以西北旱区为例，采用水足迹模型，分析主要农作物的耗水特点，并以水资源消耗量最小、生态安全和经济 效益最大化为目标，构建以耕地资源、水资源和食物安全为约束条件的多目标规划模型对种植结构进行优化。结 果表明：2000—2020 年西北旱区主要作物产量增长 2.41 倍，种植面积增长 1.24 倍，粮食作物和经济作物的种植比 例由 2:1 向 1:1 转变，种植结构由专一化向多样化发展；作物生产水足迹总量从 838.70 亿 m3增至 1109.05 亿 m3， 其中蓝水足迹占比高达 79.09?%，农业生产面临着巨大的水资源压力；调整作物种植结构，适当将蔬菜、薯类和豆 类的种植面积提高 140.593 万?hm2、1.863 万?hm2和 0.340 万?hm2，水资源消耗量可减少 107.25 亿 m3，生态效益可提高 27.47 亿元，经济效益可提高 470.74 亿元。研究结果对促进西北旱区农业结构优化调整和水资源可持续利用具 有重要的参考价值。

Northwest?China?is?a?strategic?reserve?area?for?China’s?agriculture?production.?There?are?many?key agricultural?production?areas?like?“the?northwest?breadbasket（Hexi?Corridor）”，?“the?abundant?place?outside the?Great?Wall?(Ningxia?Plain)”,?and?“the?granary?beyond?the?Great?Wall（Hetao?Plain）”,?produce?12%?of?the country's?grain?with?10%?of?the?country's?water?resources?and?15%?of?the?grain?planting?area.?With?the?rapid growth?of?urbanization?and?regional?trade,?the?pattern?of?grain?transpotation?from?the?north?to?the?south?has?gradually changed,?and?thus?northwest?China's?role?in?ensuring?national?food?security?has?become?increasingly?prominent. However,?northwest?China?is?the?most?water-scarce?place.?The?total?amount?of?water?resources?in?this?region?only accounts?for?5.7%?of?the?national?total,?and?the?amount?of?water?resources?per?unit?area?is?only?15%?of?the?national average.?But?agricultural?irrigation?water?in?this?area?accounts?for?more?than?80%?of?total?local?water?consumption, which?is?1.23?times?that?of?China.?The?shortage?and?waste?of?water?resources?in?the?region?seriously?restrict?the sustainable?development?of?agriculture.?Therefore,?optimizing?water?allocation,?adjusting?crop?planting?structure, and?maximizing?economic?and?ecological?benefits?have?important?practical?significance?for?promoting?the?efficient use?of?water?resources?and?sustainable?development?of?agriculture?in?this?region.?Based?on?the?climate?data?of?205 stations ?in ?northwest ?China ?from ?2000 ?to ?2020, ?the ?water ?footprint ?model ?was ?used ?to ?analyze ?the ?evolution characteristics?of?water?consumption?of?main?crops?in?northwest?China.?A?multi-objective?planning?model?with constraints?of?cultivated?land?resources,?water?resources,?and?food?security?is?constructed?to?optimize?the?planting structure?to?minimize?water?consumption,?ecological?security,?and?economic?benefits?maximization.?Results?showed that?(1)?from?2000?to?2020,?the?yield?of?main?crops?increased?by?1.40?times?(from?70?million?tons?in?2000?to?168 million?tons?in?2020)?and?the?planting?area?increased?by?0.24?times?(from?14.49?million?hm2?in?2000?to?17.98?million hm2?in?2020)?in?northwest?China.?The?planting?structure?developed?from?specialization?to?diversification,?and?the planting?proportion?of?food?crops?and?cash?crops?changed?from?2∶1?to?1∶1.?(2)?The?total?water?footprint?of?crop production?increased?from?83.87?billion?m3?to?110.91?billion?m3.?The?total?blue?water?footprint?increased?by?about 1.31?times,?and?the?total?green?water?footprint?increased?by?5.94?billion?m3.?(3)?Although?global?warming?has increased?precipitation?in?the?arid?northwest?region?and?alleviated?agricultural?water?consumption?in?the?region. However,?the?proportion?of?the?total?blue?water?footprint?to?the?total?water?footprint?of?crop?production?remains between?72.94%?and?81.55%,?which?reflects?that?agricultural?production?in?northwest?China?faced?huge?pressure on ?water ?resources. ?(4) ?By ?adjusting ?the ?crop ?planting ?structure, ?appropriately ?increase ?the ?planting ?area ?of vegetables,?potatoes,?and?beans?by?1?405.93?×103?hm2,?18.63×103?hm2,?and?3.40×103?hm2,?and?reduce?the?planting area?of?other?crops.?To?effectively?alleviate?the?pressure?of?the?current?agricultural?water?shortage?while?ensuring economic?benefits,?to?ensure?regional?water?security?and?ecological?security,?10.73?billion?m3?of?blue?water?resources could?be?saved,?the?ecological?benefits?could?be?increased?by?4.25%?and?the?economic?benefits?could?be?increased by?47.074?billion?yuan.?The?research?conclusion?could?provide?technical?and?decision-making?support?for?the?green and?high-quality?development?of?agriculture?in?the?northwest?arid?area.aking?support?for?the?green?and?high-quality development?of?agriculture?in?the?northwest?arid?area.