Fertigation and Carboxymethyl Cellulose Applications Enhance Water-Use Efficiency, Improving Soil Available Nutrients and Maize Yield in Salt-Affected Soil

Abstract

Conventional organic soil amendments and drip irrigation are insufficient for mitigating soil salinization. The development of a more potent soil amendment with higher water retention capability is critical. Carboxymethyl cellulose (CMC) has excellent water retention and adsorption properties and is suitable for soil water retention and amendment; however, its effects on water and salt distribution, soil nutrients, and maize yield have not been clearly investigated. We set up five treatments with flood irrigation (CK), drip irrigation (W), drip irrigation combined with 100 kg CMC ha−1 (WC1), drip irrigation combined with 200 kg CMC ha−1 (WC2), and drip irrigation combined with 300 kg CMC ha−1 (WC3). Our findings demonstrate that the application of CMC in conjunction with drip irrigation led to a significant surge in soil water content within the 0–40 cm layer, ranging from 3.73% to 16.46%, while simultaneously inducing a reduction in salt content of 4.08% to 16.61%. Consequently, this resulted in a desalination rate spanning from 10.32% to 12.93%. The salt was gradually washed down and formed a desalination area with the drip emitter as the center, and the salt distribution characteristics shifted from a surface accumulation type to a bottom deposition type. The drip irrigation and CMC application also increased the content of available nutrients, reduced surface evaporation, underground water loss, and maize evapotranspiration, and improved water-use efficiency, thus increasing the aboveground biomass and grain yield. In summary, CMC had a significant effect on water retention, desalination, and yield increases. It can serve as a novel soil amendment for salt-affected soil.