底部渗灌条件下水肥对华北落叶松容器苗生长及基质pH值、电导率的影响

摘要

Objective]The sub-irrigation is an effective irrigation method whereby water is moved upward into the growing medium by capillary action,in which water is allowed to be reused through a closed-circuit loop. This method can avoid nutrient leaching loss and whereby reduce environmental contamination and financial cost while producing high quality seedlings. Plant roots,as an important organs absorbing water and nutrients and synthesizing materials,have a direct influence on plant aboveground. However,the study on effects on container seedling cultivation technology with sub-irrigation is less in China. This study aims at finding the best combination treatments of irrigation and fertilization for the growth of Larix principis-rupprechtii container seedlings with sub-irrigation.[Method]In this study,L. principis-rupprechtii, an important forestation species in northern China,was used as the experimental material to study the effects of the sub-irrigation with different water and fertilizer supplies on morphological and physiological indexes of the containerized seedlings,and on pH and EC values of media by setting five irrigation gradients and three fertilization concentrations. The effects of the sub-irrigation with different water and fertilizer supplies on growth,media pH and EC values of containerized L. principis-rupprechtii seedlings were analyzed to determine the best combination treatment of irrigation and fertilization.[Result]The seedling biomass and root morphological index increased and then decreased with the increase of irrigation water gradient and fertilization amount. The root shoot ratio gradually decreased with the moisture gradient increase,and first increased and then decreased with the increase of fertilizer. The results showed that watering with 75% of the field saturated water holding capacity and fertilizing with 100 mg slow release fertilizer ( N∶ P∶ K =13∶13∶13 ) per plant were the best combination in improving the development of containerized L. principis-rupprechtii seedlings. The average seedling biomass reached 0. 64 g per plant,the total root length,root surface area and root volume in this watering and fertilizing pattern reached maximum value,and the proportion of fine roots (0. 0