亚洲一区欧美在线,日韩欧美视频免费观看,色戒的三场床戏分别是在几段,欧美日韩国产在线人成

Emitter clogging caused by simultaneous irrigation and fertilization (fertigation) has negative influence on the normal operation of drip irrigation systems. This study was carried out to determine the effects of fertigation amount and irrigation amount on labyrinth emitter clogging. Additionally, sediments in the labyrinth passage were analyzed by field emission scanning electron microscope (FESEM) to determine their composition. Results indicated that average discharge of the emitters decreased between 1.51% and 14.16% with the increase of the irrigation or fertigation amount after operating the drip irrigation system for 21 weeks. Statistical analysis showed that fertigation amount significantly affected emitter average discharge (P<0.01). Dissection of the clogged emitters revealed that the sediments located in the front labyrinth passage comprised primarily of sealing tape, insoluble fertilizer particles, and white powdery chemical precipitation. The chemical precipitation was found to be constituted of carbon, oxygen, phosphorus, calcium, magnesium, and other minerals. Consequently, emitter clogging was mainly caused by the combined effect of physical and chemical clogging.