基于临界氮浓度稀释模型的棉花开花后氮动态需求定量诊断研究

在大田栽培条件下,于江苏南京(长江中下游棉区)和河南安阳(黄淮棉区)设置棉花氮素水平试验,依据Justes的临界氮浓度稀释曲线确定方法,确立了开花后棉花地上干物质临界氮浓度稀释模型,以此为基础,建立了棉花开花后动态氮吸收、累积、临界需求量及氮累积亏缺的定量诊断模型。结果表明,安阳、南京2试点的棉株地上干物质氮浓度均随施氮水平的提高而增加,随开花后棉花生育进程的延后而降低,安阳试点不同施氮水平间棉株地上干物质氮浓度值的差值明显小于南京。临界氮浓度稀释模型为CNFNC=aⅹDM_M^-b(安阳:a=3.837,b=0.131,南京:a=2.858,b=0.131),参数a的差异表明在达到同样的生物量条件下,安阳试点的氮吸收能力大于南京。棉花开花后动态氮吸收速率、累积、临界需求量及氮累积适宜度的定量诊断模型可精确定量描述不同施氮水平棉花从开花至吐絮以日为时间步长的干物质增长速率、氮吸收速率、氮累积量。施氮水平对地上干物质瞬时增长速率有较大影响,施氮水平过低或过高时其增长速率均下降。棉株日氮吸收量和总氮累积量均随施氮量的增加而增加,但棉株对氮的容纳有一定的限度。通过对比2试点氮累积量与临界需氮量差值的动态变化,认为安阳试...

Mathematical Model of Quantitative Diagnosis on Dynamic Nitrogen Demand of Cotton after Anthesis Based on Critical Nitrogen Concentration Diluation Model

The critical nitrogen concentration of a plant can be defined as the minimum nitrogen concentration required for maximum biomass grown at any time. The critical nitrogen concentration dilution curve can be described by the power equationCN_EN=a×DM^-b_M , FN_C=aⅹDM^-b_M,where CN_FNC(%) is the total nitrogen concentration in the aboveground dry matter,DM_M is the aboveground biomass(mg·ha^-1,a represents the nitrogen concentration in aboveground dry biomass when DM_M =1 mg·ha^-1 and b is a statistical parameter g...