[Double mulching application for Panax notoginseng growing seedlings].
In order to improve the irrigation for Panax notginseng growing seedlings, different mulching ways were carried out to investigate the effects of double mulching. Field experiment was applied to study soil moisture, soil temperature and bulk density of different mulching ways while the germination rate and seedlings growth also were investigated. Compared with the traditional single mulching with pine leaves or straw, double mulching using plastic film combined with pine leaves or straw could reduce 2/3 volumes of irrigation at the early seedling time Double mulching treatments didn't need to irrigate for 40 days from seeding to germination, and kept soil moisture and temperature steady at whole seedling time about 30% and 9.0-16.6 degrees C, respectively. The steady soil moisture and temperature benefited to resist late spring cold and germinate earlier while kept germination regularly, higher rate and seedlings quality. In contrast, single mulching using pine leaves or straw had poor soil moisture and temperature preserving, needed to irrigate every 12-day, meanwhile dropped the germination and booming time 14 days and 24-26 days, respectively, reduced germination rate about 11.3%-8.7%. However, single pine leaves mulching was better than straw mulching. In addition, though better effects of soil moisture and temperature preserving as well as earlier and higher rate of germination with single plastic films mulching had, some disadvantages had also been observed, such as daily soil temperature changed greatly, seedling bed soil hardened easily, more moss and weeds resulted difficulty in later management. To the purpose of saving water and labor as well as getting higher germination rate and seedlings quality, double mulching using plastic films combined pine leaves at the early time and single mulching removing plastic films at the later time is suggested to apply in the growing seedlings of P. notoginseng.