Influence Of Plastic Film Mulching On Soil Moisture And Temperature In Wheat

The effect of plastic film mulching with three methods on soil moisture content in wheat (winter and spring wheat) were investigated under in the loess plateau semi-arid areas rainfed conditions in the Northwest of China from September 2008 to August 2009. The tested type of winter and spring wheats are both approved by the state, the former is Longzhong No.1, and the latter, Xihan No.1. On the same geographical condition, five dealings of the experiment of winter wheat were set up: Gangu model(A), Gansu model(B), Shanxi model(C), Sowing in drill in open ground(CK1) and Bunch planting in open ground(CK2); and seven dealings of spring wheat: membrane mulching in Spring (Gangu model(A1), Gansu model(B1), Shanxi model(C1)), membrane mulching in autumn (Gangu model(A2), Gansu model(B2), Shanxi model(C2)) and Sowing in drill in open ground(CK). The result shows that:1.The plastic film mulching could significantly effect the soil moisture. The water content of the mulching on soil surface layer from the initial stage of wintering to the turning-green stage were 2.8~6.4 percentage point higher than the open field. However, after jointing stage, the moisture content of soil surface layer was close among mulching and the open field treatments, the deep soil (below 20cm)moisture content of mulching was gradually lower than that of open field. From jointing to mature stage, the average moisture content of open field in 20~200cm was 2.0 percentage point higher than the mulching.Although the moisture content of planting patterns and each soil layer are assumes declining trend through with the growth stages, and it also found that the soil moisture content was showed the former high-low after the trend in individual session. The differences of mulching treatments were significantly lower than those between mulching treatment and open field contrast. The biggest difference exists in soil layers 120~200 cm, and in growth stages were winter wheat heading stage and spring wheat seedling stage.The average of 0~200cm soil water can comprehensively reflect the condition of water supply during whole growth. The soil moisture content of plastic film mulching winter and spring wheat was generally worse than the control, viewed by the average moisture condition during the whole period of growth of soil layers(2m), but autumn mulching of spring wheat is higher than the open field. Though the high grain yield of film mulching was based on high water consumption, the soil moisture of film mulching stubble field in 0~200cm could be fully restored to the level of the open field before autumn seeding by water compensation of fallow period.By comparison of the average moisture content of whole growth period in 0~200 cm among different mulching methods, Gangu pattern was the highest and Gansu pattern was the lowest of winter wheat; autumn mulching was higher than spring mulching , Gangu and Gansu was also higher than Shanxi model of spring wheat. But in different periods and soil layers, the soil moisture content was not entirely the same in order of frequency, that were close to each other the difference of consumption and operation deployment for different planting treatment.2.The plastic membrane mulching could commonly improve the temperature in the early growth stages, but the membrane mulching reduces the temperature in middle and later periods. Plastic membrane mulching can commonly improve the temperature 0.3~1℃began turning green stage for lands with depth of 0~25cm, however, after the period of seedling establishment, membrane mulching reduces the temperature, with a common reduction of 1~2℃lower than that of open ground, especially for the land located 5cm. Viewed also by the average amount of moisture during the whole period of growth, the reduction level of Gansu model was the highest, with Gangu model and Shanxi model taking the second and the third places.The spring mulching could commonly improve the temperature1.2~1.5℃was than open field in seedling ~ tillering stages, but it reduced temperature after jointing, with the temperature of soil layers (0~25cm) even lower than that of the open ground 0.2~0.4℃in heading and booting stages, the temperature of the soil layers(0~5cm) was lower than that of the open field after jointing. Spring mulching was significantly higher than autumn mulching 1℃in The whole growth at soil layers 0~25cm. Compared different mulching pattens, the larger decrease was Shanxi model, Gangu model cames second. The temperature had large changes of different layers in Shanxi model, that were close to each other the special characteristics of heat exchange and transmit for incomplete mulching. Compared the winter and spring wheat, mulching reduced temperature significantly on winter wheat in middle and later periods .3.Plastic film mulching could dramatically increase production and the output higher than open field of winter and spring wheat. With the average yield rate was 49.4% of winter wheat , among the different mulching models, the output of Gansu model was the most outstanding with the yield rate was 64.4%, Gangu and Shanxi models stand the second and third places respectively. With the average yield rate was 44.5% of spring wheat, among the different models of mulching, the output increase of Gangu model (A2) was the most obvious, with Gansu model(B1) and Shanxi model(C1) taking the second and the third places respectively, autumn mulching was higher than spring mulching; among the six models, the output of Gangu model (62.5%)with membrane mulching in autumn was the highest and output increasing was the most remarkable.The output of winter whea(t3412kg/hm2) was higher than spring whea(t2211 kg/hm2), the average output than spring wheat 54% in the same environment with the same test conditions. The results showed that the obvious facilitation of yield on plant the winter wheat , plastic mulching to wheat significantly increased soil water storage,crop yield and water use efficiency compared with non-mulch treatment.