不同水分供应条件下春玉米的适宜播期

Optimal sowing date of spring maize under different water supply conditions

春玉米是半干旱区重要的粮食作物,但该区降水少且年际变异大,春玉米产量低而不稳。适宜播期的选择有利于作物稳产高产,但适宜播期会随水分供应条件的变化而变化。本文以半干旱区主栽春玉米品种‘郑单958’为研究对象,使用APSIM-Maize模型探究该区分期播种试验的适宜间隔以及不同水分供应条件下[雨养、灌溉60 mm、灌溉120 mm、灌溉180 mm、灌溉240 mm、潜在条件(灌溉量308 mm)]春玉米的适宜播期范围。结果表明:1)以不同供水条件下春玉米产量的5%分位为差异阈值划分播期时,该地区春玉米分期播种试验和模拟的时间步长建议设定为4 d;2)雨养条件下,干旱年、正常年和湿润年春玉米平均产量分别为0.9 t·hm^(-2)、2.3 t·hm^(-2)和5.5 t·hm^(-2),平均水分利用效率分别为0.4 kg·m^(-3)、0.7 kg·m^(-3)和1.5 kg·m^(-3),潜在条件、灌溉240 mm、灌溉180 mm、灌溉120 mm、灌溉60 mm和雨养条件下的适宜播期范围分别为5月6日—6月2日、5月6—29日、5月10—29日、5月14—29日、5月14—25日和5月14—17日,适宜播期范围随生育期供水量的增加而提前和扩大;3)潜在条件下春玉米产量的气象决定因子是生育期辐射量,灌溉240 mm和180 mm时产量的气象决定因子分别是营养生长阶段辐射量和降水量,灌溉120 mm和60 mm及雨养条件下的产量决定因子均为生育期降水量。本文探究了春玉米的适宜播期及其随生育期供水量的变化规律,研究结果可为半干旱区春玉米适水播种提供理论参考。

Spring maize is an important food crop in the semi-arid region of northern China.However,owing to the low amount and high interannual and intramonthly variability of precipitation in this region,the yield of spring maize is low and unstable.Selecting a suitable sowing time can help increase the yield and yield stability of spring maize.However,it is difficult to determine the optimal sowing time for spring maize because it changes with the various water supply conditions in this region.To investigate the optimal in-terval of sowing time and optimal sowing time for spring maize in the semi-arid areas of northern China under different water condi-tions,this study used the calibrated and validated APSIM-Maize model to explore the optimal sowing time of spring maize under dif-ferent water supply conditions[rainfed conditions,irrigation of 60 mm,irrigation of 120 mm,irrigation of 180 mm,irrigation of 240 mm,and potential condition(irrigation of 308 mm)]at a typical site in the semi-arid region.The main results of this study are as follows:1)by taking the 5%quantile of spring maize yield as the threshold for yield difference,the optimal time interval of sowing time could be set at four days as a reference for the serial-sowing experiment and simulation of spring maize.2)When spring maize was sown between May 14 and 17,the yield guarantee rates under most water supply conditions were higher than those during the other sowing periods.The optimal sowing time for spring maize was significantly associated with water availability during the growth period.With an increase in irrigation amount,the optimal sowing time for spring maize advanced,and the range of the optimal sow-ing date was extended(rainfed condition:May 14 to 17;irrigation of 60 mm:May 14 to 25;irrigation of 120 mm:May 14 to 29;irri-gation of 180 mm:May 10 to 29;irrigation of 240 mm:May 6 to 29;potential condition:May 6 to June 2).Under rainfed conditions,the mean yields of spring maize in the dry years,normal years,and wet years were 0.9,2.3,and 5.5 t∙hm^(-2),respectively.The spring maize yield within the optimal sowing window under rainfed condition,and 60 mm,120 mm,180 mm,and 240 mm of irrigation and potential condition were 4.0,5.7,6.8,8.6,10.1,and 10.4 t∙hm^(-2),respectively.3)The meteorological determining factor of spring maize yield under the potential condition was the solar radiation during growth period.Under 240 mm and 180 mm of irrigation,the meteorological determining factors of spring maize yields were solar radiation and precipitation during the vegetative growth period of spring maize.The growth period precipitation was the meteorological determining factor of spring maize yield under rainfed condi-tions and irrigation of 120 and 60 mm.Our results revealed the optimal sowing date and its change with the water supply conditions.The results of this study provide a scientific reference for sowing spring maize at a suitable time by considering the water available in the semi-arid region of northern China.