National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
Fertilizer N management using optical sensor (GreenSeeker®) was evaluated at CCSHAU, Hisar. The experiment was laid out in randomized block design with three replications. There were 12 treatments comprising N application with and without using GreenSeeker. N application without using GreenSeeker consisted of two treatments having recommended dose (150 kg/ha) in two (75 kg/ha each) and three (50 kg/ha each) equal splits. GreenSeeker guided N application was combined with fixed rate (75, 100 and 125 kg/ha) and fixed time N application (nine treatments) as basal and at 25 DAS. GreenSeeker was used with each fixed level of N application at 2nd (50 DAS) and/or 3rd irrigation (65 DAS). One treatment was control where no fertilizer N was applied. During the procedure of finding out fertilizer N requirement using GreenSeeker, NDVI values and related parameters were calculated and analyzed. In general, NDVI values were higher in treatment having higher dose of fixed rate N at planting and CRI stage. At 65 DAS (3rd irrigation) the increase in NDVI values was more in treatment having N application at 50 DAS (2nd irrigation) with or without using GreenSeeker and it ranged from 11.7 to 22.2% as compared to treatment having no N application at 2nd irrigation where it was only 2.6 to 9.1%. Responsiveness of a particular treatment to further addition of applied fertilizer i.e. Response index (RINDVI) values were inversely proportional to amount of fixed rate N application. RINDVI values remained low throughout the crop growth stages where frequency of N application was higher. Total N uptake and NDVI values were highly correlated and values of coefficient of determination were higher at middle crop growth stages as compared to early and late stages.
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