Comparative evaluation of crop water use efficiency, economic analysis and net household profit simulation in arid Northwest China

Decreasing water availability for agricultural production has prompted researchers to focus on comparing and evaluating water use efficiency (WUE) of different crops in various water management strategies. A field survey was conducted to investigate the amount of irrigation water, inputs and yields of eight crops (spring wheat, maize, onion, cotton, hot pepper, sunflower, melons and fennel) grown under furrow irrigation systems in an arid region, Minqin county, Northwestern China (NWC). Previous publications reporting crop WUE were identified and major statistics of evapotranspiration (ET), yield (Y) and WUE were calculated for each crop. By comparing with literature reporting, the mean WUE of onion (8.71kgm^-3), cotton (0.56kgm^-3), sunflower seed (0.78kgm^-3) and fennel (0.51kgm^-3) grown in NWC were at the same high levels; while WUE of wheat (0.87kgm^-3) and maize (1.17kgm^-3) were slightly lower and WUE of hot pepper (2.68kgm^-3) and melons (3.27kgm^-3) were extremely low. Great potential of saving water could be achieved to realize increased or ideal WUE values for crops in NWC. The total net profit per household of cotton (1606.62$hh^-1) was significantly larger and of onion (-3132.30$hh^-1) significantly lower than that of other crops. Cotton, sunflower seed, melons and hot pepper had significantly higher crop production values per unit water than other crops, 0.39$m^-3, 0.36$m^-3, 0.32$m^-3 and 0.31$m^-3, respectively. The net household profits were significantly higher when excluding onion production for its extremely low price in 2011. With simulation based on different combinations of onion production and increase of migrant workers, the average net household profit could be optimized to provide benefits to local farmers and policy makers regarding income increase and rural policy design.