| This study was conducted in 2015-2016,select the ZH 505 and CD 30 as test material,By the end of March to the end of June from sowing test including the long time span of spring and summer.Different sowing date and meteorological conditions on the duration of reproductive period,plant morphological characteristics,dry matter accumulation and translocation,yield and yield components,lodging characteristics,nutrient uptake and utilization on the response of the sowing date,,and provide a theoretical reference for the scientific cultivation of Maize in the Hilly area of central Sichuan Basin.The main results are as follows:1.The total corn growth period was shortened with the delay of sowing time,the regression equation was Y2015=122.15-0.35X(R2=0.966**),Y2016=128.71-0.41X(R2=0.959*),the main period is shortened vegetative growth period and vegetative growth and reproductive phase the remaining period of change is small.Main factors affecting the growth process is the effective accumulated temperature(r=0.774**),significant correlation.2.With the delay of Sowing time,plant height,ear height,height of the center of gravity,stem diameter are first increased and then decreased,The degree of variation was not significant during sowing.Sowing date had a certain effect on Maize Photosynthetic source,the maximum LAI increased and then decreased with the delay of sowing date.Two varieties of dry matter accumulation were all in line with the Logistic function,with the delay of sowing date,two varieties of growth accelerated(T1)and deceleration point(T2)were all in advance,Suitable sowing has a tendency to increase the rapid growth period(T2-T1).With the delay of sowing date,ZH 505 total dry matter accumulation decreased in 2015.In 2016,it first increased and then decreased.The average performance of CD 30 in 2015 and 2016 were first increased and then decreased.Late sowing significantly reduced the dry matter accumulation and accumulation rate of two varieties.The formation of grain requires more dry matter accumulated before and after silking.The total amount of dry matter accumulation was positively correlated with the effective accumulated temperature(r=0.848**)and sunshine hours(r=0.816**)in the growth period,and the correlation with the rainfall was little3.In 2016 due to light more plentiful,high temperature,the yield of two varieties was higher than that of 2015.With the delay of sowing date,in 2015,ZH 505 yield is decreased,in 2016,it first increased and then decreased.To the end of March to mid April is advisable.The CD 30 yield of two years increased first and then decreased with the delay of sowing date.The yield of two varieties of spring sowing was higher than that of summer sowing,especially in late sowing and late sowing in May.The main meteorological factors affecting the yield of two varieties were the effective accumulated temperature and sunshine hours,and there was a very significant positive correlation.The smaller correlation between rainfall and yield.4.With the delay of sowing date,two varieties of internodes length,stem diameter and dry weight of unit length overall showed a trend of first increase and then decrease,The internode length was the longest in May(A4-A5),the stem diameter was the highest(A2)in the middle of April.However,the internode dry weight with the sowing date delay showed a trend of decrease,especially 15 days after silking;the mechanical strength of CD 30 basal internode(RPS,SCS and SBS)is higher than ZH 505,The mechanical strength of internodes of two varieties decreased with the increase of node position,and the sowing date had significant effects on the mechanical strength of the internode,Early sowing is beneficial to enhance the mechanical strength of basal intemodes.The lodging rate of the two varieties increased with the sowing date delayed and then decreased slightly.The lodging rate was significantly negatively correlated with the dry weight of the internode and the SCS of the basal internode.5.There was a two function change between the absorption and utilization of nutrients and the delay of sowing date in the two cultivars.The amount of nutrient accumulation,absorption efficiency,partial productivity and total nitrogen uptake of 100 kg were generally:Under the condition of spring sowing,the use of fertilizer in early sowing was lower,and the delayed application of fertilizer could improve the utilization rate of fertilizer.On the contrary,under the condition of summer sowing,the fertilizer utilization rate of early sowing was higher,and delayed sowing would cause excessive waste of fertilizer.ZH 505 is higher than CD 30.The 1000 grain weight,yield and dry matter accumulation were the main factors affecting the total nutrient accumulation and grain nutrient accumulation,but had no significant effect on the accumulation of non grain fraction.In summary,in view of the unique ecological environment and cultivation model in the Hilly area of central Sichuan Basin,Sowing date significantly affected the growth and development of maize,yield formation,mechanical strength of stems and absorption of N,P and K.In order to achieve the purpose of high yield and high efficiency,the spring sowing should not be too early.It is advisable to postpone the sowing time in mid April.Summer is completed sooner rather than later,as far as possible in the 5 months to complete the sowing.This can ensure that the growth of the corn is suitable for environmental conditions,effectively avoid lodging,to achieve efficient use of fertilizers... |
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