Saline soil from the coast is a valuable and readily available resource. It is also a valuable resource for reserving arable land. Adding organic fertilizers to salinized soils is an effective method of enhancement. However, saline soils cannot be improved using a single measure, and the effects of compound measures of organic fertilizers combined with mineral elements, such as humic acid, are significant and worthy of further examination. To explore the effects of various measures on the features of pH, electrical conductivity (EC), and nutrient changes in coastal salinized soils in Yancheng, Jiangsu Province, a ryegrass–alfalfa rotation with organic fertilizer and compound measures was designed. The findings indicated that the total nitrogen (TN) content of the soil increased and that all organic fertilizer composites decreased the electrical conductivity of the surface soil. However, the organic fertilizer with microbial fertilizer and humic acid was especially effective at regulating the pH and electrical conductivity of the surface soil when salts were prone to accumulation. In conclusion, our findings highlight new approaches to lowering salinity and boosting fertility in coastal saline soils: organic fertilizer with microbial fertilizers and humic acid, as well as organic fertilizer with attapulgite clay.

Different from the traditional deep tillage, deep vertical rotary tillage can smash deep soil without disturbing the soil layer, which improves soil water infiltration and promotes salt leaching. This has gradually been applied in the research into saline alkali improvements. However, there is limited knowledge about the effect of deep vertical rotary tillage on the temporal–spatial distributions of soil water and salt under the shallow underground water level. Therefore, a preliminary soil column experiment was carried out to explore the results of water and salt movement under three different tillage methods: traditional rotary tillage depth of 20 cm (XG−20), deep vertical rotary tillage depth of 20 cm (FL−20) and deep vertical rotary tillage depth of 40 cm (FL−40). The temporal–spatial variation in soil water and salt was analyzed. The results showed that the average infiltration rate of FL−40 increased by 1.25 and 0.46 cm h⁻¹ in 0−40 cm soil layer compared with that of XG−20 and FL−20. At the same time, soil water content was also increased, and the order of soil water content was FL−40 > FL−20 > XG−20. With the increase in tillage depth, the desalinization rate and the soil electric conductivity (EC) of FL−40 were increased and decreased, respectively. The FL−40 treatment’s average desalinization rates increased by 16.32% and 13.99% compared with XG−20 and FL−20 treatments’ in 0−60 cm soil layer. In conclusion, FL−40 had a better effect on regulating water and salt. The deep vertical rotary tillage provided an effective method for the control and optimization of water and salt in coastal saline soil.

Saline soil from the coast is a valuable resource that is readily available. It is also a valuable resource for reserving arable land. It has been demonstrated that adding organic fertilizers to salinized soils can effectively enhance them. However, since the improvement of saline soils cannot be achieved by a single measure, the effects of compound measures of organic fertilizers combined with mineral elements, humic acid, are significant and might be examined in depth. In order to explore the effects of various measures on the features of pH, electrical conductivity (EC), and nutrient changes in coastal salinized soils in Yancheng, Jiangsu Province, a ryegrass-alfalfa rotation with organic fertilizer as well as compound measures was designed. The findings indicated that the total nitrogen (TN) content of the soil increased and that all organic fertilizer composites decreased the electrical conductivity of the surface soil. However, the organic fertilizer with microbial fertilizer and humic acid was especially effective at regulating the pH and electrical conductivity of the surface soil during the time when salts were prone to accumulating. In conclusion, our findings point to new approaches to lowering salinity and boosting fertility in coastal saline soils: organic fertilizer with microbial fertilizers and humic acid, as well as organic fertilizer with Attapulgite clay.

Background: The Yellow River irrigation area in Ningxia faces spring drought, resalting, severe water resource shortage, and significant water wastage in saline–alkali soils. Objective: To explore the effects of two different improvement measures on maize fresh biomass and the basic physical and chemical properties of saline soil under four irrigation gradients, aiming to provide a theoretical basis for water-saving irrigation in the Yellow River irrigation area of Ningxia while ensuring maize yield. Methods: The experiment designed four irrigation gradients, W1: local conventional water volume (240 mm), W2: 10% water-saving (216 mm), W3: 20% water-saving (192 mm), W4: 30% water-saving (168 mm), and two different soil improvement treatments, a combination treatment of desulfurization gypsum, ETS microbial agent, and biochar (JC), and a combination treatment of desulfurization gypsum, humic acid, and mulching (FS), with a blank control (CK), resulting in 12 treatments in total. Results: The results showed that compared with CK, both JC and FS treatments reduced soil pH, with JC treatment showing a more significant reduction in soil alkalinity than FS treatment. Both JC and FS treatments inhibited the rise in soil electrical conductivity (EC), with JC showing a significantly higher ability to suppress the rise in EC than FS treatment. Both FS and JC treatments improved soil water retention, but in May 2023 during the maize seedling stage, FS treatment had a stronger water retention ability than JC treatment; however, in July at the maize big jointing stage and in September at the maize maturity stage, JC treatment exhibited better water retention ability than FS treatment. Both JC and FS treatments increased maize fresh biomass under four water conditions, but under WI and W2 conditions, there was no significant difference in the ability of JC and FS treatments to increase maize fresh biomass. Under any irrigation condition, the ability of JC treatment to improve WUE is higher than that of FS treatment. Under W3 and W4 conditions, JC treatment significantly outperformed FS treatment in increasing maize fresh biomass yield. Additionally, under W3 irrigation conditions, using JC treatment not only achieved greater water-saving goals but also prevented crop yield reduction due to water-saving measures. This article can provide a theoretical basis for agricultural irrigation management, especially in the Ningxia Yellow River irrigation area of China. It can help ensure crop yields while protecting the ecological environment and promoting sustainable agricultural development.