Evaluation of effects of water-saving superabsorbent polymer on corn (Zea mays L.) yield and phosphorus fertilizer efficiency

There is growing interest in using a reduced rate of mineral fertilizer along with water-saving superabsorbent polymer (WSAP) for field crop production in arid and semiarid regions of the world. The overall objective of this study was to evaluate the effects of hydrogel applications on the phosphorus fertilizer efficiency parameter, yield, and selected physiological properties of corn (Zea mays L.) grown at different levels of water deficiency in greenhouse conditions. The experimental design consisted of 3 completely randomized blocks in a factorial arrangement, with 9 hydrogel doses (0%, 0.01%, 0.02%, 0.04%, 0.08%, 0.12%, 0.2%, 0.4%, and 0.6%), 4 phosphorus fertilizer doses (0, 80, 160, and 240 kg ha^–1), and 4 water deficiency levels (50%, 65%, 80%, and 100%). Overall, 432 pots were used in this study. We found that the irrigation interval of 0.0% WSAP (control) application treatment at water deficient conditions (WDC 50%) was 6 days, although this value could be increased to 11 days with 0.4% WSAP application treatment. The highest yield was obtained from 0.40% WSAP with 240 kg ha^–1 P application dose at 35% deficient irrigation conditions according to leaf relative water content, the chlorophyll reading value of corn plants, and P fertilizer efficiency parameters such as agronomic efficiency, physiological efficiency, use efficiency, and apparent recovery efficiency values. These findings suggest that the application of 0.40% WSAP with 240 kg ha^–1 P and economic soil management practice could provide an efficient corn production operation in drought-affected regions such as eastern Turkey and other areas with similar ecologies.