基于Richards模型研究不同水氮水平对向日葵干物质积累与产量的影响

Effect of Irrigation and Fertilization on Dry Matter Accumulation and Yield of Sunflower Modelled with the Richards’Equation

【目的】揭示灌水施氮对向日葵生长的调控作用和产量形成与干物质积累的定量关系。【方法】2021年在北方农牧交错带内蒙古阴山北麓武川旱作区以食用向日葵(龙葵27)为研究对象,采用裂区试验设计,主因素为3种灌溉模式:不灌雨养W0(覆膜种植,播后保苗水300 m^(3)/hm^(2))、补水灌溉W1(覆膜种植,生育期总灌水量为900 m^(3)/hm^(2),播后保苗水300 m^(3)/hm^(2),苗期300 m^(3)/hm^(2),现蕾期300 m^(3)/hm^(2))和正常灌溉W2(覆膜种植,生育期总灌水量为1500m^(3)/hm^(2),播后保苗水300 m^(3)/hm^(2),苗期300 m^(3)/hm^(2),现蕾期300 m^(3)/hm^(2),花期300 m^(3)/hm^(2),灌浆期300 m^(3)/hm^(2))。副因素为3个施氮水平:0、135 kg/hm^(2)和270 kg/hm^(2),表示为N0、NE和NF。采用Richards方程定量分析了不同水氮组合下干物质积累动态变化过程以及对产量的影响。【结果】研究发现Richards方程可以较为准确地拟合向日葵地上部干物质积累;优化施氮使干物质积累更早地进入快增期,但是过量的施氮反而会延后进入快增期并且过早结束快增期,从而使快增期持续时间缩短。较不灌水的处理,苗期和现蕾期的灌水会延后进入快增期,但使干物质积累速度更快,而花期和灌浆期的灌水使快增期结束的时间更晚;水氮调控地上部干物质积累进而提高产量的决策:首要考虑通过更好的水氮调控措施来提高最大干物质积累速率,然后再考虑协调最大干物质积累速率达到峰值的时间与快增期结束时间的矛盾,以使更早达到最大干物质积累速率,更晚结束快增期。【结论】Richards模型可以较为准确的模拟向日葵地上部干物质积累的动态过程,为作物在灌溉条件下的动态生长模拟提供理论依据,过量施氮会使干物质积累快增期的时间缩短,灌水会提高干物质的积累速率。

【Objective】Soil water and nitrogen are the most important abiotic factors influencing plant growth and final yields.This paper aims to investigate the applicability of the Richards'equation for modeling growth,dry matter accumulation and yield formation of sunflower under different fertilizations and irrigations.【Method】The field experiment was conducted in 2021 in a dry area in the northern foot of Yinshan Mountain,Inner Mongolia.The variety Long Kui 27 used as the model plant;the field was mulched by plastic films.The split-plot experiment had three irrigation treatments:rain-fed plus irrigating 300 m^(3)/hm^(2)of water just after the drilling to ensure seed germination(W1),replenishing irrigation by irrigating 900 m^(3)/hm^(2)of water at seedling and budding stage,following the 300 m^(3)/hm^(2)of pro-drilling irrigation(W2),and normal irrigation by irrigating a total 1500 m^(3)/hm^(2)of water at seedling,budding,flowering,and grain filling stages,respectively.In each irrigation treatment,there were three nitrogen fertilizations:0(N0),135(N1)and 270 kg/hm^(2)(N)For each treat ent,we used the Richards’odel to quantitatively analyze the changes in dry matter accumulation(DMA)and the impact of fertilization and irrigation on yield and yield formation.【Result】The Richards model was able to describe the dynamics of DMA.The impact of water and nitrogen on DMA and sunflower yield was obtained by the path analysis and the decision coefficient calculation.Optimized fertilization made the period of quick increase in DMA occur early,while excessive fertilization not only delayed the start of the quick increase in DMA but also shortened its duration.It was found that nitrogen application expedited the occurrence of the quick dry matter accumulation period,compared to no nitrogen application,while excessive nitrogen application not only brought the rapid growth period ending earlier,but also shortened it.Irrigation in the early growth stage delayed the onset of the rapid growth but increased the dry matter accumulation rate.In contrast,irrigation in the late growth stage delayed the end of the rapid growth period.【Conclusion】Our results provide guidance for optimal regulation of irrigation and fertilization to achieve high yield and improve water and nitrogen use efficiency of sunflower production in arid areas.