Degradation Of Biodegradable Mulch Film And Its Effect On Growth And Yield Of Maize

Mulching biodegradable films is an efficient approach to reduce the white pollutioninduced by traditional plastic films that could remain in soil for hundred years. Thebiodegradability of mulch films are tested and analyzed. The methodology of random designwas used and compared the control group without mulch films with coverage of differentbiodegradable films and common plastic to compare the effects of common plastic andbiodegradable mulch films on the growth of maize. The results indicate that:(1) The decomposition rate of biodegradable films in5cm layers during60and100daysare respectively1.34%and1.18%, while in25cm layers are1.86%and1.96%. The resultsshowed that the effect of decomposition is increasing with increasing time using, and thedegradation caused almost no changes in different root systems. With longer mulching time,the horizontal tensions of biodegradable films are decreasing while the longitudinal tensionsremain constant. The result shows that horizontal tensions are4.07Mpa after100days and2.94Mpa after140days, which reduce61.9%and72.5%. The longitudinal tensions are5.4%and17.9%, which indicates that it is the single-direction rupture as a result of decomposition.(2) Biodegradable mulch films have an obvious effect on increasing soil temperature inmaize early growth. In the depth of5to25cm comparing with CK, soil temperature improves2.2℃to4.6℃during seeding stage and increases2.1℃to11.3℃in the period of jointingstage. At10clock, the soil temperature is0.8℃more and it is0.8℃less than commonplastic at14clock. In deeper soil profile, the temperature changes between biodegradablemulch films and common plastics are smaller. Differences in soil temperature due to differentmulch films are mainly the increasing extent and delay of highest temperatures under differentweather conditions. On sunny days, the increasing extent is about2.3℃to11.3℃,with animprovement of11.27%to30.54%,the peak emerges at16clock. While in cloudy weather,which shows a small increase with3.4℃to5.6℃,only improve10.18%to14.84%and thepeak around14clock. In ripe period of maize growth, temperature changes a little because ofrupturing, but common plastics remains.(3)During growth period of maize, coverage with biodegradable films enhances the abundance of root hairs and leave area evidently, thus improving growth and harvest. Duringseeding stage, the height of maize is5.36cm with an increase of24.83%.In the period ofjointing stage, there will be one more root hair. And the height improves15.25cm duringtasseling stage with the leaves area enhances59.27cm~2for above-ear leaves,58.93cm~2forear-leaves and54.49cm~2for under-ear ones, with a extent of10.83%,9.38%,7.94%,respectively.(4) The yield of film-mulched maize is higher than for the control group:1613.4kg/hm~2or18.71%for biodegradable mulch films and1523kg/hm~2or17.68%for common plasticsand with an increase of1.04cm for ear length,0.18cm for diameter,1.04cm for fruit length,and3.45for grains per row,31.3g for thousand seed weight. At the same time, theinput-output ratio of film-mulched treatment is0.3, which indicates a higher output of3694.6RMB/hm~2for CK and74.5RMB/hm~2for common plastics. Mulching can increase themaize yield significantly, gains better economic output, and can replace plastics foragricultural production.