不同有机肥氮替代化肥氮比例对马铃薯根系吸收能力和形态的影响

针对甘肃定西地区马铃薯生产长期大量施用化肥造成马铃薯产量降低、品质下降以及环境污染等问题,通过大田试验,研究了不同有机肥氮替代化肥氮比例处理对旱地覆膜马铃薯根系吸收能力和形态的影响。结果表明: 不同施用量有机肥氮替代化肥氮处理显著增加了马铃薯根系活力、活跃吸收面积和总吸收面积,且随着替代比例的增加逐渐增加,在有机肥氮替代化肥氮比例达到30%时达到最大值,而后降低;不同施用量有机肥氮替代化肥氮处理对马铃薯根系总根长、根体积、总根尖数和主根直径有显著影响,特别是增加了0~0.50、0.51~1.00和1.01~1.50mm直径范围内马铃薯根系的总根长;施用有机肥的处理显著增加了马铃薯块茎产量,与纯施化肥相比分别提高了11.32%、16.04%、23.53%和12.69%。综上所述,在定西地区,施氮量为纯氮180kg/hm²,氮、磷、钾配比为4:3:3（N:P₂O₅:K₂O）,有机肥氮替代化肥氮比例为30%是最佳施肥模式。

Effects of Different Ratio of Organic Fertilizer Nitrogen to Fertilizer Nitrogen on the Absorption Capacity and Morphology of Potato Roots

Focusing on the problems of long-term large-scale application of chemical fertilizers in potato production in Dingxi region, which caused potato yield reduction, quality decline and environmental pollution, the effects of different ratio of organic nitrogen fertilizer to chemical nitrogen fertilizer on the root absorption capacity and morphology of potato mulching in dryland were studied through field experiments. The results showed that different ratio of organic nitrogen fertilizer to chemical nitrogen fertilizer significantly increased potato root activity, active absorption area & total absorption area and gradually increased with the increase of substitution ratio reaching the maximum value when the ratio of organic nitrogen fertilizer to chemical nitrogen fertilizer reached 30%, and then decreased; different ratios of organic nitrogen fertilizer to chemical fertilizer nitrogen had significant effects on the total root length, root volume, the number of root tips and main root diameter of potato, especially increasing the total root length of potato within the diameter ranges of 0-0.50, 0.51-1.00 and 1.01-1.50mm; the application of organic fertilizer significantly increased the tuber yield of potato. Compared with the pure fertilizer treatment, the tuber yield of treatment increased by 11.32%, 16.04%, 23.53% and 12.69%. To sum up, in Dingxi area, the nitrogen application amount is 180kg/ha, the ratio of nitrogen, phosphorus and potassium is 4:3:3 (N:P₂O₅:K₂O), and the ratio of organic fertilizer nitrogen to fertilizer nitrogen is 30%.