不同生育期淋洗对微咸水滴灌玉米农田水盐及产量的影响

为了明确不同淋洗时间对微咸水滴灌农田脱盐和增产的影响,在内蒙古河套灌区进步村节水综合试验站开展了微咸水滴灌试验,分别在拔节期(T1)、抽雄期(T2)、灌浆期(T3)设置1次畦灌淋洗,以及生育期无淋洗(CK)共4个处理,研究不同生育期淋洗对微咸水滴灌农田水盐及作物产量的影响。结果表明:不同生育期淋洗后0-60 cm平均土壤含水率提高了18.9%,且T1、T2和T3处理0-40 cm土壤含水率显著高于CK处理,持续时间分别为12,25,28天;生育期淋洗后土壤储水量和作物耗水量分别平均增加了20.92%和21.52%。生育期淋洗后膜内平均盐分降低了78.0%,拔节期、抽雄期、灌浆期淋洗后盐分分别下降了0.20,0.36,0.44 mS/cm。淋洗后膜内0-60 cm脱盐率平均提高55.01%,60-100 cm脱盐率平均提高125.79%,且淋洗后膜外脱盐率高于膜内,平均高38.90%。拔节期淋洗显著提高产量及其构成因子,产量提高了18.8%,穗长、穗宽和行粒数分别提高6.8%,5.5%,7.0%,收获指数提高了7.8%(P<0.05);抽雄期淋洗产量提高了8.1%(P<0.05),而灌浆期淋洗对产量无显著影响(P>0.05),故在拔节期淋洗土壤作物受盐分胁迫时间较短,增产效应最明显。

Effects of Leaching at Different Growth Stages on Soil Water, Soil Salt and Yield in a Drip-irrigated Maize Farmland with Brackish Water

In order to improve crop yield under drip irrigation with brackish water and to clarify the effects of different leaching time on desalination and increasing yield, a salt leaching was conducted at the jointing stage (T1), tasseling stage (T2) and filling stage (T3) respectively in the Jingbu saving water experiment station of the Hetao irrigation area, Inner Mongolia. With no leaching in the growth period as control (CK), a total of 4 treatments were carried out to study the effects of leaching at different growth stages on soil water and salt and crop yield under mulched drip irrigation with brackish water. The results showed that the soil water contents increased by 18.9% from 0-60 cm after leaching at different growth stages, and the soil water contents of 0-40 cm under T1, T2 and T3 were significantly higher than that of CK, which durations were 12, 25, 28 days respectively. After the salt leaching, the soil water storages and water consumptions increased by 20.92% and 21.52%, respectively. The average salt contents below mulch decreased by 78.0% after leaching, and the salt content decreased by 0.20, 0.36, 0.44 mS/cm after leaching at jointing and tasseling and filling stage respectively. After leaching, the desalination rates below mulch increased by 55.01% from 0-60 cm, and by 125.79% from 60-100 cm. The desalination rates beyond mulch after leaching was higher than that below mulch by 38.9% averagely. The salt leaching at the jointing stage significantly increased maize yield and its components, by 18.8% for yield, by 6.8%, 5.5% and 7.0% for spike length, ear width and grain number, respectively, and by 7.8% (P<0.05) for harvest index. The salt leaching at the tasseling stage increased yield by 8.1% (P<0.05), but the effect of leaching at the filling period was not significant (P>0.05). Therefore, the salt leaching at the jointing stage resulted in the less salt stress, under which crop yield could be increased obviously.