Effects Of Different Plastic Film Mulching On Root Flow Characteristics And Yield Of Maize In Cold Region Of Eastern Jilin Province

In order to explore the effects of different mulching films on the root bleeding characteristics and yield of maize in the cold region of eastern Jilin Province,Longping 702(early maturing variety)and Dade 216(middle-early maturing variety)were used as experimental materials in this study.The root bleeding intensity,nitrogen content in root bleeding sap,root growth and development,root physiological characteristics and maize yield formation of the two varieties under transparent degradable plastic film mulching,transparent non-degradable plastic film mulching,black non-degradable plastic film mulching and no plastic film mulching were studied.The results were as follows:1.Film mulching significantly promoted root growth at seedling stage.Compared with no film mulching,root length increased by 26 %-33 %.Root dry weight,root volume and root activity of transparent film mulching were significantly higher than those of black film mulching and no film mulching.2.The activities of NR,GOGAT and GS in roots of Longping 702 under transparent plastic film mulching at early growth stage increased by 23.2 %,22.1 % and 29.0 %,respectively,compared with those without plastic film mulching,while those under black plastic film mulching increased by 8.5 %,17.1 % and 22.7 %,respectively.Transparent film mulching increased the enzyme activity of mid-early maturing varieties by 49.2 %,34.2 % and 46.9 %,and black film mulching increased by 32.2 %,29.6 % and 34 %,respectively.3.Film mulching in the early stage can significantly enhance the intensity of bleeding,ammonium nitrogen,free amino acids,soluble protein and total nitrogen content and strength,transparent film than black film effect is more significant.Under the two transparent plastic film mulching,the total nitrogen content in the sap of the mid-early maturity varieties increased by 4.7 times,which was 1.1 times higher than that under the black plastic film mulching.4.Under different plastic film mulching,the concentration and intensity of nitrogenous substances in the bleeding sap had an indirect effect on the yield.In the early growth stage,the bleeding intensity of the root system and the total nitrogen content in the bleeding sap were significantly positively correlated with the yield.The correlation coefficient was between 0.84 and 0.98.5.The yield of Longping 702 with transparent film mulching was 26 % higher than that without film mulching and 8.7 % higher than that with black film mulching.The average yield of Dade 216 under transparent film mulching was 35.9 % higher than that without film mulching and 13.9 % higher than that under black film mulching.In summary,transparent plastic film mulching can significantly increase the length,volume and dry weight of maize roots at seedling stage,improve root activity,bleeding intensity,nitrogen content in bleeding fluid,nitrogen intensity and enzyme activity,and improve the nitrogen metabolism level of maize roots,which provides a material basis for maize growth and yield formation.Early maturing varieties with transparent biodegradable plastic film mulching are the best mode of maize film mulching cultivation in eastern Jilin Province,which provides a theoretical basis for high yield and stress resistance cultivation of maize in cold regions.