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| DOI：10.13522/j.cnki.ggps.2020349 |
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| Optimizing Maize Fertilization in Hetao Irrigation Area Using the Projection Pursuit Cluster Evaluation Model |
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DAI Jialu, LI Ruiping, LI Congcong, LU Yaoze, ZOU Cunjing
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1. School of Water Conservancy and Civil Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China;2. Bayannur Water Conservancy Research Institute, Bayannur 015000, China;3. Yongji Irrigation Area Administration of Hetao Irrigation District, Inner Mongolia, Bayannur 015000, China
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| Abstract: |
| 【Background】Previous studies on maize production in Hetan irrigation district had been to seek high yield and high irrigation water and fertilizer use efficiency. With policies on agricultural production in Hetao irrigated shifting to maintaining average yields while in the meantime reducing water and fertilizer application by improving their use efficiency, there is a lack of study on appropriate irrigation and fertilization that could achieve this goal.【Objective】The purpose of the this paper is to experimentally investigate the impact of different combinations of irrigation amount and nitrogen fertilizer on maize yield and its water efficiency (WUE). We calculated the partial productivity, and the optimal irrigation and fertilization was calculated using the combination of projection pursuit clustering evaluation model and the genetic algorithm.【Method】The experiment was conducted in a maize field in Hetao irrigation district. We compared three irrigation levels: 1 800 m3/hm2, 2 250 m3/hm2, 2 700 m3/hm2, and three fertilization levels: 300 kg/hm2, 375 kg/hm2 and 450 kg/hm2, with irrigation and fertilization used by local farmers as control (CK). In each treatment, we measured yield and water use efficiency of the maize.【Result】The water consumed by the maize increased with irrigation and fertilizer, and at the same fertilization level, water consumption of the maize increased significantly with irrigation. With the increase in fertilization and irrigation, the yield and water use efficiency of the maize, along with the partial productivity of nitrogen fertilizer, all increased first and then trended downward. Compared with CK, irrigating 2 700 m3/hm2 of water coupled with 375 kg/hm2 of fertilization increased water use efficiency by 22.2% and productivity of nitrogen fertilizer by 53.5%. Reducing irrigation to less than 2 700 m3/hm2 and increasing fertilization over 375 kg/hm2 led to reductions in yield, water use efficiency and partial productivity of nitrogen fertilizer. Both water consumption and yield of the CK were higher than other treatments, but its use efficiency of water and nitrogen fertilizer was low. The results calculated from the projection pursuit cluster (RAGA-PPCE) based on the genetic algorithm showed that of all treatments, irrigating 2 700 m3/hm2 and fertilizing 375 kg/hm2 was optimal for this region.【Conclusion】Comparative field experiment revealed that irrigation of 2 700 m3/hm2 coupled with 375 kg/hm2 of fertilization was optimal for sustaining maize yield while in the meantime improving the use efficiency of both water and fertilizer in Hetao irrigated area. |
| Key words: irrigation; fertilization; maize; water use efficiency; partial factor productivity of nitrogen fertilizer |
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