| In order to investigate the effects of different mulches on soil temperature,nutrients and enzyme activities in maize fields,we used " Dade 216 " maize variety as the experimental material in Nandao Village,Songjiang Town,Antu County,Jilin Province in 2019.The effects of different types of mulching on soil temperature and humidity,soil nutrients and soil enzyme activities of maize fields were investigated in three mulching modes : large monopoly tillage +transparent degradable mulch(T1),large monopoly tillage + transparent non-degradable mulch(T2)and large monopoly tillage + black non-degradable mulch(T3),with uniform monopoly bare ground without mulch(CK)as the control.The results of the study were as follows :(1)Mulching was able to significantly increase soil temperature in the 0-20 cm of the tillage layer in the early stage of maize growth and development,and was more effective in elevating soil temperature in the shallow layer.In the early stage of maize growth and development(5/8-7/15),T1,T2 and T3 treatments increased the average daily mean soil temperature in the subsurface 5-20 cm by 2.1-4.1°C,2.9-4.9°C and 1.6-2.1°C,respectively,compared with the CK treatment,and the T1 and T2 treatments had better insulation effect and better elevation effect on the shallow soil;in the late stage of maize growth and development(7/16-9/17),the warming effect of mulching treatment was weakened,and the daily average soil temperature of underground 5-20 cm in T1,T2 and T3 treatments only increased 0.5-0.7℃,0.7-1.1℃ and 0.9-1.1℃,respectively,on average compared with bare soil treatment,and the degradable mulch film had the weakest heat preservation effect due to degradation rupture.During the day,the shallow soil temperature was higher and the temperature fluctuation of the mulching treatment was larger,and the measurement results of June 12 showed that the daily differences were 24.0,25.0,13.5 and 10.2℃ for T1,T2,T3 and CK treatments in the 5cm soil layer,and 7.5,8.3,4.9and 3.8℃ for T1,T2,T3 and CK treatments in the 15 cm soil layer,respectively,within the tillage layer Soil temperature in the tillage layer was transmitted from top to bottom,and the "peak " and " trough " of soil temperature in the deeper layer was 2-3 hours later than those in the shallow layer.The mulch significantly increased the soil water content of the tillage layer during the growth period of maize,and the soil water content of the T1,T2 and T3 treatments was6.41%,6.38% and 11.85% higher than that of the CK treatment,respectively,during the whole reproductive period.(2)Mulching had significant effects on soil nutrients during all periods of maize growth and development.Compared with CK,all mulching treatments reduced soil organic matter and total nitrogen content of the cultivated layer and increased soil alkaline nitrogen,fast-acting phosphorus and fast-acting potassium content.During the whole maize growing period,soil organic matter contents decreased by 3.16%,4.91% and 5.26% on average in T1,T2 and T3 treatments,respectively,compared with CK treatment,with less decrease in T1 treatment;soil total nitrogen content decreased by 7.99%,9.47% and 5.00% on average in T1,T2 and T3 treatments,respectively,compared with CK treatment;The alkaline nitrogen contents in the soil increased by 10.52%,12.00% and 5.75%,respectively,and the fast-acting phosphorus contents in the soil increased by 9.44%,10.98% and 5.94%,respectively,and the fast-acting potassium contents in the soil increased by 5.67%,8.34% and 12.43%,respectively.(3)Mulching significantly reduced the activities of various enzymes in the soil,and soil urease,sucrase,catalase and acid phosphatase activities were reduced in the mulch treatment.The soil urease activity decreased by 11.42%,13.31% and 14.61% on average,soil sucrase activity decreased by 7.05%,12.45% and 12.23%,soil catalase activity decreased by 7.16%,11.49% and 11.51%,and soil acid phosphatase activity decreased by 7.16%,11.49% and 11.51%on average compared with CK treatment at each period of maize fertility.(4)Mulching significantly increased maize yields,resource productivity and economic efficiency.The yield and resource productivity of each treatment showed that T1>T2>T3>CK,and the yield and resource productivity of T1,T2 and T3 treatments were 35.92%,32.60% and17.88% higher than those of CK treatment,respectively.The economic efficiency of each treatment showed that T1>T2>T3>CK,and T1,T2 and T3 treatments were 49.15%,42.87%and 17.07% higher than CK treatment,respectively.Yield,resource production efficiency and economic efficiency were highest in T1 treatment.In summary,combining the factors of soil water and heat conditions,soil nutrients,soil enzyme activity,corn yield and economic benefits,both white transparent mulch films have good effects of increasing temperature and moisture,maintaining soil fertility,and effectively improving corn yield and economic benefits,while degradable mulch film(T1)can also be degraded under natural conditions,reducing film pollution and residual film cleaning costs.It can be used in cooler areas instead of ordinary mulch. |
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