沙质农田作物不同间作采收模式休耕期的防风效应

油沙豆(Cyperus esculentus)是集粮、油、牧、饲于一体的高利用价值新兴经济作物，在我国沙区调整种植结构及沙化土地改良中有重要作用. 油沙豆茎块在采收过程中易破坏表层土壤、引发风蚀，因此，探究油沙豆防风阻沙的保护性耕作模式是实现油沙豆在沙区种植的重要前提. 本文基于乌兰布和沙漠油沙豆农田现有间作模式，通过风洞模拟试验，探究不同风速下6种间作模式(2种间作作物×3种带间距)的防风蚀效果. 结果表明:①不同带间距模式在各风速下的风速廓线均呈对数形式，粗糙度随带间距的增加而减小. ②间作作物对垂直流场结构分布特征有显著影响，间作玉米各带间距模式近地表风速均低于当地起沙风速(6 m/s)；间作向日葵各带间距模式近地表风速均高于起沙风速，约为9 m/s. ③风速对各间作模式的防风效能具有显著影响，防风效能随风速的增大呈减小趋势. ④间作带的防风效能随带间距的增加而减小，表现为带间距8 m>带间距16 m>带间距24 m. 间作玉米模式的防风效能大于间作向日葵模式，其中，玉米带间距8 m及16 m的模式其近地表防风效能均大于50%，是油沙豆农田防风阻沙的最优模式. 研究显示，考虑到农田的经济效益，带间距16 m的间作玉米模式是油沙豆农田兼顾生态效益和经济效益的最优间作模式. 

Shelter Effects of Different Intercropping and Harvesting Modes in Fallow Period of Sandy Farmland Crops

Cyperus esculentus is an emerging economic crop with a high utilization value that involves the integration of grain cultivation, oil production, animal husbandry and foraging. This crop plays an important role in adjusting the planting structure in sandy areas in China and combating desertification. However, traditional harvesting can easily damage surface soil and can cause wind erosion. Therefore, the exploration of protective farming modes of Cyperus esculentus to prevent wind and sand erosion is an important prerequisite for the realization of Cyperus esculentus planting in sandy areas.In this study, the wind erosion prevention effects of six intercropping modes (two types of intercropping crops × three types of spacings between intercropping strips) under different wind speeds on wind tunnel were studied. The results indicated that (1) The wind speed profiles of the various intercropping modes at different wind speeds conformed to logarithmic function. The roughness decreased with increasing belt spacing. (2) Intercropping significantly impacted the distribution characteristics of the vertical flow field structure. The near-surface wind speeds of the Zea mays intercropping modes were lower than 6 m/s. The wind speeds of the Helianthus annuus intercropping modes reached approximately 9 m/s on average, which is higher than the threshold wind velocity of sand movement. (3) The wind speed significantly affected the shelter efficiency of the intercropping modes. The shelter efficiency decreased with increasing wind speed. (4) The shelter efficiency of the intercropping belt decreased with increasing belt spacing. The shelter efficiency decreased with the intercropping strip spacing in the increasing order of 8 m, 16 m, and 24 m. The shelter efficiency of the Zea mays intercropping mode was higher than that of the Helianthus annuus mode. The near-surface shelter efficiency under Zea mays belt spacings of 8 m and 16 m was higher than 50%, which is the optimal mode in regard to wind and sand resistance in Cyperus esculentus farmland. Considering the economic benefits of farmland, the study demonstrated that the Zea mays intercropping mode with a spacing of 16 m was the optimal intercropping mode considering both ecological and economic benefits in Cyperus esculentus farmland. This research provides a theoretical basis and practical reference for protective tillage practices of Cyperus esculentus in sand areas to prevent wind and sand erosion.