Fertigation potentiality applying treated wastewater by partially saturated vertical flow wetland

Abstract

Water scarcity and the environmental concerns associated with chemical fertilizers underscore the need for sustainable irrigation alternatives in agriculture. This study evaluated the viability of fertigation with treated wastewater from a full-scale partially saturated vertical flow wetland (SVF wetland), focusing on corn productivity, nutrient assimilation, soil macronutrient balance, and microbiological risks. Field experiments demonstrated that using treated wastewater as the sole nitrogen (N) source resulted in corn yields of 10,070 kg ha⁻¹, comparable to conventional chemical fertilization (10,109 kg ha⁻¹), while also promoting gradual nutrient release and reduced N losses. Conversely, mixed fertigation (wastewater + chemical fertilizer) led to lower productivity (from 8800 to 9075 kg ha⁻¹), suggesting suboptimal nutrient synchronization. Soil analysis revealed that mixed N sources increased macronutrient accumulation (N: from 1.8 to 2.4 g kg⁻¹; P: from 3.0 to 4.2 g kg⁻¹; OM: from 18 to 40 g kg⁻¹), whereas exclusive wastewater application maintained balanced nutrient levels (N: 1.5 g kg⁻¹; P: 2.6 g kg⁻¹; OM: 15 g kg⁻¹). Additionally, the Quantitative Microbiological Risk Assessment confirmed that SVF wetland effluent meets safety thresholds for agricultural reuse, ensuring minimal health risks. These findings highlight the potential of SVF wetland-treated effluent as a safe, sustainable fertigation strategy, maintaining crop productivity and soil fertility while mitigating water and nutrient scarcity. Moreover, these insights support the development of water reuse policies in developing countries, where wastewater fertigation can significantly enhance agricultural sustainability, food security, and water resource management under increasing climate challenges.