| The unequal seasonal rainfall distribution in the spring maize planting area of Weibei dryland limited the stable production of maize.As an effective measure to increase moisture and temperature,plastic film mulching technology plays an important role in stabilizing and increasing yield of maize in rain-fed dry land.With the global warming,The rising global temperature has further increased the soil temperature of dryland crops.The phenomenon of "premature aging" after ordinary white plastic film is mulched.Therefore,it is of great significance to explore a mulching cultivation technique with good water retention effect,which can reduce the soil temperature of the maize root zone in time,and delay the premature senescence of maize.Different mulching patterns were tested in the drought region of Changwu,Shaanxi province during 2018 and 2019.Four treatments were set,including black plastic mulching(BFM),white plastic mulching(WFM),white plastic and soil mulching(WSM)and bare land(CK).Two maize varieties,Shandan 609 and Shandan 902 were selected to study the above-ground leaf antioxidant enzyme activity,leaf area index,relative chlorophyll content and other physiological characteristics,plant height,dry matter quality,yield and yield components of different varieties of spring maize.The main research results are as follows:1.Different mulching patterns effect the field soil temperature.The daily change of the average soil temperature of the 0-25 cm soil layer during the whole growth period of spring maize showed a curve form of rising first and then falling,and the temperature reached the highest value around 14 o'clock.Compared with bare land,mulch treatment has the effect of increasing soil temperature.White film mulching and black film mulching have the most obvious warming effect.When the temperature is high at noon,black film mulching also shows obvious cooling effect.Compared with white film mulching,black film mulching and white plastic and soil mulching can effectively reduce the soil temperature of 0-25 cm during the day,with a temperature reduction of 0.8-1.2 ? and 1.5-2.0 ? respectively.2.Different mulching patterns have different effects on the growth and protective enzyme activities of spring maize.The dry weight of single plant above spring maize showed a "S" dynamic change during the whole growth period.At maturity,the dry weight of single plant above ground under different mulching treatments reached the highest.Compared with white plastic mulching,white plastic and soil mulching and bare land,the dry weight of single plant above ground of Shandan 609 mulched with black film increased by 20.2%,8.67% and 33.3% on average in two years The average increase of Shandan 902 was 22.15%,9.89% and 34.1%.The maize leaf area index(LAI),leaf SPAD value,SOD activity,and CAT activity mulched black film are all higher than white plastic and soil film,white plastic film and bare land,and MDA content is lower,both of which reach significant levels.The influence law of different varieties is the same,but the degree of influence is different.Under the condition of maize mulching in the late stage of maize silking,the senescence type Shandan 902 leaf area index(LAI)and leaf SPAD value decreased less than that of the green-keeping variety Shandan 609.Black film mulching could improve the growth and development of the overground parts of the maize and delay leaf senescence in the later growth period.3.Black plastic film mulch can better coordinate the root-shoot ratio in the later growth stage of maize,and promote the growth of the root system of maize after silking.With the growth of maize,the root-shoot ratio under different mulching treatments showed a decreasing trend.During the filling and maturity periods,the ratio of maize of each mulching treatment decreased significantly.Greater than white plastic and soil mulching,white plastic mulching and bare soil treatment(P<0.05),the two variety of Shandan 609 mulched with black film compared with white film,white plastic and soil film and bare land,the root-shoot ratio were increased by 15.49%,14.28% and 30.58%,Shandan 902 increased by 24.28%,14.28% and 42.35% in average two years.Mulching can promote the growth of maize roots.The dry weight and volume of maize roots in the mature stage of black film mulching are significantly higher than other mulching patterns.Meanwhile,the growth of the root system also affects the growth and development of aboveground plants,increasing the leaf area index of late maize growth,and improving the root-shoot ratio and maize grain yield.4.Under the black film mulching method of the two varieties,the grain weight is larger,the grain yield is significantly increased,and the water use efficiency is significantly improved.The two-year overall water use efficiency under different cover treatments was BFM>WSM>WFM>CK,and the black film mulching treatment was significantly different from the white plastic mulching treatment,white plastic and soil mulching treatment and bare land.The grain yield of shandan 609 mulched with black film increased by 10.47%?5.38%and 14.63% compared with that of white plastic and soil mulching,white plastic mulching and bare land in average two years,and the average yield of Shaandan 902 increased by 10.39%?7.23%and 21.01%,respectively. |
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