Effects Of Plastic Film Residue And Soil Moisture Content On Corn(Zea Mays L.) Seedlings Growth And Corn Yield

In order to improve crop yields,plastic film mulching is commonly used in agricultural production.But it is usually stuck in farmland soil,because of the difficulty in processing and degradation of plastic film.So a large number of plastic film residue cause farmland pollution and crop yield reduction seriously.Soil moisture is directly related to the growth and production of crops.In order to explore the effects of plastic film residue and soil moisture on corn?Zea mays L.?seedlings growth and corn yield,this study did a pot experiment and a field experiment.In the pot experiment,a completely randomly-designed with four plastic film residue levels(0,300,600 and 1200 kg hm^-2)and three soil moisture levels?40%,60%and 80%field capacity?were set up.In two years of field experiment,a completely randomly-designed with five plastic film residue levels(0,225,450,675 and 900 kg hm^-2)was set up.We analyzed the effects of different treatments on the physiology and ecology of corn seedlings and nitrogen,phosphorus and potassium uptake in corn seedlings,and researched the effects of plastic film residue on yield characteristics of corn.Moreover,the content of organic pollutants phthalate esters?PAEs?in soil and corn kernels were analyzed preliminarily,then according to the characteristics of PAEs pollution in soil,the effects of main pollutants on the growth of corn seedlings were studied by a hydroponics experiment.The results indicated that:1.Under the same field capacity,the indices of corn seedlings in the amount of plastic film residue with 0 and 300 kg hm^-22 treatments were higher than that of the amount of plastic film residue with 600 and 1200 kg hm^-22 treatments,and the indices of corn root in the amount of plastic film residue with 1200 kg hm^-22 treatment were significantly lower than that of other plastic film residue treatments.Under the same plastic film residue,the seedling biomass,stem diameter and photosynthesis of corn seedlings at 60%FC were better than other soil moisture treatments,and the trend of the root parameters and root respiration was 60%FC>80%FC>40%FC.This showed that in the lower soil moisture conditions,residual plastic film would seriously inhibit the growth of corn seedlings,and the effect of plastic film residue on corn seedlings would be weakened with the increase of soil moisture.However,when the amount of plastic film residue reached 1200 kg hm^-2,soil moisture content of 80%still could not alleviate the harm of plastic film residues.Moderate soil moisture condition was most conducive to alleviating the adverse effects of plastic film residue on the growth of corn seedlings.2.Under the condition of 40%FC,plastic film residue suppressed the N,P and K uptake in corn seedlings.Under the condition of 60%FC and 80%FC,only the high amount of plastic film residue(1200 kg hm^-2)significantly affected the N,P and K uptake in corn seedlings,the low-middle amount of plastic film residue hardly affected absorption of nutrition.Under the same plastic film residue,the trend of the N and P uptake in corn seedlings was 60%FC>80%FC>40%FC,indicated that moderate moisture was more conducive to the absorption and utilization of N and P by corn seedlings.While the uptake of potassium increased with the increase of soil moisture.3.In a drought year,the yield of corn decreased with the increase of plastic film residue.While in a year with relatively sufficient rain,corn yield was almost unaffected by plastic film residue.Under the same plastic film residue,the corn yield in rainy year was significantly higher than that in drought year.It showed that the effects of soil moisture on corn seedlings growth and corn yield were greater than that of plastic film residue.4.The PAEs detection of in the soil with residual plastic film showed that the main pollutants in the soil were DnBP and DEHP,and DnBP had exceeded the standard of soil limit?USEPA,2013?,which should be paid more attention to by the public.5.The test of hydroponic toxicology showed that both DnBP and DEHP inhibited the growth of corn seedlings.And the inhibitory effect was enhanced with the increase of the dosage of DnBP and DEHP.Compared with the same dose of DnBP and DEHP,DnBP was more toxic to the growth of corn seedlings.