Fiber quality, yield, and profitability of cotton in response to supplemental irrigation with treated wastewater and NPK fertilization

Authors: ARAÚJO, ANTONIO - Universidade Federal Do Ceara (UFC); CAVALCANTE, EDUARDO - Universidade Federal Do Ceara (UFC); LACERDA, CLAUDIVAN - Universidade Federal Do Ceara (UFC); ALBUQUERQUE, FÁBIO - Embrapa Cotton; SALES, JONNATHAN - Universidade Federal Do Ceara (UFC); LOPES, FERNANDO - Universidade Federal Do Ceara (UFC); Ferreira, Jorge; COSTA, RAIMUNDO - Universidade Federal Do Ceara (UFC); LIMA, SILVIO - Secretary Of Economic Development And Work Of Ceara; BEZERRA, MARLOS - Embrapa Tropical Agroindustry; GHEYI, HANS - Universidade Federal Do Ceara (UFC)

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2022
Publication Date: 10/16/2022
Citation: Araújo, A.F., Cavalcante, E.S., Lacerda, C.F., Albuquerque, F.A., Sales, J.R., Lopes, F.B., Ferreira, J.F., Costa, R.N., Lima, S.C., Bezerra, M.A., Gheyi, H.R. 2022. Fiber quality, yield, and profitability of cotton in response to supplemental irrigation with treated wastewater and NPK fertilization. Agronomy. 12(10). Article 2527. https://doi.org/10.3390/agronomy12102527.
DOI: https://doi.org/10.3390/agronomy12102527

Interpretive Summary: Cotton is one of the most important cash crops and the most important source of natural fiber and seed oil worldwide. Cotton yield under the rainfed farming system in tropical semi-arid regions is significantly reduced by prolonged dry spells, especially under drought scenarios. Thus, supplemental irrigation with treated wastewater emerges as a strategy for the sustainable production of cotton in semiarid regions and to reduce fertilizer inputs to the crop. This work evaluated crop productivity, growth parameters, fiber quality, and profitability of cotton cultivation under supplemental irrigation with municipal treated wastewater (MTW) under simulated water-availability scenarios, with and without mineral fertilization. The water scenarios tested (Normal, Drought, and Severe Drought) were defined by the historical series of precipitation data of 30 years, supplemented or not with MTW, and with or without NPK fertilization. Longer dry spells under the Drought and Severe Drought scenarios required higher volumes of supplemental irrigation with MTW, resulting in greater nutrient input to the soil ensuring higher yields, high water use efficiency, and a reduction in fertilizer costs. Our results indicate that using MTW as supplemental irrigation of cotton under water-scarce semiarid scenarios has the potential to increase farmers’ income while preserving fresh water for human and animal consumption.

Technical Abstract: Cotton yield under the rain-fed farming system in tropical semi-arid regions is significantly decreased by prolonged dry spells. In this context, supplemental irrigation (SI) with treated wastewater emerges as a strategy for the sustainability of agricultural production besides contributing to the reduction of fertilizer costs. The objective of this research was to evaluate the productivity,photosynthetic parameters, fiber quality, and profitability of cotton cultivation, under supplemental irrigation (SI) with municipal treated wastewater (MTW), with and without mineral fertilization. The treatments consisted of three water scenarios (normal, drought, and severe drought), defined by the historical series of precipitation data of 30 years, and two treatments of supplemental irrigation with MTW, with or without NPK fertilization. SI with treated wastewater increased cotton yield in all three scenarios (normal, drought, and severe drought) by approximately 29%, 255%, and 251%. Longer dry spells in drought and severe drought scenarios increased the volume of SI with MTW, resulting in greater nutrient input to the soil, improved hotosynthetic response, higher physical water productivity, reduction in fertilizer costs, and higher farmers’ income. Therefore, our results show the importance of using treated wastewater in supplemental irrigation of cotton under scenarios of water scarcity in tropical semi-arid regions.