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| DOI：doi：10.13522/j.cnki.ggps.20180511 |
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| Using the ORYZA_V3 Model to Help Improve Water andFertilizer Management of Rice Field |
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YU Qianan, LI Yalong, LIU Luguang, CUI Yuanlai, CHEN Yang, HAN Huanhao
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1.State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan Univercity, Wuhan 430072, China; 2. Changjiang River Scientific Research Institute of Changjiang Water Resources Commission, Wuhan 430010, China; 3. Hubei Water Resources Reasearch Institute, Wuhan 430070, China
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| Abstract: |
| 【Objective】 Improving resource use efficiency is critical to sustaining agricultural production and this paper is to study the feasibility of using the ORYZA_V3 model to help improve water and fertilizer management in irrigated rice field. 【Method】 The study focused on Jiangi Irrigation Experimental Station. We first calibrated the ORYZA_V3 model against data collected in 2012—2013 from the station, and then used it to analyze the irrigation amount, yield, nitrogen use efficiency of the later-season rice under different hydrological years, as well as water and fertilizer management. 【Result】 Reducing the critical low soil moisture for irrigation can reduce evapotranspiration and thus irrigation amount. Particularly, setting the low soil moisture in the plowed layer for irrigation at 70%~75% of saturated water content prior to irrigation increased the yield and nitrogen use efficiency of the rice. In contrast, setting the low soil moisture in the plowed later for irrigation lower than 60%~65% of the saturated water content reduced both yield and nitrogen use efficiency. Increasing nitrogen fertilizer application reduced its use efficiency, whereas increasing fertilization frequency facilitated nitrogen use efficiency. Increasing nitrogen amount and fertilization frequency increased the yield but at expense of reducing drought-tolerance of the plant. For balancing water saving, yield and nitrogen use efficiency, keeping nitrogen application at 135 kg/hm2 and applying it in three times (base fertilization, tiller fertilization and panicle fertilization at ratio of 5∶3∶2) appeared to give the best result. In wet years, the critical soil moisture in the plowed layer for irrigation can be set at 60%~65% of saturated water content, while in normal and dry year it can be increased to 70%~75% of the saturated water content. 【Conclusion】Compared with traditional water and fertilizer application, using the above optimized fertigation can save water by 41.4%, 30.0% and 21.9%, increase yield by 7.5%, 5.4%, 3.4%, and nitrogen use efficiency by 57.3%, 51.2%, 44.9% in wet, normal and dry year, respectively. On average, it can overall save nitrogen fertilizer by 25%. |
| Key words: lowland rice; model; water and fertilizer; utilization rate of nitrogen; irrigated area |
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