内蒙古地区甜菜临界氮浓度稀释模型的构建及应用

Construction and application of the critical nitrogen concentration dilution model of sugar beet in Inner Mongolia,China

甜菜是我国两大主要糖料作物之一,然而氮素过量或者不足不仅会影响甜菜产量和含糖量,而且过量的氮素还会造成一定的环境风险,如何判别甜菜的氮素营养在一个合理的范围对于保障甜菜产量、品质和减少环境风险具有重要意义。临界氮浓度稀释曲线是作物氮素营养诊断的基础,本研究的主要目的是构建我国甜菜临界氮浓度稀释曲线模型,并利用相应的氮素营养指数进行甜菜氮素营养诊断。研究于2017—2018年在内蒙古呼和浩特市和赤峰市进行了2个甜菜品种、不同施氮量的田间试验。在甜菜的苗期、叶丛生长期、块根膨大期、糖分积累期和收获期5个关键时期进行地上部叶片和地下部块根取样测定生物量和氮浓度,并计算出甜菜全株生物量和全株氮浓度。根据全株生物量和全株氮浓度建立临界氮浓度稀释模型和相应的氮素营养指数。结果表明,甜菜地上部生物量和地上部氮浓度以及全株生物量和全株氮浓度都是随着生育时期的推进呈现出负幂函数关系,基于地上部生物量和地上部氮浓度建立的临界氮浓度稀释曲线决定系数平均在0.45,而以全株生物量和全株氮浓度建立临界氮浓度稀释曲线决定系数平均在0.94,较前者有显著提高。以全株生物量和全株氮浓度建立临界氮浓度稀释模型更为合理,且受品种影响较小,甜菜品种KWS9167和KWS1676的共用临界氮浓度稀释曲线决定系数达0.94,构建的氮素营养模型可以进行甜菜氮素营养诊断。我国北方地区主要甜菜品种临界氮浓度稀释模型为Nc=4.23W–0.49,基于该模型计算的KWS9167和KWS1676合理施氮量分别为160 kg N hm^(–2)和180 kg N hm^(–2)左右。

Sugar beet is one of the two major sugar crops in China.However,both nitrogen sufficiency and deficiency will affect the yield and sugar content in sugar beet,and excessive nitrogen will cause environmental risks.Judging nitrogen nutrition of sugar beet in a reasonable range is of great significance for ensuring the yield,quality and reducing environmental risks of sugar beet.The critical nitrogen concentration dilution curve is the basis of crop nitrogen nutrition diagnosis.The objective of this present study was establishing the dilution curve model of the critical nitrogen concentration of sugar beet in China and to diagnose the nitrogen nutrition of sugar beet by using the corresponding nitrogen nutrient index.Four experiments with different N rates for two cultivars of sugar beet were conducted in Inner Mongolia from 2017 to 2018.The above-ground biomass and under-ground tubers were sampled and their nitrogen concentration was determined at seedling,leaf cluster growth,tuber bulking,sugar accumulation,and harvest stages.The total plant biomass and nitrogen concentration were calculated.Based on the calculation,the critical nitrogen concentration dilution model and the corresponding nitrogen nutrient index were established.The results indicated that the negative power relationship between the above-ground biomass and nitrogen concentration was observed.The determination coefficient(R2) for the relationship was 0.45 on average.The R2 for the negative power relationship between total plant biomass and nitrogen concentration was 0.94 on average,which was higher than the relationship between the above-ground biomass and nitrogen concentration.It was more reasonable to establish a critical nitrogen concentration dilution model based on the total plant biomass and nitrogen concentration,which was less affected by the cultivars.The R2 for the integrated critical nitrogen concentration dilution curve of sugar beet varieties KWS9167 and KWS1676 reached 0.94.The constructed nitrogen nutrition model can be used to estimate the plant nitrogen status in sugar beet.The critical nitrogen concentration dilution model for the main sugar beet varieties in Northern China was Nc = 4.23 W–0.49.The optimized nitrogen rate of KWS9167 and KWS1676 based on the model was about 160 kg hm^(-2) and 180 kg hm^(-2),respectively.