang Engineering College, Nanchang 330099, China; 3. Rural water Management Administration, Ningbo Resources Bureau, Ningbo 315000, China
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| Abstract: |
| 【Background】Drip irrigation combined with fertilization has been widely used to irrigate various cash crops to meet their simultaneous requirement for both water and nutrients. It is not only efficient in water and fertilizer use, but also flexible to be used at different terrains. The design parameters of drip irrigation affect water and fertilizer distribution in soil, thereby their use efficiency by crops. Soil texture, topography and the amount of irrigation and fertilization are factors that affect water and fertilizer distribution during and following an irrigation.【Objective】The purpose of this paper is to investigate nitrate distribution in red soil under drip fertigation in hilly areas aimed to provide a guidance for designing drip fertigation system in such areas.【Method】Field experiments were conducted at a hilly orange orchard to measure migration and distribution of NO3 in red soil under drip fertigation with different emitter spacing; a solute transport model was developed to simulate movement of nitrate emanating from multi-point sources from the irrigation system using the Hydrus-3D.【Result】Both emitter spacing and dripping rate affected nitrate movement and distribution in the soil. Under the same emitter spacing, increasing the dripping rate made the wetting fronts emanating from different emitters merge more quickly and NO3- spread more widely. When the dripping rate was the same, increasing emitter spacing made the wetting fronts originating from different emitters difficult to merge, resulting in non-wetting zones and thus reducing the availability of nutrients for the crops to take up. The average errors between the Hydrus-3D simulations and the measured data were less than 11%, and the model accurately reproduced water and nitrate movement in the soil.【Conclusion】The parameters suitable for drip fertigation of the orchards on the hilly red soil are: emitter spacing 30 cm, dripping rate 1 L/h. The Hydrus-3D can be used to simulate water and nutrients movement in the red soil. |
| Key words: hilly red soil; multi-point sources drip irrigation; nitrate movement; 3D numerical simulation |
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