Evaluation of Effect of Nitrogen Topdress Fertilizer Application by Using Chlorophyll Meter on Yield, Yield Components and Growth Indices of Potato

پژوهشهای زراعی ایران

Article 5, Volume 11, Issue 4 - Serial Number 32, January 2014, Pages 573-582   

Document Type: Research Article

DOI: 10.22067/gsc.v11i4.32654

Authors

M. J Arshadi^* ; H. R Khazaei; M Kafi

Abstract

Nitrogen as a essential nutritious element in plant structure has a vital role and among the essential elements for potato (Solanum tuberosum L.( crop growth, nitrogen has the more important role in leaf area increment, shoots growth rate and tuber yield. Therefore, to determine the time and value of supplemental nitrogen fertilizer in different stages of potato crop growth, it is required to use a reliable method to assess the uptakable nitrogen of soil during growth season. So, in order to use chlorophyll meter to identify the required proper time of potato crop to nitrogen fertilizer and increment of nitrogen use efficiency, an experiment was conducted based on randomized complete blocks design with three replications in research field of Ferdowsi University Agricultural College. Nitrogen topdress fertilizer was applied in two levels of 100 and 150 kgN.ha-1 and in two nitrogen indices of 90 and 95 percent. The results indicated that 95 percent nitrogen index versus 90 percent nitrogen index has a better efficiency in increment of potato crop yield. But in 95 percent index, nitrogen fertilizer levels of 100 and 150 kgN.ha-1 did not showed significant difference in tuber yield. Nitrogen indices and nitrogen fertilizer levels did not have significant effect on number of main stems and number of tubers in plant. The percentage of medium and large tubers were increased when the nitrogen fertilizer was increased. Also increment of topdress fertilizer lead to increase dry plant weight, crop growth rate (CGR) and leaf area index (LAI) and decreased net assimilation rate (NAR) and not obvious change in relative growth rate (RGR). In generally it seems that application of nitrogen fertilizer by using chlorophyll meter, in addition to make desirable yield of tuber, leads to economy in nitrogen fertilizers.

Keywords

Nitrogen fertilizer; Yield and yield components of potato; Chlorophyll meter; Growth indices; Nitrogen index