| Temporal-spatial variation of yield potential and yield gaps of summer maize during the past 50 years in Henan province |
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| DOI：10.16302/j.cnki.1000-7601.2015.01.034 |
| Key Words: photo-thermo productivity climate productivity yield gap summer maize climate change |
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| Abstract: |
| The objective of this study is to make full use of natural resources, to analyze the yield potential of summer maize in different regions in Henan province and to find the ways to bridge the gap between potential and actual crop yield. Based on daily meteorological observation data, yield data of summer maize in 96 counties in the target region from 1961 to 2010, a successive correcting model was used to calculate photo-thermo productivity (YT) and climate productivity (YW) and clarify the yield gap between YT and ΔYW, the yield gap between YT and actual productivity (ΔYA), the spatial-temporal characteristics of two types of yield gap in the past 50 years. The results showed that YT increased from the north to the south and form the east to the west of the province, but it showed a diminishing trend during the past 50 years, with a decreasing rate of -696.8kg·hm-2·10a-1. This is in particular obvious for most of the stations in northern and central areas and part of the stations in southern areas. ΔYW decreased obviously, with a rate of -958.7 kg·hm-2·10a-1. The actual yield of summer maize increased significantly, while ΔYA decreased with a rate of -1 718.0 kg·hm-2·10a-1. The yield gaps were over 24 000 kg·hm-2,in 71.9% of stations, indicating a substantial yield potential. The precipitation is the key restricting factor on yield in the west of Henan province, suggesting the necessity of irrigation. The shortage of heat resources at later stage is the influencing factor in the north, implying the importance of selecting early maturity varieties and improving agronomical practices in this area. In addition, expending irrigation area, choosing suitable varieties and reasonable fertilization can be used to bridge the yield gaps in the east. |
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