| The northeast region in China is the main production base of maize.Climate indexes such as temperature and precipitation are the key factors determined maize yield.Clarifying the impact of climate on maize yield and modifying the cultivation managements are important to ensure increasing of the yield stably.The experiment was carried out at shengyang city,Liaoning province,in which effective accumulative temperature,correlation between air temperature and soil temperature,and conversion relationship between accumulated air temperature and accumulated temperature were used to analyzes the effect of transparent mulch and black mulch on accumulated temperature and temperature compensation.Based on meteorological data,field crop data,soil data,and field managements data,modified AquaCrop model were used to simulated growth and development for spring maize.Furthermore,to analysis the mechanism of growth process affected by these factors,the cumulative temperature factor replaced time in the Logistic model to simulated cumulative process of biomass and then describe the effect of cultivation managements on accumulation and transformation of biomass.The main conclusions as follows:(1)Daily variation of soil temperature gradually decreased with the increase of the soil depth,and the maximum difference of soil temperature during a day was in 5 cm soil layer.The dynamic of soil temperature in 5 cm soil layer covered by film was similar with that of air temperature.In 2016 and 2017,compared with non-mulching treatment,transparent film and black film accelerate the day with 98%of seedling emergence rate by 5,3 d,and 6,4days,respectively.(2)The relationship between ground temperature and air temperature and the conversion relationship between accumulated air temperature and accumulated temperature were used to improve the temperature module of AquaCrop model.The parameters of the improved AquaCrop model were calibrated and validated by the meteorological,crop,soil,and field management data of 2016 and 2017,and the some parameters of AquaCrop model were adjusted by trial and error method.The results showed that the simulated values of spring canopy cover(CC),biomass grain(BY),soil moisture content in 0~60 cm soil depth,and yield(Y)were basically consistent with the measured values.Additionally,the coefficient of determination(R~2)of CC between the measured values was ranging from 0.72to 0.98,and the R~2 of BY was above 0.94.The root mean square error(RMSE)of the CC and BY was between 8.46~21.58%and 2837.99~5664.49 kg/hm~2,respectively.The model has a good correlation between simulated and measured values of 0~60 cm soil moisture,whose R~2 was 0.63.The relative error(R_e)between simulated and measured values of spring maize yield for two years was both less than 6%.(3)The results of simulation of dry matter accumulation of spring maize in film mulching and planting density based on logistic model showed that there was a good linear relationship between the simulated value of dry matter accumulation and field measured values,with R~2 ranging from 0.97 to 0.98(P<0.01).The order of the influence of various factors on the dynamic process of dry matter accumulation was:year>planting density>mulch film color>mulch film color interacts with density,and the mulching and planting density mainly affect the maximum growth rate of dry matter and the maximum growth rate.The accumulated temperature influenced the maximum dry matter,and the maximum dry matter had the greatest impact on spring maize yield.(4)Film mulching treatment could significantly increase the dry matter accumulation and yield of spring maize;Increasing of planting density could increase dry matter accumulation and stem-leaf dry matter transport.Dry matter of the black film treatment during the growth period was increased by 3.11~6.75%and 10.28~23.08%in these two experimental year,respectively,compared with other treatments.The dry matter of 82500plants/hm~2 was highest at the end of growth stage in 2016.In 2017,compared with 60,000plants/hm~2treatment,the dry matter of 75,000 plants/hm~2treatment increased by 34.94%.However,compared with treatment of 75,000 plants/hm~2,dry matter of 90,000 plants/hm~2decreased by 3.18%.The transport effects of dry matter in different organs of maize were expressed as leaf>stem.Transparent film mulching treatment significantly improved the dry matter transport effect of spring maize.Increasing of planting density increased the transport effect of stem,but it decrease the leaf dry matter transport effect.The yields of combination of black film mulching and 82,500 and black film mulching and 75,000plants/hm~2 were both highest which were 14692.43 and 13211.27 kg/hm~2,respectively.Above all,the adjusted AquaCrop model can better simulate the growth of spring maize in rainfed areas.The establishment of Logistic model revealed the influence mechanism of cultivation management on dry matter accumulation and transportation in maize.This research results can provide a theoretical basis for clarifying the growth dynamics of spring maize and choosing optimal agronomic measures to increase the yield of spring maize in northern regions. |
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