Effects Of Tillage And Sowing Time On Soil Physical And Chemical Properties And Maize Growth In Semi-arid Area Of Songnen Plain

In recent years,the warming of climate has caused the crop growth season to be prolonged,the growth period of maize to be shortened,the planting boundary to move north,to coordinate the contradiction between the growth season and the growth period of maize,and to avoid the bad weather conditions during the critical period of growth and development,which is an urgent problem to be solved in production.For a long time,the traditional single-spin tillage ridge farming method has been widely used in agricultural production in the semi-arid area of Songnen Plain.Based on this,"Xianyu 335" was used as the test material to set up early,middle and late sowing dates(sowing on April 23,May 1 and May 10,respectively).Deep autumn ridges(QSL),deep autumn flattening(QSP),autumn rotary tillage(QSL),autumn rotary tillage culture(QXP),autumn rotary tillage culture with shallow loose(QXQP),autumn rotary tillage culture deepen the pine(QXSP),spring rotary tillage(CKL),spring rotary tillage culture(CKP),no-till(MG)and no-till deepen pine(MGS),10 kinds of farming methods,and early,middle and late sowing dates(sowing on April 23,May 1 and May 10,respectively).The combination of farming methods and sowing date of main physical and chemical properties of soil,the influence of the maize growth and yield.In order to establish a suitable cultivation method for high and stable maize yield in this region,determine an appropriate sowing date,and provide scientific basis and technical support for high and stable maize yield in this region,the research results are as follows:1.The soil moisture content,soil temperature and soil bulk density of maize varied with precipitation and temperature in different growth periods.Soil bulk density can be reduced by0.72%-23.85% in autumn compared with that in spring,6.33%-21.77% lower than that in no-tillage.A low of 6.50%-22.09%,loose soil structure,conducive to the increase of ground temperature.2.The soil structure can be loosened,fertilizer infiltration can be increased and soil enzyme activity and soil nutrient can be increased.Maize under early sowing treatment,full growth,strong root metabolic activity,increased root exudates,can improve soil enzyme activity and soil nutrient content.Therefore,early sowing can improve soil enzyme activity and soil nutrient content,which is helpful to high yield of maize.3.Flat cropping,deep tillage and spring tillage could increase root activity,increase dry matter accumulation and leaf area index,increase chlorophyll content,increase dry weight of maize,and increase maize yield.With the delay of maize sowing date,the growth period of maize was shortened gradually,and the growth period of maize under the condition of late sowing was shortened by 2 d-9 d,10 d-14 d.than that of early sowing.During the late sowing,the temperature was higher,the plant height of maize increased,the late sowing increased1.06%-3.12%,0.39%-29.79%.However,the dry matter accumulation and leaf area index decreased,and early sowing could increase the root injury flow and leaf chlorophyll content of maize,which was beneficial to the increase of dry weight of maize grain.The dry weight of maize grain increased 1.73%-23.02 and 4.11%-22.67% compared with late sowing,which was helpful to the high yield of maize.It can lay the foundation for the high yield of corn by using the treatment of deep fall and early sowing.4.Maize yield gradually decreased with the delay of maize sowing date in 2018,maize yield for early sowing was 4.18%-22.46% higher than middle sowing,and middle sowing was1.70%-22.36% higher than late sowing in 2019,early sowing was 2.18%-20.62% higher than middle sowing,and middle sowing was 9.86%-34.57% higher than late sowing.However,maize seedling stage is vulnerable to low temperature chilling injury under early sowing condition.Under early sowing condition,maize seedling stage MDA content is the lowest and yield is higher under autumn rotation tillage leveling treatment.The yield of maize was the highest under the condition of early sowing,and the yield was 12784.35 kg/ha in 2018.For 2019,it was12821.42 kg/ha followed by fall tillage.Under the condition of medium sowing and late sowing,the highest yield of maize under autumn deep leveling treatment was 11141.93 kg /ha and,9899.18 kg/ha in 2018,111826.19 kg/ha and 10612.79 kg/ha.in 2019,respectively.Therefore,it is beneficial to the high yield of maize in the semi-arid area of Songnen Plain under the condition of early sowing,medium sowing and late sowing.