Effects of different irrigation patterns on paddy field environment and rice growth in non-water-retaining areas

Abstract In order to find the optimal irrigation mode to balance the growth and development of rice and water-saving irrigation in paddy fields in non-water-retaining areas, the non-water-retaining areas were selected in this experiment. Three water-saving irrigation modes were set up: shallow irrigation when there was no aquifer on the field(QS), shallow irrigation when the soil moisture content reached the lower limit(QSG), and deep irrigation when the soil moisture content reached the lower limit(SSG). The spearman correlation coefficient method was used to analyze the influence of water temperature on soil temperature in different soil layers, and the changes of nitrate nitrogen and ammonium nitrogen were monitored by ultraviolet spectrophotometry, and the growth and development of rice at different growth stages were observed. The results showed that the temperature of paddy field showed better heat transfer under shallow irrigation with moderate water control, nitrogen loss was reduced during shallow irrigation, and rice growth and development depended on irrigation frequency. Therefore, the irrigation mode of 'frequent irrigation and less irrigation' is recommended for planting rice without water retention. Compared with QSG and SSG, the growth rate of plant height in QS mode was increased by 0.46 cm/d and 0.32 cm/d compared with QSG and SSG mode, respectively, the number of tillers increased by 0.27 and 0.20 plants/(hole·d) in the middle and late tillering stages,and yield increased by 45.61% and 40.53%. In the key growth period of rice, the irrigation frequency should be increased to reach the lower limit of irrigation in time, so as to meet the water demand of rice, promote the growth and development of rice, and promote the growth and yield of rice under the joint action of water, heat and fertilizer.