Combined organic-inorganic fertilization mitigates emitter clogging in brackish water drip irrigation systems

Emitter clogging severely limits the use of brackish water in drip irrigation. While the application of individual targeted organic or inorganic fertilizers has proven to be an eco-friendly strategy for mitigating emitter clogging, their integrated application is widely adopted in agricultural practice. However, the efficacy and optimal selection of such organic-inorganic combinations for controlling emitter clogging remain unknown. To address this, a systematic drip irrigation experiment was conducted with four distinct treatments: a non-fertilized control (CK), ammonium sulfate alone (AS), fulvic acid alone (FA), and their combination (AS-FA). The results demonstrated that the combination of AS and FA (AS-FA) achieved significant fouling control, with inhibition rates of 52.4–56.9%. This effectively alleviated emitter clogging, thereby improving the relative discharge (Dra) and coefficient of uniformity (CU) by 54.6–58.1% and 56.4–60.8%, respectively. Notably, the AS-FA treatment exhibited a synergistic effect, with a fouling inhibition capacity exceeding the sum of the individual effects of AS and FA by 19.1–23.8%. Consequently, this co-application strategy effectively overcomes the inherent limitations of single-fertilizer regimens. These findings propose a promising fertigation management strategy for mitigating emitter clogging, thereby extending the operational lifespan of drip irrigation systems and promoting the sustainable utilization of brackish water resources.