微润灌溉定额及微润带埋深对农田水盐动态及向日葵水分利用效率的影响

为探明微润灌溉对盐渍化土壤水盐变化及向日葵产量的影响,以河套灌区中度盐渍化向日葵农田为研究对象,设置了2种微润带埋设深度分别是20 cm(T1~T4),10 cm (T5~T8),4种灌溉定额(充分灌溉:T1,T5;轻度缺水:T2,T6;中度缺水:T3,T7;重度缺水:T4,T8)共8个处理。研究不同微润带埋设深度与灌溉定额对土壤水分、盐分分布,向日葵产量以及水分利用效率(WUE)的影响。结果表明:微润带埋深相同,灌溉定额越大,土壤含水率越高,土壤盐分越低。微润带埋深是影响土壤水盐分布的重要因素。灌溉定额相同,与微润带埋深为10 cm的处理相比,埋深为20 cm的处理在20-30 cm内土壤含水率更大,在10-60 cm内土壤含水率变异系数较小,且含盐量显著降低。微润带埋深20 cm条件下,充分灌溉有利于抑制向日葵根区土壤盐分累积。在2015年向日葵成熟收获后,T1处理0-60 cm土层内土壤相对积盐率为9.3%,比T2,T5处理降低53.3%,45.9%。而2016年向日葵成熟收获后,0-60 cm土层内土壤呈现脱盐现象且相对脱盐量随着灌溉定额减少而减少,随着埋深增加而增大。在相同埋深下,产量随着灌溉水量的增多呈逐渐递增的趋势;在相同灌溉定额下,微润带埋深为20 cm与10 cm各对应处理(T1与T5对应,依次类推)产量相比具有增加趋势,且差异显著。综合来看,埋深为20 cm时,充分灌溉的处理,在0-60 cm土层内土壤积盐率最小为9.3%,并且作物产量最高,WUE较高。推荐河套地区种植向日葵农田的微润带布置埋深为20 cm,进行充分灌水的应用模式,并进行秋浇将土壤表层盐分淋洗。该研究为微润灌溉在盐渍化地区的应用提供参考。

Effects of Moistube-Irrigation Quota and Buried Depth on Soil Water and Salt Dynamics of Farmland and Water Use Efficiency of Sunflower

Moderately salinized sunflower field in Hetao Irrigation District were used to explore the effects of moistube-irrigation on the changes of soil water and salt distribution and crop yield to support the generalization and application of moistube-irrigation technology. Two soil buried depths (10, 20 cm) and four irrigation quotas (Full irrigation:T1, T5, mild water shortage:T2, T6, moderate water shortage:T3, T7, severe water shortage:T4, T8) were set up to study the changes of soil water and salt distribution and sunflower yield and water use efficiency (WUE). The results showed that in the same depth of moistube, as the irrigation quotas increased, the soil moisture was the higher and soil salinity was lower. The buried depth of moistube was an important factor affecting the distribution of soil water and salt. In the same irrigation quota, compared with the buried depth of 20 cm, The soil moisture contents with the buried depth of 10 cm was larger in 20-30 cm, the coefficient of variation of soil water content was less in 10-60 cm, and the salt content was significantly reduced. Under the condition of full irrigation and moistube buried depth of 20 cm, it was beneficial to inhibit the accumulation of soil salt in the root zone of sunflower. After the ripening of sunflower in 2015, the average relative salt accumulation rate of 0-60 cm treated by T1 was 9.3%, which was respectively lower than those of T2 and T5 treatment by 53.3% and 45.9% respectively. After the ripening of sunflower in 2016, the soil of 0-60 cm showed desalting and the amount of desalination decreased with the decrease of irrigation quotas, and increased with the increase of buried depth. At the same burial depth, the yield gradually increased with the increase of irrigation water volume. Under the same irrigation quota, moistube with buried depth of 20 cm had an increasing trend and the difference was significant compared with the depth of 10 cm. In summary, in the case of sufficient irrigation and moistube buried depth of 20 cm, the soil salt accumulation rate of 0-60 cm was 9.3%, and the crop yield was the highest, and the WUE was higher. It is recommended that the moistube buried depth of 20 cm and sufficient irrigation should be carried out in the sunflower field, and the soil should be leached by autumn flooding to decrease salt of surface layer in the Hetao area. This study provides a reference for the application of moistube-irrigation in moderately salinized areas.