不同采收间隔双排油莎豆(Cyperus esculentus)带风场结构与防风效能的模拟研究

Wind flow field and windbreak efficiency of double-row Cyperus esculentus belt with different harvest interval

油莎豆(Cyperus esculentus)根系发达,具有作为防风固沙作物的巨大潜力。开展不同条带状采收方式下油莎豆带的防风固沙效益研究,对于合理利用油莎豆进行防风固沙具有重要意义。以风洞模拟为手段,分别在6 m·s^(-1)、8 m·s^(-1)、10 m·s^(-1)3种风速下,对隔一带采收一带(H1)、隔一带采收两带(H2)、隔一带采收三带(H3)3种不同油莎豆采收模型在风洞不同位置的风速进行测定,并对不同模型的流场特征、风速加速率及防风效能进行分析。结果表明:(1)3种不同油莎豆采收模型中,气流均在近床面内受油莎豆模型阻挡,风速被急剧削减形成一定面积风影区,H2与H3模型的流场结构稳定性、风影区面积均比H1模型高。(2)随着风速增加,不同模型的防风效能均有所下降。H2与H3模型背风面在不同风速下的平均防风效能没有显著差异,但显著大于H1模型。在采收间距内,H2与H3模型防风效能均>50%,H1模型<40%。(3)从防风固沙效益及流场稳定性来看,H2与H3模型之间没有显著差异且显著大于H1模型。但从经济效益来看,H2模型采收间距减小,经济效益降低。综合防风固沙的生态效益与获取油莎豆的经济效益来看,H3模型为推荐采收方式。本研究通过对不同油莎豆采收模式的防风固沙效益,为利用油莎豆进行防风固沙提供了指导,并为在干旱半干旱地区推广种植油莎豆,获得更大的生态经济效益提供了理论依据。

With a developed root system,Cyperus esculentus has great potential as a windbreak and sand-fixing crop in the farmland ecosystem.Cyperus esculentus models are important for obtaining more ecological and economic benefits by investigating the change of wind flow field and windbreak efficiency of different harvesting distances.We established three trip-harvesting distance models:harvest one belt interval one belt(H1),harvest two belt interval one belt(H2),and harvest three belt interval one belt(H3).We measured the flow field structure,wind speed acceleration rate,and windbreak efficiency of the three models at 6 m·s^(-1),8 m·s^(-1),and 10 m·s^(-1)wind speed rates.The results are as follows:(1)The wind speed decreases rapidly because of the resistance of the three plant models,resulting in the formation of a wind shadow area in the ground layer.The stability and wind shadow areas of H2 and H3 are greater than those of H1.(2)An increase in the wind speed acceleration rate decreases windbreak efficiency.The windbreak efficiency of H2 and H3 on the leeward side is significantly higher than that of H1,but there is no significant difference in windbreak efficiency between H2 and H3.In the harvest area,the windbreak efficiency of H2 and H3 is>50%,whereas that of H1 is<40%.(3)There is no significant difference between the H2 and H3 models in terms of windbreak and sand-fixation benefits.However,the harvest spacing of H2 is less than that of H3,as are the economic benefits.Thus,considering the ecological and economic benefits,H3 is the recommended harvesting method.