Improving alfalfa growth through amending alkalized soil with mixture of desulfurization gypsum and fly ash

Abstract

【Objective】 Soil alkalinization is an abiotic stress affecting agricultural production in many countries. Amending it by soil conditioners is a technique to ameliorate the adversary effect of alkalization and safeguard crop growth. In this paper, we study the efficacy of mixture of desulfurization gypsum and fly ash for improving alfalfa growth in a newly reclaimed alkalized soil. 【Method】 The field experiments were conducted in plots which were amended with mixture of desulfurization gypsum and fly ash at different ratios: 30 t/hm2 of desulfurization gypsum and 15 t/hm2 of fly ash (T1), 30 t/hm2 of desulfurization gypsum and 30 t/hm2 of fly ash (T2), 30 t/hm2 of desulfurization gypsum and 45 t/hm2 of fly ash (T3), 45 t/hm2 of desulfurization gypsum and 15 t/hm2 of fly ash (T4), 45 t/hm2 of desulfurization gypsum and 30 t/hm2 of fly ash (T5), 45 t/hm2 of desulfurization gypsum and 45 t/hm2 of fly ash (T6). The control is without amendment (CK). In each treatment, we measured the changes in soil properties and plant growth. 【Result】 Regardless of the mixture ratios, soil amendment significantly improved physical properties of the soil. Compared with CK, T3 reduced soil bulk density by 7.69% and increased porosity and water-holding capacity of the soil by 9.69% and 18.70%, respectively. The amendments also improved chemical properties of the soil, with T4 reducing the pH in the 0-10 and 10-20 cm of soil layers by 10.51% and 11.66%, alkalinity reduced by 56.76% and 50.27%, respectively. T4 also reduced soluble salt content in the 0-10, 10-20 and 20-40 cm of the soil layers by 32.33%, 52.55% and 3.04% respectively, compared to CK. Alfalfa grew better in T4 and T1, with its fresh weight increasing by 61.76% and 43.21%, and dry matter by 48.80% and 30.72%, respectively, compared to CK. It was found that overapplication of the conditioners comprised yield, with T6 reducing the fresh and dry matter by 19.69% and 10.24%, respectively, compared to CK. 【Conclusion】 Amending the alkalinized soil with a mixture of desulfurization gypsum and fly ash at appropriate ratios can improve soil physical properties and reduce soil pH, alkalinity and soluble salt content in the soil, thereby promoting alfalfa growth. For all the treatments we compared, amending the soil with 45 t/hm2 of desulfurization gypsum and 15 t/hm2 of fly ash worked best.

Keywords

• desulfurization gypsum
• fly ash
• alkalized soil
• alfalfa
• yield