Germination Characteristics and Seedling Emergence of Switchgrass with Different Agricultural Practices under Arid Conditions in China

Switchgrass (Panicum virgatum L.) is an important feedstock for bioenergy production, but establishment is difficult in cold arid areas. This study determined the conditions required to improve its germination and emergence in the field. Under controlled conditions, the effects of temperature, water status, and light on germination were studied by exposure to 12-h alternating temperatures of 15/5, 20/5, 20/10, 25/10, 35/20, 40/20, and 45/20 degrees C (day/night) and water potentials of 0, -0.2, -0.4, -0.6, -0.8, and -1.2 MPa in culture medium. Maximum percentage germination occurred at 35/20 degrees C, 0 MPa water potential, and in continuous dark. In the field when planted in early spring (April), no emergence occurred when there was no surface cover or covered with straw mulch (SM) whereas using plastic film mulch (FM), emergence reached 383 seedlings m(-2) with pre-sowing irrigation but only 273 without irrigation. This was associated with higher soil temperatures and better soil moisture. However, in July seeding, SM lead to better water status and cooler soil conditions and thus better stand establishment. In contrast, FM treatment had poor establishment primarily due to the high temperatures. Our study indicates that emergence of switchgrass in an arid environment was (i) enhanced by pre-sowing irrigation and shallow seeding, (ii) made possible in spring by the use of FM, and (iii) improved with SM for summer seeding.