The Mechanism of Yield Decrease of Spring Wheat Resulted from Plastic Film Mulching

Abstract

Field experiments were carried out to study the mechanism of yield decrease of spring wheat resulted from plastic film mulching. Four treatments were employed: CK was a control; P was just applied phosphorous fertilizer in plough layer of field; M was mulched with plastic film during the period of 0'-62 days after sowing; PM was P plus M . Both the film mulching treatments promoted significantly the growth of root system, and more root biomass was distributed in deep soil layer at anthesis and grain filling period. The water absorbed from soil profile, however, was not increased as the same proportion, which resulted in the waste of the root biomass in deep soil. Shoot biomass of the plants mulched with film did not increase after 70 days after sowing, and the reproductive organs did not also developed well. In the experiment, soil moisture before sowing was sufficient for shoot emergence. Film mulching promoted water use from soil profile in the early period of growth, and there was no sufficient rainfall after that period to support the growth of plants, which resulted in the soil drying. The yields of the CK, P, M, PM treatments were 2516.5, 2734. 1, 1269.4 and 1625. 1 kg/ha, respectively.