Analysis Of Suitable Sowing Date Of Spring Maize In Northern Xinjiang Based On Both APSIM Model And Field Sowing Date Experiment

?Objective?In this study,the optimal sowing date of spring maize was analyzed by APSIM model and field sowing experiment in medium-late maturing maize area of Xinjiang province.The suitable sowing date of maize production process can increase the utilization efficiency of solar and heat resources to reach high and stable yield and avoid the risks of low-temperature that caused by early sowing or late ones.This research promote the application of APSIM model in maize production and provide provides theoretical base for the high yield and efficiency in Xinjiang province.?Method?This study focused on the maize hybrid of KWS9384 with the plant density of 9×10~4 plants /hm~2.The high-yield potential experiment were conducted from 2015 to 2017 at Qitai Farm,Qitai 108 Corp and Gongqingtuan Farm.In 2017,the five sowing dates experiment were conducted in Qitai Farm,which were April 20,April 27,May 5,May 13 and May 20 respectively.In this study we explored the effects of sowing date on maize growth and development,morphology characteristics of plant,dry matter accumulation,yield,the demand of active accumulated temperature and the meteorological factors of different growth stage.Based on the data of high-yield experiment and sowing date experiment,using APSIM model with 2 days as sowing step simulated the yield under a series of treatments.The less variable time period with highest yield were the suitable sowing date for maize.?Result?(1)Sowing date was significantly affected the growth duration of maize,especially from sowing to emergence.Compared to the treatment of SD1,the duration of SD2-SD5 shortened by 1-9d.the anthesis-silking interval of maize population were extended with the delayed sowing date.SD1-SD3 can complete physiological maturity,and the growth period were 129d,126d,129d respectively,but the SD4and SD5 cannot reach maturity.(2)With the delayed sowing date,the plant height,ear height and ear height coefficient of maize increased gradually,resulting in the higher risk of lodging rate.Early sowing or late ones have negative impact on dry matter accumulation.Source and sink traits all affected by sowing date,the shortage of sink number is the key factor to limit the increase of yield with postponing sowing date.The maize yield increased first and then decreased with the delaying of sowing date.The treatment of the SD3 got the highest grain yield,peaking at 15784.2 kg/ha,and the yield of SD1-SD3 have no significant difference.Compared to SD3,the yield of SD4 and SD5 decreased by 15.3%and 24.8%.In this study,the decreased of grain yield mainly led by the reduction of grains per ear.(3)The different sowing date can regulate the average daily sunshine duration,active accumulated temperature and temperature in maize growth duration,therefore they influence maize growth and yield.The demand of GDD and?10?accumulated temperature of maize each growth duration is stable.Few days of extreme high temperatures in this region.There is no significant difference in GDD and accumulated temperature between different growth stages of maize.That also indicated that the period of extremely high temperature were short in this region.(4)These results indicated that APSIM model performed well in simulating phenology and yield of maize in Xinjiang province.In the sowing date experiments,there were a quadratic curve relationship between maize sowing date and grain yield(R~2=0.85),the regression equation reached significant level at 0.01,the extreme value of the regression equation got from the simulation results of sowing on April 30.Compared to the field sowing date experiment the durations from sowing to emergence based on APSIM model were relatively short,after emergence the simulated and measured value of maize growth durations shown good consistently.Accordance with the suitable sowing date from April 28 to May 12,the emergence time were from May 3 to May 17,based on APSIM model.According to the field sowing date experiment,the suitable emergence time from May 5 to May 14 can obtain the high maize yield,which fairly near the results simulated by APSIM model.Based on both APSIM model and field sowing date experiment,the optimum sowing date of medium-late maturing maize in spring in Xinjiang province was from April 20th to May 5th.?Conclusion?Sowing in the suitable period was a good way to increase the utilization efficiency of solar and heat resources,coordinate the growth and development of maize population,avoid the negative effect of adverse climate factor,and achieve high-stable yield of maize.This study combined APSIM model and field sowing date experiment,the results indicated that the optimum sowing date of medium-late maturing maize in spring in Xinjiang province was from April 20 to May 5.This research can provide some reference and scientific basis for integrated analysis of field experiment and APSIM model simulation.This also can analyze optimum sowing date in different regions,which provide feasible method approach to future research.