银北灌区稻田回归水灌溉对土壤盐分分布及作物产量的影响

The Impact of Rice Field Reuse Water Irrigation on Soil Salinity Distribution and Crop Yield in Yinbei Irrigation District

银北灌区面临引黄水量锐减挑战的同时,也存在水资源利用效率低,灌溉用水不科学合理,水资源浪费严重等问题。寻求适宜的灌溉模式是减少黄河水依赖、提高水资源利用率以及保证作物产量的重要途径。采用大田试验种植水稻,设置6种不同的灌溉模式,分别为回归水漫灌(T1)、黄河水灌溉(T2)、适量回归水灌溉(T3)、黄河水回归水交替灌溉(T4)、退水再灌(T5)、常规灌溉(T6),研究不同灌溉模式对稻田土壤盐分分布和水稻生长及产量的影响。不同灌溉模式对稻田盐分分布影响显著。全生育期不同灌溉模式都存在表层土壤脱盐,底层土壤积盐的现象,T1处理脱盐深度最大,使盐分累积在土壤60 cm以下,其余处理累积在土壤40 cm以下。土壤脱盐率最大在T1处理,较初始土壤含盐量降低9.58%;根区脱盐率最大出现在T2处理,为27.36%;根区盐分变化量最大为T1处理,水稻生育期内,盐分向下迁移量为4.82 t/hm^(2)。回归水漫灌处理下水稻产量最大,为10029.42 kg/hm^(2)。T3处理生产单位重量的水稻可节省黄河水0.56 m3/kg,生产一季水稻单位面积可节省黄河水5003.41 m3/hm^(2)。综上所述,针对宁夏银北灌区,采用适量的回归水进行灌溉,可以在保证作物产量的同时,降低对于引用黄河水灌溉的需求程度。

The Yin Bei Irrigation Area is facing a sharp decline in the amount of water diverted from the Yellow River,while also facing problems such as low water resource utilization efficiency,insufficient scientific and reasonable irrigation water use,and serious water resource waste.Seeking suitable irrigation modes is an important way to ensure crop yield,reduce water dependence on the Yellow River,and improve water resource utilization efficiency.Using field experiments to plant rice,six different irrigation modes were set up,namely return flood irrigation(T1),Yellow River water irrigation(T2),moderate return water irrigation(T3),Yellow River water return alternating irrigation(T4),return water irrigation(T5),and conventional irrigation(T6).The effects of different irrigation modes on soil water and salt distribution,rice growth,and yield in rice fields were studied.Different irrigation modes have a significant impact on the distribution of salt in paddy fields.The phenomenon of surface soil desalination and bottom soil salt accumulation exists in different irrigation modes throughout the entire growth period.T1 treatment has the highest desalination depth,causing salt accumulation below 60 cm of soil,while the rest of the treatments accumulate below 40 cm of soil.The maximum soil desalination rate was observed in T1 treatment,which decreased by 9.58%compared to the initial soil salinity;The highest root zone desalination rate occurred in T2 treatment,at 27.36%;The maximum change in salt content in the root zone was observed in T1 treatment,and during the rice growth period,the downward migration of salt was 4.82 t/hm^(2).The maximum rice yield was 10029.42 kg/hm^(2) under the treatment of flood irrigation with return water.T3 processing can save 0.56 m3/kg of Yellow River water per unit weight of rice production,and producing one season of rice can save 5003.41 m3/hm^(2) of Yellow River water per unit area.In summary,for the Yin Bei Irrigation Area in Ningxia,using an appropriate amount of return water for irrigation can ensure crop yield while reducing the demand for irrigation using Yellow River water.