覆膜对不同播期冬小麦根系生长和产量的影响

为探究覆膜对冬小麦根系生长和产量的影响，于2017—2018和2018—2019年度在冬小麦生育期设置2种栽培模式（CK: 裸地穴播，PM: 全膜穴播）和3个播种日期（0：传统播期，10：晚播10 d，20：晚播20 d），分析了覆膜措施对不同播期冬小麦地上部和根系生长、产量及其构成，以及水分利用效率的影响。结果表明，覆膜处理有效增加了不同播期冬小麦返青期后的根长密度（RLD）、根表面积密度（RSD）、根系生物量、地上部生物量；各生育期PM0处理的RLD、RSD、根系生物量、地上部生物量均最大。覆膜对晚播冬小麦根系生长具有一定的加速作用，使得两季冬小麦PM10处理的RLD、RSD和根系生物量在返青期分别比CK0处理高2.90%、13.63%和23.04%。与CK0处理相比，两季冬小麦灌浆期 PM0、PM10、PM20处理的地上部生物量分别显著增加65.63%、75.57%和54.71%（P<0.05）。两季冬小麦覆膜处理的产量和水分利用效率均比同播期裸地处理高，其中，两季冬小麦PM0、PM10处理的产量分别比CK0处理提高28.92%、14.35%，水分利用效率分别比CK0处理提高17.87%、7.90%。此外，研究还发现，冬小麦返青期、开花期、灌浆期总RLD均与有效穗数、产量、水分利用效率呈极显著正相关关系（P<0.01）；冬小麦返青期总RSD、根系生物量均与有效穗数、产量及水分利用效率呈极显著正相关关系（P<0.01）。综上，覆膜措施通过改良土壤的水热环境，加速并促进了冬小麦根系的生长发育，进而改善了冬小麦根系对水分和养分的吸收，增加冬小麦植株的抗逆性。

Effects of plastic mulching on root growth and yield of winter wheat under different sowing dates

In order to explore the effects of film mulching on the growth of root system and yield of winter wheat, in this study, during the whole growth period of winter wheat in 2017-2018 and 2018-2019, two planting modes (CK: uncovered hole sowing, PM: full film hole sowing) and three sowing dates (0: traditional sowing date; 10: 10 days for late sowing; 20: 20 days for late sowing) to analyze the effects of film mulching on the growth of aboveground system and root system at different growth stages, yield and its composition as well as water use efficiency of winter wheat under different treatment. The results showed that after greening period of the two seasons of winter wheat, the mulching measures effectively increased root length density (RLD), root surface area density (RSD), root biomass, and above\|ground biomass. Among the different growth periods, RLD, RSD, root biomass, and above\|ground biomass of PM0 treatment was the largest. Film mulching could accelerate the growth of the root system of late sowing winter wheat, making the average RLD, RSD and root biomass of PM10 treatments increased by 2.90%, 13.63% and 23.04% than CK0 treatment of winter wheat during the greening period, respectively. Compared with CK0 treatment, the average above\|ground biomass of PM0, PM10 and PM20 treatments in the two seasons of winter wheat during the filling period increased significantly by 65.63%, 75.57% and 54.71% (P<0.05), respectively. The average yield and water use efficiency in the two seasons of winter wheat of mulching measures were higher than those without mulching at the same sowing period, respectively. Compared with CK0 treatment, the average yield of PM0 and PM10 in the two seasons of winter wheat increased by 28.92% and 14.35%, and the water use efficiency was increased by 17.87% and 7.90%. In addition, the study also found the total RLD in the greening period, flowering period, and filling period of winter wheat all had strong positive correlations with the spike number, yield, and water use efficiency (P<0.01); the total RSD, root biomass in the greening period all had strong positive correlations with the spike number, yield, and water use efficiency (P<0.01). In summary, film mulching can improve environment of the soil to accelerate and promote the growth and development of winter wheat root system, thus improves the absorption of water and nutrients by the winter wheat root system, increases the stress resistance of winter wheat plants.