干旱绿洲农田盐渍化对土壤理化特性和农艺特征的影响

在河西走廊西部大田试验条件下,通过一个生长季的观测,分析研究农田盐渍化对土壤理化特性和典型牧草(紫花苜蓿)和农作物(大麦)农艺性状、干物质积累和产量的影响。结果表明:(1)在0 ～ 20 cm土层,牧草土壤容重沿盐渍化梯度增加了3％,4.54％,8.62％,9.96％,农作物土壤容重没有明显变化规律；土壤有机质显著降低,且0～ 10 cm土层的降低速率快于10 ～ 20 cm土层；(2)盐渍化程度等于或高于中度盐渍化水平时,大麦植株的穗长、穗粒数和秸秆重受到显著影响；在开花、孕穗和灌浆期的盐度既会降低籽粒产量也降。低秸秆产量。与农作物相比,盐渍化程度等于或高于轻度盐渍化水平时,牧草植株的株高、主侧枝长和主根直径会受到影响,进而导致牧草产量的降低。因此,在农业生产中,可根据两种作物在不同盐渍化梯度各生育期的受害状况进行相应的水盐调控和耕作管理,以实现盐渍化农田作物产量的维持和增加。

Effects of salinization on soil physicochemical characteristics and agronomic traits in arid oasis

In attempt to study effects of farmland salinization on soil physicochemical properties and agronomic traits, dry matter accumulations and yields of one-growing-season of representative forage(Medicago sativa L.)and ce-real(Hordeum vulgare L.) were studied in field eonditions in Hexi Corridor of West China. The results showed that:(1)In the depth of0~20 cm, along with the salinization gradients, soil bulk density in forage was increased by 3%, 4.54%, 8.62%, 9.96%, No soil bulk density change was observed in cereal, but its soil organie matter was significantly decreased, and the deerease rate in the depth of 0~10 cm was faster than that in the depth of 10~20 cm;(2)When soil salinity level equal to or higher than moderate salinization level, ear length, grain number and straw weight of barley plant were significantly affected. Salinity at flowering, early ear formation and grain-filling stages reduced both grain and straw yields. When soil salinity level equal to or higher than slightly salinization gradient, plant height, length of main and secondary braneh, and tap root diameter of alfalfa plant were decreased. In conclusion, based on the agro-nomic traits and the different impact of salinization on these two crops at different growth stages, water and salt need to be regulated and controlled and proper cultural practices need to be employed to maintain, stabilize, and increase crop yield in saline environment.