| Aimed on the"White Pollution"caused by the universal utilization of normal mulching films in arid and semi-arid areas, the degradable mulching films and liquid mulching films were chosen to research the soil moisture, soil temperature, soil nutrients, the change of soil enzymes as well as the ecological and physiological response of corn planted under the coverage of those environmental friendly mulching films from the year 2008 to 2010. A series of experiments were carried out in the experiment base located in Ganjing town, Heyang county, Shannxi province with the comparison of normal mulching films and bare land. The results were concluded as follows:1 influence on the soil moisture and temperatureThe rainwater harvesting efficiency of normal mulching film (PM) and degradable film (SM) were better than liquid film (YM) and the contrast (CK), and compared with normal mulching film, the rainwater harvesting efficiency of degradable film decreased a little compared with normal mulching film (PM) while that of liquid films decreased evidently as the experiment went on. The dynamic analysis of soil water storage treated with environmental friendly mulching films during growth period indicated that the water storage in the 0～200 cm soil increased evidently under the degradable film (SM), which had the same effect with normal mulching film (PM); The soil water storage treated by liquid film (YM) was apparently less than normal mulching film (PM), and showed no significant difference with bare land(CK). As for the soil temperature, normal mulching film (PM) and degradable film (SM) had the same promotion effect, especially for the 0～10 cm soil, while the promotion effect on soil temperature of liquid film (YM) was not so significant compared with the bare land(CK).2 influence on soil nutrients and enzymesThe experiment showed that all the rain harvesting materials could increase the soil nutrients and had the same promotion effect compared to each other. The nutrients analysis of 0～100cm soil founded that rain harvesting coverage effectively increased the nutrients of 0～20cm soil other than the deeper ones, which indicated that rain harvesting coverage would not cause a leakage of soil nutrient and had no bad influence on crop's nutrient absorption.The activity of soil enzymes was very sensitive to environment changes in this experiment, the activity of invertase, urease and phosphatase under the treatment of degradable film (SM) and liquid film (YM) compared with the CK, while showed no difference with the normal mulching film (PM), and all the enzyme activities decreased along with the depth of soil. The analysis of nutrient using efficiency indicated that the degradable film (SM), liquid film (YM) and normal film (PM) had the same promotion effect compared to CK, of which the nitrogen using efficiency (NUEN) respectively increased by 33.93%, 12.60% and 34.73%, the phosphorous using efficiency (NUEP) respectively increased by 59.15%, 19.48% and 67.47%, and the potassium using efficiency (NUEK) respectively increased by 53.58%, 10.96% and 57.24%.3 influence on corn photosynthetic characteristicsFrom the measurement results of leaf chlorophyll content, photosynthetic rate, transpiration rate, stomata conductance, leaf WUE and fluorescence parameters, the conclusion could be drawn as the degradable film (SM) and normal film (PM) had the same promotion effect on corn photosynthetic characteristics compared to CK, while the liquid film (YM) showed no significant promotion effect.4 influence on corn growthAll the rainwater harvesting materials could accelerate the growth of corn, of which the normal mulching film and degradable film had much more obvious effects. compared with CK, the average height of corn increased by 5.83%, 2.08% and 6.03% covered respectively by degradable film, liquid film and normal mulching film while the increase of dry biomass increased were 20.03%, 3.63% and 19.51%. The height and biomass of corn covered by normal mulching film and degradable film had a significant difference(P﹤0.05)with CK, but there were no obvious difference between liquid film and CK. The analysis of yield characteristic indicated that the seed yields, 1000-grain weight, grain number per spike and spike length of corn covered by normal mulching film and degradable film had great significance(P﹤0.05)with CK, but the influence of liquid film were not significant. The variance analysis of water use efficiency (WUE) showed that in the 3 years experiment, the WUE of corn covered by degradable film and normal mulching film increased by 19.06% and 20.02%, but the influence of liquid film was not significant.As a conclusion, compared with normal film, the degradable film had the same promotion effect on corn growth and soil water harvesting, which means that it can replace the normal film so as to resolve the"white pollution"problems. The applicability of liquid film needs more research because lower water harvesting effect and unstable promotion effect on corn growth.
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