{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,18]],"date-time":"2026-03-18T02:27:12Z","timestamp":1773800832366,"version":"3.50.1"},"reference-count":45,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2016,11,24]],"date-time":"2016-11-24T00:00:00Z","timestamp":1479945600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004837","name":"Spanish Ministry of Science and Innovation","doi-asserted-by":"publisher","award":["AGL2012-35122"],"award-info":[{"award-number":["AGL2012-35122"]}],"id":[{"id":"10.13039\/501100004837","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The growing use of commercial unmanned aerial vehicles (UAV) and the need to adjust N fertilization rates in maize (Zea mays L.) currently constitute a key research issue. In this study, different multispectral vegetation indices (green-band and red-band based indices), SPAD and crop height (derived from a multispectral compact camera mounted on a UAV) were analysed to predict grain yield and determine whether an additional sidedress application of N fertilizer was required just before flowering. Seven different inorganic N rates (0, 100, 150, 200, 250, 300, 400 kg\u00b7N\u00b7ha\u22121), two different pig slurry manure rates (Ps) (150 or 250 kg\u00b7N\u00b7ha\u22121) and four different inorganic-organic N combinations (N100Ps150, N100Ps250, N200Ps150, N200Ps250) were applied to maize experimental plots. The spectral index that best explained final grain yield for the N treatments was the Wide Dynamic Range Vegetation Index (WDRVI). It identified a key threshold above\/below 250\u2013300 kg\u00b7N\u00b7ha\u22121. WDRVI, NDVI and crop height showed no significant response to extra N application at the economic optimum rate of fertilization (239.8 kg\u00b7N\u00b7ha\u22121), for which a grain yield of 16.12 Mg\u00b7ha\u22121 was obtained. This demonstrates their potential as yield predictors at V12 stage. Finally, a ranking of different vegetation indices and crop height is proposed to overcome the uncertainty associated with basing decisions on a single index.<\/jats:p>","DOI":"10.3390\/rs8120973","type":"journal-article","created":{"date-parts":[[2016,11,24]],"date-time":"2016-11-24T10:19:15Z","timestamp":1479982755000},"page":"973","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":176,"title":["Analysis of Vegetation Indices to Determine Nitrogen Application and Yield Prediction in Maize (Zea mays L.) from a Standard UAV Service"],"prefix":"10.3390","volume":"8","author":[{"given":"\u00c1ngel","family":"Maresma","sequence":"first","affiliation":[{"name":"Department of Field Crops and Forest Science, Agrotecnio Center, University of Lleida, Av. Rovira Roure 191, Lleida 25198, Spain"}]},{"given":"Mar","family":"Ariza","sequence":"additional","affiliation":[{"name":"Research Group in AgroICT and Precision Agriculture, Agrotecnio Center, University of Lleida, Av. Rovira Roure 191, Lleida 25198, Spain"}]},{"given":"El\u00edas","family":"Mart\u00ednez","sequence":"additional","affiliation":[{"name":"Department of Field Crops and Forest Science, Agrotecnio Center, University of Lleida, Av. Rovira Roure 191, Lleida 25198, Spain"}]},{"given":"Jaume","family":"Lloveras","sequence":"additional","affiliation":[{"name":"Department of Field Crops and Forest Science, Agrotecnio Center, University of Lleida, Av. Rovira Roure 191, Lleida 25198, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1480-3632","authenticated-orcid":false,"given":"Jos\u00e9","family":"Mart\u00ednez-Casasnovas","sequence":"additional","affiliation":[{"name":"Research Group in AgroICT and Precision Agriculture, Agrotecnio Center, University of Lleida, Av. Rovira Roure 191, Lleida 25198, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2016,11,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"984","DOI":"10.2134\/agronj1982.00021962007400060013x","article-title":"Fifty years of Minnesota corn production: Sources of yield increase","volume":"74","author":"Cardwell","year":"1982","journal-title":"Agron. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"543","DOI":"10.2134\/agronj2007.0280","article-title":"Corn grain yield response to crop rotation and nitrogen over 35 years","volume":"100","author":"Stanger","year":"2008","journal-title":"Agron. J."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"635","DOI":"10.1016\/j.eja.2008.01.010","article-title":"Fertilisation of irrigated maize with pig slurry combined with mineral nitrogen","volume":"28","author":"Berenguer","year":"2008","journal-title":"Eur. J. 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