Effects Of The Film-mulching On The Accumulation And Transportation Of Assimilates In Wheat On Dry Land

Field experiments were carried out at Yangling region in the south part of the loess plateau with 632mm average precipitation per year. Using the winter wheat varities as test crops, the experiments were carried out only depending on the stored water in the soil and the rainfall without any irrigation during the whole growth stage, in order to study the effect of the film-muching on the soil temperature, water status in the soil and the growth stages of the winter wheat; the effect the film-muching on the dry matter accumulation and nitrogen transportation in the wheat crops, the effect of the film-mulching on the remobilization and distribution of 14C-assimilates before and after the wheat anthesis, and the effect on the senescence features of the roots and leaves in wheat after the anthesis. The main purpose os these investigations is to elucidate the effect of the film-mulching on the physiological mechanism of the wheat yield increase on the dry land, and to provide clues to the cultivation mode with good quality, high yield and high performance in the north-west regions of china. The main results obtained from the experiments are as follows:1. The influence of the film-mulching on the soil temperatureincrease mainly occurred from wintering to the booting stage. The soil temperature on 5 cm depth under the film-mulching increased 2.4℃, 3.1℃, 1.8℃, 1.1℃, respectively. The influence of the film-muching on the maintaining of the soil water content mainly occurred from the rising to the anthesis stage. The soil water of the film-mulching increased 2.50%, 4.78%, 3.71%, 4.65%, respectively. These provided better conditions for the wheat growth and development during the early and middle growth stage.2. Each growth stage under the film-mulching moved ahead of schedule for about 1～4d, the duration from tillering to elongation were shortened about 1～2d, and the duration from booting to flowering were shortened about 1～2d. However, the duration from flowering to ripening increased for about 1～2d. The wheat growth process under the film-mulching got quicker, and the tiller numbers and nutritive substance accumulation increased. These were better for the formation of larger spikes and higher yields.3. The film-mulching was profitable for the dry matter accumulation in the leaves, stalk sheaths and the grains in wheat. The total accumulations of dry matter under the...