中重度盐碱地咸淡水轮灌对玉米生产及土壤盐分的影响

Effects of Alternate Irrigation with Saline and Fresh Water on Maize Production and Soil Salinity in Moderate-Severe Saline-Alkaline Land

摘要: 为探究滨海中重度盐碱地暗管排盐模式下咸淡水轮灌对玉米生产及土壤盐分变化的影响，以明确适宜的咸淡水轮灌方式，为微咸水资源安全利用、节约淡水资源及保障玉米安全生产提供理论依据。本研究选用“理查德”矮玉米，在河北省唐山市曹妃甸区中重度盐碱地设置5个处理：CK (雨养旱作)、T1 (喇叭口期和吐丝期均灌淡水)、T2 (喇叭口期微咸水 + 吐丝期淡水)、T3 (喇叭口期淡水 + 吐丝期微咸水)、T4 (喇叭口期和吐丝期均灌微咸水)，研究了不同轮灌方式对玉米产量、水分利用效率及耕层(0~20 cm)、深层(20~40 cm)土壤盐分的影响。结果表明，咸淡水轮灌方式对土壤盐分和玉米产量、水分利用效率有显著影响，但适度微咸水滴灌未对产量形成严重影响；受夏季降雨和暗管排盐综合作用，所有处理收获后耕层土壤盐分均控制在0.15%~0.31%区间，20~40 cm土层盐分未出现显著积盐现象；玉米亩产均处于380~490 kg范围，水分利用效率表现为T3 > T2 > T1 > CK > T4，产量表现为T1 > T3 > T2 > CK > T4，T3处理产量较T1仅降低2.9%，无显著差异，较CK提高12.4%，水分利用效率较T1提高13.6%。综上，滨海中重度盐碱地暗管排盐条件下，适度微咸水滴灌可在适当生育期(吐丝期)使用，既不会显著降低玉米产量、也不会导致土壤显著积盐，同时能节约50%淡水资源，实现微咸水资源安全利用。

Abstract: To explore the effects of alternate irrigation with saline and fresh water on maize production and soil salinity changes under the subsurface pipe drainage mode in coastal saline-alkaline lands, so as to clarify the suitable alternate irrigation method and provide a theoretical basis for the safe utilization of brackish water resources, water conservation, and the guarantee of safe maize production. This study selected “Richard” dwarf maize as the research material and conducted a field experiment in the moderate-severe saline-alkaline lands of Caofeidian District, Tangshan City, Hebei Province, with five treatments established: CK (rain-fed dry farming), T1 (irrigated with fresh water at both the trumpet stage and silking stage), T2 (irrigated with brackish water at the trumpet stage + fresh water at the silking stage), T3 (irrigated with fresh water at the trumpet stage + brackish water at the silking stage), and T4 (irrigated with brackish water at both the trumpet stage and silking stage). The effects of different alternate irrigation methods on maize yield, water use efficiency (WUE), and soil salinity in the plough layer (0~20 cm) and deep layer (20~40 cm) were investigated. The results showed that alternate irrigation with saline and fresh water had significant effects on soil salinity, maize yield, and WUE, but moderate drip irrigation with brackish water did not cause serious negative impacts on yield. Under the combined action of summer rainfall and subsurface pipe drainage, the soil salinity in the plough layer of all treatments after harvest was controlled within the range of 0.15%~0.31%, and no significant salt accumulation was observed in the 20~40 cm soil layer. The maize yield per mu (667 m²) ranged from 380 kg to 490 kg, with the WUE ranking as T3 > T2 > T1 > CK > T4 and the yield ranking as T1 > T3 > T2 > CK > T4. Compared with T1, the yield of T3 only decreased by 2.9% (no significant difference) but increased by 12.4% compared with CK, and its WUE was 13.6% higher than that of T1. In conclusion, under the condition of subsurface pipe drainage in coastal moderate to severe saline-alkaline lands, moderate drip irrigation with brackish water can be applied at the appropriate growth stage (silking stage). This method not only does not significantly reduce maize yield or cause obvious soil salt accumulation but also saves 50% of freshwater resources, realizing the safe utilization of brackish water resources.