Research On Effects Of Degradable Film On Soil Water-heat Movement And Crop Growth Of Maize Under Drip Irrigation

Object:In order to use irrigation water scientifically and rationally and control residual film pollution in field for sustainable development,field experiments were carried out for two consecutive years to study the effects of degradable film on soil water and heat movement,soil respiration,crop physiological growth index,yield and ecological and economic benefits of drip irrigated maize,in order to provide a theoretical basis for water-saving irrigation and residual film pollution control in arid areas of Xinjiang.Methods:This experiment was conducted in the key laboratory experimental base of modern water saving irrigation corps and water saving irrigation experimental station of Shihezi University from 2019 to 2020,with maize variety"Xinyu 66"as the research object.The double factor field experiment of irrigation amount and film was carried out under the condition of drip irrigation.And four biodegradable films,M1:the induction period was 100 days,black oxidation biological double degradation film;M2:the induction period was 80 days,white oxidation biological double degradation film;M3:the induction period was 80 days,and the black film was completely biodegradable,M4:the induction period was 100 days,white completely biodegradable film,and ordinary polyethylene mulch（PE）were applied in the experiment under four irrigation amounts,W1:4875 m³/hm²,W2:5250 m³/hm²,W3:5625 m³/hm² and W4:6000 m³/hm².A total of20 treatments were tested and repeated for 3 times.Results:（1）The diurnal variation of soil temperature in 0～25 cm soil layer in 2019 and 2020 is similar,showing a trend of low high low.Under the same irrigation level,M1 treatment was 0.2～2.6℃higher than PE treatment,M3 treatment was 1.0～1.5℃higher than PE treatment.With the increase of irrigation amount,the rising rate of soil temperature decreased.During the growth period of drip irrigation,black film M1 and M3 had better heat preservation effect.（2）In 2019 and 2020,the change trend of soil water storage in drip irrigation maize growth period was consistent,and the maximum value was reached in tasseling period.With the advance of growth period,the longer the induction period,the greater the soil water storage.With the increase of irrigation amount,the difference between degradable film and common film treatment decreased.On the whole,under the same irrigation level,the average value of soil water storage in 0～100 cm soil layer under different film mulching treatments during the growth period of drip irrigation maize was PE>M1>M4>M2>M3,and the water retention effect of degradable film M1 and M4 was better.（3）The diurnal variation of soil respiration rate showed a single peak trend of first increasing and then decreasing under different irrigation levels,and the soil respiration rate was PE>M1>M4>M3>M2.The monthly variation of soil respiration showed a single peak with the growth of maize,and the maximum value appeared in the tasseling stage of maize（mid late July）.There was a positive correlation between soil respiration rate and soil temperature,and the correlation reached a very significant level.The correlation between soil respiration rate and soil volume moisture content was not significant.Under W3 irrigation level,the temperature sensitivity Q₁₀ of M1 treatment was the highest,reaching 1.949.（4）The effects of irrigation amount and degradable film on photosynthetic characteristics and fluorescence characteristics were as follows:with the increase of irrigation amount,the differences between degradable film and PE film decreased gradually,and P_n,T_r,G_s,C_i,F_v/F_m,F_v/F₀,q P,NPQ,Y（II）and ETR were significantly affected by single factor irrigation quota（P<0.01）,and were significantly affected by the interaction of irrigation quota and film（P<0.01）,At the filling stage,the effect of single factor film was significant（P<0.05）,the maximum value appeared in W4PE treatment,and W4M1 treatment was second only to W4PE treatment.The plant height and leaf area index showed a single peak trend,and the dry matter accumulation increased with the development of maize.（5）The maximum yield and iWUE in two years occurred in W3PE treatment,and W3M1 treatment only reduced yield by 0.27%～2.36%compared with W3PE treatment（P>0.05）,the iWUE of W3M1 treatment was only 0.71%～2.21%lower than that of W3PE treatment（P>0.05）.The net income of W3M1 treatment with 100 d induction period and 5625 m³/hm² irrigation quota was 5100～6500 yuan/hm²,which was 6.56%～21.42%higher than that of W3PE treatment,and the residual amount of plastic film was reduced by 16.41%～36.29%.Conclusions:In general,increasing irrigation amount can make up for the loss of water evaporation caused by the degradation of degradable film at the later stage.Considering the film of crop growth and the reduction of film residue in arid areas,100 d degradable film with induction period and W3M1 with irrigation quota of5625 m³/hm² are the most suitable modes for maize planting under film drip irrigation in oasis of Xinjiang.