棉花冷床育苗使用有孔薄膜覆盖,基本上解决了增温和降湿的矛盾,对控制病害、提高棉苗素质有良好的作用,而且苗床管理方便,节省工本。当然,如果措施不当,也会影响增温效果。现根据近两年的实践观察,对影响有孔薄膜增温降湿的因子作如下分析:(一)孔径、孔距的影响有孔薄膜的孔径、孔距是影响苗床温、湿度的直接因子。一般说来,孔径愈大,打孔密度增加,即孔距缩小,增温性能差,降湿效果好;相反,孔径缩小,打孔密度放稀,即孔距 Cotton cold bed nursery using perforated film coverage, basically solved the contradiction between warming and dehumidification, to control diseases and improve the quality of cotton seedlings have a good effect, and the management of convenient seedbed, save the cost. Of course, improper measures can also affect the warming effect. According to the past two years of practical observation, the factors affecting the temperature and humidity of the perforated film are analyzed as follows: (A) the pore size and hole spacing affect the pore size of the apertured film, the pore distance is a direct factor that affects the temperature and humidity of the seedbed . In general, the larger the pore size, hole density increases, that is, the pitch is reduced, poor temperature performance, dehumidification effect is good; the contrary, the aperture decreases, dilute the hole density, the pitch