Effects Of Different Water Treatments On Growth And Development Of Spring Wheat In Dryland Based On APSIM Model

The Loess Plateau is one of the most serious soil erosion regions in the world.This area is located in arid and semi-arid area.The crop yield is low and extremely unstable for a long time.In the face of the problems of agricultural ecological environment deterioration and water shortage,crop production assessment is needed to take appropriate measures to improve crop yield.After the localization of the parameters is corrected,the APSIM model can be used to predict and evaluate crop production in the Loess Plateau.A field plot experiment was carried out in anjiapo village,Dingxi,Gansu province.Taking "Dingxi 42" spring wheat as the research object,150kg/hm perphosphate diphosphate and 62.5kg/hm urea(including N46.5%)were applied as base fertilizer,and the whole growth period was divided into 6 stages(tillering stage,jointing stage,booting stage,flowering period,filling period and grain filling period).At maturity),5 different water gradients were set up: control CK(0mm),W1(50mm),W2(100mm),W3(150mm),W4(200mm).All the water gradients were divided on average three times in the tillering period(May 8th),jointing stage(June 7th),and flowering period(June 28th),using APSIM model model.Effects of different moisture treatments on growth and development of spring wheat in dryland were studied under different water gradients.The main conclusions are as follows:(1)APSIM model can simulate more accurately the growth and development of spring wheat under different water treatments.The simulation values of plant height,leaf area index(LAI),yield and its components and aboveground biomass of spring wheat in dry land are close to the 1:1 line,the correlation coefficient R is more than 0.9,the normalized mean square root error(NRMSE)is less than 10%,and the model validity parameter(ME)is more than 0.5.(2)The simulation results of spring wheat plant height in dry land under different water treatments showed that the height of wheat plant height increased with the increase of irrigation.The average plant height treated by W1,W2,W3 and W4 was 12.11%,19.05%,22.86% and 26.42% higher than that of CK respectively.The growth rate was "slow fast slow",and the growth rate was the highest in the booting and flowering period.Big.(3)The simulation results of leaf area index of spring wheat in dry land under different water treatments showed that the leaf area index of Dryland Spring Wheat under different water treatments was the same in the growth period,and all of them increased first and then decreased,and reached the maximum at the booting stage.Except for tillering stage,the effects of different treatments on spring wheat LAI were significant at the other growth stages,all of which were W4>W3>W2>W1>CK.(4)The simulated results of the aboveground biomass of dry land spring wheat under different water treatments showed that the trend of aboveground biomass of each treatment was "S",and the accumulation amount reached the peak in the mature period.The aboveground biomass of wheat at maturity stage was W3>W4>W2>W1>CK,and W3 treatment was the most suitable for the accumulation of aboveground biomass.With the advance of growth period,the accumulation rate showed a trend of "slow fast slow",and the accumulation rate reached its peak at flowering stage.(5)The effects of different water treatments on dry wheat yield,grain number per spike and 1000 grain weight were significant(p<0.05),but no significant effect on panicle number(p>0.05).The yield of wheat treated by W3 was the highest.The effects of different treatments on wheat yield were as follows: W3>W4>W2>W1>CK,CK,W1,W2,W3 treatment had significant effect on wheat yield(p<0.05),W3 and W4 treatment had no significant effect on wheat yield(p>0.05).(6)In the range of 0~200mm test,the irrigation amount in the whole growth period was positively correlated with the growth index of wheat(plant height,leaf area index,biomass)and yield formation,and the irrigation amount had a significant effect on the growth of wheat in the study area.The effects of wheat plant height,biomass,yield and irrigation amount are two parabola of opening downward.The threshold is 179.42 mm,148.87 mm,172.04 mm,and the effect of leaf area index and irrigation amount is increasing linearly.The direct path coefficients of wheat yield components and wheat yield are as follows: the number of spikes(0.954)> grain number(0.312)> 1000 grain weight(0.218).The spike number has a negative effect on the yield of wheat indirectly through the number of spikes,and the number of spikes can produce a negative effect on the yield of wheat indirectly through the number of spikes,and the other factors have an indirect effect on the yield of wheat.The use is positive effect.