Plastic film mulching can increase temperature and moisture in the topsoil, and promote earlier germination and plant establishment (Li et al., 2001). Several studies have illustrated that grain yield and straw biomass of wheat is significantly promoted by PFM
in semi-arid areas (Ibarra et al., 2001; Li et al., 1999), which is consistent
with our results. The grain yield and straw biomass of the M treatment in both years were higher than those of the B treatment by more than 70% and 50%, respectively. Analogously, the two treatments had a different impact on grain P content and straw P content.
Li et al. (1999) suggested that improved soil moisture and temperature
under PFM was beneficial to the redistribution of nutrients in
wheat organs. The ratio of grain P to aboveground P suggested that
more P was redistributed to grain in the M treatment than the B
treatment. The ratios in both treatments in 2009 were significantly
higher than in 2010.