Indicators and criteria to define the priority for irrigation water use in the Baixo Jaguaribe basin, Brazil

Abstract

The Baixo Jaguaribe basin has the smallest area of that Watershed (upper, middle and lower Jaguaribe river), but it has enormous importance in terms of water resources. The amount of water for crops irrigation is quite representative in relation to the total volume of water demanded in the entire Jaguaribe river basin. The research presents a methodology of indicators and criteria to define the priority of use of irrigation water in conditions of water scarcity. The analysis of four requirements of socioeconomic security (productive, economic, water and social) indicated a recommendation to cultivate tomato, forage palm, melon, cassava and papaya, that required the smallest water cuts for irrigation at the River Basin (less than 21%). However, crops as orange, rice, soursop, coconut, lemon, custard apple, guava, mango, banana and sugarcane must present the highest water cuts (more than 37%), mainly orange, rice, soursop, coconut, lemon and custard apple which may present values higher than 46% due to their low profitability and yield, and high water consumption.

Socio-Economic Indexes for Water Use in Irrigation in a Representative Basin of the Tropical Semiarid Region

“…Although the LJ sub-basin has the smallest area among all Jaguaribe River sub-basins, it is of great importance in the context of water resources. The amount of water required for irrigation is quite representative relative to the total volume of water demanded throughout the basin [14].…”

“…To this end, it is necessary to know and monitor water demand and define indicators and criteria for water use in agriculture and other sectors of the economy, as well as the rules for the operation of reservoirs [11][12][13]. It is important to consider production security to ensure food production, water security to ensure availability, accessibility and sustainability, economic security to ensure income to the farmer and maintenance of production, and social security to ensure jobs and fixation of rural workers in the field [7,14].…”

“…The indicators of production, water, economic, and social security help in the decisionmaking processes related to irrigated agriculture, focusing on water saving and on results for farmers. However, evaluating them separately may generate contradictory results, since some crops may have high water and production security, but generate less employment and lower income than others [14]. In this context, the definition of a general index, applicable to different scenarios, which assists in decision-making on water management in the river basin, is of great relevance for farmers and for the definition of development policies.…”

Produtividade da área e da água em soja irrigada para diferentes variedades e metodologias de manejo da irrigação

“…Muitos estudos vêm sendo realizados para avaliar estratégias de irrigação em termos de reposição plena ou deficitária de água para a cultura irrigada. A irrigação com déficit hídrico controlado em períodos não críticos do desenvolvimento da planta (onde a produção não é prejudicada pelo déficit hídrico), promove uma reposição hídrica ao solo inferior à lâmina evapotranspirada pela cultura no campo irrigado (FRIZZONE, 2007;FRANÇÓIS, 2012).…”

“…Um desafio para a agricultura é realizar o uso eficiente dos recursos hídricos, uma vez que a tecnologia da irrigação se torna cada vez mais necessária em decorrência do aumento de demanda alimentar e das mudanças climáticas. Assim, a seleção da estratégia de irrigação adequadas à realidade do produtor é uma forma de racionalizar o uso da água na agricultura, proporcionando um aumento da eficiência do uso desse recurso natural, reduzindo custos de energia e aumentando da chamada "produtividade da água" (FRIZZONE, 2007;DU et al, 2015).…”