Abstract

                                Nutrients are essential for the growth of plants, and they also increase the yield. Among the major nutrients, nitrogen is the most important nutrient for crop growth. The current study aims to estimatechlorophyll content vis-a-vis nitrogen content using different techniquesand attempts to establish comparative benefits among available techniques. Maize crop,being highly known for fertilizer responsiveness, was chosen to carry out experiments with different levels of nitrogenous fertilizers. A preliminary field survey was taken in the farmer's field in Coimbatore and Salem districts. Two field experiments and one pot culture experiment at different doses of nitrogen input were conductedin 2019, 2020, and 2021 in the Department of Nano science and Technology at Tamil Nadu Agricultural University. In this study conventional nitrogen was applied with various dosage viz.,0kgha-1(T1), 50kgha-1(T2), 100kgha-1(T3), 150kgha-1(T4), 200kgha-1(T5), 250kgha-1(T6), 300kgha-1(T7). In the pot culture experiment, IFFCO Nano nitrogen was sprayed on the maize leaves with seven different doses, which were control (no spray) (T1),conventional nitrogen (T2), 0.5X RDF(Recommended Dose of Fertilizer) (T3), 1.0X RDF (T4), 1.5X RDF (T5), 2.0X RDF (T6), 2.5X RDF (T7). The chlorophyll contentin all the trials wasestimated using Dimethylsulfoxide(DMSO), a portable in-house developed nutrient meter, and Spectroradio meter method.Chlorophyll content was measured at two different growth stages of maize viz., 60 & 90 days after sowing.The total nitrogen was analyzed using Kjeldahl method in the maize leaf.Among the treatments, with different doses of nitrogen levels, 300kgha-1 RDN & 2.5X RDF (T7) recorded higher SPAD (Soil Plant Analysis Development) values, chlorophyll “a” and chlorophyll “b” content and total nitrogen content at 60 DAS (Days After Sowing) in all tested methods.Chlorophyll and total nitrogen content weresignificantly decreased in later days. In a stressed environment withno nitrogen (T1)applied condition,the chlorophyll and nitrogen content showed significantly lower levels.

Key words : Nitrogen; Chlorophyll; Spectral values; SAPD values; DMSO method