{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,6]],"date-time":"2026-01-06T15:25:46Z","timestamp":1767713146896,"version":"build-2065373602"},"reference-count":56,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2015,1,26]],"date-time":"2015-01-26T00:00:00Z","timestamp":1422230400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Agricultural practices determine the level of food production and, to great extent, the state of the global environment. During the last decades, the indiscriminate recourse to fertilizers as well as the nitrogen losses from land application have been recognized as serious issues of modern agriculture, globally contributing to nitrate pollution. The development of a reliable Near-Infra-Red Spectroscopy (NIRS)-based method, for the simultaneous monitoring of nitrogen and chlorophyll in fresh apple (Malus domestica) leaves, was investigated on a set of 133 samples, with the aim of estimating the nutritional and physiological status of trees, in real time, cheaply and non-destructively. By means of a FT (Fourier Transform)-NIR instrument, Partial Least Squares (PLS) regression models were developed, spanning a concentration range of 0.577%\u20130.817% for the total Kjeldahl nitrogen (TKN) content (R2 = 0.983; SEC = 0.012; SEP = 0.028), and of 1.534\u20132.372 mg\/g for the total chlorophyll content (R2 = 0.941; SEC = 0.132; SEP = 0.162). Chlorophyll-a and chlorophyll-b contents were also evaluated (R2 = 0.913; SEC = 0.076; SEP = 0.101 and  R2 = 0.899; SEC = 0.059; SEP = 0.101, respectively). All calibration models were validated by means of 47 independent samples. The NIR approach allows a rapid evaluation of the nitrogen and chlorophyll contents, and may represent a useful tool for determining nutritional and physiological status of plants, in order to allow a correction of nutrition programs during the season.<\/jats:p>","DOI":"10.3390\/s150202662","type":"journal-article","created":{"date-parts":[[2015,1,26]],"date-time":"2015-01-26T13:26:37Z","timestamp":1422278797000},"page":"2662-2679","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":21,"title":["Development of FT-NIR Models for the Simultaneous Estimation of Chlorophyll and Nitrogen Content in Fresh Apple  (Malus Domestica) Leaves"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9830-7649","authenticated-orcid":false,"given":"Elena","family":"Tamburini","sequence":"first","affiliation":[{"name":"Department of Life Sciences and Biotechnology, University of Ferrara, Via L. Borsari 46,  Ferrara 44121, Italy"}]},{"given":"Giuseppe","family":"Ferrari","sequence":"additional","affiliation":[{"name":"CHI Italia S.r.l., Via Galileo Galilei, 34, Cornaredo (MI) 20010, Italy"}]},{"given":"Maria","family":"Marchetti","sequence":"additional","affiliation":[{"name":"Department of Life Sciences and Biotechnology, University of Ferrara, Via L. Borsari 46,  Ferrara 44121, Italy"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3185-7798","authenticated-orcid":false,"given":"Paola","family":"Pedrini","sequence":"additional","affiliation":[{"name":"Department of Life Sciences and Biotechnology, University of Ferrara, Via L. Borsari 46,  Ferrara 44121, Italy"}]},{"given":"Sergio","family":"Ferro","sequence":"additional","affiliation":[{"name":"Department of Chemical and Pharmaceutical Sciences, University of Ferrara,  Via Fossato di Mortara, 17-27, Ferrara 44121, Italy"}]}],"member":"1968","published-online":{"date-parts":[[2015,1,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"401","DOI":"10.17660\/ActaHortic.1995.383.43","article-title":"Nitrogen fertilization in apple orchards\u2014Relationships between available nitrogen in soil samples, nitrates in water and leaching of nitrogen","volume":"383","author":"Rupp","year":"1995","journal-title":"Acta Hortic."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Fragoso, M.A.C., van Beusichem, M.L., and Houvers, A. (1993). 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