| With the increasing shortage of water resources,the research on reclaimed water irrigation has become a hot topic in this discipline.In this paper,the rice planting field of rural domestic sewage regeneration irrigation is taken as the main research subject,and different irrigation sources(primary treatment water of rural domestic sewage,secondary treatment water,and clear water of river course)and different water level regulation(low water level regulation,medium water level regulation,high water level regulation)are taken as the main research means.To study the variation of rice irrigation water use and water use efficiency under different water sources and water levels.To explore the influence mechanism of different water sources and different water levels on the total amount of water required by rice,the pattern of water consumption and the water use efficiency of rice field.To study the conversion rule of population growth index of rice in different growth stages under the regulation of different water sources and water levels and to explore the reaction and response mechanism of different water sources and water levels on crop growth;To study the effects of different water sources and water levels on soil characteristics,and to explore the mechanism of soil risk assessment by different water sources and water levels.The main conclusions are as follows:1.Three different water level regulation modes had significant effects on rice water demand,and three different irrigation water sources had significant effects on rice water demand;Three different water level regulation modes had no significant effect on rice water demand law,while three different irrigation sources had significant effect on rice water demand law.2.Compared with conventional irrigation sources,irrigation with reclaimed water sources can play a certain role in increasing yield and effectively improving water use efficiency.The experimental study in this paper showed that the rice yield of reclaimed water source irrigation was significantly higher than that of river water source irrigation,and the irrigation water productivity of reclaimed water source irrigation was significantly higher than that of river water source treatment.Irrigation water productivity is affected by both yield and irrigation amount due to the calculation formula,which is the accumulation of the combined effects of both.3.Irrigation with reclaimed water sources can promote the population growth index of rice to some extent.Under the three water level control modes,the reclaimed water source irrigation was beneficial to the increase of tiller number,the accumulation of effective panicle number and the suitable growth of leaf area of rice,and had a certain optimization effect on the accumulation and distribution of dry matter in rice.However,the reclaimed water source irrigation had no significant effect on the growth of rice plant height.Under the control mode of medium water level,the physiological growth performance of rice was the best under the secondary treatment of rural sewage irrigation.4.Use reclaimed water for irrigation in a short time without causing any harm to the soil.Use reclaimed water for irrigation for 3-4 years continuously,and the heavy metals will reach the screening value of soil heavy metal pollution.After a single irrigation test,the contents and effects of five heavy metals in the soil were statistically analyzed by single factor index method,Nemerow comprehensive pollution index method and potential ecological risk assessment method,and all of them were at low risk and slightly ecological harm. |
