Establishing dynamic thresholds for potato nitrogen status diagnosis with the SPAD chlorophyll meter  

作　　者：ZHENG Hong-li LIU Yan-chun QIN Yong-lin CHEN Yang FAN Ming-shou 

机构地区：[1]College of Agronomy,Inner Mongolia Agricultural University [2]Center of Biotechnology,Chifeng Academy of Agricultural and Animal Husbandry Sciences [3]College of Ecology and Environment Science,Inner Mongolia Agricultural University

出　　处：《Journal of Integrative Agriculture》2015年第1期190-195,共6页农业科学学报（英文版）

基　　金：supported by the National Nature Science Foundation of China (31360502);the Pre-973 Project of China (2012CB126307);the Inner Mongolia Nature Science Foundation, China (2013ZD04)

摘　　要：The hand-held soil plant analysis development （SPAD） chlorophyll meter nitrogen status of the potato and guiding fertilization recommendations N recommendation, it is critical to establish the threshold SPAD value has proved to be a promising tool in evaluating the n the process of N evaluation of potato plants and （SPAD reading）, below which nitrogen supplement is required. And taking convenient using into account, the threshold needs to be dynamic throughout the potato growing season so that the users can test their potato plants and make fertilization decision at any growing time of potato. To complete this goal, field experiments with different nitrogen supply levels were conducted in different sites in northern China from 2009 to 2011. The results showed that threshold SPAD values decrease as the growing season progresses for all cultivars and planting sites. By statistical analysis, the threshold regression models were established respectively as： y=-0.003χ2-0.0507χ＋58.213 （y, threshold SPAD value; χ, days after emergence） for the potato cultivar Kexin 1, and y=-0.003χ2＋0.017χ＋52.489 （y, threshold SPAD value; χ, days after emergence） for the cultivar Shepody, from which, the threshold SPAD value at any day after emergence can be calculated.The hand-held soil plant analysis development （SPAD） chlorophyll meter nitrogen status of the potato and guiding fertilization recommendations N recommendation, it is critical to establish the threshold SPAD value has proved to be a promising tool in evaluating the n the process of N evaluation of potato plants and （SPAD reading）, below which nitrogen supplement is required. And taking convenient using into account, the threshold needs to be dynamic throughout the potato growing season so that the users can test their potato plants and make fertilization decision at any growing time of potato. To complete this goal, field experiments with different nitrogen supply levels were conducted in different sites in northern China from 2009 to 2011. The results showed that threshold SPAD values decrease as the growing season progresses for all cultivars and planting sites. By statistical analysis, the threshold regression models were established respectively as： y=-0.003χ2-0.0507χ＋58.213 （y, threshold SPAD value; χ, days after emergence） for the potato cultivar Kexin 1, and y=-0.003χ2＋0.017χ＋52.489 （y, threshold SPAD value; χ, days after emergence） for the cultivar Shepody, from which, the threshold SPAD value at any day after emergence can be calculated.

关 键 词：DIAGNOSIS dynamic threshold N status POTATO SPAD meter 

分 类 号：S532[农业科学—作物学]