不同覆盖物对农田防护林防风效能影响

Windbreak effect of different coverings on farmland shelter

为揭示不同覆盖物对农田林网内风速分布及防风效能的影响,选取4种不同覆盖物和对照(无覆盖物)林网模型,对其防风效能进行了风洞模拟试验。结果表明:林网中防护林带高度范围内,覆盖物对林带前后的风速流场具有显著影响,尤其是高大果树类作物对风速削减程度较大。8m·s^(-1)风速条件下,各模式林网内平均风速排序为核桃+小麦间作模式<苹果+小麦间作模式<红枣+小麦间作模式<纯小麦模式<无覆盖物。林网中1cm和2cm高度处平均防效能分析表明,3种果树模式林网防风效能最佳,纯小麦模式防效虽弱于果树模式,但是较对照仍有一定的防效,表明林网内覆盖物(特别是果树类作物)对林带防风效能有明显增强作用。因此,随着集约化和精准农业推进,进行农田防护林网配置时,应充分考虑林网内作物本身的防风效能,尤其是高大果树类作物农田防护林网配置时,可适当调整林网大小,合理配置林带结构,提高经济效益。

In order to study the influence of different coverings on wind velocity distribution in forest and windbreak effect,we examined 4 shelterbelt models which were different covering models.These models were used for a wind tunnel simulation under wind speed to evaluate the effects of coverings on the wind field and the protective effects of the shelterbelt.The results showed that within the height range of shelterbelt in the forest network,the coverings had a significant impact on the wind speed field before and after the forest belt,especially for the tall fruit crops.Under the wind speed of 8 m·s^(-1)the order of the average wind speed in each model forest network was Walnut+wheat mode<Apple+wheat mode<jujube+wheat mode<pure wheat mode<CK.The analysis of average control efficiency at 1 cm and 2 cm height in forest net showed that the windbreak efficiency of three fruit tree models was the best.Although the control effect of pure wheat model was weaker than that of fruit tree model,it still had a certain control effect.The results showed that the windbreak efficiency of the forest belt was significantly enhanced by the mulch in the forest net,especially the fruit crops.Therefore,with the advance of intensification and precision of agriculture,we should consider the wind proof effect of the crops especially a tall crops in the forest network when the shelterbelt is set.In order to improve economic benefits,the size of forest network should be adjusted properly and the structure of forest belt should be allocated reasonably.