摘要：

淡水资源短缺是限制农业可持续发展的重要因素,而采用适宜浓度的咸水灌溉成为弥补这一短板的有效途径,但是持续利用咸水灌溉可能增加土壤次生盐渍化风险,因此,利用咸水灌溉的同时应保证盐分淋洗。为准确评估咸水灌溉对土壤的长期影响以及增施有机肥对盐分淋洗的效果,依托连续10 a旱作处理以及1,3,5 g/L的咸水灌溉,分别施用化肥和化肥基础上增施有机肥开展工作。通过分析0~200 cm土壤剖面每20 cm土壤含水量、电导率、pH值、有机质、全氮、有效磷和全磷含量,发现不同浓度咸水灌溉对表层土壤电导率等特征没有显著影响,而采用5 g/L的咸水灌溉处理增加了增施有机肥下0~20 cm和120 cm以下土层土壤含盐量。此外,相较于化肥处理,增施有机肥处理显著提高了土壤耕层含水量、有机质、全氮、有效磷和全磷含量,各指标提高幅度为14.16%,38.27%,32.39%,44.25%,9.56%。可见,尽管增施有机肥提高了土壤电导率,但是土壤仍处于低盐环境,而增施有机肥对土壤养分(尤其是有效磷)含量的提升幅度更大。同时,由于降雨和冬小麦种植前的淡水灌溉,在该区域采用<5 g/L的咸水灌溉不会引起表层土壤积盐。

关键词: 咸水, 有机肥, 土壤水盐分布, 有效磷

Abstract:

The shortage of fresh water resources is an important factor restricting the sustainable development of agriculture,and the adoption of saltwater irrigation with appropriate concentration is an effective way to make up for this shortage,but the continuous use of saltwater irrigation may increase the risk of soil secondary salinization.Therefore,salt leaching should be ensured when using saltwater irrigation.In order to accurately evaluate the long-term effects of saline irrigation on soil and the effect of increased application of organic fertilizer on salt leaching,this study relied on 10 consecutive years of dry treatment and 1,3,5 g/L saline water irrigation,respectively.Applying chemical fertilizer and increasing the application of organic fertilizer based on chemical fertilizer.By analyzing soil water content,electrical conductivity,pH,organic matter,total nitrogen,available phosphorus and total phosphorus contents per 20 cm of 0-200 cm soil profile,it was found that saline irrigation with different concentrations had no significant effect on surface soil electrical conductivity and other characteristics.The saline water irrigation treatment of 5 g/L increased the soil salt content below 0-20 cm and 120 cm under the application of organic fertilizer.In addition,compared with chemical fertilizer treatment,the addition of organic fertilizer treatment significantly increased the soil surface water content,organic matter,total nitrogen,available phosphorus and total phosphorus contents,and the indexes increased by 14.16%,38.27%,32.39%,44.25% and 9.56%.It can be seen that although the application of organic fertilizer increased the soil conductivity,the soil was still in a low salt environment,and the increase of organic fertilizer increased the content of soil nutrients(especially available phosphorus)more significantly.At the same time,due to rainfall and freshwater irrigation before winter wheat planting,saline water irrigations<5 g/L in this area will not cause salt accumulation in the surface soil.

Key words: Salt water, Organic fertilizer, Soil water salt distribution, Available phosphorus