Van Evert, FritsCoelho, José Paulo Pimentel de CastroGonçalves, Júlia Alves Roque2021-05-142021-05-142019Gonçalves, J.A.R. - Yield gap explaining factors and solutions to improve yields in a maize farm in Portugal. Lisboa: ISA, 2019, 55 p.http://hdl.handle.net/10400.5/21289Mestrado em Engenharia Agronómica / Instituto Superior de Agronomia. Universidade de LisboaOver the decades, it has been found that agricultural intensification, that is, the increase in production per hectare, is substantially urgent and necessary, justified by the observed and expected population increase and the impossibility of agricultural expansion. One of the methods for achieving this goal is the study and investigation of yield gaps, which may be explained by unfavorable soil and climate conditions, or less adequate input management. Given the socio-economic importance of maize crop in Portugal and the need for case studies that exemplify agricultural intensification methods, this dissertation aims to discover which are the reducing factors that justify the gap between the maximum and actual yields, known as yield gaps, which were analyzed between plots and years, and how large was the yield gap over the 10 years. Through a database of irrigation appropriations, nitrogen applications, sowing dates and climate data, collected over 10 years and provided by Milho Amarelo company, located in the Santarem region, other variables were calculated, such as degree-day accumulation, cultural evapotranspiration and intercepted radiation. These data were analyzed annually according to the whole cycle and according to different phenological phases (vegetative and reproductive). Once all variables were obtained and organized, statistical methods of bivariate and multivariate analysis were performed. The magnitude of yield gap was calculated according to the Approach 2 indicated by FAO 41. The results show that interaction of sowing dates with climatic conditions are in the nature of this deviation, with gap’s magnitude ranging from 5% to 20%, depending on the climatic conditions of the yearengmaizeyield variabilitysowing datesreducing factorsyield gap analysismaster thesis203746287