Responses of water productivity to irrigation and N supply for hybrid maize seed production in an arid region of Northwest China
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摘要:
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 (WPY-ET) and final biomass (WPB-ET) of fdm-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 WPY-ET and WPB-ET to different irrigation amounts were different.WPY-ETwas significantly reduced by lowering irrigation amounts while WWPB-ET stayed relatively insensitive to irrigation amounts.However,WPY-ET and WPB-ETbehaved consistendy when subjected to different N treatments.There was a slight effect of reducing N input from 500 to 300 kg/hm2 on the WPY-ET and WPBxT,however,when reducing N input to 100 kg/hm2,the values of WPY-ET and WPBxT 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 (R2=0.8588) was much better than that between Y and ET (R2=0.6062).When ET increased,WPY-ETlinearly increased and WPB-ETdecreased.Taking the indices of Y,B,WPY.ET,WPB-ET and PFPN 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.