RELATIONSHIP BETWEEN NITROGEN LEVEL AND CHLOROPHYLL CONTENT AS AFFECTED BY GROWTH STAGE IN POTATO UNDER RAINFED CONDITIONS OF HIMACHAL PRADESH

Abstract

ABSTRACT: A field experiment was conducted for two consecutive years to study the relationship of chlorophyll content chlorophyll concentration index (CCI) of the potato leaf measured using hand-held chlorophyll meter with nitrogen content of the leaf and potato tuber yield as affected by crop growth duration and nitrogen levels. The results revealed that a significant and positive relationship existed between nitrogen application rate and leaf chlorophyll content upto 3 to 4 weeks after application of nitrogen. The relationship between leaf N concentration and CCI was positive and significant correlated up to one to one and a half months after the application of second split dose of N to potato. Thus CCI can be used as an indicator of nitrogen content of leaf at least upto a month after the application of N, which is sufficient to take a decision about application of nitrogen to potato as a mid-term correction to meet its requirement. It was also concluded from the study that the association of leaf N and CCI is a function of the sampling stage as such the absolute CCI value alone can not be considered for working out nitrogen needs as it varies greatly from year to year in rainfed crop.