Evaluation of Phosphogypsum Application Rates on Sodic Soil Reclamation and Haricot Bean Performance
Haile Hasana
*
Department of Natural Resource Management, Sidama Agricultural Research Institute, Hawassa, Ethiopia.
*Author to whom correspondence should be addressed.
Abstract
The effect of phosphogypsum (PG) on sodic soils has been extensively studied in the laboratory or in small-scale trials. However, there is little/no information available on the influence of PG on haricot performance on sodic soils. Thus, we evaluated the effects of PG amendment on the performance of haricot beans on sodic soils in two successive years (2020 and 2021). The pot trials were arranged as a completely randomised design with four replications. Five PG levels (0, 50, 100, 150 and 200% GR) were randomly used as treatments. Results showed that the soil pH and ESP obtained from 0%GR decreased 22.55% (2020) and 22.60% (2021), and 56.29% (2020) and 62.98% (2021), respectively, over 200% GR. Application of the highest PG rate (200% GR) increased available P contents by 63.70% (2020) and 82.80% (2021) over control. Similarly, the application of the highest PG (200% GR) rate boosted the grain yield of haricot bean by 100% in both 2020 and 2021 compared with the control. Grain yields of the crop were significantly (P<0.01) decreased in 2021 compared with 2020 due to the reduction in available P under rotations. However, the growth of the plant and yield continuously increased with PG levels without reaching the optimum curve, indicating the need for using higher levels of PG. Accordingly, further experimentation with elevated PG doses in field conditions, particularly on sodic or saline–sodic soils, is suggested to ensure valid conclusions.
Keywords: Grain yield, leaching, reclamation, sodic soils