Differences in Physiological Age Affect Diagnosis of Nitrogen Deficiencies in Cornfields  

作　　者：J. ZHANG A. M. BLACKMER T. M. BLACKMER 

机构地区：[1]Statistical Consulting Center, Wright State University, 3640 Colonel Glenn Highway, Dayton, Ohio 45435 （USA）. [2]Department of Agronomy, Iowa State University, Ames, Iowa 50011 （USA） [3]Iowa Soybean Association, 4554 114th Street, Urbandale, Iowa 50322 （USA）

出　　处：《Pedosphere》2008年第5期545-553,共9页土壤圈（英文版）

基　　金：the Iowa Soybean Association, USA through the ISA On-Farm NetworkTM and Watershed Programming.

摘　　要：Many studies have shown that chlorophyll meter readings （CMRs） can be used to diagnose deficiencies of nitrogen （N） during the growth of corn （Zea mays L.） in small-plot trials, but there is need to address additional problems encountered when diagnoses are made in fields of the size managed in production agriculture. A noteworthy difference between smallplot trials and production agriculture is the extent to which the effects of N are confounded with the effects of other factors such as tillage, landscape, soil organic matter and moisture content. We illustrate how some of these factors can cause differences in the physiological age of plants and introduce errors in the diagnoses of N deficiencies. We suggest methods （measuring the height to the youngest leaf collar and assigning leaf numbers by using the first leaf with pubescence and the ear leaf as references to identify growth stages） for minimizing these errors. The simplified method of growth stage identification can be used to select appropriate plants and leaves for making diagnoses in fields and to distinguish the effects of N from the effects of other factors that influence plant growth.Many studies have shown that chlorophyll meter readings(CMRs) can be used to diagnose deficiencies of nitrogen(N) during the growth of corn(Zea mays L.) in small-plot trials,but there is need to address additional problems encountered when diagnoses are made in fields of the size managed in production agriculture. A noteworthy difference between smallplot trials and production agriculture is the extent to which the effects of N are confounded with the effects of other factors such as tillage,landscape,soil organic matter and moisture content. We illustrate how some of these factors can cause differences in the physiological age of plants and introduce errors in the diagnoses of N deficiencies. We suggest methods(measuring the height to the youngest leaf collar and assigning leaf numbers by using the first leaf with pubescence and the ear leaf as references to identify growth stages) for minimizing these errors. The simplified method of growth stage identification can be used to select appropriate plants and leaves for making diagnoses in fields and to distinguish the effects of N from the effects of other factors that infiuence plant growth.

关 键 词：CHLOROPHYLL corn （Zea mays L.） nitrogen deficiency physiological age 

分 类 号：S513[农业科学—作物学]