Effect Plastic Film Mulching Of Wheat On Soil Temperature In Dryland

The effects of plastic film mulching on of winter wheat and spring wheat were investigated therain-fed conditions of semi-arid areas in loess plateau. Xihan-1and Longzhong-1were selected fortested cultivars of winter wheat and spring wheat，respectively. Experimental treatments weredesigned on the basis of different periods, and there were three cover modes of plastic film mulchingsuch as Gangu model, Gansu mode and the Shanxi model, and two different periods of plastic filmmulching such as sowing time and November of previous year. Determination of soil temperature hadbeen done from different soil layer and different growth stage for winter wheat and spring wheat inthe same place. The purpose was to explore mechanism for increasing production and furtherunderstand the cultivation technique of plastic film mulching, and the results were as follow:Plastic film mulching could generally increase soil temperature, the average mulchingtemperature of0-25cm soil layer at the whole growth period was higher(0.29-1.37℃) than bare landdrilling (CK) for spring wheat, and for winter wheat was higher0.36℃. In general, soil temperaturechanged with different cover modes of plastic film mulching, the increasing extent of Gangu modelwas the highest, followed by the Gansu model and the Shanxi model was the least. the spring wheatincreased among The soil temperature of increasing for spring wheat was1.88,0.49and0.06℃respectively, for winter wheat was0.67℃-0.21℃-0.75℃respectively; compared to the differentsoil temperature, it was the lower greater than upper; the soil temperature of spring plastic filmmulching higher than plastic film mulching for November of previous year periods; average soiltemperature for spring wheat spring plastic film mulching increased1.06℃, average soiltemperature of the autumn Film increased0.56℃for continuous3-years.Although plastic film mulching could generally increase soil temperature, the condition todecreasing soil temperature would be coming among three cover modes of plastic film mulching. Forexample, the soil temperature of the Shanxi model would be decreased. And the period of increasingsoil temperature was in earlier growing stage, and there was decreasing in middle and late growthstage, esapeasilly at jointing stage.The soil absolute temperature changed daily for spring and winter wheat. With the increasing ofsoil depth, soil temperature decreased; the soil temperature at0-25cm changed in the form ofascendant curves in whole growth stage, and the curve was similar to the curves of atmospheric temperature among all treatments, especially at maturity stage. The law of soil temperature diurnalvariation as follows: in the morning, the soil temperature increased with the increasing soil depth, butdecreased in the noon and evening; compared by three cover modes of plastic film mulching,the soiltemperature was B> A> C in the noon and evening, while in the morning was B> C> A; there was thehighest significant at5-10cm soil layer in a day.