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Responses of water productivity to irrigation and N supply for hybrid maize seed production in an arid region of Northwest China
- Ran, Hui, Kang, Shaozhong, Li, Fusheng, Du, Taisheng, Ding, Risheng, Li, Sien, Tong, Ling
- Journal of Arid Land 2017 v.9 no.4 pp. 504-514
- arid lands, arid zones, biomass, corn, crop yield, evapotranspiration, field capacity, field experimentation, hybrids, irrigation rates, nitrogen, sustainable development, China
- Water and nitrogen (N) are generally two of the most important factors in determining the crop productivity. Proper water and N managements are prerequisites for agriculture sustainable development in arid areas. Field experiments were conducted to study the responses of water productivity for crop yield (WP Y₋ET) and final biomass (WP B₋ET) of film-mulched hybrid maize seed production to different irrigation and N treatments in the Hexi Corridor, Northwest China during April to September in 2013 and also during April to September in 2014. Three irrigation levels (70%–65%, 60%–55%, and 50%–45% of the field capacity) combined with three N rates (500, 400, and 300 kg N/hm²) were tested in 2013. The N treatments were adjusted to 500, 300, and 100 kg N/hm² in 2014. Results showed that the responses of WP Y₋ET and WP B₋ET to different irrigation amounts were different. WP Y₋ET was significantly reduced by lowering irrigation amounts while WP B₋ET stayed relatively insensitive to irrigation amounts. However, WP Y₋ET and WP B₋ET behaved consistently when subjected to different N treatments. There was a slight effect of reducing N input from 500 to 300 kg/hm² on the WP Y₋ET and WP B₋ET , however, when reducing N input to 100 kg/hm², the values of WP Y₋ET and WP B₋ET were significantly reduced. Water is the primary factor and N is the secondary factor in determining both yield (Y) and final biomass (B). Partial factor productivity from applied N (PFPN) was the maximum under the higher irrigation level and in lower N rate (100–300 kg N/hm²) in both years (2013 and 2014). Lowering the irrigation amount significantly reduced evapotranspiration (ET), but ET did not vary with different N rates (100–500 kg N/hm²). Both Y and B had robust linear relationships with ET, but the correlation between B and ET (R ²=0.8588) was much better than that between Y and ET (R ²=0.6062). When ET increased, WP Y₋ET linearly increased and WP B₋ET decreased. Taking the indices of Y, B, WP Y₋ET , WP B₋ET and PFP N into account, a higher irrigation level (70%–65% of the field capacity) and a lower N rate (100–300 kg N/hm²) are recommended to be a proper irrigation and N application strategy for plastic film-mulched hybrid maize seed production in arid Northwest China.