Chlorophyll meter-based leaf nitrogen status to manage nitrogen in tropical potato production

Autor(es)

Fernandes, Fabiana M. ^[1] ; Soratto, Rogerio P. ^{[2, 1]} ; Fernandes, Adalton M. ^[2] ; Souza, Emerson F. C. ^[3]

Afiliação do(s) autor(es)

^[1] Sao Paulo State Univ UNESP, Coll Agr Sci, Dept Crop Sci, Ave Univ, 3780, BR-18610034 Botucatu, SP - Brazil

^[2] Sao Paulo State Univ UNESP, Ctr Trop Roots & Starches, Botucatu, SP - Brazil

^[3] Univ Minnesota, Dept Soil Water & Climate, St Paul, MN 55108 - USA

• Tipo de documento: Artigo Científico
• Fonte: AGRONOMY JOURNAL; v. 113, n. 2 MAR 2021.
• Citações Web of Science: 0

Resumo

Potato (Solanum tuberosum L.) is a N intensive crop, and meeting its requirements with N fertilization is the primary practice to improve N recovery and achieve suitable tuber yield. A 3-site-year (SY) study was conducted to assess soil plant analysis development (SPAD)-502 chlorophyll meter efficacy for providing potato leaf real-time N status to adjust N timing and rate using nitrogen sufficiency index (NSI) thresholds of 90 or 95%. We evaluated effects of in-season SPAD-based N managements, as well as a reference with non-limiting N application, a fixed-timing (planting and hilling) conventional N fertilization, and a zero-N control on crop N uptake, tuber yield, and N-use efficiency of potato cultivar Agata grown in tropical clay soils. Tuber yields were similar in both SPAD-based managements. Under no intensive rainfall events after N applications, SPAD-based managements reduced N applications by 38-63% and resulted in comparable tuber set, bulking, and yield relative to conventional N fertilization. Additionally, SPAD-based management at a NSI threshold of 90% resulted in greater potato N-uptake efficiency and tuber yield per unit of N applied. SPAD-502 sensor was efficient for detecting plant N status when environmental conditions were more conducive for potato production and optimized N management by reducing application rates. However, with less favorable temperature and solar radiation for potato cultivation, and with intensive rainfall events following N application, SPAD readings did not guide to a proper N fertilization and resulted in reduced tuber yield. Therefore, under such conditions, a more accurate method for detecting plant N status should be used. (AU)

• Processo FAPESP: 16/15396-5 - Técnicas para o monitoramento da nutrição nitrogenada e estimativa da necessidade de nitrogênio na cultura da batata
• Beneficiário: Rogério Peres Soratto
• Modalidade de apoio: Bolsas no Exterior - Pesquisa