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Universidade Federal do Rio Grande do Norte (UFRN) 2021

Influência dos extremos climáticos e do balanço hídrico na produtividade agrícola

Vale, Tásia Moura Cardoso do

Titre : Influência dos extremos climáticos e do balanço hídrico na produtividade agrícola

Influence of climate extrems and water balance on agricultural productivity

Auteur : Vale, Tásia Moura Cardoso do

Université de soutenance : Universidade Federal do Rio Grande do Norte (UFRN)

Grade : Doutorado em Ciências Climáticas 2021

In a scenario of climate change, the current levels of productivity, under broad environmental conditions, production per harvested area is intrinsically linked to issues of water availability in the soil. Understanding climate influence and water balance on agricultural productivity can assist in the performance of practices in the field and policies to reduce climate-related vulnerability. In this perspective, the objective of this thesis is to analyze the behavior of the productivity of the crops : cassava, corn and beans in view of the climatic variability and water balance, in the Northeast Region of Brazil. Two articles were developed : the first identifies space-time patterns of daily precipitation, verifying associations with crop yields, in the state of Rio Grande do Norte, 1980 to 2013 ; the second analyzes the Climatological Normal Water Balance and the sequential and its relationship with crop productivity in the Northeast region of Brazil, 1990 to 2019.Daily and climatic data provided by Xavier et al. (2015), from 1980 to 2013 and data from the Era Retrospective Analysis for Research and Applications version 2 (MERRA-2) from the Global Modeling and Assimilation Office (GMAO) with the support of the modeling program of America’s Space Agency (NASA), for the period from 1990 to 2019. Various statistical methods were used : correlation analysis, Mann Kendall trend test, Cluster analysis, Tukey test, Factor Analysis, among others. The first study observed from moderate to strong positive and significant correlations of precipitation indicators with the productivity of subsistence agriculture, its trends, regions of greater agricultural aptitude and better periods indicated for the beginning of planting, according to the climatology of each region of the state of Rio Grande do Norte. The second study evaluated, based on the Thornthwaite climate classification of the Moisture Index, six typologies : Arid (28 municipalities) ; Semiarid (746 municipalities) ; Dry Su b-humid (536 municipalities) ; Sub-humid (389 municipalities), Humid B1 (73 municipalities) and Humid B2 (20 municipalities). The results showed an increase in radiation, temperature and evapotranspiration, mainly in the humid regions of the NEB. There was also an increase in water deficiency in SON and, consequently, a reduction in storage in all regions during the DJF period. It was found that in the two most humid regions, evapotranspiration and temperature correlated positively with the yields of beans and corn, while in the less humid areas, storage and water surplus had greater positive associations with agricultural productivity. According to the monthly climatological water balance, the periods of greatest water capacity for the regions were different between January and April. It is concluded, therefore, that the understanding of the behavior of the water balance variables and their relationship with agricultural productivity help in management strategies associated with climatic variations / trends, especially for the purposes of agricultural and hydrological planning and for irrigation projects for farmers and local managers in Northeast Brazil.

Mots Clés  : Classificação climática Thornthwaite ;Agricultura de subsistência ;Déficit hídrico ;Janela de plantio ideal


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