The Study Of Degradation Of Different Biodegradable Film And Effects Of It On Variation Characteristics Of Soil Water,Temperature,Salinity And Nitrogen

This article mainly aimed at the promblems the grim reality of agricultural residues in Hetao irrigation area of Inner Mongolia,to study the biodegradable plastic degradation process of different degradation rate and the effects on farmland soil environmental change research.Through two years of field experiment,Mainly studied the the biodegradable plastic degradation process and plastic film mulching soil water,heat,salt,nitrogen variation characteristics,and explores the different degradation rate mulch on crop growth,yield and water use efficiency,in order to screening for the region suitable for the local crop growth of biodegradable plastic,water and fertilizer saving,high yield and income for the region to provide theoretical and technical basis,the results of the study to reduce"white pollution" in plastic film and improve the efficient use of water is of great significance,especially lay the foundation for the promotion of biological membrane application.The conclusions are as follows:1.The apparent characteristics and mechanical properties of degradable films are different from the ordinary plastic mulch during crop growth period.Harvest,the common plastic degradation rate and the damage rate are about 3%,and the degradation rate of different degradable films is 14%?30%,and the breakage rate is 30%?60%,compared with common plastic film significant difference(P<0.05).For the SEM scanning of film surface,degradable mulching film and common film are more evenly distributed before the laying,good compatibility between particles.After 100 days,the PM surface structure is loose and the gap between particles is fine,but slow degradation.The surface of the degraded film showed a large number of holes and uneven sizes,the mechanical properties decrease.2.Covering the film significantly increased soil(0-40cm)temperature and moisture content,the soil temperature and soil water content between degradation of membrane treatment and ordinary film treatment difference increases gradually with the increase of breakage of biodegradation film,significantly lower than ordinary plastic late in crop growth.With the increase of soil depth,soil temperature is reduced.High fertilizer treatment,0-40cm soil moisture content from 17.23%decline to 14.78%by W1(600m3/hm2)increased to W3(1200 m3/hm2)of irrigation water and the temperature dropped from 23.41? to 22.30?.which showed that the water content is proportional to the amount of irrigation,and the ground temperature is inverseiy proportional to the amount of irrigation.3.At the beginning of the crop growth,the degradable film and common plastic film are not degraded,soil conductivity value between different treatment had no significant difference(P>0.05).In the crops mature,mostly broken into pieces and cover area reducing because of degradable mulch in phase disintegration,evaporation is serious,the significant difference between the different treatment(P<0.05).0?40cm soil layer in the whole stages of ordinary plastic processing and degradable film processing soil EC was significantly lower than not coated area.Covering film can effectively reduce the 0?40cm soil electrical conductivity,and for 60?100 cm soil salt effect is small.Increase the irrigation water can effectively control table salt phenomenon.4.Covering different plastic film mulching have significantly influence of the 0?40cm soil NO3-N content and 40?100cm soil NO3--N less affected.With the time of film mulching,the content of nitrate nitrogen decreased gradually.During harvest,the content of nitrate nitrogen in 0?40cm soil layer treated with plastic film was higher than that under the degradation film treatment.The increase of irrigation water,makes the lower obviously increase the nitrate nitrogen content in the soil and cause leaching.5.Respectively,covering common membrane water use efficiency than slow(OM3),medium speed(OM2),fast(OM1)degradation of membrane treatment increased by 6.05%,9.16%,9.16%,significant difference(P<0.05).Under the condition of the same fertilizer,irrigation water by W1(600m3/hm2)increased to W3(1200m3/hm2),water use efficiency decreased from 22.56%to 20.51%,increase of irrigation make water use efficiency reduced.In order to avoid the unnecessary waste of water resource and can be used to a great extent,should choose reasonable irrigation,in arid regions has great significance.