Reclaimed water irrigation is one of the most important ways to solve the shortage of water for agriculture in China. Utilizing reclaimed water to replace conventional water resources is suitable for the rapid growth of China's water demand, and can reduce pollutants discharged from surface water and lower the cost of sewage treatment. Therefore, using reclaimed water for irrigation is an inevitable choice to achieve urban wastewater reuse and reduce clean water and pollutant emissions. Reclaimed water brings rich nitrogen, phosphorus, organic matter and other nutrients to soil and crops, improves soil physicochemical properties, and increases soil fertility. However, some studies have shown that too much organic matter in reclaimed water can lead to a decrease in soil porosity, which reduces soil water-holding capacity and hydraulic conductivity, leading to a decrease in soil productivity. In addition, although reclaimed water is treated sewage, it still contains a certain amount of pathogenic bacteria, heavy metals and other pollutants. If reclaimed water is used improperly, it can be harmful to the ecological environment and human health. Therefore, it is necessary to systematically sort out the current research status of reclaimed water irrigation, clarify the main problems, and put forward reasonable suggestions, which are of great significance to improve the efficiency and safety of reclaimed water irrigation.

Reclaimed water irrigation carries a certain risk of contamination by pathogenic bacteria. Once pathogenic bacteria enter the soil, they will multiply in the soil, thus causing large-scale contamination of the soil and even contamination of groundwater bodies, threatening the health and safety of humans and livestock. Therefore, it is of great significance to study the adsorption and transportation of pathogenic bacteria in soil under reclaimed water irrigation conditions. However, the current domestic research on the safety of reclaimed water irrigation mainly focuses on organic pollutants, inorganic salts, heavy metal pollution, etc., and has little effect on soil pathogenic bacteria contamination, which should be strengthened in the future by the treatment of reclaimed water.The kinetic process of pathogenic bacteria transport in soil by ER irrigation. The effects of different irrigation methods and irrigation technologies on the distribution, transfer and metabolism of pathogenic bacteria in soil were studied. Effective measures are taken to reduce the health risk of pathogenic bacteria during ER irrigation and reasonable predictions are made to minimize the threat of pathogenic bacteria during ER irrigation.

The contradiction between supply and demand of water resources in China is rising year by year. With the gradual improvement of domestic sewage treatment technology and the continuous expansion of sewage treatment plants, the use of reclaimed water instead of traditional water resources for agricultural irrigation will be an inevitable choice to alleviate the pressure on agricultural water and to relieve the pressure on agricultural water. Improve the utilization rate of sewage. Reasonable use of reclaimed water for farmland irrigation can also reduce the amount of irrigation and fertilizer application, promote crop growth and development, and achieve the effect of increased food production. There are many studies on reclaimed water recharge irrigation at home and abroad, but so far there are few studies on the effects of different irrigation methods and different irrigation techniques on crop physiology and quality under reclaimed water irrigation conditions. The experimental research on reclaimed water mainly focuses on short-term experiments, and long-term experimental observation should be strengthened.

Reasonable application of irrigation technology and irrigation methods is of great significance to reduce soil heavy metal pollution and improve the safety and efficiency of reclaimed water irrigation. In the future, research on different irrigation methods and techniques under reclaimed water irrigation conditions should be strengthened to characterize the response of reclaimed water irrigation to soil physicochemical properties and safety under inadequate conditions. Irrigation should be explored. Research on the migration and distribution of heavy metals in soil under inadequate irrigation conditions should be strengthened to study the mechanism of their impact on soil and crop safety and to reveal the regulatory mechanism of inadequate medium water irrigation on soil. Second crop safety.

There is a prominent contradiction between supply and demand of water resources in China, especially for agricultural irrigation. Reasonable use of reclaimed water for farm irrigation is the future trend of agricultural irrigation development. Reclaimed water is not only a source of water and fertilizer, but also a source of pollution. If it is not used properly, it can have negative impacts on crops and soil.